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Prediction of fluid responsiveness using lung recruitment manoeuvre in paediatric patients receiving lung-protective ventilation: A prospective observational study. Eur J Anaesthesiol 2021; 38:452-458. [PMID: 33186310 DOI: 10.1097/eja.0000000000001387] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Pressure-based dynamic variables are poor predictors of fluid responsiveness in children, and their predictability is expected to reduce further during lung-protective ventilation with a low tidal volume. OBJECTIVE We hypothesised that lung recruitment manoeuvre (LRM)-induced changes in dynamic variables improve their ability to predict fluid responsiveness in children. DESIGN Prospective observational study. SETTING Tertiary care children's hospital, single-centre study performed from June 2017 to May 2019. PATIENTS We included patients less than 7 years of age undergoing cardiac surgery. Neonates and patients with pulmonary hypertension, significant dysrhythmia, ventricular ejection fraction of less than 30% or pulmonary disease were excluded. INTERVENTION All patients were provided with lung-protective volume-controlled ventilation (tidal volume 6 ml kg-1, positive end-expiratory pressure 6 cmH2O). A LRM was applied with a continuous inspiratory pressure of 25 cmH2O for 20 s. MAIN OUTCOME MEASURE The ability of dynamic variables to predict fluid responsiveness was evaluated by the area under the receiver operating characteristic curve [area under the curve (AUC)]. Fluid responsiveness was defined as an increase in the cardiac index by more than 15% with crystalloid administration (10 ml kg-1). RESULTS Thirty patients were included in the final analysis, of whom 19 were responders. The baseline pleth variability index (PVI) (AUC 0.794, 95% confidence interval 0.608 to 0.919, P < 0.001) and LRM-induced PVI (AUC 0.711, 95% confidence interval 0.517 to 0.861, P = 0.026) could predict fluid responsiveness. The respiratory variation of pulse oximetry photoplethysmographic waveform and pulse pressure variation did not predict fluid responsiveness regardless of the LRM. CONCLUSION The PVI is effective in predicting fluid responsiveness in paediatric patients with lung-protective ventilation regardless of a LRM. However, the LRM did not improve the ability of the other dynamic variables to predict fluid responsiveness in these patients. CLINICAL TRIAL REGISTRATION www.clinicaltrials.gov identifier: NCT03184961.
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Booth GJ, Cole J, Geiger P, Adams J, Barnhill J, Hughey S. Pulse Arrival Time Is Associated With Hemorrhagic Volume in a Porcine Model: A Pilot Study. Mil Med 2021; 187:e630-e637. [PMID: 33620076 DOI: 10.1093/milmed/usab069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 11/20/2020] [Accepted: 02/09/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Hemorrhage is a major cause of preventable death worldwide, and early identification can be lifesaving. Pulse wave contour analysis has previously been used to infer hemodynamic variables in a variety of settings. We hypothesized that pulse arrival time (PAT), a form of pulse wave contour analysis which is assessed via electrocardiography (ECG) and photoplethysmography (PPG), is associated with hemorrhage volume. METHODS Yorkshire-Cross swine were randomized to hemorrhage (30 mL/kg over 20 minutes) vs. control. Continuous ECG and PPG waveforms were recorded with a novel monitoring device, and algorithms were developed to calculate PAT and PAT variability throughout the respiratory cycle, termed "PAT index" or "PAT_I." Mixed effects models were used to determine associations between blood loss and PAT and between blood loss and PAT_I to account for clustering within subjects and investigate inter-subject variability in these relationships. RESULTS PAT and PAT_I data were determined for ∼150 distinct intervals from five subjects. PAT and PAT_I were strongly associated with blood loss. Mixed effects modeling with PAT alone was substantially better than PAT_I alone (R2 0.93 vs. 0.57 and Akaike information criterion (AIC) 421.1 vs. 475.5, respectively). Modeling blood loss with PAT and PAT_I together resulted in slightly improved fit compared to PAT alone (R2 0.96, AIC 419.1). Mixed effects models demonstrated significant inter-subject variability in the relationships between blood loss and PAT. CONCLUSIONS Findings from this pilot study suggest that PAT and PAT_I may be used to detect blood loss. Because of the simple design of a single-lead ECG and PPG, the technology could be packaged into a very small form factor device for use in austere or resource-constrained environments. Significant inter-subject variability in the relationship between blood loss and PAT highlights the importance of individualized hemodynamic monitoring.
