Assessment of autonomic dysfunction following spinal cord injury: rationale for additions to International Standards for Neurological Assessment

Microclimate evaluation of strap-based wheelchair seating systems for persons with spinal cord injury: A pilot study

STUDY PURPOSE

The purpose of this pilot study was to assess microclimate characteristics of two versions of a strap-based wheelchair seating system (perforated and solid straps) and to conduct preliminary microclimate comparisons of subjects' current wheelchair seating systems.

MATERIALS AND METHODS

In this pilot study, the microclimate properties of two variations (solid and perforated) of a strap-based seating system were compared with two commonly used seating systems. Six subjects sat on three different seating systems each for 100-min test periods, while temperature and relative humidity were measured with a single sensor adjacent to the skin-seat interface. Additionally, thermal images of the seat interface were collected before and after each test period.

RESULTS

The thermal images revealed that the maximum surface temperature of the solid-strap-based seating system was significantly lower than the other seating systems, -1.21 °C. (95% CI -2.11 to -0.30, p = 0.02), immediately following transfer out of the seat. Five minutes after transferring out of the seat, the perforated-strap seat was significantly cooler than the other seats -0.94 °C. (95% CI -1.59 to -0.30), p = 0.01, as was the solid-strap-based seat, -1.66 °C. (95% CI -2.69 to -0.63), p = 0.01. There were no significant differences in interface temperature or relative humidity measured with the single sensor near the skin-seat interface.

CONCLUSION

This pilot study offers preliminary evidence regarding the microclimate of the strap-based seating systems compared with other common seating systems. Clinically, the strap-based seating system may offer another option for those who struggle with microclimate management.

Neonatal spinal injury induces de novo projections of primary afferents to the lumbosacral intermediolateral nucleus in rats

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Neonatal spinal injury induces dextran amine-labeled primary afferent projections to the sacral intermediolateral nucleus.

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Dextran amine-labeled afferent fibers form varicose terminals on the parasympathetic preganglionic neurons.

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Dextran amine tends to be incorporated preferentially in dorsal root ganglion neurons with myelinated fibers.

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De novo projections of myelinated afferents might contribute to the recovery of micturition following neonatal spinal injury.

Complete spinal transection in adult rats results in poor recovery of hind limb function and severe urinary bladder dysfunction. Neonatal rats with spinal cord transection, however, exhibit spontaneous and significant recovery of micturition control. A previous study in which biotinylated-dextran amine (BDA) was used as an anterograde tracer demonstrated that primary afferent fibers from the fifth lumbar dorsal root ganglion (DRG) project more strongly and make more terminals in the ventral horn after neonatal spinal cord transection at the mid-thoracic level. In the present study, we injected BDA into the sixth lumbar (L6) DRG of neonatally spinalized rats to label primary afferent fibers that include visceral afferents. The labeled fibers projected to the intermediolateral nucleus (IML) in the intermediate zone on ipsilateral side of the L6 spinal segment, whereas no projections to the IML were observed in sham-operated or intact rats. The BDA-labeled fibers of neonatally spinalized rats formed varicose terminals on parasympathetic preganglionic neurons in the IML. These findings suggest that some primary afferent projections from the L6 DRG to the IML appear after neonatal spinal cord transection, and these de novo projections might contribute to the recovery of autonomic function such as micturition following spinal cord injury in the neonatal stage.

Open surgery for haemorrhoids in persons with spinal cord injury

Study design

Pilot retrospective study on the outcome of open surgery for grade III and IV haemorrhoids in patients with SCI.

Objective

Haemorrhoids and anal fissures are common in patients with spinal cord injury (SCI). Grade I to III haemorrhoids are usually managed medically or by surgical ligation. Grade III and IV haemorrhoids are treated with surgical haemorrhoidectomy in the general population, but not in patients with SCI, most probably due to fear of complications.

Setting

Fondation Hopale, Berck-sur Mer, France.

Methods

The surgical database was searched for open haemorrhoidectomies performed between 2007 and 2016. Seventeen patients were included. There were mostly males with complete paraplegia, mean age: 50 years and mean time since injury: 15.9 years. Open haemorrhoidectomy (Milligan and Morgan) was performed for isolated haemorrhoids (n = 4), and combined with Leopold Bellan procedure (posterior anoplasty and internal sphincterotomy) for associated anal fissures (n = 13). Short-term follow-up was performed by the surgeon (post-operative weeks 2 and 6), long-term follow-up by telephone interview (mean 5.7 years, SD 1.9).

Results

At 6-weeks post-operative, no significant complications had occurred and all wounds had healed, however 1 patient had recurrence of anal fissure. At long-term follow-up, 75% of patients reported a significant improvement in anorectal symptoms. Recurrences were reported by 5 patients: 3 haemorrhoids (18%) and 2 anal fissures (25%). Anal incontinence occurred in 1 patient who required an anal plug. All patients maintained the same bowel programs as pre-operative.

Conclusions

Open surgery procedures were well tolerated and should be considered in persons with SCI.

Prediction of autonomic dysreflexia during urodynamics: a prospective cohort study

BACKGROUND

Autonomic dysreflexia is a severe and potentially life-threatening condition in patients with spinal cord injury, as it can lead to myocardial ischemia, brain hemorrhage, or even death. Urodynamic investigation is the gold standard to assess neurogenic lower urinary tract dysfunction due to spinal cord injury and reveal crucial pathological findings, such as neurogenic detrusor overactivity. However, neurogenic detrusor overactivity and urodynamic investigation are known to be leading triggers of autonomic dysreflexia. Therefore, we aimed to determine predictors of autonomic dysreflexia in individuals with spinal cord injury during urodynamic investigation.

METHODS

This prospective cohort study included 300 patients with spinal cord injuries and complete datasets of continuous non-invasive cardiovascular monitoring, recorded during same session repeat urodynamic investigation. We used logistic regression to reveal predictors of autonomic dysreflexia during urodynamic investigation.

RESULTS

We found that level of injury and presence of neurogenic detrusor overactivity were the only two independent significant predictors for autonomic dysreflexia during urodynamic investigation. A lesion at spinal segment T6 or above (odds ratio (OR) 5.5, 95% CI 3.2-9.4) compared to one at T7 or below, and presence of neurogenic detrusor overactivity (OR 2.7, 95% confidence interval (CI) 1.4-4.9) were associated with a significant increased odds of autonomic dysreflexia during urodynamic investigation. Both odds persisted after adjustment for age, sex, and completeness and stage of injury (adjusted OR (AOR) 6.6, 95% CI 3.8-11.7, and AOR 2.2, 95% CI 1.1-4.5, respectively). Further stratification by lesion level showed level-dependent significantly increased adjusted odds of autonomic dysreflexia, i.e., from C1-C4 (AOR 16.2, 95% CI 5.9-57.9) to T4-T6 (AOR 2.6, 95% CI 1.3-5.2), compared to lesions at T7 or below.

CONCLUSIONS

In patients with neurogenic lower urinary tract dysfunction due to spinal cord injury, autonomic dysreflexia is independently predicted by lesion level and presence of neurogenic detrusor overactivity. Considering the health risks associated with autonomic dysreflexia, such as seizures, stroke, retinal bleeding, or even death, we recommend both continuous cardiovascular monitoring during urodynamic investigation in all spinal cord-injured patients with emphasis on those with cervical lesions, and appropriate neurogenic detrusor overactivity treatment to reduce the probability of potentially life-threatening complications.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01293110 .

