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Naik GR, Breen PP, Jayarathna T, Tong BK, Eckert DJ, Gargiulo GD. Morphic Sensors for Respiratory Parameters Estimation: Validation against Overnight Polysomnography. BIOSENSORS 2023; 13:703. [PMID: 37504102 PMCID: PMC10377422 DOI: 10.3390/bios13070703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/19/2023] [Accepted: 06/26/2023] [Indexed: 07/29/2023]
Abstract
Effective monitoring of respiratory disturbances during sleep requires a sensor capable of accurately capturing chest movements or airflow displacement. Gold-standard monitoring of sleep and breathing through polysomnography achieves this task through dedicated chest/abdomen bands, thermistors, and nasal flow sensors, and more detailed physiology, evaluations via a nasal mask, pneumotachograph, and airway pressure sensors. However, these measurement approaches can be invasive and time-consuming to perform and analyze. This work compares the performance of a non-invasive wearable stretchable morphic sensor, which does not require direct skin contact, embedded in a t-shirt worn by 32 volunteer participants (26 males, 6 females) with sleep-disordered breathing who performed a detailed, overnight in-laboratory sleep study. Direct comparison of computed respiratory parameters from morphic sensors versus traditional polysomnography had approximately 95% (95 ± 0.7) accuracy. These findings confirm that novel wearable morphic sensors provide a viable alternative to non-invasively and simultaneously capture respiratory rate and chest and abdominal motions.
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Affiliation(s)
- Ganesh R Naik
- Adelaide Institute for Sleep Health (Flinders Health and Medical Research Institute: Sleep Health), College of Medicine and Public Health, Flinders University, Bedford Park, SA 5042, Australia
- College of Science and Engineering, Flinders University, Bedford Park, SA 5042, Australia
| | - Paul P Breen
- The MARCS Institute, Western Sydney University, Westmead, NSW 2145, Australia
| | - Titus Jayarathna
- The MARCS Institute, Western Sydney University, Westmead, NSW 2145, Australia
| | - Benjamin K Tong
- Neuroscience Research Australia, Randwick, NSW 2031, Australia
- Sleep Research Group, Charles Perkins Centre, School of Medicine, University of Sydney, Camperdown, NSW 2006, Australia
| | - Danny J Eckert
- Adelaide Institute for Sleep Health (Flinders Health and Medical Research Institute: Sleep Health), College of Medicine and Public Health, Flinders University, Bedford Park, SA 5042, Australia
- Neuroscience Research Australia, Randwick, NSW 2031, Australia
| | - Gaetano D Gargiulo
- The MARCS Institute, Western Sydney University, Westmead, NSW 2145, Australia
- School of Engineering, Design and Built Environment, Western Sydney University, Penrith, NSW 2751, Australia
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Kohlbrenner D, Marillier M, Randy H, Ghaith A, Furian M, Vergès S. Characterisation of the acute hypoxic response using breathing variability parameters: a pilot study in humans. Respir Physiol Neurobiol 2023:104096. [PMID: 37355056 DOI: 10.1016/j.resp.2023.104096] [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: 03/28/2023] [Revised: 06/19/2023] [Accepted: 06/20/2023] [Indexed: 06/26/2023]
Abstract
PURPOSE We aimed to investigate respiratory rate variability (RRV) and tidal volume (Vt) variability during exposure to normobaric hypoxia (i.e., reduction in the fraction of inspired oxygen - FiO2), and the association of the changes in RRV and Vt variability with the changes in pulse oxygen saturation (SpO2). METHODS Thirty healthy human participants (15 females) were exposed to: (1) 15-min normoxia, (2) 10-min hypoxia simulating 2200m, (3) 10-min hypoxia simulating 4000m, (4) 10-min hypoxia simulating 5000m, (5) 15-min recovery in normoxia. Linear regression modelling was applied with SpO2 (dependent variable) and the changes in RRV and Vt variability (independent variables), controlling for FiO2, age, sex, changes in heart rate (HR), changes in HR variability (HRV), and changes in minute ventilation (VE). RESULTS When modelling breathing parameter variability as root-mean-square standard deviation (RMSSD), a significant independent association of the changes in RRV with the changes in SpO2 was found (B=-4.3e-04, 95% CI=-8.3e-04/-2.1e-05, p=0.04). The changes in Vt variability showed no significant association with the changes in SpO2 (B=-1.6, 95% CI=-5.5/2.4, p=0.42). When modelling parameters variability as SD, a significant independent association of the changes in RRV with the changes in SpO2 was found (B=-8.2e-04, 95% CI=-1.5e-03/-9.4e-05, p=0.03). The changes in Vt variability showed no significant association with the changes in SpO2 (B=1.4, 95% CI=-5.8/8.6, p=0.69). CONCLUSION Higher RRV is independently associated with lower SpO2 during acute hypoxic exposure, while Vt variability parameters are not. Therefore, RRV may be a potentially interesting parameter to characterize individual responses to acute hypoxia.
