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Schoffl J, Arora M, Pozzato I, McBain C, Rodrigues D, Vafa E, Middleton J, Davis GM, Gustin SM, Bourke J, Kifley A, Krassioukov AV, Cameron ID, Craig A. Heart Rate Variability Biofeedback in Adults with a Spinal Cord Injury: A Laboratory Framework and Case Series. J Clin Med 2023; 12:7664. [PMID: 38137732 PMCID: PMC10743967 DOI: 10.3390/jcm12247664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 11/30/2023] [Accepted: 12/12/2023] [Indexed: 12/24/2023] Open
Abstract
Heart rate variability biofeedback (HRV-F) is a neurocardiac self-regulation therapy that aims to regulate cardiac autonomic nervous system activity and improve cardiac balance. Despite benefits in various clinical populations, no study has reported the effects of HRV-F in adults with a spinal cord injury (SCI). This article provides an overview of a neuropsychophysiological laboratory framework and reports the impact of an HRV-F training program on two adults with chronic SCI (T1 AIS A and T3 AIS C) with different degrees of remaining cardiac autonomic function. The HRV-F intervention involved 10 weeks of face-to-face and telehealth sessions with daily HRV-F home practice. Physiological (HRV, blood pressure variability (BPV), baroreflex sensitivity (BRS)), and self-reported assessments (Fatigue Severity Scale, Generalised Anxiety Disorder Scale, Patient Health Questionnaire, Appraisal of Disability and Participation Scale, EuroQol Visual Analogue Scale) were conducted at baseline and 10 weeks. Participants also completed weekly diaries capturing mood, anxiety, pain, sleep quality, fatigue, and adverse events. Results showed some improvement in HRV, BPV, and BRS. Additionally, participants self-reported some improvements in mood, fatigue, pain, quality of life, and self-perception. A 10-week HRV-F intervention was feasible in two participants with chronic SCI, warranting further investigation into its autonomic and psychosocial effects.
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Affiliation(s)
- Jacob Schoffl
- John Walsh Centre Rehabilitation Research, Northern Sydney Local Health District, Sydney, NSW 2065, Australia; (M.A.); (I.P.); (C.M.); (D.R.); (E.V.); (J.M.); (J.B.); (A.K.); (I.D.C.); (A.C.)
- The Kolling Institute, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2065, Australia
| | - Mohit Arora
- John Walsh Centre Rehabilitation Research, Northern Sydney Local Health District, Sydney, NSW 2065, Australia; (M.A.); (I.P.); (C.M.); (D.R.); (E.V.); (J.M.); (J.B.); (A.K.); (I.D.C.); (A.C.)
- The Kolling Institute, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2065, Australia
| | - Ilaria Pozzato
- John Walsh Centre Rehabilitation Research, Northern Sydney Local Health District, Sydney, NSW 2065, Australia; (M.A.); (I.P.); (C.M.); (D.R.); (E.V.); (J.M.); (J.B.); (A.K.); (I.D.C.); (A.C.)
- The Kolling Institute, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2065, Australia
| | - Candice McBain
- John Walsh Centre Rehabilitation Research, Northern Sydney Local Health District, Sydney, NSW 2065, Australia; (M.A.); (I.P.); (C.M.); (D.R.); (E.V.); (J.M.); (J.B.); (A.K.); (I.D.C.); (A.C.)
- The Kolling Institute, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2065, Australia
| | - Dianah Rodrigues
- John Walsh Centre Rehabilitation Research, Northern Sydney Local Health District, Sydney, NSW 2065, Australia; (M.A.); (I.P.); (C.M.); (D.R.); (E.V.); (J.M.); (J.B.); (A.K.); (I.D.C.); (A.C.)
- The Kolling Institute, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2065, Australia
| | - Elham Vafa
- John Walsh Centre Rehabilitation Research, Northern Sydney Local Health District, Sydney, NSW 2065, Australia; (M.A.); (I.P.); (C.M.); (D.R.); (E.V.); (J.M.); (J.B.); (A.K.); (I.D.C.); (A.C.)
- The Kolling Institute, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2065, Australia
- School of Health Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2050, Australia;
| | - James Middleton
- John Walsh Centre Rehabilitation Research, Northern Sydney Local Health District, Sydney, NSW 2065, Australia; (M.A.); (I.P.); (C.M.); (D.R.); (E.V.); (J.M.); (J.B.); (A.K.); (I.D.C.); (A.C.)
- The Kolling Institute, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2065, Australia
| | - Glen M. Davis
- School of Health Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2050, Australia;
| | - Sylvia Maria Gustin
- NeuroRecovery Research Hub, University of New South Wales, Sydney, NSW 2052, Australia;
- The Centre for Pain IMPACT, Neuroscience Research Australia, Sydney, NSW 2052, Australia
| | - John Bourke
- John Walsh Centre Rehabilitation Research, Northern Sydney Local Health District, Sydney, NSW 2065, Australia; (M.A.); (I.P.); (C.M.); (D.R.); (E.V.); (J.M.); (J.B.); (A.K.); (I.D.C.); (A.C.)
- The Kolling Institute, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2065, Australia
| | - Annette Kifley
- John Walsh Centre Rehabilitation Research, Northern Sydney Local Health District, Sydney, NSW 2065, Australia; (M.A.); (I.P.); (C.M.); (D.R.); (E.V.); (J.M.); (J.B.); (A.K.); (I.D.C.); (A.C.)
- The Kolling Institute, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2065, Australia
| | - Andrei V. Krassioukov
- ICORD, Faculty of Medicine, University of British Columbia, Vancouver, BC V6T 1Z4, Canada;
| | - Ian D. Cameron
- John Walsh Centre Rehabilitation Research, Northern Sydney Local Health District, Sydney, NSW 2065, Australia; (M.A.); (I.P.); (C.M.); (D.R.); (E.V.); (J.M.); (J.B.); (A.K.); (I.D.C.); (A.C.)
- The Kolling Institute, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2065, Australia
| | - Ashley Craig
- John Walsh Centre Rehabilitation Research, Northern Sydney Local Health District, Sydney, NSW 2065, Australia; (M.A.); (I.P.); (C.M.); (D.R.); (E.V.); (J.M.); (J.B.); (A.K.); (I.D.C.); (A.C.)
- The Kolling Institute, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2065, Australia
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2
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Trueblood CT, Singh A, Cusimano MA, Hou S. Autonomic Dysreflexia in Spinal Cord Injury: Mechanisms and Prospective Therapeutic Targets. Neuroscientist 2023:10738584231217455. [PMID: 38084412 PMCID: PMC11166887 DOI: 10.1177/10738584231217455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
High-level spinal cord injury (SCI) often results in cardiovascular dysfunction, especially the development of autonomic dysreflexia. This disorder, characterized as an episode of hypertension accompanied by bradycardia in response to visceral or somatic stimuli, causes substantial discomfort and potentially life-threatening symptoms. The neural mechanisms underlying this dysautonomia include a loss of supraspinal control to spinal sympathetic neurons, maladaptive plasticity of sensory inputs and propriospinal interneurons, and excessive discharge of sympathetic preganglionic neurons. While neural control of cardiovascular function is largely disrupted after SCI, the renin-angiotensin system (RAS), which mediates blood pressure through hormonal mechanisms, is up-regulated after injury. Whether the RAS engages in autonomic dysreflexia, however, is still controversial. Regarding therapeutics, transplantation of embryonic presympathetic neurons, collected from the brainstem or more specific raphe regions, into the injured spinal cord may reestablish supraspinal regulation of sympathetic activity for cardiovascular improvement. This treatment reduces the occurrence of spontaneous autonomic dysreflexia and the severity of artificially triggered dysreflexic responses in rodent SCI models. Though transplanting early-stage neurons improves neural regulation of blood pressure, hormonal regulation remains high and baroreflex dysfunction persists. Therefore, cell transplantation combined with selected RAS inhibition may enhance neuroendocrine homeostasis for cardiovascular recovery after SCI.
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Affiliation(s)
- Cameron T. Trueblood
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, College of Medicine, Drexel University, Philadelphia, PA, USA
| | - Anurag Singh
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, College of Medicine, Drexel University, Philadelphia, PA, USA
| | - Marissa A. Cusimano
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, College of Medicine, Drexel University, Philadelphia, PA, USA
| | - Shaoping Hou
- Marion Murray Spinal Cord Research Center, Department of Neurobiology and Anatomy, College of Medicine, Drexel University, Philadelphia, PA, USA
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3
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Baroreflex-sympathoneural without baroreflex-cardiovagal failure in neurogenic orthostatic hypotension. Clin Auton Res 2023; 33:205-208. [PMID: 36881269 DOI: 10.1007/s10286-023-00935-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 02/21/2023] [Indexed: 03/08/2023]
Abstract
We describe a patient with neurogenic orthostatic hypotension (nOH) after brainstem neurosurgery in whom baroreflex-cardiovagal function was normal despite baroreflex-sympathoneural failure. We also cite other conditions entailing differential alterations in the two efferent limbs of the baroreflex. Any condition involving nOH from selective loss of sympathetic noradrenergic innervation, interference with sympathetic pre-ganglionic transmission in the thoracolumbar spinal cord, sympathectomies, or attenuated intra-neuronal synthesis, storage, or release of norepinephrine would be expected to manifest with selective baroreflex-sympathoneural dysfunction. We advise caution in relying on indices of baroreflex-cardiovagal function for diagnosing nOH, since normal values for these indices do not exclude nOH.
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Berger MJ, Dorey T, Nouraei H, Krassioukov AV. Test-retest reliability of the Valsalva maneuver in spinal cord injury. J Spinal Cord Med 2022; 45:230-237. [PMID: 32795170 PMCID: PMC8986309 DOI: 10.1080/10790268.2020.1798134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Objective: To determine the test-retest reliability of quantitative and qualitative baroreflex sensitivity (BRS) parameters derived from the Valsalva maneuver (VM) in individuals with traumatic cervical SCI.Design: Test-retest reliability.Setting: Tertiary rehabilitation center.Participants: Fourteen participants with cervical SCI (ranging from C3-C8 neurological level).Outcome Measurements: Beat-to-beat systolic blood pressure (SBP) traces (finger photoplethysmography) were obtained during a 15-second forced expiration at two time points (7.6 ± 2.9 days between sessions) to assess VM reliability. Test-retest reliability of BRS metrics from derived from the VM (Valsalva ratio; VR, pressure recovery time; PRT, vagal baroreflex sensitivity; BRSv, adrenergic baroreflex sensitivity; BRSa1, and total recovery; TR) were assessed by intra-class correlation coefficient (ICC, with 95% confidence interval; CI) and by qualitative reproducibility (V, N, or M pattern).Results: ICCs for quantitative parameters were (CI): VR = 0.894 (0.703-0.965), TR = 0.927 (0.789-0.976), BRSa1 = 0.561 (0.149-0.911), PRT = 0.728 (0.343-0.904), BRSv = 0.243 (-0.309-0.673). Qualitatively, 12 subjects (85.7%) demonstrated reproducible VM patterns at both time points (3 "M" pattern, 8 "V" pattern and one "N" pattern).Conclusion: VR (a measure of cardiovagal function) and TR (a measure of sympathetic adrenergic function) are reliable quantitative parameters that can be derived from SBP response to VM in participants with SCI. Qualitative waveform analysis was reproducible in 12/14 participants. This provides the foundational evidence required to pursue further validity testing to establish a role for VM in the assessment of autonomic functions in SCI.