Autoimmune Neurological Conditions Associated With Zika Virus Infection

Zika virus (ZIKV) is an emerging flavivirus rapidly spreading throughout the tropical Americas. Aedes mosquitoes is the principal way of transmission of the virus to humans. ZIKV can be spread by transplacental, perinatal, and body fluids. ZIKV infection is often asymptomatic and those with symptoms present minor illness after 3 to 12 days of incubation, characterized by a mild and self-limiting disease with low-grade fever, conjunctivitis, widespread pruritic maculopapular rash, arthralgia and myalgia. ZIKV has been linked to a number of central and peripheral nervous system injuries such as Guillain-Barré syndrome (GBS), transverse myelitis (TM), meningoencephalitis, ophthalmological manifestations, and other neurological complications. Nevertheless, mechanisms of host-pathogen neuro-immune interactions remain incompletely elucidated. This review provides a critical discussion about the possible mechanisms underlying the development of autoimmune neurological conditions associated with Zika virus infection.

Incidence and Natural Progression of Neurogenic Shock after Traumatic Spinal Cord Injury

Neurogenic shock, a distributive type of circulatory shock after spinal cord injury (SCI), results in profound hypotension. The consequent hemodynamic instability complicates clinical management, delays surgical intervention, and impacts neurological outcome. Moreover, the reported incidence of this condition varies significantly. We establish the true incidence of neurogenic shock by comparing the most common clinical definitions used to diagnose the condition. Further, we characterize the acute progression and recovery of neurogenic shock. Daily blood pressure, heart rate, and fluid management as well as vasopressor therapy and neurologic status were collected over 30 days from 84 adults admitted to our tertiary trauma center after cervical (n = 56) and thoracic (n = 28) SCI. We found that the reported incidence of neurogenic shock varied greatly depending on which clinical definition was applied. By using a novel combination of hemodynamic and laboratory criteria to define neurogenic shock, the calculated incidence (29% cervical SCI) in our sample most appropriately reflects the true incidence, finding that hypovolemia was the primary factor responsible for the inconsistency in incidence reports between studies. In addition, we found a characteristic decline in blood pressure after the first week post-injury and that fluid management is not currently an integral aspect of clinical management (all persons were treated at a net fluid intake ≤ zero). The results demonstrate the need for accurate identification of neurogenic shock through consistent and appropriate criteria, which is not only important from a clinical point of view, but also in establishing accurate epidemiology to responsibly allocate resources to its management.

Thermodysregulation in persons with spinal cord injury: case series on use of the autonomic standards

INTRODUCTION

The ability to maintain core body temperature (Tcore) within a narrow range (37 ± 0.6 °C), despite exposure to a wide range of ambient temperatures, is essential in order to provide an optimal environment for vital organs, the central nervous system (CNS), and cellular processes to function. High-level (above T6) spinal cord injury (SCI) interrupts the autonomic nervous system's ability to carry out hypothalamic regulation of thermoregulatory mechanisms for both heat dissipation and conservation. This interruption leaves persons with high-level SCI vulnerable to hyper and hypothermia even during exposure to relatively mild ambient temperatures. The goal of the Autonomic Standards is to enable the clinician to quickly identify those individuals with SCI who may be most at risk for thermoregulatory dysfunction.

CASE PRESENTATION

Case 1: Heat Exhaustion, Case 2: Heat Stroke in absence of CNS symptoms, Case 3: Heat Exhaustion.

DISCUSSION

The three cases demonstrate the signs and symptoms that may accompany hyperthermia in persons with SCI. The onset may be quite rapid and the condition persistent, despite ambient temperatures being much less intense than expected to be necessary to induce similar conditions in able-bodied (AB) persons. The responses of the persons in the case studies to the temperature regulation and autonomic control of sweating sections of the Autonomic Standards would identify them as being vulnerable and warrant providing appropriate exposure guidelines and precautions to them and their caregivers.

Cardiovascular Stress During Inpatient Spinal Cord Injury Rehabilitation

OBJECTIVES

(1) To measure the amount of cardiovascular stress, self-reported physical activity, and accelerometry-measured physical activity by individuals with spinal cord injury (SCI) during physical therapy (PT) and occupational therapy (OT); and (2) to investigate the relations between these measures.

DESIGN

Observational study.

SETTING

Two inpatient SCI rehabilitation centers.

PARTICIPANTS

Patients with SCI (N=87) were recruited from consecutive admissions to rehabilitation.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Heart rate was recorded by a Holter monitor, whereas physical activity was captured by self-report (Physical Activity Recall Assessment for People with SCI questionnaire) and real-time wrist accelerometry during a total of 334 PT and OT inpatient sessions. Differences between individuals with paraplegia and tetraplegia were assessed via Mann-Whitney U tests. Spearman correlations were used to explore the relation between measurements of physical activity and heart rate.

RESULTS

Time spent at a heart rate within a cardiovascular training zone (≥40% heart rate reserve) was low and did not exceed a median of 5 minutes. In contrast, individuals reported at least 60 minutes of higher-intensity time during therapy. There was a low but statistically significant correlation between all measures.

CONCLUSIONS

The cardiovascular stress incurred by individuals with SCI during inpatient PT and OT sessions is low and not sufficient to obtain a cardiovascular training effect to optimize their neurologic, cardiovascular, or musculoskeletal health; this represents a lost opportunity to maximize rehabilitation. Self-reported minutes of higher-intensity physical activity do not reflect actual time spent at a higher intensity measured objectively via a heart rate monitor.

Pure distraction injury of T1-2 with quad fever

INTRODUCTION

We report a pure distraction injury of the upper thoracic spine and uncontrolled hyperthermia without an infectious cause. Quad fever appears in the first several weeks to months after a cervical or upper thoracic SCI and is characterized by an extreme elevation in body core temperature beyond 40 °C without an infectious cause. Discriminating between infectious and noninfectious causes is important, and a thorough clinical assessment is required.

MATERIALS AND METHODS

A 52-year-old male visited the emergency room complaining of back pain with complete paralysis [American Spinal Injury Association (ASIA) A] of both lower extremities after a pedestrian-motor vehicle accident. He had trouble breathing due to a hemothorax and flail chest caused by fractures of the right second to eleventh and left fourth to seventh ribs. A computed tomography scan revealed severe distraction of the T1-2 intervertebral space. A magnetic resonance image showed signal changes in the spinal cord and a clean-cut margin between the T1-2 disc and T2 body. The neurological level of injury was C8 upon the initial neurological assessment. Emergency surgery was performed. C6-T3 posterior instrumentation and an autologous iliac bone graft were performed.

RESULTS

After surgery, the core temperature increased gradually to above 38.0 °C on post-trauma day 4 and increased to 40.8 °C on post-trauma day 7. None of the repeated aerobic, anaerobic, or fungal cultures of the blood, tracheal aspirate, line tips, urine, or stool was positive until post-trauma day 21, when Candida tropicalis was identified in the urine culture. On post-trauma day 63, the blood pressure, pulse, and body temperature stabilized and the patient was transferred to the general ward. At post-trauma year 6, the injury state was still complete and the neurological level of injury was changed to C4.