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Affiliation(s)
- Dario Kohlbrenner
- HP2 Laboratory, INSERM, Grenoble Alpes University, Grenoble, France; Faculty of Medicine, University of Zurich, Zurich, Switzerland; Department of Pulmonology, University Hospital Zurich, Zurich, Switzerland.
| | | | - Hugo Randy
- HP2 Laboratory, INSERM, Grenoble Alpes University, Grenoble, France
| | - Abdallah Ghaith
- HP2 Laboratory, INSERM, Grenoble Alpes University, Grenoble, France
| | - Michael Furian
- HP2 Laboratory, INSERM, Grenoble Alpes University, Grenoble, France
| | - Samuel Vergès
- HP2 Laboratory, INSERM, Grenoble Alpes University, Grenoble, France
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Augusto TRDL, Peroni J, de Vargas W, Santos PC, Dantas W, Padavini RL, Koch R, Saraiva E, Bastos MAV, Müller PDT. Carotid-body modulation through meditation in stage-I hypertensive subjects: Study protocol of a randomized and controlled study. Medicine (Baltimore) 2023; 102:e32295. [PMID: 36607871 PMCID: PMC9829266 DOI: 10.1097/md.0000000000032295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Adjunctive therapy for hypertension is in high demand for clinical research. Therefore, several meta-analyses have provided sufficient evidence for meditation as an adjunct therapy, without being anchored on reliable physiological grounds. Meditation modulates the autonomic nervous system. Herein, we propose a hierarchical-dependent effect for the carotid body (CB) in attenuating blood pressure (BP) and ventilatory variability (VV) fine-tuning due to known nerve connections between the CB, prefrontal brain, hypothalamus, and solitary tract nucleus. The aim of this exploratory study was to investigate the role of CB in the possible decrease in BP and changes in VV that could occur in response to meditation. This was a prospective, single-center, parallel-group, randomized, controlled clinical trial with concealed allocation. Eligible adult subjects of both sexes with stage 1 hypertension will be randomized into 1 of 2 groups: transcendental meditation or a control group. Subjects will be invited to 3 visits after randomization and 2 additional visits after completing 8 weeks of meditation or waiting-list control. Thus, subjects will undergo BP measurements in normoxia and hyperoxia, VV measurements using the Poincaré method at rest and during exercise, and CB activity measurement in the laboratory. The primary outcome of this study was the detection of changes in BP and CB activity after 8 weeks. Our secondary outcome was the detection of changes in the VV at rest and during exercise. We predict that interactions between hyperoxic deactivation of CB and meditation; Will reduce BP beyond stand-alone intervention or alternatively; Meditation will significantly attenuate the effects of hyperoxia as a stand-alone intervention. In addition, VV can be changed, partially mediated by a reduction in CB activity. Trial registration number: ReBEC registry (RBR-55n74zm). Stage: pre-results.