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Affiliation(s)
- Michael J Berger
- Division of Physical Medicine & Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, Canada.,International Consortium on Repair Discoveries (ICORD), Vancouver, Canada
| | - Tristan Dorey
- Libin Cardiovascular Institute of Alberta, Department of Cardiac Sciences, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Hirmand Nouraei
- Division of Physical Medicine & Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, Canada
| | - Andrei V Krassioukov
- Division of Physical Medicine & Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, Canada.,International Consortium on Repair Discoveries (ICORD), Vancouver, Canada
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5
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Hayes BD, Fossey MPM, Poormasjedi-Meibod MS, Erskine E, Soriano JE, Scott B, Rosentreter R, Granville DJ, Phillips AA, West CR. Experimental high thoracic spinal cord injury impairs the cardiac and cerebrovascular response to orthostatic challenge in rats. Am J Physiol Heart Circ Physiol 2021; 321:H716-H727. [PMID: 34448635 DOI: 10.1152/ajpheart.00239.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 08/24/2021] [Indexed: 11/22/2022]
Abstract
Spinal cord injury (SCI) impairs the cardiovascular responses to postural challenge, leading to the development of orthostatic hypotension (OH). Here, we apply lower body negative pressure (LBNP) to rodents with high-level SCI to demonstrate the usefulness of LBNP as a model for experimental OH studies, and to explore the effect of simulated OH on cardiovascular and cerebrovascular function following SCI. Male Wistar rats (n = 34) were subjected to a sham or T3-SCI surgery and survived into the chronic period postinjury (i.e., 8 wk). Cardiac function was tracked via ultrasound pre- to post-SCI to demonstrate the clinical utility of our model. At study termination, we conducted left-ventricular (LV) catheterization and insonated the middle cerebral artery to investigate the hemodynamic, cardiac, and cerebrovascular response to a mild dose of LBNP that is sufficient to mimic clinically defined OH in rats with T3-SCI but not sham animals. In response to mimicked OH, there was a greater decline in stroke volume, cardiac output, maximal LV pressure, and blood pressure in SCI compared with sham (P < 0.034), whereas heart rate was increased in sham but decreased in SCI (P < 0.029). SCI animals also had an exaggerated reduction in peak, minimum and mean middle cerebral artery flow, for a given change in blood pressure, in response to LBNP (P < 0.033), implying impaired dynamic cerebral autoregulation. Using a preclinical SCI model of OH, we demonstrate that complete high thoracic SCI impairs the cardiac response to OH and disrupts dynamic cerebral autoregulation.NEW & NOTEWORTHY This is the first use of LBNP to interrogate the cardiac and cerebrovascular responses to simulated OH in a preclinical study of SCI. Here, we demonstrate the utility of our simulated OH model and use it to demonstrate that SCI impairs the cardiac response to simulated OH and disrupts dynamic cerebrovascular autoregulation.
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Affiliation(s)
- Brian D Hayes
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Mary Pauline Mona Fossey
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
- Experimental Medicine, Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Erin Erskine
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jan Elaine Soriano
- Departments of Physiology and Pharmacology, Cardiac Sciences, Clinical Neurosciences, Libin Cardiovascular Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Berkeley Scott
- Departments of Physiology and Pharmacology, Cardiac Sciences, Clinical Neurosciences, Libin Cardiovascular Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Ryan Rosentreter
- Departments of Physiology and Pharmacology, Cardiac Sciences, Clinical Neurosciences, Libin Cardiovascular Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - David J Granville
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Aaron A Phillips
- Departments of Physiology and Pharmacology, Cardiac Sciences, Clinical Neurosciences, Libin Cardiovascular Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Christopher R West
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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Cerebral Autoregulation during Postural Change in Patients with Cervical Spinal Cord Injury-A Carotid Duplex Ultrasonography Study. Diagnostics (Basel) 2021; 11:diagnostics11081321. [PMID: 34441256 PMCID: PMC8393722 DOI: 10.3390/diagnostics11081321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 07/13/2021] [Accepted: 07/21/2021] [Indexed: 11/17/2022] Open
Abstract
Patients with a spinal cord injury (SCI) frequently experience sudden falls in blood pressure during postural change. Few studies have investigated whether the measurement of blood flow velocity within vessels can reflect brain perfusion during postural change. By performing carotid duplex ultrasonography (CDU), we investigated changes in cerebral blood flow (CBF) during postural changes in patients with a cervical SCI, determined the correlation of CBF change with presyncopal symptoms, and investigated factors affecting cerebral autoregulation. We reviewed the medical records of 100 patients with a cervical SCI who underwent CDU. The differences between the systolic blood pressure, diastolic blood pressure, and CBF volume in the supine posture and after 5 min at 50° tilt were evaluated. Presyncopal symptoms occurred when the blood flow volume of the internal carotid artery decreased by ≥21% after tilt. In the group that had orthostatic hypotension and severe CBF decrease during tilt, the body mass index and physical and functional scores were lower than in other groups, and the proportion of patients with a severe SCI was high. The higher the SCI severity and the lower the functional score, the higher the possibility of cerebral autoregulation failure. CBF should be assessed by conducting CDU in patients with a high-level SCI.
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Hubbard ME, Phillips AA, Charbonneau R, Squair JW, Parr AM, Krassioukov A. PRES secondary to autonomic dysreflexia: A case series and review of the literature. J Spinal Cord Med 2021; 44:606-612. [PMID: 31140946 PMCID: PMC8288129 DOI: 10.1080/10790268.2019.1616146] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Context: Autonomic dysreflexia (AD) is a complex syndrome seen in patients with spinal cord injuries (SCI) and can be life-threatening with a significant negative impact on the health of the individual. Posterior reversible encephalopathy syndrome (PRES) is thought to be caused, in part, by rapid elevations in blood pressure; leading to posterior cerebral circulatory edema. This can result in seizures, blindness and can progress to fatal intracranial hemorrhages.Findings: Here we present two cases of patients with SCI who developed PRES from AD. Each patient was correctly diagnosed, leading to appropriate treatment of the factors leading to their AD and subsequent resolution of their PRES symptoms.Conclusions/Clinical Relevance: In SCI patients who present with new seizures, visual deficits, or other neurologic signs, PRES should be considered as a part of the differential diagnosis as a good outcome relies on rapid recognition and treatment of AD.
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Affiliation(s)
- Molly E. Hubbard
- Department of Neurosurgery, University of Minnesota, Minneapolis, Minnesota, USA,Correspondence to: Molly E. Hubbard, Department of Neurosurgery, University of Minnesota, MMC 96 Room D-429, Mayo Building, 420 Delaware St SE, Minneapolis, MN55455, USA; Ph: 612-624-6666.
| | - Aaron A. Phillips
- Departments of Physiology and Pharmacology and Clinical Neurosciences, University of Calgary, Calgary, AB, Canada
| | - Rebecca Charbonneau
- Department of Physical Medicine and Rehabilitation, University of Alberta, Calgary, AB, Canada
| | - Jordan W. Squair
- Department of Physical Medicine and Rehabilitation, University of British Columbia, Vancouver, BC, Canada
| | - Ann M. Parr
- Department of Neurosurgery, University of Minnesota, Minneapolis, Minnesota, USA
| | - Andrei Krassioukov
- Department of Physical Medicine and Rehabilitation, University of British Columbia, Vancouver, BC, Canada
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8
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Postprandial Hypotension and Spinal Cord Injury. J Clin Med 2021; 10:jcm10071417. [PMID: 33915893 PMCID: PMC8037943 DOI: 10.3390/jcm10071417] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/25/2021] [Accepted: 03/27/2021] [Indexed: 11/17/2022] Open
Abstract
Postprandial hypotension (PPH) is defined as a fall of ≥20 mmHg in systolic blood pressure (SBP) or a SBP of <90 mmHg after having been >100 mmHg before the meal within two hours after a meal. The prevalence of PPH among persons with spinal cord injury (SCI) is unknown. Ambulatory blood pressure measurement was performed in 158 persons with SCI, 109 men, median age was 59.1 years (min.:13.2; max.: 86.2). In total, 78 persons (49.4%) had PPH after 114 out of 449 meals (25.4%). The median change in SBP during PPH was −28 mmHg (min.: −87; max.: −15 mmHg) and 96% of the PPH episodes were asymptomatic. The occurrence of PPH was correlated to older age (p = 0.001), level of injury (p = 0.023), and complete SCI (p = 0.000), but not, gender or time since injury. Further studies are needed to elucidate if PPH contributes to the increased cardiovascular mortality in the SCI population.
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9
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Squair JW, Gautier M, Mahe L, Soriano JE, Rowald A, Bichat A, Cho N, Anderson MA, James ND, Gandar J, Incognito AV, Schiavone G, Sarafis ZK, Laskaratos A, Bartholdi K, Demesmaeker R, Komi S, Moerman C, Vaseghi B, Scott B, Rosentreter R, Kathe C, Ravier J, McCracken L, Kang X, Vachicouras N, Fallegger F, Jelescu I, Cheng Y, Li Q, Buschman R, Buse N, Denison T, Dukelow S, Charbonneau R, Rigby I, Boyd SK, Millar PJ, Moraud EM, Capogrosso M, Wagner FB, Barraud Q, Bezard E, Lacour SP, Bloch J, Courtine G, Phillips AA. Neuroprosthetic baroreflex controls haemodynamics after spinal cord injury. Nature 2021; 590:308-314. [PMID: 33505019 DOI: 10.1038/s41586-020-03180-w] [Citation(s) in RCA: 80] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 12/11/2020] [Indexed: 01/30/2023]
Abstract
Spinal cord injury (SCI) induces haemodynamic instability that threatens survival1-3, impairs neurological recovery4,5, increases the risk of cardiovascular disease6,7, and reduces quality of life8,9. Haemodynamic instability in this context is due to the interruption of supraspinal efferent commands to sympathetic circuits located in the spinal cord10, which prevents the natural baroreflex from controlling these circuits to adjust peripheral vascular resistance. Epidural electrical stimulation (EES) of the spinal cord has been shown to compensate for interrupted supraspinal commands to motor circuits below the injury11, and restored walking after paralysis12. Here, we leveraged these concepts to develop EES protocols that restored haemodynamic stability after SCI. We established a preclinical model that enabled us to dissect the topology and dynamics of the sympathetic circuits, and to understand how EES can engage these circuits. We incorporated these spatial and temporal features into stimulation protocols to conceive a clinical-grade biomimetic haemodynamic regulator that operates in a closed loop. This 'neuroprosthetic baroreflex' controlled haemodynamics for extended periods of time in rodents, non-human primates and humans, after both acute and chronic SCI. We will now conduct clinical trials to turn the neuroprosthetic baroreflex into a commonly available therapy for people with SCI.