CONCLUSIONS

Based on the Grand Round case and relevant literature, we discuss the case of pure distraction injury of T1-2 with quad fever. Spinal surgeons should be knowledgeable regarding quad fever as well as the differential diagnoses and treatment strategies.

Exploring daily blood pressure fluctuations and cardiovascular risk among individuals with motor complete spinal cord injury: a pilot study

BACKGROUND

Clinically silent autonomic dysfunction with bowel and bladder care, are postulated to contribute to cardiovascular disease after chronic spinal cord injury (SCI).

OBJECTIVE

We describe the frequency and severity of dysreflexic episodes, termed transient blood pressure elevations (T-BPE) over 48 hours in adults with cervical or high-thoracic motor-complete SCI.

SETTING

Tertiary SCI Rehabilitation Centre in Toronto, Canada.

PARTICIPANTS

Individuals with chronic SCI, C1-T3 AIS A or B, >1 year post-injury, living in the community (n=19).

OUTCOME MEASURES

Data were obtained via 48-hour ambulatory blood pressure (BP) and heart rate (HR) monitoring, with data captured at 10-minute intervals and a concurrent diary describing activities of daily living, and bladder/bowel routines. T-BPE were defined as a ≥ 40 mmHg elevation in systolic blood pressure (SBP) above the participant's supine baseline. Severe (≥ 60-79 mmHg) and Extreme ≥80 mmHg elevations in SBP were described.

RESULTS

Thirteen participants experienced T-BPE within the assessment period, with 7/13 experiencing "severe", and 3/13 experiencing "extreme" SBP elevations. The median number of T-BPE was 8 (IQR = 3), and the mean ± SD SBP during T-BPE was 150 ± 16 mmHg, These T-BPE were verified as dysreflexic events using a conservative definition of a >40 mmHg increase in SBP, with a concurrent 10 bpm decrease in HR, above the 48-hour average SBP, yielding 12/19 participants with T-BPE.

CONCLUSIONS

T-BPE were frequent, often with severe or extreme elevations in SBP, despite few reported symptoms. Recognition and management of these dysreflexic events associated with T-BPE are needed, which may ameliorate cardiovascular disease risk.

Self-reported effects of cold temperature exposure in persons with tetraplegia

OBJECTIVE

Cervical spinal cord injury (tetraplegia) is known to interrupt sympathetic vasculature control, thereby preventing shunting of blood from the periphery to central organs when exposed to cold temperatures. As a result, persons with tetraplegia are at risk to develop hypothermia. However, information regarding the discomfort experienced during the cooler months (late fall, winter, early spring) is overwhelmingly anecdotal. It is not known, with any certainty, how those with tetraplegia perceive cold and if discomfort in colder environments restricts them from performing activities that they routinely would perform.

DESIGN

Prospective, two-group, self-report surveys.

SETTING

VA Medical Center and Kessler Institute for Rehabilitation.

PARTICIPANTS

Forty-four subjects with tetraplegia; 41 matched non-SCI controls.

OUTCOME MEASURES

Tetraplegic and control groups responded "yes" or "no" when asked whether cold seasonal temperatures allowed comfort or negatively affected participation in routine activities.

RESULTS

Percentage of responses of tetraplegia compared to controls was different as to whether they felt cold when others in the same room were comfortable (82 vs. 24%; χ² = 28.2, P < 0.0001), felt comfortable outdoors (17 vs. 43%; χ² = 6.8, P = 0.009), or whether cold negatively affected bathing routines (55 vs. 15%; χ² = 14.8, P = 0.0001), keeping physician appointments (46 vs. 12%; χ² = 11.3, P = 0.0008), thinking clearly (41 vs. 7%; χ² = 12.9, P = 0.0003), and completing usual work duties (46 vs. 10%; χ² = 13.3, P = 0.0003).

CONCLUSION

Cold seasonal temperatures have a reported greater negative impact on personal comfort and ability to perform vital activities in persons with tetraplegia than that of non-SCI controls. These findings highlight the need to address thermoregulatory impairment in persons with tetraplegia.

QUAD fever: beware of non-infectious fever in high spinal cord injuries

A case of cervical spinal cord injury and quadriparesis with prolonged fever is being described. Initially, the patient received treatment for well-documented catheter-related bloodstream infection. High spiking fever returned and persisted with no obvious evidence of infection. The usual non-infectious causes too were carefully excluded. QUAD fever or fever due to spinal cord injury itself was considered. The pathogenetic basis of QUAD fever is unclear but could be attributed to autonomic dysfunction and temperature dysregulation. Awareness of this little known condition could help in avoiding unnecessary antimicrobial therapy and in more accurate prognostication. Unlike several previous reported cases that ended fatally, the present case ran a relatively benign course. The spectrum of presentations may therefore be broader than hitherto appreciated.

Remodeling Brain Activity by Repetitive Cervicothoracic Transspinal Stimulation after Human Spinal Cord Injury

Interventions that can produce targeted brain plasticity after human spinal cord injury (SCI) are needed for restoration of impaired movement in these patients. In this study, we tested the effects of repetitive cervicothoracic transspinal stimulation in one person with cervical motor incomplete SCI on cortical and corticospinal excitability, which were assessed via transcranial magnetic stimulation with paired and single pulses, respectively. We found that repetitive cervicothoracic transspinal stimulation potentiated intracortical facilitation in flexor and extensor wrist muscles, recovered intracortical inhibition in the more impaired wrist flexor muscle, increased corticospinal excitability bilaterally, and improved voluntary muscle strength. These effects may have been mediated by improvements in cortical integration of ascending sensory inputs and strengthening of corticospinal connections. Our novel therapeutic intervention opens new avenues for targeted brain neuromodulation protocols in individuals with cervical motor incomplete SCI.

Mesenteric vascular dysregulation and intestinal inflammation accompanies experimental spinal cord injury

Cervical and high thoracic spinal cord injury (SCI) drastically impairs autonomic nervous system function. Individuals with SCI at thoracic spinal level 5 (T5) or higher often present cardiovascular disorders that include resting systemic arterial hypotension. Gastrointestinal (GI) tissues are critically dependent upon adequate blood flow and even brief periods of visceral hypoxia triggers GI dysmotility. The aim of this study was to test the hypothesis that T3-SCI induces visceral hypoperfusion, diminished postprandial vascular reflexes, and concomitant visceral inflammation. We measured in vivo systemic arterial blood pressure and superior mesenteric artery (SMA) and duodenal blood flow in anesthetized T3-SCI rats at 3 days and 3 wk postinjury either fasted or following enteral feeding of a liquid mixed-nutrient meal (Ensure). In separate cohorts of fasted T3-SCI rats, markers of intestinal inflammation were assayed by qRT-PCR. Our results show that T3-SCI rats displayed significantly reduced SMA blood flow under all experimental conditions (P < 0.05). Specifically, the anticipated elevation of SMA blood flow in response to duodenal nutrient infusion (postprandial hyperemia) was either delayed or absent after T3-SCI. The dysregulated SMA blood flow in acutely injured T3-SCI rats coincides with abnormal intestinal morphology and elevation of inflammatory markers, all of which resolve after 3 wk. Specifically, Icam1, Ccl2 (MCP-1), and Ccl3 (MIP-1α) were acutely elevated following T3-SCI. Our data suggest that arterial hypotension diminishes mesenteric blood flow necessary to meet mucosal demands at rest and during digestion. The resulting GI ischemia and low-grade inflammation may be an underlying pathology leading to GI dysfunction seen following acute T3-SCI.