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Affiliation(s)
- Tiago Rodrigues de Lemos Augusto
- Laboratory of Respiratory Pathophysiology (LAFIR), Maria Aparecida Pedrossian Universitary Hospital (HUMAP), Campo Grande, Mato Grosso do Sul, Brazil
| | - Juliana Peroni
- Laboratory of Respiratory Pathophysiology (LAFIR), Maria Aparecida Pedrossian Universitary Hospital (HUMAP), Campo Grande, Mato Grosso do Sul, Brazil
| | - Wandriane de Vargas
- Laboratory of Respiratory Pathophysiology (LAFIR), Maria Aparecida Pedrossian Universitary Hospital (HUMAP), Campo Grande, Mato Grosso do Sul, Brazil
| | - Priscilla Caroll Santos
- Laboratory of Respiratory Pathophysiology (LAFIR), Maria Aparecida Pedrossian Universitary Hospital (HUMAP), Campo Grande, Mato Grosso do Sul, Brazil
| | - Wendel Dantas
- Laboratory of Respiratory Pathophysiology (LAFIR), Maria Aparecida Pedrossian Universitary Hospital (HUMAP), Campo Grande, Mato Grosso do Sul, Brazil
| | - Roberta Lazari Padavini
- Laboratory of Respiratory Pathophysiology (LAFIR), Maria Aparecida Pedrossian Universitary Hospital (HUMAP), Campo Grande, Mato Grosso do Sul, Brazil
| | - Rodrigo Koch
- Laboratory of Respiratory Pathophysiology (LAFIR), Maria Aparecida Pedrossian Universitary Hospital (HUMAP), Campo Grande, Mato Grosso do Sul, Brazil
| | | | - Marco Aurélio Vinhosa Bastos
- Laboratory of Respiratory Pathophysiology (LAFIR), Maria Aparecida Pedrossian Universitary Hospital (HUMAP), Campo Grande, Mato Grosso do Sul, Brazil
| | - Paulo de Tarso Müller
- Laboratory of Respiratory Pathophysiology (LAFIR), Maria Aparecida Pedrossian Universitary Hospital (HUMAP), Campo Grande, Mato Grosso do Sul, Brazil
- * Correspondence: Paulo de Tarso Müller, Laboratory of Respiratory Pathophysiology (LAFIR); Respiratory Division of University Hospital, Federal University of Mato Grosso do Sul (UFMS), Rua Filinto Müller S/N, Vila Ipiranga CEP:79080-090, Campo Grande, Brazil (e-mail: )
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Feinstein JS, Gould D, Khalsa SS. Amygdala-driven apnea and the chemoreceptive origin of anxiety. Biol Psychol 2022; 170:108305. [PMID: 35271957 DOI: 10.1016/j.biopsycho.2022.108305] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 02/09/2022] [Accepted: 03/03/2022] [Indexed: 12/13/2022]
Abstract
Although the amygdala plays an important part in the pathogenesis of anxiety and generation of exteroceptive fear, recent discoveries have challenged the directionality of this brain-behavior relationship with respect to interoceptive fear. Here we highlight several paradoxical findings including: (1) amygdala lesion patients who experience excessive fear and panic following inhalation of carbon dioxide (CO2), (2) clinically anxious patients who have significantly smaller (rather than larger) amygdalae and a pronounced hypersensitivity toward CO2, and (3) epilepsy patients who exhibit apnea immediately following stimulation of their amygdala yet have no awareness that their breathing has stopped. The above findings elucidate an entirely novel role for the amygdala in the induction of apnea and inhibition of CO2-induced fear. Such a role is plausible given the strong inhibitory connections linking the central nucleus of the amygdala with respiratory and chemoreceptive centers in the brainstem. Based on this anatomical arrangement, we propose a model of Apnea-induced Anxiety (AiA) which predicts that recurring episodes of apnea are being unconsciously elicited by amygdala activation, resulting in transient spikes in CO2 that provoke fear and anxiety, and lead to characteristic patterns of escape and avoidance behavior in patients spanning the spectrum of anxiety. If this new conception of AiA proves to be true, and activation of the amygdala can repeatedly trigger states of apnea outside of one's awareness, then it remains possible that the chronicity of anxiety disorders is being interoceptively driven by a chemoreceptive system struggling to maintain homeostasis in the midst of these breathless states.