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Affiliation(s)
- Jordan W Squair
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.,Department of Neurosurgery, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland.,Department of Clinical Neuroscience, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland.,Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Clinical Neurosciences, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,MD/PhD Training Program, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada.,RestoreNetwork, Hotchkiss Brain Institute, Libin Cardiovascular Institute, McCaig Institute for Bone and Joint Health, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Matthieu Gautier
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland
| | - Lois Mahe
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland
| | - Jan Elaine Soriano
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Clinical Neurosciences, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,RestoreNetwork, Hotchkiss Brain Institute, Libin Cardiovascular Institute, McCaig Institute for Bone and Joint Health, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Andreas Rowald
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland
| | - Arnaud Bichat
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland
| | - Newton Cho
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland.,Department of Neurosurgery, University of Toronto, Toronto, Ontario, Canada
| | - Mark A Anderson
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland
| | - Nicholas D James
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland
| | - Jerome Gandar
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland
| | - Anthony V Incognito
- RestoreNetwork, Hotchkiss Brain Institute, Libin Cardiovascular Institute, McCaig Institute for Bone and Joint Health, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Giuseppe Schiavone
- Centre for Neuroprosthetics, Institute of Microengineering, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
| | - Zoe K Sarafis
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland
| | - Achilleas Laskaratos
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland
| | - Kay Bartholdi
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland
| | - Robin Demesmaeker
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland
| | - Salif Komi
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland
| | - Charlotte Moerman
- Department of Clinical Neuroscience, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland
| | - Bita Vaseghi
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Clinical Neurosciences, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Berkeley Scott
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Clinical Neurosciences, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,RestoreNetwork, Hotchkiss Brain Institute, Libin Cardiovascular Institute, McCaig Institute for Bone and Joint Health, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Ryan Rosentreter
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Clinical Neurosciences, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,RestoreNetwork, Hotchkiss Brain Institute, Libin Cardiovascular Institute, McCaig Institute for Bone and Joint Health, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Claudia Kathe
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland
| | - Jimmy Ravier
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland
| | - Laura McCracken
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland
| | - Xiaoyang Kang
- Centre for Neuroprosthetics, Institute of Microengineering, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
| | - Nicolas Vachicouras
- Centre for Neuroprosthetics, Institute of Microengineering, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
| | - Florian Fallegger
- Centre for Neuroprosthetics, Institute of Microengineering, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
| | - Ileana Jelescu
- Center for Biomedical Imaging, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
| | | | - Qin Li
- Motac Neuroscience Ltd, Manchester, UK
| | | | | | - Tim Denison
- Department of Engineering Science and Clinical Neurosciences, University of Oxford, Oxford, UK.,Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Sean Dukelow
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Clinical Neurosciences, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,RestoreNetwork, Hotchkiss Brain Institute, Libin Cardiovascular Institute, McCaig Institute for Bone and Joint Health, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Radiology, McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, Alberta, Canada
| | - Rebecca Charbonneau
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,RestoreNetwork, Hotchkiss Brain Institute, Libin Cardiovascular Institute, McCaig Institute for Bone and Joint Health, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Ian Rigby
- Department of Emergency Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Steven K Boyd
- Department of Radiology, McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, Alberta, Canada
| | - Philip J Millar
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Eduardo Martin Moraud
- Department of Clinical Neuroscience, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland
| | - Marco Capogrosso
- Faculty of Biology, University of Fribourg, Fribourg, Switzerland
| | - Fabien B Wagner
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland.,Institut des Maladies Neurodégénératives, Université de Bordeaux, UMR, 5293, Bordeaux, France
| | - Quentin Barraud
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland
| | - Erwan Bezard
- Motac Neuroscience Ltd, Manchester, UK.,Institut des Maladies Neurodégénératives, Université de Bordeaux, UMR, 5293, Bordeaux, France.,Institut des Maladies Neurodégénératives, CNRS, UMR, 5293, Bordeaux, France
| | - Stéphanie P Lacour
- Centre for Neuroprosthetics, Institute of Microengineering, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
| | - Jocelyne Bloch
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.,Department of Neurosurgery, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland.,Department of Clinical Neuroscience, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland.,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland
| | - Grégoire Courtine
- Center for Neuroprosthetics and Brain Mind Institute, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland. .,Department of Neurosurgery, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland. .,Department of Clinical Neuroscience, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland. .,Defitech Center for Interventional Neurotherapies (.NeuroRestore), CHUV/UNIL/EPFL, Lausanne, Switzerland.
| | - Aaron A Phillips
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada. .,Department of Clinical Neurosciences, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada. .,Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada. .,International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada. .,RestoreNetwork, Hotchkiss Brain Institute, Libin Cardiovascular Institute, McCaig Institute for Bone and Joint Health, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
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10
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Zahner MR, Beaumont E. Intermittent Fasting After Spinal Cord Injury Does Not Improve the Recovery of Baroreflex Regulation in the Rat. Front Physiol 2020; 11:865. [PMID: 32792982 PMCID: PMC7387690 DOI: 10.3389/fphys.2020.00865] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Accepted: 06/26/2020] [Indexed: 01/04/2023] Open
Abstract
Modest recovery of somatic function after incomplete spinal cord injury (SCI) has been widely demonstrated. Recently we have shown that spontaneous recovery of baroreflex regulation of sympathetic activity also occurs in rats. Dietary restriction in the form of every other day fasting (EODF) has been shown to have beneficial effects on the recovery of motor function after SCI in rats. The goal of this study was to determine if EODF augments the improvement of baroreflex regulation of sympathetic activity after chronic left thoracic (T8) surgical spinal hemisection. To determine this, we performed baroreflex tests on ad-lib fed or EODF rats 1 week or 7 weeks after left T8 spinal hemisection. One week after T8 left hemisection baroreflex testing revealed that gain of baroreflex responsiveness, as well as the ability to increase renal sympathetic nerve activity (RSNA) at low arterial pressure, was significantly impaired in the ad-lib fed but not the EODF rats compared with sham lesioned control rats. However, baroreflex tests performed 7 weeks after T8 left hemisection revealed the inability of both ad-lib and EODF rats to decrease RSNA at elevated arterial pressures. While there is evidence to suggest that EODF has beneficial effects on the recovery of motor function in rats, EODF did not significantly improve the recovery of baroreflex regulation of sympathetic activity.
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Affiliation(s)
- Matthew R. Zahner
- Department of Health Sciences, College of Public Health, East Tennessee State University, Johnson City, TN, United States
| | - Eric Beaumont
- Department of Biomedical Science, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
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11
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A Legal and Forensic Medicine Approach to Police Physical Intervention Techniques in High-Risk Situations. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17082809. [PMID: 32325816 PMCID: PMC7215352 DOI: 10.3390/ijerph17082809] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 04/15/2020] [Accepted: 04/17/2020] [Indexed: 12/01/2022]
Abstract
Background: The physical intervention techniques (PITs) typically used by the police in troublesome situations are examined in terms of injuring potential depending on whether they target a body zone of high, medium or low vulnerability. Based on legal and forensic considerations, and principles of congruence, opportunity and proportionality, a need exists to favor opponent locking and arrest techniques targeting non-vulnerable zones to minimize the risk of severe damage. Methods: A search of the training manuals for the different kind of law of enforcement officers was carried out. Revision of injuries was available from electronic databases of academic o medical journals. Results: Three different locking and arrest PITs based on operational tactical procedures (OTP) that avoid zones of high or medium vulnerability are proposed. The new techniques use blocking, diverting and grabbing of the upper and lower limbs, followed by dislocation and locking of the same targets. Conclusions: The damaging potential of such PITs was assessed in terms of anatomical region and most were found to have a high risk of severe damage. The alternative PITs proposed here, which rely on OTP, improve in legal and forensic medical terms on existing choices and dramatically reduce the risk of injuring arrestees.
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12
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Sarafis ZK, Monga AK, Phillips AA, Krassioukov AV. Is Technology for Orthostatic Hypotension Ready for Primetime? PM R 2019; 10:S249-S263. [PMID: 30269810 DOI: 10.1016/j.pmrj.2018.04.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 04/04/2018] [Accepted: 04/12/2018] [Indexed: 01/29/2023]
Abstract
Spinal cord injury (SCI) often results in the devastating loss of motor, sensory, and autonomic function. After SCI, the interruption of descending sympathoexcitatory pathways disrupts supraspinal control of blood pressure (BP). A common clinical consequence of cardiovascular dysfunction after SCI is orthostatic hypotension (OH), a debilitating condition characterized by rapid profound decreases in BP when assuming an upright posture. OH can result in a diverse array of insidious and pernicious health consequences. Acute effects of OH include decreased cardiac filling, cerebral hypoperfusion, and associated presyncopal symptoms such as lightheadedness and dizziness. Over the long term, repetitive exposure to OH is associated with a drastically increased prevalence of heart attack and stroke, which are leading causes of death in those with SCI. Current recommendations for managing BP after SCI primarily include pharmacologic interventions with prolonged time to effect. Because most episodes of OH occur in less than 3 minutes, this delay in action often renders most pharmacologic interventions ineffective. New innovative technologies such as epidural and transcutaneous spinal cord stimulation are being explored to solve this problem. It might be possible to electrically stimulate sympathetic circuitry caudal to the injury and elicit rapid modulation of BP to manage OH. This review describes autonomic control of the cardiovascular system before injury, resulting cardiovascular consequences after SCI such as OH, and the clinical assessment tools for evaluating autonomic dysfunction after SCI. In addition, current approaches for clinically managing OH are outlined, and new promising interventions are described for managing this condition.