Coronary vasospasm in intractable autonomic dysreflexia

INTRODUCTION

Coronary vasospasm is a transient sudden vasoconstriction of one of the coronary arteries that can lead to myocardial ischaemia, myocardial infarction, fatal arrhythmia and sudden death. Most patients with coronary spasm have underlying cardiac pathology.

CASE PRESENTATION

This paper presents a rare case of intractable autonomic dysreflexia in a 36-year-old patient with chronic C5 paraplegia with silent myocardial ischaemia secondary to coronary vasospasm in the absence of underlying cardiac pathology. The MRI perfusion study revealed normal left ventricular contractility and no evidence of coronary artery occlusion.

DISCUSSION

This case highlights the cardiac complications associated with paroxysmal heightened sympathetic nervous system and proposes that autonomic dsyreflexia can predisposes to coronary vasospasm via uncontrolled sympathetic nervous system. The disruption of sensory input from the myocardium to the brain in patient with SCI predisposes them to asymptomatic myocardial ischaemia. The challenges in the diagnosis and management of coronary vasospasm associated with autonomic dysreflexia are described.

Implication of Hypothalamus in Alleviating Spinal Cord Injury-Induced Neuropathic Pain

Neuropathic pain (NP) is common among spinal cord injury (SCI) patients, and there remain clinical difficulties in treating NP due to the lack of understanding of underlying mechanisms. Extracellular proteins, such as matrix metalloproteinase and β-catenin, have been shown to be activated in the spinal cord regions following an injury, and may play a key role in contributing to NP states. While these extracellular proteins have been used as therapeutic targets in the spinal cord, there has also been evidence of up-regulation in the hypothalamus following a SCI. We hypothesize that the hypothalamus is involved in regulating NP following a SCI, and hence should be researched further to determine if it is a viable target for future therapeutic treatments.

Contributors to Metabolic Disease Risk Following Spinal Cord Injury

Spinal cord injury (SCI) induced changes in neurological function have significant impact on the metabolism and subsequent metabolic-related disease risk in injured individuals. This metabolic-related disease risk relationship is differential depending on the anatomic level and severity of the injury, with high level anatomic injuries contributing a greater risk of glucose and lipid dysregulation resulting in type 2 diabetes and cardiovascular disease risk elevation. Although alterations in body composition, particularly excess adiposity and its anatomical distribution in the visceral depot or ectopic location in non-adipose organs, is known to significantly contribute to metabolic disease risk, changes in fat mass and fat-free mass do not fully account for this elevated disease risk in subjects with SCI. There are other negative adaptations in body composition including reductions in skeletal muscle mass and alterations in muscle fiber type, in addition to significant reduction in physical activity, that contribute to a decline in metabolic rate and increased metabolic disease risk following SCI. Recent studies in adult humans suggest cold- and diet-induced thermogenesis through brown adipose tissue metabolism may be important for energy balance and substrate metabolism, and particularly sensitive to sympathetic nervous signaling. Considering the alterations that occur in the autonomic nervous system (SNS) (sympathetic and parasympathetic) following a SCI, significant dysfunction of brown adipose function is expected. This review will highlight metabolic alterations following SCI and integrate findings from brown adipose tissue studies as potential new areas of research to pursue.

Standardization of Data for Clinical Use and Research in Spinal Cord Injury

Increased survival after spinal cord injury (SCI) worldwide has enhanced the need for quality data that can be compared and shared between centers, countries, as well as across research studies, to better understand how best to prevent and treat SCI. Such data should be standardized and be able to be uniformly collected at any SCI center or within any SCI study. Standardization will make it possible to collect information from larger SCI populations for multi-center research studies. With this aim, the international SCI community has obtained consensus regarding the best available data and measures for use in SCI clinical practice and research. Reporting of SCI data is likewise standardized. Data elements are continuously updated and developed using an open and transparent process. There are ongoing internal, as well as external review processes, where all interested parties are encouraged to participate. The purpose of this review paper is to provide an overview of the initiatives to standardize data including the International Spinal Cord Society's International SCI Data Sets and the National Institutes of Health, National Institute of Neurological Disorders and Stroke Common Data Elements Project within SCI and discuss future opportunities.

The influence of regular physical activity on lung function in paraplegic people

STUDY DESIGN

Cross-sectional study.

OBJECTIVES

The main goal of this study was to examine the influence of regular physical activity (PA) on lung volumes and flows.

SETTING

The study was conducted in the Vall d'Hebrón Hospital, Barcelona (Spain), and La Fe Hospital, Valencia (Spain).

METHODS

Spirometric tests were performed to 67 paraplegics, and differences were established between the active group (AG) (n=37) that performed >60 min per week of moderate-to-vigorous PA (MVPA) and 30 non-AG (NAG). Further, we established the relationship between the spirometric and PA variables and between being active and reaching the lower limit of normal (LLN) of the spirometric variables.

RESULTS

AG had greater values than the NAG: FVC (P<0.01), FEV₁ (P<0.01) and PEF (P<0.01). Moderate correlations between the MVPA and FVC (r=0.41, P<0.01) and the MVPA and FEV₁ (r=0.39, P<0.01) were obtained. The relationship between being physically active and reaching the LLN was statistically significant for FEV₁ (χ²=6.184, P<0.05) but not for FVC (P>0.05).

CONCLUSIONS

The performance of MVPA for a minimum of 60 min per week can have a beneficial effect, both on lung volumes and on expiratory flow, and led to an achievement of the LLN in FEV₁.

Prolonged bradycardia, asystole and outcome of high spinal cord injury patients: Risk factors and management

BACKGROUND

High spinal cord injury (HSCI) is one of the devastating traumatic injuries. 80% of these patients are young male, and 93% will have major neurological disabilities. There is a paucity of literature about prolonged bradycardia in HSCI patients. The aim of this study was to know the prevalence, risk factors, precipitating factors for prolonged bradycardia in the HSCI patients.

MATERIALS AND METHODS

All patients who were admitted to the Intensive Care Unit (ICU) of a tertiary hospital, with spinal cord injury above level of dorsal (D4) were enrolled in this study prospectively. Patient's demographic data, mechanism, level and type of spinal injury, associated injuries, injury severity score (ISS), spinal shock, vasopressors used, time of occurrence of bradycardia, treatment for bradycardia, precipitating as well as risk factors and outcome were recorded.

RESULTS

During the study period, a total of 138 patients were admitted to the ICU with HSCI. Majority of patients were male. The most frequently associated injury in these patients was skeletal fractures (38.4%). Most common complication was pneumonia 56 (41%). Forty-five (33%) of the total patients had prolonged bradycardia; 87% of these patients had pneumonia when bradycardia occurred. 53.4% had cardiac asystole. 29 (21%) patients had bradycardia at the time of endotracheal suctioning, whereas 27 (20%) patients developed bradycardia at the time of positioning. Majority of the patients were managed conservatively. Those HSCI patients who developed prolonged bradycardia, their ISS score was statistically higher, ICU and hospital stay was significantly higher compared with those HSCI patient who did not have prolonged bradycardia. Multivariate analysis revealed that hypotension on admission; pneumonia, and tracheostomy were risk factors for the development of prolonged bradycardia in HSCI patients.