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Affiliation(s)
- Justin S Feinstein
- Laureate Institute for Brain Research, Tulsa, Oklahoma, USA, 74136; University of Tulsa, Oxley College of Health Sciences, Tulsa, Oklahoma, USA, 74104; University of Iowa, Department of Neurology, Iowa City, Iowa, USA, 52242.
| | - Dylan Gould
- Laureate Institute for Brain Research, Tulsa, Oklahoma, USA, 74136
| | - Sahib S Khalsa
- Laureate Institute for Brain Research, Tulsa, Oklahoma, USA, 74136; University of Tulsa, Oxley College of Health Sciences, Tulsa, Oklahoma, USA, 74104
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van den Bosch OFC, Alvarez-Jimenez R, de Grooth HJ, Girbes ARJ, Loer SA. Breathing variability-implications for anaesthesiology and intensive care. Crit Care 2021; 25:280. [PMID: 34353348 PMCID: PMC8339683 DOI: 10.1186/s13054-021-03716-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 07/29/2021] [Indexed: 12/04/2022] Open
Abstract
The respiratory system reacts instantaneously to intrinsic and extrinsic inputs. This adaptability results in significant fluctuations in breathing parameters, such as respiratory rate, tidal volume, and inspiratory flow profiles. Breathing variability is influenced by several conditions, including sleep, various pulmonary diseases, hypoxia, and anxiety disorders. Recent studies have suggested that weaning failure during mechanical ventilation may be predicted by low respiratory variability. This review describes methods for quantifying breathing variability, summarises the conditions and comorbidities that affect breathing variability, and discusses the potential implications of breathing variability for anaesthesia and intensive care.
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Affiliation(s)
- Oscar F C van den Bosch
- Departments of Anesthesiology and Intensive Care, Amsterdam UMC, VUMC, ZH 6F 003, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands.
| | - Ricardo Alvarez-Jimenez
- Departments of Anesthesiology and Intensive Care, Amsterdam UMC, VUMC, ZH 6F 003, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Harm-Jan de Grooth
- Departments of Anesthesiology and Intensive Care, Amsterdam UMC, VUMC, ZH 6F 003, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Armand R J Girbes
- Departments of Anesthesiology and Intensive Care, Amsterdam UMC, VUMC, ZH 6F 003, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Stephan A Loer
- Departments of Anesthesiology and Intensive Care, Amsterdam UMC, VUMC, ZH 6F 003, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
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van den Bosch OFC, Alvarez-Jimenez R, Stam MMH, den Boer FC, Loer SA. Variations in respiratory rate do not reflect changes in tidal volume or minute ventilation after major abdominal surgery. J Clin Monit Comput 2020; 35:787-796. [PMID: 32488678 PMCID: PMC8286957 DOI: 10.1007/s10877-020-00538-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 05/26/2020] [Indexed: 12/22/2022]
Abstract
Monitoring of postoperative pulmonary function usually includes respiratory rate and oxygen saturation measurements. We hypothesized that changes in postoperative respiratory rate do not correlate with changes in tidal volume or minute ventilation. In addition, we hypothesized that variability of minute ventilation and tidal volume is larger than variability of respiratory rate. Respiratory rate and changes in tidal volume and in minute ventilation were continuously measured in 27 patients during 24 h following elective abdominal surgery, using an impedance-based non-invasive respiratory volume monitor (ExSpiron, Respiratory Motion, Waltham, MA, US). Coefficients of variation were used as a measure for variability of respiratory rate, tidal volume and minute ventilation. Data of 38,149 measurements were analyzed. We found no correlation between respiratory rate and tidal volume or minute ventilation (r2 = 0.02 and 0.01). Mean respiratory rate increased within the first 24 h after abdominal surgery from 13.9 ± 2.5 to 16.2 ± 2.4 breaths/min (p = 0.008), while tidal volume and minute ventilation remained unchanged (p = 0.90 and p = 0.18). Of interest, variability of respiratory rate (0.21 ± 0.06) was significantly smaller than variability of tidal volume (0.37 ± 0.12, p < 0.001) and minute ventilation (0.41 ± 0.12, p < 0.001). Changes in postoperative respiratory rate do not allow conclusions about changes in tidal volume or minute ventilation. We suggest that postoperative alveolar hypoventilation may not be recognized by monitoring respiratory rate alone. Variability of respiratory rate is smaller than variability in tidal volume and minute ventilation, suggesting that adaptations of alveolar ventilation to metabolic needs may be predominately achieved by variations in tidal volume.