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Affiliation(s)
- Zoe K Sarafis
- ICORD-BSCC, University of British Columbia, Vancouver, BC, Canada(∗)
| | - Aaron K Monga
- ICORD-BSCC, University of British Columbia, Vancouver, BC, Canada(†)
| | - Aaron A Phillips
- Departments of Physiology and Pharmacology, Clinical Neurosciences, Cardiac Sciences, Libin Cardiovascular Institute of Alberta, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada(‡)
| | - Andrei V Krassioukov
- ICORD-BSCC; Experimental Medicine Program; Division of Physical Medicine and Rehabilitation, Department of Medicine, University of British Columbia; GF Strong Rehabilitation Center, Vancouver Coastal Health; 818 West 10th Avenue, Vancouver, BC, Canada, V5Z1M9(§).
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13
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Katzelnick CG, Weir JP, Jones A, Galea M, Dyson-Hudson TA, Kirshblum SC, Wecht JM. Blood Pressure Instability in Persons With SCI: Evidence From a 30-Day Home Monitoring Observation. Am J Hypertens 2019; 32:938-944. [PMID: 31125393 DOI: 10.1093/ajh/hpz089] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 05/16/2019] [Accepted: 05/23/2019] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND To determine the degree of blood pressure instability over a 30-day home observation in participants with spinal cord injury grouped by level of injury pertaining to cardiovascular autonomic regulation. METHODS This is an observational study completed at the Kessler Foundation and James J. Peters Veterans Medical Center. Seventy-two participants with tetraplegia (C1-T1), 13 with high thoracic (T2-T4), and 28 with low thoracic (T5-T12) injury participated in this study. Participants were asked to record their blood pressure using an ambulatory blood pressure monitor three times a day for 30 days. RESULTS The number of blood pressure fluctuations was significantly increased in the tetraplegia group compared with the paraplegia groups. Age and duration of injury contributed to an increase in the observation of 30-day blood pressure instability; however, completeness of injury did not. CONCLUSION The data indicate significant blood pressure instability that may not be exclusive to persons with tetraplegia; in fact, individuals with low thoracic injuries demonstrated severe blood pressure fluctuations. The use of a monitor at home for an extended period may help document dangerous and extreme fluctuations in blood pressure and should be considered an important adjunctive clinical practice for tracking of the secondary consequences in the spinal cord injury population.
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Affiliation(s)
- Caitlyn G Katzelnick
- Spinal Cord Injury Research, James J Peters VA Medical Center, Bronx, New York, USA
- Kessler Foundation, West Orange, New Jersey, USA
| | - Joseph P Weir
- Department of Health, Sport, and Exercise Science, University of Kansas, Lawrence, Kansas, USA
| | - April Jones
- Spinal Cord Injury Research, James J Peters VA Medical Center, Bronx, New York, USA
| | - Marinella Galea
- Spinal Cord Injury Research, James J Peters VA Medical Center, Bronx, New York, USA
- Department of Rehabilitation Medicine, the Icahn School of Medicine, Mount Sinai, New York, New York, USA
| | - Trevor A Dyson-Hudson
- Kessler Foundation, West Orange, New Jersey, USA
- Department of Physical Medicine and Rehabilitation, Rutgers New Jersey Medical School, Newark, New Jersey, USA
| | - Steven C Kirshblum
- Department of Physical Medicine and Rehabilitation, Rutgers New Jersey Medical School, Newark, New Jersey, USA
- Spinal Cord Injury Rehabilitation, Kessler Institute for Rehabilitation, West Orange, New Jersey, USA
| | - Jill M Wecht
- Spinal Cord Injury Research, James J Peters VA Medical Center, Bronx, New York, USA
- Department of Rehabilitation Medicine, the Icahn School of Medicine, Mount Sinai, New York, New York, USA
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14
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Trueblood CT, Iredia IW, Collyer ES, Tom VJ, Hou S. Development of Cardiovascular Dysfunction in a Rat Spinal Cord Crush Model and Responses to Serotonergic Interventions. J Neurotrauma 2019; 36:1478-1486. [PMID: 30362884 DOI: 10.1089/neu.2018.5962] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Selection of a proper spinal cord injury (SCI) rat model to study therapeutic effects of cell transplantation is imperative for research in cardiovascular functional recovery, due to the local harsh milieu inhibiting cell growth. We recently found that a crushed spinal cord lesion can minimize fibrotic scarring and grafted cell death compared with open-dura injuries. To determine if this SCI model is applicable for studying cardiovascular recovery, we examined hemodynamic consequences following crushed SCI and tested cardiovascular responses to serotonin (5-HT) or dopamine (DA) receptor agonists. Using a radio-telemetric system, multiple cardiovascular parameters were recorded prior to, 2, and 4 weeks after SCI, including resting mean arterial pressure (MAP) and heart rate (HR), as well as spontaneous or colorectal distension (CRD)-induced autonomic dysreflexia (AD). The results showed that this injury caused tachycardia at rest as well as the occurrence of spontaneous or artificially induced dysreflexic events. Four weeks post-injury, specific activation of 5-HT2A receptors by subcutaneous (s.c.) or intrathecal (i.t.) delivery of Dimethoxy-4-iodoamphetamine (DOI) remarkably increased resting MAP levels in a dose-dependent fashion. During CRD-induced autonomic dysreflexia, systemic administration of DOI alleviated the severity of bradycardia responsive to episodic hypertension. In contrast, selective stimulation of 5-HT1A receptors with 8-OH-DPAT or non-selective activation of DA receptors with apomorphine did not affect cardiovascular performance. Thus, crush injuries induce cardiovascular abnormalities in rats that are sensitive to 5-HT2A receptor stimulation, indicating a reliable SCI model to study how cell-based approaches impact the severity of autonomic dysreflexia and identify a possible target for pharmacological interventions.
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Affiliation(s)
- Cameron T Trueblood
- Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Idiata W Iredia
- Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Eileen S Collyer
- Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Veronica J Tom
- Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Shaoping Hou
- Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania
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15
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Leonardi-Figueiredo MM, de Souza HCD, Martins EJ, Squiaveto M, Mattiello-Sverzut AC. Damaged cardiovascular autonomic control in wheelchair-using children and adolescents with myelomeningocele: a case-control study. Braz J Phys Ther 2018; 23:27-32. [PMID: 30243858 DOI: 10.1016/j.bjpt.2018.09.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/08/2018] [Accepted: 09/04/2018] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Cardiovascular autonomic dysfunction is associated with the development of cardiovascular diseases, but little is known about it in children and adolescents with myelomeningocele. OBJECTIVE This study investigated the cardiovascular autonomic function in wheelchair-using children and adolescents with myelomeningocele. METHODS Twenty-two participants were assigned to one of two groups: myelomeningocele group (n=11) and Control group (n=11). Heart rate variability and systolic blood pressure variability were collected in supine resting position using spectral analyses. Spontaneous baroreflex sensitivity was collected by time-domain through the sequence method. RESULTS At rest, heart rate was higher in myelomeningocele group when compared to Control group (mean difference 22.1, 95% CI 4.82-39.40; p=0.01). The heart rate and systolic blood pressure variability parameters did not show differences between groups. However, myelomeningocele showed lower gain mean in baroreflex sensitivity (mean difference -4.5, 95% CI -8.47 to -0.60; p=0.02), when compared to Control. CONCLUSION Wheelchair-using children and adolescents with myelomeningocele presented differences in the autonomic cardiovascular function. This may be associated with hypomobility due to wheelchair dependence, and venous muscle pump insufficiency due to paraplegia.
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Affiliation(s)
| | - Hugo Celso Dutra de Souza
- Department of Healthy Sciences, Ribeirão Preto Medical School, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil
| | - Emanuela Juvenal Martins
- Department of Healthy Sciences, Ribeirão Preto Medical School, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil
| | - Monalisa Squiaveto
- Department of Healthy Sciences, Ribeirão Preto Medical School, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil
| | - Ana Claudia Mattiello-Sverzut
- Department of Healthy Sciences, Ribeirão Preto Medical School, Universidade de São Paulo (USP), Ribeirão Preto, SP, Brazil.
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16
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Shahzad T, Saleem S, Usman S, Mirza J, Islam QU, Ouahada K, Marwala T. System dynamics of active and passive postural changes: Insights from principal dynamic modes analysis of baroreflex loop. Comput Biol Med 2018; 100:27-35. [PMID: 29975851 DOI: 10.1016/j.compbiomed.2018.06.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 06/21/2018] [Accepted: 06/22/2018] [Indexed: 10/28/2022]
Abstract
The baroreflex being a key modulator of cardiovascular control ensures adequate blood pressure regulation under orthostatic stress which otherwise may cause severe hypotension. Contrary to conventional baroreflex sensitivity indices derived across a-priori traditional frequency bands, the present study is aimed at proposing new indices for the assessment of baroreflex drive which follows active (supine to stand-up) and passive (supine to head-up tilt) postural changes. To achieve this, a novel system identification approach of principal dynamic modes (PDM) was utilized to extract data-adaptive frequency components of closed-loop interactions between beat-to-beat interval and systolic blood pressure recorded from 10 healthy humans. We observed that the gain of low-pass global PDM of cardiac arm (:feedback reflex loop, mediated by pressure sensors to adjust heart rate in response to arterial blood pressure), and 0.2 Hz global PDM of mechanical arm (:feed-forward pathways, originating changes in arterial blood pressure in response to heart rate variations) may function as potential markers to distinguish active and passive orthostatic tests in healthy subjects.
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Affiliation(s)
- Tariq Shahzad
- Department of Electrical and Electronic Engineering Science, University of Johannesburg, South Africa.
| | - Saqib Saleem
- Department of Electrical Engineering, COMSATS University Islamabad, Sahiwal Campus, Sahiwal, Pakistan.
| | - Saeeda Usman
- Department of Electrical Engineering, COMSATS University Islamabad, Sahiwal Campus, Sahiwal, Pakistan.
| | - Jawad Mirza
- Department of Electrical Engineering, COMSATS University Islamabad, Islamabad, Pakistan.
| | - Qamar-Ul Islam
- Department of Space Science, Institute of Space Technology, Islamabad, Pakistan.
| | - Khmaies Ouahada
- Department of Electrical and Electronic Engineering Science, University of Johannesburg, South Africa.
| | - Tshilidzi Marwala
- Department of Electrical and Electronic Engineering Science, University of Johannesburg, South Africa.