CONCLUSION

Prolonged bradycardia was associated with significantly higher incidence of asystole. Endotracheal suctioning and positioning of HSCI patients were significant provocative factors for prolonged bradycardia; hypotension on admission, pneumonia and tracheostomy were the risk factors for the development of prolonged bradycardia in these patients.

Changes in Body Temperature in Incomplete Spinal Cord Injury by Digital Infrared Thermographic Imaging

Objective

To investigate changes in the core temperature and body surface temperature in patients with incomplete spinal cord injuries (SCI). In incomplete SCI, the temperature change is difficult to see compared with complete spinal cord injuries. The goal of this study was to better understand thermal regulation in patients with incomplete SCI.

Methods

Fifty-six SCI patients were enrolled, and the control group consisted of 20 healthy persons. The spinal cord injuries were classified according to International Standards for Neurological Classification of Spinal Cord Injury. The patients were classified into two groups: upper (neurological injury level T6 or above) and lower (neurological injury level T7 or below) SCIs. Body core temperature was measured using an oral thermometer, and body surface temperature was measured using digital infrared thermographic imaging.

Results

Twenty-nine patients had upper spinal cord injuries, 27 patients had lower SCIs, and 20 persons served as the normal healthy persons. Comparing the skin temperatures of the three groups, the temperatures at the lower abdomen, anterior thigh and anterior tibia in the patients with upper SCIs were lower than those of the normal healthy persons and the patients with lower SCIs. No significant temperature differences were observed between the normal healthy persons and the patients with lower SCIs.

Conclusion

In our study, we found thermal dysregulation in patients with incomplete SCI. In particular, body surface temperature regulation was worse in upper SCIs than in lower injuries. Moreover, cord injury severity affected body surface temperature regulation in SCI patients.

Contemporary Cardiovascular Concerns after Spinal Cord Injury: Mechanisms, Maladaptations, and Management

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.

Thermophysiological responses induced by a body heat removal system with Peltier devices in a hot environment

Individuals with spinal cord injuries often experience thermoregulation disorders as well as sensory and motor disabilities. In order to prevent such individuals from becoming hyperthermic, we developed a body heat removal system (BHRS) with thermoelectric devices. Our BHRS comprises four Peltier devices mounted on a wheelchair backrest and continuously transfers body heat through the contacting interface to the external environment. Here, we characterized thermophysiological responses induced by this novel contact-type cooling system. A cooling experiment in a hot environment with five able-bodied subjects demonstrated that sweating and systolic blood pressure in the back-cooling (BC) trial were significantly suppressed compared with those in no-cooling (NC) trial, while no difference was found in oral and skin temperatures. A correlation was observed between chest skin temperature and blood flow in the NC trial; this was not observed in the BC trial. These results suggest that BHRS modulates normal thermoregulatory responses, including sweating and vascular dilation and has the capability to partly replace these functions.

Autonomic consequences of spinal cord injury

Spinal cord injury (SCI) results not only in motor and sensory deficits but also in autonomic dysfunctions. The disruption of connections between higher brain centers and the spinal cord, or the impaired autonomic nervous system itself, manifests a broad range of autonomic abnormalities. This includes compromised cardiovascular, respiratory, urinary, gastrointestinal, thermoregulatory, and sexual activities. These disabilities evoke potentially life-threatening symptoms that severely interfere with the daily living of those with SCI. In particular, high thoracic or cervical SCI often causes disordered hemodynamics due to deregulated sympathetic outflow. Episodic hypertension associated with autonomic dysreflexia develops as a result of massive sympathetic discharge often triggered by unpleasant visceral or sensory stimuli below the injury level. In the pelvic floor, bladder and urethral dysfunctions are classified according to upper motor neuron versus lower motor neuron injuries; this is dependent on the level of lesion. Most impairments of the lower urinary tract manifest in two interrelated complications: bladder storage and emptying. Inadequate or excessive detrusor and sphincter functions as well as detrusor-sphincter dyssynergia are examples of micturition abnormalities stemming from SCI. Gastrointestinal motility disorders in spinal cord injured-individuals are comprised of gastric dilation, delayed gastric emptying, and diminished propulsive transit along the entire gastrointestinal tract. As a critical consequence of SCI, neurogenic bowel dysfunction exhibits constipation and/or incontinence. Thus, it is essential to recognize neural mechanisms and pathophysiology underlying various complications of autonomic dysfunctions after SCI. This overview provides both vital information for better understanding these disorders and guides to pursue novel therapeutic approaches to alleviate secondary complications.

Pediatric Spinal Cord Injury: Recognition of Injury and Initial Resuscitation, in Hospital Management, and Coordination of Care

Spinal cord injury is uncommon in the pediatric population with a lifelong impact for the patient and family. Knowledge of spine embryology, mechanisms of injury that lead to specific injuries, appropriate utilization of radiographic imaging based on suspected injury, prehospital and hospital management of various spinal cord injuries is essential for providers attending to traumatically injured patients. In addition to patients who present with soft tissue and bony injuries diagnosed with clinical examination and confirmed with computed tomography or magnetic resonance imaging, it is important to note that the pediatric population is at a higher risk for spinal cord injury without radiographic abnormality than the adult population. Patients who survive the acute phase of injury face long-term rehabilitation and have an increased risk of depression and mortality. Understanding the long-term sequelae of spinal cord injuries is also an essential management component of traumatically injured children. A program that provides long-term rehabilitation, psychosocial and spiritual support, and adaptive environmental supports gives patients and their families the best opportunity for long-term recovery. A review of the current literature on the diagnosis, management, and follow-up of pediatric spinal cord injury is presented.

Autonomic dysreflexia and repeatability of cardiovascular changes during same session repeat urodynamic investigation in women with spinal cord injury

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.

Prevalence of abnormal systemic hemodynamics in veterans with and without spinal cord injury

OBJECTIVE

Increased prevalence of heart rate and blood pressure abnormalities are evident in persons with spinal cord injury (SCI), but age, comorbid medical conditions, and prescription medication use may contribute. To determine differences in the prevalence of cardiac acceleration (heart rate ≥80 beats per minute), hypotension (blood pressure ≤110/70mmHg), orthostatic hypotension (OH) (-20/-10mmHg with upright positioning), and hypertension (HTN) (blood pressure ≥140/90mmHg) in veterans with and without SCI.

DESIGN

Observational trial.

SETTING

Medical center.

PARTICIPANTS

Subjects included veterans with SCI (n=62; cervical: tetraplegia, C3-8; high thoracic, T1-5; low thoracic, T7-L2) and veterans without SCI (n=160).

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

We assessed medical history, prescription medication use, and heart rate and blood pressure during a routine clinical visit. Prevalence rates of cardiac acceleration, hypotension, OH, and HTN were calculated using binary logistic regression analysis with 95% confidence intervals. The influence of SCI status, age, smoking status, cardiovascular diagnoses, and use of prescribed antihypertensive medications on the prevalence of abnormal heart rate and blood pressure recordings was determined.