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Affiliation(s)
- O F C van den Bosch
- Department of Anesthesiology, Amsterdam UMC, VU University, Amsterdam, The Netherlands.
| | - R Alvarez-Jimenez
- Department of Anesthesiology, Amsterdam UMC, VU University, Amsterdam, The Netherlands
| | - M M H Stam
- Department of Anesthesiology, Zaandam Medical Center, Zaandam, The Netherlands
| | - F C den Boer
- Department of Surgery, Zaandam Medical Center, Zaandam, The Netherlands
| | - S A Loer
- Department of Anesthesiology, Amsterdam UMC, VU University, Amsterdam, The Netherlands
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Xie L, Di X, Zhao F, Yao J, Liu Z, Li C, Liu B, Wang X, Zhang J. Increased Respiratory Modulation of Blood Pressure in Hypertensive Patients. Front Physiol 2019; 10:1111. [PMID: 31507459 PMCID: PMC6718561 DOI: 10.3389/fphys.2019.01111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 08/12/2019] [Indexed: 11/20/2022] Open
Abstract
Objective Although the important role of respiratory modulation of the cardiovascular system in the development of hypertension has been demonstrated in animal studies, little research has assessed this modulation in essential hypertensive patients. We aimed to explore whether respiratory-related variations in cardiovascular variables are changed in hypertensive patients and their potential relationships with the respiratory pattern. Methods Respiration, ECG, and beat-to-beat blood pressure (BP) were simultaneously measured in 46 participants (24 hypertensive patients and 22 normotensive participants) during rest and a mental arithmetic task (MAT). Respiratory-triggered averaging and orthogonal subspace projection methods were used to assess the respiratory modulations of BP and heart rate (HR). Respiratory parameters including inspiratory time, expiratory time, respiratory rate and their variabilities were also characterized. Results The inspiratory time, expiratory time, respiratory rate and their variabilities were not different between hypertensive and normotensives. Additionally, the modulation of HR by respiration was also similar between the two groups. Hypertensive patients exhibited an amplified respiratory modulation of systolic BP (SBP), as assessed from the amplitude of respiratory-related changes and the percentage of the power of respiratory-related variation, and also reflected from the temporal pattern of respiratory modulation of SBP. The exaggerated respiratory-related variation of SBP in hypertensive patients accounted for ≈23% of the total power of SBP, producing an absolute change of ≈4.5 mmHg in SBP. MAT was characterized by decreased inspiratory time and increased variabilities of expiratory time and respiratory rate with no changes in the amplitude of respiratory modulations. Conclusion Hypertensive patients had excessive respiratory modulation of SBP, despite having similar respiratory pattern with normotensives. These findings highlight the importance of respiratory influence in BP variation and suggest that respiratory modulation of SBP may have prognostic information for cardiovascular events in hypertensive patients.