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17
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Saleem S, Vucina D, Sarafis Z, Lee AHX, Squair JW, Barak OF, Coombs GB, Mijacika T, Krassioukov AV, Ainslie PN, Dujic Z, Tzeng YC, Phillips AA. Wavelet decomposition analysis is a clinically relevant strategy to evaluate cerebrovascular buffering of blood pressure after spinal cord injury. Am J Physiol Heart Circ Physiol 2018; 314:H1108-H1114. [PMID: 29600896 DOI: 10.1152/ajpheart.00152.2017] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The capacity of the cerebrovasculature to buffer changes in blood pressure (BP) is crucial to prevent stroke, the incidence of which is three- to fourfold elevated after spinal cord injury (SCI). Disruption of descending sympathetic pathways within the spinal cord due to cervical SCI may result in impaired cerebrovascular buffering. Only linear analyses of cerebrovascular buffering of BP, such as transfer function, have been used in SCI research. This approach does not account for inherent nonlinearity and nonstationarity components of cerebrovascular regulation, often depends on perturbations of BP to increase the statistical power, and does not account for the influence of arterial CO2 tension. Here, we used a nonlinear and nonstationary analysis approach termed wavelet decomposition analysis (WDA), which recently identified novel sympathetic influences on cerebrovascular buffering of BP occurring in the ultra-low-frequency range (ULF; 0.02-0.03Hz). WDA does not require BP perturbations and can account for influences of CO2 tension. Supine resting beat-by-beat BP (Finometer), middle cerebral artery blood velocity (transcranial Doppler), and end-tidal CO2 tension were recorded in cervical SCI ( n = 14) and uninjured ( n = 16) individuals. WDA revealed that cerebral blood flow more closely follows changes in BP in the ULF range ( P = 0.0021, Cohen's d = 0.89), which may be interpreted as an impairment in cerebrovascular buffering of BP. This persisted after accounting for CO2. Transfer function metrics were not different in the ULF range, but phase was reduced at 0.07-0.2 Hz ( P = 0.03, Cohen's d = 0.31). Sympathetically mediated cerebrovascular buffering of BP is impaired after SCI, and WDA is a powerful strategy for evaluating cerebrovascular buffering in clinical populations.
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Affiliation(s)
- Saqib Saleem
- Department of Electrical Engineering, COMSATS Institute of Information Technology , Sahiwal , Pakistan.,Wellington Medical Technology Group, Centre for Translational Physiology, University of Otago , Wellington , New Zealand
| | - Diana Vucina
- Department of Neurology, Clinical Hospital Center Split , Split , Croatia
| | - Zoe Sarafis
- International Collaboration on Repair Discoveries, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Amanda H X Lee
- International Collaboration on Repair Discoveries, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,Experimental Medicine Program, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jordan W Squair
- Departments of Physiology and Pharmacology, Cardiac Sciences, and Clinical Neurosciences, Libin Cardiovascular Institute of Alberta, Hotchkiss Brain Institute, University of Calgary, Alberta, Canada.,MD/PhD Training Program, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,International Collaboration on Repair Discoveries, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,Experimental Medicine Program, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Otto F Barak
- Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia.,Faculty of Sport and Physical Education, University of Novi Sad, Novi Sad, Serbia
| | - Geoff B Coombs
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan , Kelowna, British Columbia , Canada
| | - Tanja Mijacika
- Department of Integrative Physiology, University of Split School of Medicine , Split , Croatia
| | - Andrei V Krassioukov
- International Collaboration on Repair Discoveries, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan , Kelowna, British Columbia , Canada
| | - Zeljko Dujic
- Department of Integrative Physiology, University of Split School of Medicine , Split , Croatia
| | - Yu-Chieh Tzeng
- Wellington Medical Technology Group, Centre for Translational Physiology, University of Otago , Wellington , New Zealand
| | - Aaron A Phillips
- Departments of Physiology and Pharmacology, Cardiac Sciences, and Clinical Neurosciences, Libin Cardiovascular Institute of Alberta, Hotchkiss Brain Institute, University of Calgary, Alberta, Canada
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Wecht JM, Wilson J, Previnaire JG. Using the autonomic standards to assess orthostatic hypotension in persons with SCI: a case series. Spinal Cord Ser Cases 2018; 3:17087. [PMID: 29423293 DOI: 10.1038/s41394-017-0021-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 09/19/2017] [Accepted: 10/10/2017] [Indexed: 11/09/2022] Open
Abstract
Introduction Spinal cord injury (SCI) creates a complex and unique syndrome of medical issues related to disruption of somatic and autonomic pathways. Among these impaired control of blood pressure (BP) can significantly impede patients' activities of daily living. The International Standards for the Assessment of Autonomic Function after SCI (ISAFSCI) is used to document the impact of SCI on resting BP (abnormal if below 90 mmHg) and the presence or absence of orthostatic hypotension (OH), defined as a symptomatic or asymptomatic decrease in BP (>/=20/10 mmHg) upon moving to an upright position. Case presentation Case 1 documents the adverse influence of prescribed medications (antidepressants for neuropathic pain) on OH; case 2 describes the influence of bladder management on cardiovascular instability (autonomic dysreflexia and subsequent OH); case 3 describes the association between spasticity and OH; case 4 describes OH associated with a Valsalva maneuver. Discussion Impaired control of BP can stem from a combination of medical issues and autonomic dysfunction in persons with SCI. Management strategies for OH will vary depending on the stage of the SCI, the root cause of the OH and other confounding medical conditions. Non-pharmacological treatment should be considered as a first line of intervention and consideration should be given to cessation of potentially contributory medications prior to implementing pharmaceutical interventions. The systematic use of ISAFSCI by clinicians is recommended to document BP irregularities and to describe the effects of treatment strategies aimed at improving BP control in the SCI population.
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Affiliation(s)
- Jill M Wecht
- 1James J Peters VA Medical Center, Room 7A-13, 130 West Kingsbridge Road, Bronx, NY 10468 USA.,2Icahn School of Medicine, Mount Sinai, New York, NY USA
| | - James Wilson
- 3Department of Physical Medicine and Rehabilitation, MetroHealth Rehabilitation Institute of Ohio, Case Western Reserve University, Cleveland, OH USA
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Brown R, Burton AR, Macefield VG. Autonomic dysreflexia: Somatosympathetic and viscerosympathetic vasoconstrictor responses to innocuous and noxious sensory stimulation below lesion in human spinal cord injury. Auton Neurosci 2018; 209:71-78. [DOI: 10.1016/j.autneu.2017.07.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 06/24/2017] [Accepted: 07/11/2017] [Indexed: 11/17/2022]
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20
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Wecht JM, Bauman WA. Implication of altered autonomic control for orthostatic tolerance in SCI. Auton Neurosci 2018; 209:51-58. [DOI: 10.1016/j.autneu.2017.04.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 03/16/2017] [Accepted: 04/25/2017] [Indexed: 12/22/2022]
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21
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Cold pressor test in spinal cord injury—revisited. Spinal Cord 2017; 56:528-537. [DOI: 10.1038/s41393-017-0037-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 11/08/2017] [Accepted: 11/11/2017] [Indexed: 11/08/2022]
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22
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Phillips AA, Squair JW, Sayenko DG, Edgerton VR, Gerasimenko Y, Krassioukov AV. An Autonomic Neuroprosthesis: Noninvasive Electrical Spinal Cord Stimulation Restores Autonomic Cardiovascular Function in Individuals with Spinal Cord Injury. J Neurotrauma 2017; 35:446-451. [PMID: 28967294 PMCID: PMC5793952 DOI: 10.1089/neu.2017.5082] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Despite autonomic dysfunction after spinal cord injury (SCI) being the major cause of death and a top health priority, the clinical management options for these conditions are limited to drugs with delayed onset and nonpharmacological interventions with equivocal effectiveness. We tested the capacity of electrical stimulation, applied transcutaneously over the spinal cord, to manage autonomic dysfunction in the form of orthostatic hypotension after SCI. We assessed beat-by-beat blood pressure (BP), stroke volume, and cardiac contractility (dP/dt; Finometer), as well as cerebral blood flow (transcranial Doppler) in 5 individuals with motor-complete SCI (4 cervical, 1 thoracic) during an orthostatic challenge with and without transcutaneous electrical stimulation applied at the TVII level. During the orthostatic challenge, all individuals experienced hypotension characterized by a 37 ± 4 mm Hg decrease in systolic BP, a 52 ± 10% reduction in cardiac contractility, and a 23 ± 6% reduction in cerebral blood flow (all p < 0.05), along with severe self-reported symptoms. Electrical stimulation completely normalized BP, cardiac contractility, cerebral blood flow, and abrogated all symptoms. Noninvasive transcutaneous electrical spinal cord stimulation may be a viable therapy for restoring autonomic cardiovascular control after SCI.
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Affiliation(s)
- Aaron A Phillips
- 1 ICORD-BSCC, University of British Columbia , Vancouver, British Columbia, Canada
| | - Jordan W Squair
- 1 ICORD-BSCC, University of British Columbia , Vancouver, British Columbia, Canada
| | - Dimitry G Sayenko
- 2 Department of Integrative Biology and Physiology, University of California , Los Angeles, Los Angeles, California
| | - V Reggie Edgerton
- 2 Department of Integrative Biology and Physiology, University of California , Los Angeles, Los Angeles, California.,3 Neurobiology, University of California , Los Angeles, Los Angeles, California.,4 Department of Neurosurgery, David Geffen School of Medicine, University of California , Los Angeles, Los Angeles, California.,5 Brain Research Institute, University of California , Los Angeles, Los Angeles, California
| | - Yury Gerasimenko
- 2 Department of Integrative Biology and Physiology, University of California , Los Angeles, Los Angeles, California.,6 Pavlov Institute of Physiology , Saint-Petersburg, Russia
| | - Andrei V Krassioukov
- 1 ICORD-BSCC, University of British Columbia , Vancouver, British Columbia, Canada
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Ondrusova K, Svacinova J, Javorka M, Novak J, Novakova M, Novakova Z. Impaired Baroreflex Function during Orthostatic Challenge in Patients after Spinal Cord Injury. J Neurotrauma 2017; 34:3381-3387. [PMID: 28605971 DOI: 10.1089/neu.2017.4989] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The level of spinal cord injury (SCI) affects baroreflex regulation of blood pressure. While a parasympathetic cardiac chronotropic effect is preserved, baroreflex response could be impaired by sympathetic dysfunction under the SCI level. This study was aimed to evaluate the baroreflex function in SCI patients by the analysis of causal interaction between systolic blood pressure (SBP) and inter-beat intervals (IBI). Blood pressure was continuously recorded in 13 cervical SCI patients (CSCI), nine thoracic SCI (ThSCI) and 13 able-bodied controls (Con) during two phases: sitting (PS) and orthostatic challenge (PO). Beat-to-beat SBP and IBI sequences were obtained from continuous blood pressure recording. Closed loop of SBP-IBI interaction was mathematically opened by bivariate autoregressive model; causal coherence and baroreflex sensitivity (BRS) were calculated in baroreflex direction. Coherence quantifies causal synchronicity between SBP and IBI. The gain of transfer function from SBP to IBI represents BRS. PS (medians of CSCI/ThSCI/Con) coherence was 0.28/0.33/0.25 (no significant difference) and PS BRS was 6.98/7.54/6.66 (no difference). PO coherence was 0.18/0.58/0.45 (CSCI < ThCSI and Con; p < 0.01) and PO BRS was 2.38/5.87/6.22 (CSCI < ThCSI and Con; p < 0.01). For position change effect, there was no change in CSCI coherence; for ThSCI and Con, PS < PO (p < 0.05). For BRS in the CSCI group, PS < PO (p < 0.01); for ThSCI and Con, there was no change. BRS and coherence correlated negatively with SCI level (p < 0.01). In conclusion, baroreflex dysfunction in SCI patients was detected using causal analysis methods during orthostatic challenge only. Baroreflex dysfunction is probably an important mechanism of the more expressed blood pressure decrease associated with CSCI. The severity of autonomic dysfunction was related to SCI level.