RESULTS

The diagnosis of HTN was reduced in the high thoracic and tetraplegia groups compared with the non-SCI and low thoracic groups. Use of antihypertensive medications was increased in the low thoracic group compared with the other 3 groups and was increased in the non-SCI group compared with the tetraplegia group. The prevalence of cardiac acceleration was reduced, and the prevalence of systolic hypotension was increased in the tetraplegia group. The prevalence of diastolic hypotension was increased in all SCI groups compared with the non-SCI group. For all analyses, increased prevalence of abnormal heart rate and blood pressure recordings was not further explained by the covariates, with the exception of age, cardiovascular diagnoses, and antihypertensive medications in the cardiac acceleration model; however, SCI status remained significant and was the dominant predictor variable.

CONCLUSIONS

Our data suggest that SCI status contributes to the prevalence of cardiac acceleration and systolic and diastolic hypotension regardless of cardiovascular medical conditions or prescription antihypertensive medication use.

Neuroprotection, Plasticity Manipulation, and Regenerative Strategies to Improve Cardiovascular Function following Spinal Cord Injury

Damage to the central nervous system, as in the case of spinal cord injury (SCI), results in disrupted supraspinal sympathetic influence and subsequent cardiovascular control impairments. Consequently, people with SCI suffer from disordered basal hemodynamics and devastating fluctuations in blood pressure, as in the case of autonomic dysreflexia (AD), which likely contribute to this population's leading cause of mortality: cardiovascular disease. The development of AD is related, at least in part, to neuroanatomical changes that include disrupted descending supraspinal sympathetic control, changes in propriospinal circuitry, and inappropriate afferent sprouting in the dorsal horn. These anatomical mechanisms may thus be targeted by neural regenerative and protective therapies to improve cardiovascular control and reduce AD. Here, we discuss the relationship between abnormal cardiovascular control and its underlying neuroanatomy. We then review current studies investigating biochemical strategies to reduce the severity of AD through: 1) reducing aberrant calcitonin gene-related peptide immunoreactive afferent sprouting; 2) inhibiting inflammatory processes; and 3) re-establishing descending supraspinal sympathetic control. Finally, we discuss why additional biochemical agents and combinational approaches may be needed to completely ameliorate this condition.

Assessment of clinical adherence to the international autonomic standards following spinal cord injury

STUDY DESIGN

Retrospective chart analysis.

OBJECTIVES

To investigate the use of the International Autonomic Standards (IAS, 2009 edition) for classification of remaining autonomic function following spinal cord injury (SCI) over a 1-year period in a rehabilitation center, to determine clinical adherence to use of the IAS, and to examine the most common autonomic dysfunctions, as determined by using the IAS.

SETTING

Tertiary rehabilitation hospital.

METHODS

A retrospective study was conducted on the use of the IAS at admission and discharge over a 1-year period on patients admitted to an in-patient SCI unit in a tertiary rehabilitation center. We examined the consistency of the form completion, as well as the completion of separate components of the forms. Finally, we examined the prevalence of each autonomic impairment.

RESULTS

A total of 70 patients were admitted to the unit. The clinical adherence to the IAS was lower than the International Standards for Neurological Classification of SCI (ISNCSCI) at both admission (63% and 93%, respectively) and discharge (39% and 78%, respectively). Blood pressure dysfunction was most common among the general autonomic function disorders. However, urinary, bowel and sexual dysfunctions were present in almost all individuals with acute SCI.

CONCLUSION

The IAS is in the initial stages of being incorporated into routine admission and discharge clinical examinations of individuals with SCI. The current results suggest that the clinical adherence to the IAS is low; however, it is expected that increased education, experience, and accumulating evidence for the IAS will improve its use.

Refined assessment of blood pressure instability after spinal cord injury

BACKGROUND

This study determined whether the Autonomic Dysfunction Following Spinal Cord Injury (ADFSCI) questionnaire, a measure of self-reported frequency and severity of symptoms during hypo- and hypertensive episodes, correlates with blood pressure (BP) instability. In addition, test-retest reliability of the ADFSCI questionnaire was assessed.

METHODS

Thirty individuals with spinal cord injury (SCI) (aged 42±12 years; level of lesion = C3-L1; American Spinal Injury Association Impairment Scale = A-C; lesion duration = 1 month to 30 years after injury) participated in this study. Twenty-four-hour ambulatory BP monitoring (ABPM) was used to assess BP instability. ABPM recorded systolic BP (SBP), diastolic BP (DBP), and heart rate at 15-minute intervals during the daytime and 1-hour intervals during the nighttime. Test-retest reliability was performed by completion of the ADFSCI questionnaire on 2 occasions (i.e., 9±4 days in between).

RESULTS

Individuals with SCI who self-reported autonomic dysreflexia (AD) episodes showed significantly higher SBP coefficient of variation (CV) (14%) and more AD events (n = 11) than individuals who reported never having AD symptoms (CV = 9%; AD events = 1). Both the number of AD events over the 24-hour period and the BP variability (SBP CV) were significantly related to the patients' self-reported total AD score (rho = 0.522, P = 0.005; rho = 0.584, P = 0.001, respectively) and daily AD frequency (rho = 0.553, P = 0.003; rho = 0.586, P = 0.001, respectively). Conversely, no significant correlations existed between the number of hypotensive events over the 24-hour period and self-reported frequency and severity in the ADFSCI questionnaire.

CONCLUSIONS

This study provides evidence that ABPM offers a strong clinical basis for documenting and understanding BP instability, such as AD, and related symptoms in individuals with SCI.

Acute complications of spinal cord injuries

The aim of this paper is to give an overview of acute complications of spinal cord injury (SCI). Along with motor and sensory deficits, instabilities of the cardiovascular, thermoregulatory and broncho-pulmonary system are common after a SCI. Disturbances of the urinary and gastrointestinal systems are typical as well as sexual dysfunction. Frequent complications of cervical and high thoracic SCI are neurogenic shock, bradyarrhythmias, hypotension, ectopic beats, abnormal temperature control and disturbance of sweating, vasodilatation and autonomic dysreflexia. Autonomic dysreflexia is an abrupt, uncontrolled sympathetic response, elicited by stimuli below the level of injury. The symptoms may be mild like skin rash or slight headache, but can cause severe hypertension, cerebral haemorrhage and death. All personnel caring for the patient should be able to recognize the symptoms and be able to intervene promptly. Disturbance of respiratory function are frequent in tetraplegia and a primary cause of both short and long-term morbidity and mortality is pulmonary complications. Due to physical inactivity and altered haemostasis, patients with SCI have a higher risk of venous thromboembolism and pressure ulcers. Spasticity and pain are frequent complications which need to be addressed. The psychological stress associated with SCI may lead to anxiety and depression. Knowledge of possible complications during the acute phase is important because they may be life threatening and/ or may lead to prolonged rehabilitation.

Hyponatremia in spinal cord injury patients: new insight into differentiating between the dilution and depletion forms

STUDY DESIGN

This is a retrospective study.

OBJECTIVES

The objectives of this study were to present a new model for differentiating between the dilution and depletion forms of hyponatremia in patients in the postacute phase after spinal cord injury (SCI), and to identify possible etiological factors contributing to hyponatremia in these patients.

SETTING

University Hospital Motol, Prague, Czech Republic.