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Affiliation(s)
- Lin Xie
- Key Laboratory of Biomedical Information Engineering of Education Ministry, Xi'an Jiaotong University, Xi'an, China
| | - Xiaohui Di
- Key Laboratory of Biomedical Information Engineering of Education Ministry, Xi'an Jiaotong University, Xi'an, China
| | - Fadong Zhao
- Key Laboratory of Biomedical Information Engineering of Education Ministry, Xi'an Jiaotong University, Xi'an, China
| | - Jie Yao
- Key Laboratory of Biomedical Information Engineering of Education Ministry, Xi'an Jiaotong University, Xi'an, China
| | - Zhiheng Liu
- Department of Cardiology, No. 451 Hospital of Chinese People's Liberation Army, Xi'an, China
| | - Chaomin Li
- Department of Cardiology, No. 451 Hospital of Chinese People's Liberation Army, Xi'an, China
| | - Binbin Liu
- Key Laboratory of Biomedical Information Engineering of Education Ministry, Xi'an Jiaotong University, Xi'an, China
| | - Xiaoni Wang
- Key Laboratory of Biomedical Information Engineering of Education Ministry, Xi'an Jiaotong University, Xi'an, China
| | - Jianbao Zhang
- Key Laboratory of Biomedical Information Engineering of Education Ministry, Xi'an Jiaotong University, Xi'an, China
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Helvig A, Wade S, Hunter-Eades L. Rest and the associated benefits in restorative sleep: a concept analysis. J Adv Nurs 2015; 72:62-72. [PMID: 26370516 DOI: 10.1111/jan.12807] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/10/2015] [Indexed: 11/30/2022]
Affiliation(s)
- Ashley Helvig
- Byrdine F. Lewis School of Nursing and Health Professions; Georgia State University; Atlanta Georgia USA
| | - Sonya Wade
- Byrdine F. Lewis School of Nursing and Health Professions; Georgia State University; Atlanta Georgia USA
| | - Lee Hunter-Eades
- Byrdine F. Lewis School of Nursing and Health Professions; Georgia State University; Atlanta Georgia USA
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Huang CT, Tsai YJ, Lin JW, Ruan SY, Wu HD, Yu CJ. Application of heart-rate variability in patients undergoing weaning from mechanical ventilation. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2014; 18:R21. [PMID: 24456585 PMCID: PMC4056081 DOI: 10.1186/cc13705] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 01/20/2014] [Indexed: 01/08/2023]
Abstract
Introduction The process of weaning may impose cardiopulmonary stress on ventilated patients. Heart-rate variability (HRV), a noninvasive tool to characterize autonomic function and cardiorespiratory interaction, may be a promising modality to assess patient capability during the weaning process. We aimed to evaluate the association between HRV change and weaning outcomes in critically ill patients. Methods This study included 101 consecutive patients recovering from acute respiratory failure. Frequency-domain analysis, including very low frequency, low frequency, high frequency, and total power of HRV was assessed during a 1-hour spontaneous breathing trial (SBT) through a T-piece and after extubation after successful SBT. Results Of 101 patients, 24 (24%) had SBT failure, and HRV analysis in these patients showed a significant decrease in total power (P = 0.003); 77 patients passed SBT and were extubated, but 13 (17%) of them required reintubation within 72 hours. In successfully extubated patients, very low frequency and total power from SBT to postextubation significantly increased (P = 0.003 and P = 0.004, respectively). Instead, patients with extubation failure were unable to increase HRV after extubation. Conclusions HRV responses differ between patients with different weaning outcomes. Measuring HRV change during the weaning process may help clinicians to predict weaning results and, in the end, to improve patient care and outcome.
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Hripcsak G, Albers DJ, Perotte A. Exploiting time in electronic health record correlations. J Am Med Inform Assoc 2011; 18 Suppl 1:i109-15. [PMID: 22116643 DOI: 10.1136/amiajnl-2011-000463] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVE To demonstrate that a large, heterogeneous clinical database can reveal fine temporal patterns in clinical associations; to illustrate several types of associations; and to ascertain the value of exploiting time. MATERIALS AND METHODS Lagged linear correlation was calculated between seven clinical laboratory values and 30 clinical concepts extracted from resident signout notes from a 22-year, 3-million-patient database of electronic health records. Time points were interpolated, and patients were normalized to reduce inter-patient effects. RESULTS The method revealed several types of associations with detailed temporal patterns. Definitional associations included low blood potassium preceding 'hypokalemia.' Low potassium preceding the drug spironolactone with high potassium following spironolactone exemplified intentional and physiologic associations, respectively. Counterintuitive results such as the fact that diseases appeared to follow their effects may be due to the workflow of healthcare, in which clinical findings precede the clinician's diagnosis of a disease even though the disease actually preceded the findings. Fully exploiting time by interpolating time points produced less noisy results. DISCUSSION Electronic health records are not direct reflections of the patient state, but rather reflections of the healthcare process and the recording process. With proper techniques and understanding, and with proper incorporation of time, interpretable associations can be derived from a large clinical database. CONCLUSION A large, heterogeneous clinical database can reveal clinical associations, time is an important feature, and care must be taken to interpret the results.
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Affiliation(s)
- George Hripcsak
- Department of Biomedical Informatics, Columbia University, New York, New York 10032, USA.
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