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Affiliation(s)
| | - Jana Svacinova
- 1 Department of Physiology, Masaryk University , Brno, Czech Republic
| | - Michal Javorka
- 2 Department of Physiology, Comenius University in Bratislava , Martin, Slovakia .,3 Biomedical Center Martin, Comenius University in Bratislava , Martin, Slovakia
| | - Jan Novak
- 1 Department of Physiology, Masaryk University , Brno, Czech Republic
| | - Marie Novakova
- 1 Department of Physiology, Masaryk University , Brno, Czech Republic .,4 International Clinical Research Center, St. Anne's University Hospital Brno , Brno, Czech Republic
| | - Zuzana Novakova
- 1 Department of Physiology, Masaryk University , Brno, Czech Republic
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Wang K, Duan S, Wen X, Wang W, Fang S, Qi D, Huan X, Wang L, He Z. Angiotensin II system in the nucleus tractus solitarii contributes to autonomic dysreflexia in rats with spinal cord injury. PLoS One 2017; 12:e0181495. [PMID: 28742157 PMCID: PMC5524360 DOI: 10.1371/journal.pone.0181495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 07/03/2017] [Indexed: 11/25/2022] Open
Abstract
Background Autonomic dysreflexia (AD) is a potentially life-threating complication after spinal cord injury (SCI), characterized by episodic hypertension induced by colon or bladder distension. The objective of this study was to determine the role of impaired baroreflex regulation by the nucleus tractus solitarii(NTS) in the occurrence of AD in a rat model. Methods T4 spinal cord transection animal model was used in this study, which included 40 Male rats Colorectal distension (CD) was performed to assess AD and compare the changes of BP, HR, and BRS, six weeks after operation. After that, SCI rats with successfully induced AD were selected. Losartan was microinjected into NTS in SCI rats, then 10, 30, 60 minutes later, CD was performed to calculate the changes of BP, HR, and BRS in order to explicit whether Ang II system was involved in the AD occurrence. Ang II was then Intra-cerebroventricular infused in sham operation rats with CD to mimic the activation of Ang II system in AD. Finally, the level of Ang II in NTS and colocalization of AT1R and NMDA receptor within the NTS neurons were also detected in SCI rats. Results Compared with sham operation, SCI significantly aggravated the elevation of blood pressure (BP) and impaired baroreflex sensitivity (BRS) induced by colorectal distension; both of which were significantly improved by microinjection of the angiotensin receptor type I (AT1R) antagonist losartan into the NTS. Level of angiotensin II (Ang II) in the NTS was significantly increased in the SCI rats than sham. Intracerebroventricular infusion of Ang II also mimicked changes in BP and BRS induced by colorectal distension. Blockade of baroreflex by sinoaortic denervation prevented beneficial effect of losartan on AD. Conclusion We concluded that the activation of Ang II system in NTS may impair blood pressure baroreflex, and contribute to AD after SCI.
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Affiliation(s)
- Kai Wang
- Department of Anesthesiology, Central Hospital of Xuzhou, Jiangsu, China
| | - Shaoxia Duan
- Department of Anesthesiology and ICU, South Campus, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Xueping Wen
- Department of Orthopedics, Ningxiang People’s Hospital of Hunan Province, Ningxiang, Hunan, China
| | - Weizhong Wang
- Department of Physiology, Second Military Medical University, Shanghai, China
| | - Shangping Fang
- Department of Anesthesiology, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Dunyi Qi
- Department of Anesthesiology, Affiliated Hospital of Xuzhou Medical University, Jiangsu, China
| | - Xiang Huan
- Department of Anesthesiology, Central Hospital of Xuzhou, Jiangsu, China
| | - Liwei Wang
- Department of Anesthesiology, Central Hospital of Xuzhou, Jiangsu, China
- * E-mail: (ZH); (LW)
| | - Zhenzhou He
- Department of Anesthesiology and ICU, South Campus, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- * E-mail: (ZH); (LW)
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Berger MJ, Kimpinski K, Currie KD, Nouraei H, Sadeghi M, Krassioukov AV. Multi-Domain Assessment of Autonomic Function in Spinal Cord Injury Using a Modified Autonomic Reflex Screen. J Neurotrauma 2017; 34:2624-2633. [PMID: 28537464 DOI: 10.1089/neu.2016.4888] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The aim of this study was to characterize autonomic lesions in participants with spinal cord injury (SCI; n = 10) using an autonomic reflex screen, incorporating sudomotor, cardiovagal, and sympathetic adrenergic tests, as well as hemodynamic responses to head-up tilt (HUT). Hemodynamic responses were compared to healthy controls (n = 20) and previously published normative cutoffs in order better identify autonomic impairments. Sympathetic skin responses (SSRs), heart rate response to deep breathing (HRDB), and heart rate and beat-to-beat blood pressure responses to Valsalva maneuver (VM) and HUT were measured. SCI participants demonstrated impairment in at least one domain, with 7 of 10 demonstrating autonomic impairment across all domains. No single test was concordant with orthostatic hypotension on HUT, in all participants. Measures of cardiovagal function, including HRDB (SCI = 7.7 ± 3.8 beats/min vs. controls = 17.6 ± 8.1 beats/min) and Valsalva ratio (SCI = 1.53 ± 0.29 vs. controls = 1.85 ± 0.37), were significantly reduced in SCI participants, compared to controls (p < 0.05). These findings suggest that an autonomic reflex screen, which includes standardized testing protocol and normative data for comparison, is useful for determining the autonomic domains affected by the neurological injury in SCI. We also demonstrated significant cardiovagal impairment in SCI participants compared to controls, which warrants further investigation to determine whether cardiovagal dysfunction is associated with the negative cardiovascular outcomes, which are known to occur in SCI.
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Affiliation(s)
- Michael J Berger
- 1 Division of Physical Medicine & Rehabilitation, Department of Medicine, University of British Columbia , Vancouver, British Columbia, Canada
| | - Kurt Kimpinski
- 2 Department of Clinical Neurological Sciences and School of Kinesiology, Western University , London, Ontario, Canada
| | - Katharine D Currie
- 3 Faculty of Kinesiology and Education, University of Toronto , Toronto, Ontario, Canada
| | - Hirmand Nouraei
- 4 Faculty of Medicine, University of British Columbia , Vancouver, British Columbia, Canada
| | - Mahsa Sadeghi
- 5 Division of Neurology, Wayne State University , Detroit, Michigan
| | - Andrei V Krassioukov
- 1 Division of Physical Medicine & Rehabilitation, Department of Medicine, University of British Columbia , Vancouver, British Columbia, Canada .,6 International Collaboration On Repair Discoveries (ICORD) , Vancouver, British Columbia, Canada
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Davidson R, Phillips A. Cardiovascular Physiology and Responses to Sexual Activity in Individuals Living with Spinal Cord Injury. Top Spinal Cord Inj Rehabil 2017; 23:11-19. [PMID: 29339873 PMCID: PMC5340505 DOI: 10.1310/sci2301-11] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Background: Spinal cord injury (SCI) may profoundly impact autonomic function producing a variable degree of dysfunction in cardiovascular, bronchopulmonary, sweating, bladder, bowel, and sexual function. The cardiovascular system is crucially important for sexual function, as it is responsible for blood flow shifts to cavernous and musculoskeletal tissue during sexual activity. This system is prone to 3 main abnormalities after SCI including low resting blood pressure (LRBP), orthostatic hypotension (OH), and autonomic dysreflexia (AD), all of which have important effects on sexual function. Methods: We review the current etiological mechanisms and manifestations of cardiovascular dysfunction after SCI and discuss how this is documented to impact sexual function in individuals living with SCI. Conclusions: All individuals with SCI at or above the T6 neurologic level have an increased risk of AD during sexual stimulation, with increasing risk associated with higher levels of injury and greater completeness of injury. AD can be silent, and individuals living with SCI should be aware of blood pressure values at baseline and during sexual activity. Clinicians performing vibrostimulation fertility procedures need to be aware of the risk of AD and consider pretreatment if needed. Researchers studying the cardiovascular response to sexual stimulation should consider continuous monitoring of blood pressure, as intermittent monitoring may underestimate true blood pressure values.