METHODS

Eighty-seven of 352 patients hospitalized in 2008-2012 in the Spinal Cord Unit were hyponatremic. Seventy-four patients had SNa+=130-135 mmol l(-1) and 13 patients had SNa+ below 130 mmol l(-1). We propose a simple model of an electrolyte solution in which the Na(+) concentration is higher than the Cl(-) concentration, making it possible to compare the effects of dilution and depletion of Na(+) and Cl(-) on the Na(+) concentration. The depletion of Na(+) and Cl(-) leads to a significant increase in the Na(+)/Cl(-) ratio, with the Na(+)-Cl(-) value remaining unchanged. Dilution with water results in a decrease of Na(+)-Cl(-) with the Na(+)/Cl(-) ratio remaining unchanged.

RESULTS

In patients with SNa+ below 130 mmol l(-1), hyponatremia was consistent with the depletion model in 46% and with the dilution model in 32%. In patients with SNa+ ranging between 130 and 135 mmol l(-1), the respective rates were 34 and 12%.

CONCLUSION

Examination of SNa+-SCl- and SNa+/SCl- in patients with SCI could be helpful in considering whether hyponatremia is consistent either with the NaCl dilution model or with the NaCl depletion model. Further studies are needed for more accurate interpretation of the results, particularly with respect to volume and acid-base disorders.

Cardiac acceleration at the onset of exercise: a potential parameter for monitoring progress during physical training in sports and rehabilitation

There is a need for easy-to-use methods to assess training progress in sports and rehabilitation research. The present review investigated whether cardiac acceleration at the onset of physical exercise (HRonset) can be used as a monitoring variable. The digital databases of Scopus and PubMed were searched to retrieve studies investigating HRonset. In total 652 studies were retrieved. These articles were then classified as having emphasis on HRonset in a sports or rehabilitation setting, which resulted in 8 of 112 studies with a sports application and 6 of 68 studies with a rehabilitation application that met inclusion criteria. Two co-existing mechanisms underlie HRonset: feedforward (central command) and feedback (mechanoreflex, metaboreflex, baroreflex) control. A number of studies investigated HRonset during the first few seconds of exercise (HRonsetshort), in which central command and the mechanoreflex determine vagal withdrawal, the major mechanism by which heart rate (HR) increases. In subsequent sports and rehabilitation studies, interest focused on HRonset during dynamic exercise over a longer period of time (HRonsetlong). Central command, mechanoreflexes, baroreflexes, and possibly metaboreflexes contribute to HRonset during the first seconds and minutes of exercise, which in turn leads to further vagal withdrawal and an increase in sympathetic activity. HRonset has been described as the increase in HR compared with resting state (delta HR) or by exponential modeling, with measurement intervals ranging from 0-4 s up to 2 min. Delta HR was used to evaluate HRonsetshort over the first 4 s of exercise, as well as for analyzing HRonsetlong. In exponential modeling, the HR response to dynamic exercise is biphasic, consisting of fast (parasympathetic, 0-10 s) and slow (sympathetic, 1-4 min) components. Although available studies differed largely in measurement protocols, cross-sectional and longitudinal training studies showed that studies analyzing HRonset in relation to physical training primarily incorporated HRonsetlong. HRonsetlong slowed in athletes as well as in patients with a coronary disease, who have a relatively fast HRonsetlong. It is advised to include both HRonsetlong and HRonsetshort in further studies. The findings of this review suggest that HRonset is a potential tool for monitoring and titrating training in sports as well as in rehabilitation settings, particularly in patients with ventricular fibrillation. Monitoring HRonset in the early phase of training can help optimize the effectiveness of training and therapy. More research is needed to gain a better understanding of the mechanisms underlying HRonset in relation to their application in sports and rehabilitation settings.

Neurologic disease with pregnancy and considerations for the obstetric anesthesiologist

Women with neurologic conditions present a challenge during pregnancy and in the peripartum period. Given the low prevalence of these diseases during pregnancy, most management decisions are guided by retrospective reviews and case reports. This article reviews current literature for some of the more common or complex neurologic conditions affecting pregnancy with special consideration for anesthetic management. In particular, epilepsy; multiple sclerosis; primary intracranial hypertension; secondary intracranial hypertension-Arnold-Chiari malformations and intracranial neoplasms; spinal cord injury; neuromuscular junction disorders-myasthenia gravis; and hereditary neuromuscular disorders-myotonic dystrophy and spinal muscular atrophy will be discussed. By increasing understanding of anesthetic issues for parturients with neurologic disease, providers may more effectively anticipate anesthetic considerations, thereby optimizing care plans.

Sympathetic skin responses and autonomic dysfunction in spinal cord injury

Sympathetic skin responses (SSRs), a measure of sympathetic cholinergic sudomotor function, have been used in the assessment of autonomic dysfunction in patients with spinal cord injury (SCI). This review highlights the basic mechanisms underlying SSRs as well as their application to the SCI population. We address the utility of SSRs in assessing autonomic function, the relationship between autonomic and sensorimotor impairment, and the association between SSRs and the sequelae of autonomic dysfunction in SCI, particularly autonomic dysreflexia and orthostatic hypotension. Overall, SSRs are a rapid, convenient and non-invasive method illustrating that the severity of autonomic impairment can be independent from sensorimotor impairment. We suggest that SSRs be used in conjunction with other validated autonomic tests in order to predict or document autonomic dysfunction in SCI.

Comparison of changes in heart rate variability and sacral skin perfusion in response to postural changes in people with spinal cord injury

The current clinical practice has established guidelines to assess influences of severity of autonomic injury on the control of heart and blood pressure following spinal cord injury (SCI). However, the influences of SCI-induced autonomic impairment on microvascular dysfunction have not yet been established. Heart rate variability (HRV) has been shown to be a potential tool for quantifying residual sympathovagal regulation of the cardiovascular system following SCI and may be used to assess the effect of autonomic injury on skin microvascular dysfunction. A total of 26 people were recruited into the study, including 12 people with SCI and 14 nondisabled controls. HRV and sacral skin intervals and sacral skin perfusion were continually recorded during 10 min upright and 10 min prone postures. The sympathovagal balance was defined as the ratio of the power of the low frequency to the high frequency of HRV. The results showed that postural changes of nondisabled people produced significant changes in the sympathovagal balance; lower sympathovagal balance was associated with higher skin perfusion (p < 0.05). People with SCI did not show a significant change of HRV and skin perfusion in response to postural changes. In this study, we have demonstrated that the sympathovagal balance assessed by HRV was associated with the skin vasoconstrictive response to postural changes.

Cardiac arrhythmias the first month after acute traumatic spinal cord injury

OBJECTIVE

Cardiovascular complications including cardiac arrest and arrhythmias remain a clinical challenge in the management of acute traumatic spinal cord injury (SCI). Still, there is a lack of knowledge regarding the characteristics of arrhythmias in patients with acute traumatic SCI. The aim of this prospective observational study was to investigate the occurrence of cardiac arrhythmias and cardiac arrests in patients with acute traumatic SCI.

METHODS

As early as possible after SCI 24-hour Holter monitoring was performed. Additional Holter recordings were performed 1, 2, 3, and 4 weeks after SCI. Furthermore, 12-lead electrocardiograms (ECGs) were obtained shortly after SCI and at 4 weeks.