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Affiliation(s)
- Ross Davidson
- International Collaboration On Repair Discoveries, Vancouver, BC, Canada
- Faculty of Medicine, Division of Physical Medicine and Rehabilitation, University of British Columbia, British Columbia, Canada
| | - Aaron Phillips
- International Collaboration On Repair Discoveries, Vancouver, BC, Canada
- Faculty of Medicine, Division of Physical Medicine and Rehabilitation, University of British Columbia, British Columbia, Canada
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Baroreceptor reflex during forced expiratory maneuvers in individuals with chronic spinal cord injury. Respir Physiol Neurobiol 2016; 229:65-70. [PMID: 27137412 DOI: 10.1016/j.resp.2016.04.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 04/19/2016] [Accepted: 04/19/2016] [Indexed: 02/07/2023]
Abstract
Pulmonary and cardiovascular dysfunctions are leading causes of morbidity and mortality in patients with chronic Spinal Cord Injury (SCI). Impaired respiratory motor function and decreased Baroreflex Sensitivity (BS) are predictors for the development of cardiopulmonary disease. This observational case-controlled clinical study was undertaken to investigate if respiratory motor control deficits in individuals with SCI affect their ability to perform the Valsalva maneuver, and to determine if a sustained Maximum Expiratory Pressure (MEP) effort can serve as an acceptable maneuver for determination of the BS in the event that the Valsalva maneuver cannot be performed. The BS outcomes (ms/mmHg) were obtained using continuous beat-to-beat arterial blood pressure (BP) and heart rate (HR) recordings during Valsalva or MEP maneuvers in thirty nine individuals with chronic C3-T12 SCI. Twenty one participants (54%) reported signs of intolerance during the Valsalva maneuver and only 15 individuals (39%) were able to complete this task. Cervical level of injury was a significant risk factor (p=0.001) for failing to complete the Valsalva maneuver, and motor-complete injury was a significant risk factor for symptoms of intolerance (p=0.04). Twenty eight participants (72%) were able to perform the MEP maneuver; the other 11 participants failed to exceed the standard airway pressure threshold of 27cm H2O. Neither level nor completeness of injury were significant risk factors for failure of MEP maneuver. When the required airway pressure was sustained, there were no significant differences between BS outcomes obtained during Valsalva and MEP maneuvers. The results of this study indicate that individuals with high-level and motor-complete SCI are at increased risk of not completing the Valsalva maneuver and that baroreflex-mediated responses can be evaluated by using sustained MEP maneuver when the Valsalva maneuver cannot be performed.
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Respiratory Training Improves Blood Pressure Regulation in Individuals With Chronic Spinal Cord Injury. Arch Phys Med Rehabil 2015; 97:964-73. [PMID: 26718236 DOI: 10.1016/j.apmr.2015.11.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 11/23/2015] [Accepted: 11/30/2015] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To investigate the effects of respiratory motor training (RMT) on pulmonary function and orthostatic stress-mediated cardiovascular and autonomic responses in individuals with chronic spinal cord injury (SCI). DESIGN Before-after intervention case-controlled clinical study. SETTING SCI research center and outpatient rehabilitation unit. PARTICIPANTS A sample of (N=21) individuals with chronic SCI ranging from C3 to T2 diagnosed with orthostatic hypotension (OH) (n=11) and healthy, noninjured controls (n=10). INTERVENTIONS A total of 21±2 sessions of pressure threshold inspiratory-expiratory RMT performed 5d/wk during a 1-month period. MAIN OUTCOME MEASURES Standard pulmonary function test: forced vital capacity, forced expiratory volume in one second, maximal inspiratory pressure, maximal expiratory pressure, beat-to-beat arterial blood pressure, heart rate, and respiratory rate were acquired during the orthostatic sit-up stress test before and after the RMT program. RESULTS Completion of RMT intervention abolished OH in 7 of 11 individuals. Forced vital capacity, low-frequency component of power spectral density of blood pressure and heart rate oscillations, baroreflex effectiveness, and cross-correlations between blood pressure, heart rate, and respiratory rate during the orthostatic challenge were significantly improved, approaching levels observed in noninjured individuals. These findings indicate increased sympathetic activation and baroreflex effectiveness in association with improved respiratory-cardiovascular interactions in response to the sudden decrease in blood pressure. CONCLUSIONS Respiratory training increases respiratory capacity and improves orthostatic stress-mediated respiratory, cardiovascular, and autonomic responses, suggesting that this intervention can be an efficacious therapy for managing OH after SCI.
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Phillips AA, Krassioukov AV. Contemporary Cardiovascular Concerns after Spinal Cord Injury: Mechanisms, Maladaptations, and Management. J Neurotrauma 2015; 32:1927-42. [PMID: 25962761 DOI: 10.1089/neu.2015.3903] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Cardiovascular (CV) issues after spinal cord injury (SCI) are of paramount importance considering they are the leading cause of death in this population. Disruption of autonomic pathways leads to a highly unstable CV system, with impaired blood pressure (BP) and heart rate regulation. In addition to low resting BP, on a daily basis the majority of those with SCI suffer from transient episodes of aberrantly low and high BP (termed orthostatic hypotension and autonomic dysreflexia, respectively). In fact, autonomic issues, including resolution of autonomic dysreflexia, are frequently ranked by individuals with high-level SCI to be of greater priority than walking again. Owing to a combination of these autonomic disturbances and a myriad of lifestyle factors, the pernicious process of CV disease is accelerated post-SCI. Unfortunately, these secondary consequences of SCI are only beginning to receive appropriate clinical attention. Immediately after high-level SCI, major CV abnormalities present in the form of neurogenic shock. After subsiding, new issues related to BP instability arise, including orthostatic hypotension and autonomic dysreflexia. This review describes autonomic control over the CV system before injury and the mechanisms underlying CV abnormalities post-SCI, while also detailing the end-organ consequences, including those of the heart, as well as the systemic and cerebral vasculature. The tertiary impact of CV dysfunction will also be discussed, such as the potential impediment of rehabilitation, and impaired cognitive function. In the recent past, our understanding of autonomic dysfunctions post-SCI has been greatly enhanced; however, it is vital to further develop our understanding of the long-term consequences of these conditions, which will equip us to better manage CV disease morbidity and mortality in this population.
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Affiliation(s)
- Aaron A Phillips
- 1 Center for Heart, Lung, and Vascular Health, Faculty of Health and Social Development, University of British Columbia , Kelowna, British Columbia, Canada .,2 Experimental Medicine Program, Faculty of Medicine, University of British Columbia , Vancouver, British Columbia, Canada .,3 International Collaboration on Repair Discoveries (ICORD), University of British Columbia , Vancouver, British Columbia, Canada
| | - Andrei V Krassioukov
- 2 Experimental Medicine Program, Faculty of Medicine, University of British Columbia , Vancouver, British Columbia, Canada .,3 International Collaboration on Repair Discoveries (ICORD), University of British Columbia , Vancouver, British Columbia, Canada .,4 Department of Physical Medicine and Rehabilitation, University of British Columbia , Vancouver, British Columbia, Canada
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Functional electrical stimulation: cardiorespiratory adaptations and applications for training in paraplegia. Sports Med 2015; 45:71-82. [PMID: 25205000 DOI: 10.1007/s40279-014-0250-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Regular exercise can be broadly beneficial to health and quality of life in humans with spinal cord injury (SCI). However, exercises must meet certain criteria, such as the intensity and muscle mass involved, to induce significant benefits. SCI patients can have difficulty achieving these exercise requirements since the paralysed muscles cannot contribute to overall oxygen consumption. One solution is functional electrical stimulation (FES) and, more importantly, hybrid training that combines volitional arm and electrically controlled contractions of the lower limb muscles. However, it might be rather complicated for therapists to use FES because of the wide variety of protocols that can be employed, such as stimulation parameters or movements induced. Moreover, although the short-term physiological and psychological responses during different types of FES exercises have been extensively reported, there are fewer data regarding the long-term effects of FES. Therefore, the purpose of this brief review is to provide a critical appraisal and synthesis of the literature on the use of FES for exercise in paraplegic individuals. After a short introduction underlying the importance of exercise for SCI patients, the main applications and effects of FES are reviewed and discussed. Major findings reveal an increased physiological demand during FES hybrid exercises as compared with arms only exercises. In addition, when repeated within a training period, FES exercises showed beneficial effects on muscle characteristics, force output, exercise capacity, bone mineral density and cardiovascular parameters. In conclusion, there appears to be promising evidence of beneficial effects of FES training, and particularly FES hybrid training, for paraplegic individuals.
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Walter M, Knüpfer SC, Leitner L, Mehnert U, Schubert M, Curt A, Kessler TM. Autonomic dysreflexia and repeatability of cardiovascular changes during same session repeat urodynamic investigation in women with spinal cord injury. World J Urol 2015; 34:391-7. [PMID: 26055644 DOI: 10.1007/s00345-015-1589-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Accepted: 05/05/2015] [Indexed: 12/31/2022] Open
Abstract
PURPOSE To investigate autonomic dysreflexia (AD) and repeatability of cardiovascular changes during same session repeat urodynamic investigation (UDI) in women with spinal cord injury (SCI). METHODS Prospective investigation of 33 consecutive women with suprasacral SCI suffering from neurogenic lower urinary tract dysfunction (NLUTD) undergoing same session repeat UDI and synchronous continuous cardiovascular monitoring [systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR)]. UDIs were performed according to the International Continence Society guidelines. AD was defined according to the International Standards to document remaining Autonomic Function after SCI. Neurological level of SCI was determined using the American Spinal Injury Association impairment scale. RESULTS Mean age and duration since SCI of the 33 women were 58 ± 19 and 6 ± 11 years, respectively. Overall AD incidence was 73 % (24/33), and 19 of the 33 women (58 %) showed AD in both UDIs. The repeatability of detecting AD between the two same session UDIs was good (κ = 0.67, 95 % CI 0.4-0.94). When applying the Bland and Altman method, wide 95 % limits of agreement for differences in same session SBP, DBP and HR indicated poor repeatability. There was a significant increase in SBP (p < 0.001) and DBP (p < 0.001) and a significant decrease in HR (p = 0.007) in patients with compared to those without AD. CONCLUSIONS In all women with NLUTD due to suprasacral SCI, we strongly recommend continuous cardiovascular monitoring during UDI and repeat measurements considering the high incidence of AD, the relevant risks involved with sudden hypertension and the poor repeatability of cardiovascular monitoring.
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Affiliation(s)
- Matthias Walter
- Neuro-Urology, Spinal Cord Injury Center and Research, University of Zürich, Balgrist University Hospital, Zürich, Switzerland
| | - Stephanie C Knüpfer
- Neuro-Urology, Spinal Cord Injury Center and Research, University of Zürich, Balgrist University Hospital, Zürich, Switzerland
| | - Lorenz Leitner
- Neuro-Urology, Spinal Cord Injury Center and Research, University of Zürich, Balgrist University Hospital, Zürich, Switzerland
| | - Ulrich Mehnert
- Neuro-Urology, Spinal Cord Injury Center and Research, University of Zürich, Balgrist University Hospital, Zürich, Switzerland
| | - Martin Schubert
- Neurology, Spinal Cord Injury Center and Research, University of Zürich, Balgrist University Hospital, Zürich, Switzerland
| | - Armin Curt
- Neurology, Spinal Cord Injury Center and Research, University of Zürich, Balgrist University Hospital, Zürich, Switzerland
| | - Thomas M Kessler
- Neuro-Urology, Spinal Cord Injury Center and Research, University of Zürich, Balgrist University Hospital, Zürich, Switzerland.
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Abstract
PURPOSE OF REVIEW The autonomic nervous system functions to control heart rate, blood pressure, respiratory rate, gastrointestinal motility, hormone release, and body temperature on a second-to-second basis. Here we summarize some of the latest literature on autonomic dysfunction, focusing primarily on the perioperative implications. RECENT FINDINGS The variety of autonomic dysfunction now extends to a large number of clinical conditions in which the cause or effect of the autonomic component is blurred. Methods for detecting dysautonomia can be as simple as performing a history and physical examination that includes orthostatic vital signs measured in both recumbent and vertical positions; however, specialized laboratories are required for definitive diagnosis. Heart rate variability monitoring is becoming more commonplace in the assessment and understanding of autonomic instability. Degenerative diseases of the autonomic nervous system include Parkinson's disease and multiple system atrophy, with the most serious manifestations being postural hypotension and paradoxical supine hypertension. Other conditions occur in which the autonomic dysfunction is only part of a larger disease process, such as diabetic autonomic neuropathy, traumatic brain injury, and spinal cord injury. SUMMARY Patients with dysautonomia often have unpredictable and paradoxical physiological responses to various perioperative stimuli. Knowledge of the underlying pathophysiology of their condition is required in order to reduce symptom exacerbation and limit morbidity and mortality during the perioperative period.
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Hou S, Blesch A, Lu P. A radio-telemetric system to monitor cardiovascular function in rats with spinal cord transection and embryonic neural stem cell grafts. J Vis Exp 2014:e51914. [PMID: 25350486 DOI: 10.3791/51914] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
High thoracic or cervical spinal cord injury (SCI) can lead to cardiovascular dysfunction. To monitor cardiovascular parameters, we implanted a catheter connected to a radio transmitter into the femoral artery of rats that underwent a T4 spinal cord transection with or without grafting of embryonic brainstem-derived neural stem cells expressing green fluorescent protein. Compared to other methods such as cannula insertion or tail-cuff, telemetry is advantageous to continuously monitor blood pressure and heart rate in freely moving animals. It is also capable of long term multiple data acquisitions. In spinal cord injured rats, basal cardiovascular data under unrestrained condition and autonomic dysreflexia in response to colorectal distension were successfully recorded. In addition, cardiovascular parameters before and after SCI can be compared in the same rat if a transmitter is implanted before a spinal cord transection. One limitation of the described telemetry procedure is that implantation in the femoral artery may influence the blood supply to the ipsilateral hindlimb.
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Affiliation(s)
- Shaoping Hou
- Spinal Cord Research Center, Department of Neurobiology & Anatomy, Drexel University College of Medicine;
| | - Armin Blesch
- Spinal Cord Injury Center, Heidelberg University Hospital
| | - Paul Lu
- Veterans Administration Medical Center, San Diego, CA; Department of Neurosciences, University of California, San Diego
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West CR, Wong SC, Krassioukov AV. Autonomic cardiovascular control in Paralympic athletes with spinal cord injury. Med Sci Sports Exerc 2014; 46:60-8. [PMID: 23739527 DOI: 10.1249/mss.0b013e31829e46f3] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Disruption of autonomic control after spinal cord injury (SCI) results in life-threatening cardiovascular dysfunctions and impaired endurance performance; hence, an improved ability to recognize those at risk of autonomic disturbances is of critical clinical and sporting importance. PURPOSE The objective of this study is to assess the effect of neurological level, along with motor, sensory, and autonomic completeness of injury, on cardiovascular control in Paralympic athletes with SCI. METHODS Fifty-two highly trained male Paralympic athletes (age, 34.8 ± 7.1 yr) from 14 countries with chronic SCI (C2-L2) completed three experimental trials. During trial 1, motor and sensory functions were assessed according to the American Spinal Injury Association Impairment Scale. During trial 2, autonomic function was assessed via sympathetic skin responses (SSR). During trial 3, cardiovascular control was assessed via the beat-by-beat blood pressure response to orthostatic challenge. RESULTS Athletes with cervical SCI exhibited the lowest seated blood pressure and the most severe orthostatic hypotension (P < 0.025). There were no differences in cardiovascular function between athletes with different American Spinal Injury Association Impairment Scale grades (P > 0.96). Conversely, those with the lowest SSR scores exhibited the lowest seated blood pressure and the most severe orthostatic hypotension (P < 0.002). Linear regression demonstrated that the combined model of neurological level and autonomic completeness of SCI explained the most variance in all blood pressure indices. CONCLUSION We demonstrate for the first time that neurological level and SSR score provide the optimal combination of assessments to identify those at risk of abnormal cardiovascular control. We advocate the use of autonomic testing in the clinical and sporting classification of SCI athletes.
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Affiliation(s)
- Christopher R West
- 1International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, BC, CANADA; 2Division of Physical Medicine and Rehabilitation, Department of Medicine, University of British Columbia, Vancouver, BC, CANADA; and 3GF Strong Rehabilitation Centre, Vancouver, BC, CANADA
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Phillips AA, Krassioukov AV, Ainslie PN, Cote AT, Warburton DER. Increased central arterial stiffness explains baroreflex dysfunction in spinal cord injury. J Neurotrauma 2014; 31:1122-8. [PMID: 24634993 DOI: 10.1089/neu.2013.3280] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
After cervical spinal cord injury (SCI), orthostatic hypotension and intolerance commonly ensue. The cardiovagal baroreflex plays an important role in the acute regulation of blood pressure (BP) and is associated with the onset of presyncope. The cardiovagal baroreflex is dysfunctional after SCI; however, this may be influenced by either increased stiffening of the arteries containing the stretch-receptors (which has been shown in SCI) or a more downstream neural mechanism (i.e., solitary nucleus, sinoatrial node). Identifying where along this pathway baroreflex dysfunction occurs may highlight a potential therapeutic target. This study examined the relationship between spontaneous cardiovagal baroreflex sensitivity (BRS) and common carotid artery (CCA) stiffness in those with high level SCI before and after midodrine (alpha1-agonist) administration, as well as in able-bodied controls, to evaluate: (1) the role arterial stiffening plays mediating baroreflex function after SCI and (2) the effect of normalizing BP on these parameters. Three to five min recordings of beat-by-beat BP and heart rate, as well as 30 sec duration recordings of CCA diameter were used for analysis. All participants were tested supine and during upright-tilt. Arterial stiffness (β-stiffness index) was elevated in those with SCI when upright (+12%; p<0.05). Further, β-stiffness index was negatively related to reduced BRS in those with SCI when upright (R2=0.55; p<0.05), but not in able-bodied persons. Normalizing BP did not improve BRS or CCA stiffness. This study clearly shows that reduced BRS is closely related to increased arterial stiffness in the population with SCI.
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Affiliation(s)
- Aaron A Phillips
- 1 Cardiovascular Physiology and Rehabilitation Laboratory , Physical Activity Promotion and Chronic Disease Prevention Unit, University of British Columbia , Vancouver, Canada
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Phillips AA, Ainslie PN, Krassioukov AV, Warburton DER. Regulation of cerebral blood flow after spinal cord injury. J Neurotrauma 2013; 30:1551-63. [PMID: 23758347 DOI: 10.1089/neu.2013.2972] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Significant cardiovascular and autonomic dysfunction occurs after era spinal cord injury (SCI). Two major conditions arising from autonomic dysfunction are orthostatic hypotension and autonomic dysreflexia (i.e., severe acute hypertension). Effective regulation of cerebral blood flow (CBF) is essential to offset these drastic changes in cerebral perfusion pressure. In the context of orthostatic hypotension and autonomic dysreflexia, the purpose of this review is to critically examine the mechanisms underlying effective CBF after an SCI and propose future avenues for research. Although only 16 studies have examined CBF control in those with high-level SCI (above the sixth thoracic spinal segment), it appears that CBF regulation is markedly altered in this population. Cerebrovascular function comprises three major mechanisms: (1) cerebral autoregulation, (i.e., ΔCBF/Δ blood pressure); (2) cerebrovascular reactivity to changes in PaCO2 (i.e. ΔCBF/arterial gas concentration); and (3) neurovascular coupling (i.e., ΔCBF/Δ metabolic demand). While static cerebral autoregulation appears to be well maintained in high-level SCI, dynamic cerebral autoregulation, cerebrovascular reactivity, and neurovascular coupling appear to be markedly altered. Several adverse complications after high-level SCI may mediate the changes in CBF regulation including: systemic endothelial dysfunction, sleep apnea, dyslipidemia, decentralization of sympathetic control, and dominant parasympathetic activity. Future studies are needed to describe whether altered CBF responses after SCI aid or impede orthostatic tolerance. Further, simultaneous evaluation of extracranial and intracranial CBF, combined with modern structural and functional imaging, would allow for a more comprehensive evaluation of CBF regulatory processes. We are only beginning to understand the functional effects of dysfunctional CBF regulation on brain function on persons with SCI, which are likely to include increased risk of transient ischemic attacks, stroke, and cognitive dysfunction.
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Affiliation(s)
- Aaron A Phillips
- Cardiovascular Physiology and Rehabilitation Laboratory, University of British Columbia, Vancouver, Canada
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Neurovascular coupling of the posterior cerebral artery in spinal cord injury: a pilot study. Brain Sci 2013; 3:781-9. [PMID: 24961424 PMCID: PMC4061840 DOI: 10.3390/brainsci3020781] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 04/26/2013] [Accepted: 04/29/2013] [Indexed: 11/16/2022] Open
Abstract
PURPOSE To compare neurovascular coupling in the posterior cerebral artery (PCA) between those with spinal cord injury (SCI) and able bodied (AB) individuals. METHODS A total of seven SCI and seven AB were matched for age and sex. Measures included PCA velocity (PCAv), beat-by-beat blood pressure and end-tidal carbon dioxide. Posterior cerebral cortex activation was achieved by 10 cycles of (1) 30 s eyes closed (pre-stimulation), (2) 30 s reading (stimulation). RESULTS Blood pressure was significantly reduced in those with SCI (SBP: 100 ± 13 mmHg; DBP: 58 ± 13 mmHg) vs. AB (SBP 121 ± 12 mmHg; DBP: 74 ± 9 mmHg) during both pre-stimulation and stimulation, but the relative increase was similar during the stimulation period. Changes in PCAv during stimulation were mitigated in the SCI group (6% ± 6%) vs. AB (29% ± 12%, P < 0.001). Heart rate and end-tidal carbon dioxide responded similarly between groups. CONCLUSIONS Clearly, NVC is impaired in those with SCI. This study may provide a link between poor perfusion of the posterior cerebral region (containing the medullary autonomic centres) and autonomic dysfunction after SCI.
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