RESULTS

Thirty patients were included. Bradycardia (heart rate (HR) <50 b.p.m.) was present in 17-35% of the patients with cervical (C1-C8) SCI (n = 24) within the first 14 days. In the following 14 days, the occurrence was 22-32%. Bradycardia in the thoracic (Th1-Th12) SCI group (n = 6) was present in 17-33% during the observation period. The differences between the two groups were not statistically significant. The mean minimum HR was significantly lower in the cervical group compared with the thoracic group both on 12-lead ECGs obtained shortly after SCI (P = 0.030) and at 4 weeks (P = 0.041).

CONCLUSION

Many patients with cervical SCI experience arrhythmias such as bradycardia, sinus node arrest, supraventricular tachycardia, and more rarely cardiac arrest the first month after SCI. Apart from sinus node arrests and limited bradycardia, no arrhythmias were seen in patients with thoracic SCI. Standard 12-lead ECGs will often miss the high prevalence these arrhythmias have.

Circulating angiogenic biomolecules at rest and in response to upper-limb exercise in individuals with spinal cord injury

OBJECTIVE

Individuals with spinal cord injury (SCI) show structural and functional vascular maladaptations and muscle loss in their lower limbs. Angiogenic biomolecules play important roles in physiological and pathological angiogenesis, and are implicated in the maintenance of muscle mass. This study examined the responses of angiogenic molecules during upper-limb aerobic exercise in patients with SCI and in able-bodied (AB) individuals.

METHODS

Eight SCI patients with thoracic lesions (T6-T12, ASIA A) and eight AB individuals performed an arm-cranking exercise for 30 minutes at 60% of their VO2max. Plasma concentrations of vascular endothelial growth factor (VEGF-A165), VEGF receptor 1 (sVEGFr-1), VEGF receptor 2 (sVEGFr-2), metalloproteinase 2 (MMP-2), and endostatin were measured at rest, after exercise, and at 1.5 and 3.0 hours during recovery.

RESULTS

The two-way analysis of variance showed non-significant main effects of "group" and significant main effects of "time/exercise" for all angiogenic biomolecules examined (P < 0.01-0.001). The arm-cranking exercise significantly increased plasma concentrations of VEGF, sVEGFr-1, sVEGFr-2, MMP-2, and endostatin in both groups (P < 0.001-0.01). The magnitude of the increase was similar in both patients with SCI and AB individuals, as shown by the non-significant group × time interaction for all angiogenic parameters.

CONCLUSIONS

Upper-limb exercise (arm-cranking for 30 minutes at 60% of VO2max) is a sufficient stimulus to trigger a coordinated circulating angiogenic response in patients with SCI. The response of angiogenic molecules to upper-limb aerobic exercise in SCI appears relatively similar to that observed in AB individuals.

Life-threatening outcomes associated with autonomic dysreflexia: a clinical review

Context Autonomic dysreflexia (AD) is a life-threatening complication of chronic traumatic spinal cord injury (SCI). Objective To document and provide insight into the life-threatening sequelae associated with AD. Methods A review was conducted to identify literature which documented cases of AD associated with life-threatening outcomes (and death). The search strategy comprised of a keyword search on the PubMed database as well as manual searches of retrieved articles. Outcomes were categorized into three main classes: central nervous system (CNS), cardiovascular (CV), and pulmonary. Results Thirty-two cases of death or life-threatening complications of AD were found. Twenty-three (72%) cases were CNS-related, seven (22%) cases were CV-related, and two (6%) cases were pulmonary-related. In total, seven (22%) deaths were noted as a direct result of complications following an AD attack. Conclusion AD is a well-known consequence of SCI among individuals with high thoracic and cervical injuries. Many of these individuals experience this condition on a daily basis. Medical personnel, care givers, and individuals with SCI should be aware of the importance of timely diagnosis and management of this life-threatening condition, which can result in a variety of significant complications including stroke, seizures, myocardial ischemia, and death.

Reappearance of sympathetic skin response below a thoracic level-9 complete spinal cord injury

Reappearance of sympathetic skin response (SSR) below lesion is reported in a patient with a complete thoracic-9 spinal cord injury 6 months following injury. SSR was elicited by electrical stimulation of supraorbital nerve (SON) and pudendal nerve (PN). SON stimulation induced SSRs only in the hand. SSRs were initially absent below the level of SCI but reappeared only with PN stimulation. This case suggests that 6 months following a complete lesion, the isolated spinal cord can generate a SSR. Possible underlying mechanisms and implications for autonomic plasticity below spinal lesion are discussed in view of the literature.

Partial restoration of cardiovascular function by embryonic neural stem cell grafts after complete spinal cord transection

High-level spinal cord injury can lead to cardiovascular dysfunction, including disordered hemodynamics at rest and autonomic dysreflexia during noxious stimulation. To restore supraspinal control of sympathetic preganglionic neurons (SPNs), we grafted embryonic brainstem-derived neural stem cells (BS-NSCs) or spinal cord-derived neural stem cells (SC-NSCs) expressing green fluorescent protein into the T4 complete transection site of adult rats. Animals with injury alone served as controls. Implanting of BS-NSCs but not SC-NSCs resulted in recovery of basal cardiovascular parameters, whereas both cell grafts alleviated autonomic dysreflexia. Subsequent spinal cord retransection above the graft abolished the recovery of basal hemodynamics and reflexic response. BS-NSC graft-derived catecholaminergic and serotonergic neurons showed remarkable long-distance axon growth and topographical innervation of caudal SPNs. Anterograde tracing indicated growth of medullar axons into stem cell grafts and formation of synapses. Thus, grafted embryonic brainstem-derived neurons can act as functional relays to restore supraspinal regulation of denervated SPNs, thereby contributing to cardiovascular functional improvement.

Evidence-based risk assessment and recommendations for physical activity clearance: Consensus Document 2011

The Physical Activity Readiness Questionnaire (PAR-Q) and the Physical Activity Readiness Medical Evaluation (PARmed-X) are internationally known preparticipation screening tools developed on the basis of expert opinion. The primary purposes of this consensus document were to seek evidence-based support for the PAR-Q and PARmed-X forms, to identify whether further revisions of these instruments are warranted, to determine how people responding positively to questions on the PAR-Q can be safely cleared without medical referral, and to develop exercise clearance procedures appropriate for various clinical conditions across the human lifespan. Seven systematic reviews were conducted, examining physical-activity-related risks and effective risk-stratification procedures for various prevalent chronic conditions. An additional systematic review assessed the risks associated with exercise testing and training of the general population. Two gap areas were identified and evaluated systematically: the role of the qualified exercise professional and the requisite core competencies required by those working with various chronic conditions; and the risks associated with physical activity during pregnancy. The risks associated with being physically inactive are markedly higher than transient risks during and following an acute bout of exercise in both asymptomatic and symptomatic populations across the lifespan. Further refinements of the PAR-Q and the PARmed-X (including online versions of the forms) are required to address the unique limitations imposed by various chronic health conditions, and to allow the inclusion of individuals across their entire lifespan. A probing decision-tree process is proposed to assist in risk stratification and to reduce barriers to physical activity. Qualified exercise professionals will play an essential role in this revised physical activity clearance process.