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Affiliation(s)
- Gregory J Booth
- Department of Anesthesiology and Pain Medicine, Naval Medical Center Portsmouth, Portsmouth, VA 23708, USA.,Naval Biotechnology Group, Naval Medical Center Portsmouth, Portsmouth, VA 23708, USA
| | - Jacob Cole
- Department of Anesthesiology and Pain Medicine, Naval Medical Center Portsmouth, Portsmouth, VA 23708, USA.,Naval Biotechnology Group, Naval Medical Center Portsmouth, Portsmouth, VA 23708, USA
| | - Phillip Geiger
- Department of Anesthesiology and Pain Medicine, Naval Medical Center Portsmouth, Portsmouth, VA 23708, USA.,Naval Biotechnology Group, Naval Medical Center Portsmouth, Portsmouth, VA 23708, USA
| | - Jacob Adams
- Department of Anesthesiology and Pain Medicine, Naval Medical Center Portsmouth, Portsmouth, VA 23708, USA
| | - Joshua Barnhill
- Department of Anesthesiology and Pain Medicine, Naval Medical Center Portsmouth, Portsmouth, VA 23708, USA
| | - Scott Hughey
- Department of Anesthesiology and Pain Medicine, Naval Medical Center Portsmouth, Portsmouth, VA 23708, USA.,Naval Biotechnology Group, Naval Medical Center Portsmouth, Portsmouth, VA 23708, USA
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Min TJ. Easy sedation anesthesia guide for non-anesthetic medical personnel. JOURNAL OF THE KOREAN MEDICAL ASSOCIATION 2020. [DOI: 10.5124/jkma.2020.63.1.36] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Too Jae Min
- Department of Anesthesiology and Pain Medicine, Korea University Ansan Hospital, Ansan, Korea
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Hoff IE, Hisdal J, Landsverk SA, Røislien J, Kirkebøen KA, Høiseth LØ. Respiratory variations in pulse pressure and photoplethysmographic waveform amplitude during positive expiratory pressure and continuous positive airway pressure in a model of progressive hypovolemia. PLoS One 2019; 14:e0223071. [PMID: 31560715 PMCID: PMC6764667 DOI: 10.1371/journal.pone.0223071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 09/12/2019] [Indexed: 11/18/2022] Open
Abstract
PURPOSE Respiratory variations in pulse pressure (dPP) and photoplethysmographic waveform amplitude (dPOP) are used for evaluation of volume status in mechanically ventilated patients. Amplification of intrathoracic pressure changes may enable their use also during spontaneous breathing. We investigated the association between the degree of hypovolemia and dPP and dPOP at different levels of two commonly applied clinical interventions; positive expiratory pressure (PEP) and continuous positive airway pressure (CPAP). METHODS 20 healthy volunteers were exposed to progressive hypovolemia by lower body negative pressure (LBNP). PEP of 0 (baseline), 5 and 10 cmH2O was applied by an expiratory resistor and CPAP of 0 (baseline), 5 and 10 cmH2O by a facemask. dPP was obtained non-invasively with the volume clamp method and dPOP from a pulse oximeter. Central venous pressure was measured in 10 subjects. Associations between changes were examined using linear mixed-effects regression models. RESULTS dPP increased with progressive LBNP at all levels of PEP and CPAP. The LBNP-induced increase in dPP was amplified by PEP 10 cmH20. dPOP increased with progressive LBNP during PEP 5 and PEP 10, and during all levels of CPAP. There was no additional effect of the level of PEP or CPAP on dPOP. Progressive hypovolemia and increasing levels of PEP were reflected by increasing respiratory variations in CVP. CONCLUSION dPP and dPOP reflected progressive hypovolemia in spontaneously breathing healthy volunteers during PEP and CPAP. An increase in PEP from baseline to 10 cmH2O augmented the increase in dPP, but not in dPOP.
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Affiliation(s)
- Ingrid Elise Hoff
- Norwegian Air Ambulance Foundation, Sentrum, Oslo, Norway
- Department of Anesthesiology, Oslo University Hospital, Nydalen, Oslo, Norway
- * E-mail:
| | - Jonny Hisdal
- Section of Vascular Investigations, Department of Vascular Surgery, Oslo University Hospital, Nydalen, Oslo, Norway
- Faculty of Medicine, University of Oslo, Blindern, Oslo, Norway
| | | | - Jo Røislien
- Norwegian Air Ambulance Foundation, Sentrum, Oslo, Norway
| | | | - Lars Øivind Høiseth
- Department of Anesthesiology, Oslo University Hospital, Nydalen, Oslo, Norway
- Section of Vascular Investigations, Department of Vascular Surgery, Oslo University Hospital, Nydalen, Oslo, Norway
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Sun S, Peeters WH, Bezemer R, Long X, Paulussen I, Aarts RM, Noordergraaf GJ. Finger and forehead photoplethysmography-derived pulse-pressure variation and the benefits of baseline correction. J Clin Monit Comput 2018; 33:65-75. [PMID: 29644558 PMCID: PMC6314999 DOI: 10.1007/s10877-018-0140-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 04/05/2018] [Indexed: 11/25/2022]
Abstract
To non-invasively predict fluid responsiveness, respiration-induced pulse amplitude variation (PAV) in the photoplethysmographic (PPG) signal has been proposed as an alternative to pulse pressure variation (PPV) in the arterial blood pressure (ABP) signal. However, it is still unclear how the performance of the PPG-derived PAV is site-dependent during surgery. The aim of this study is to compare finger- and forehead-PPG derived PAV in their ability to approach the value and trend of ABP-derived PPV. Furthermore, this study investigates four potential confounding factors, (1) baseline variation, (2) PPV, (3) ratio of respiration and heart rate, and (4) perfusion index, which might affect the agreement between PPV and PAV. In this work, ABP, finger PPG, and forehead PPG were continuously recorded in 29 patients undergoing major surgery in the operating room. A total of 91.2 h data were used for analysis, from which PAV and PPV were calculated and compared. We analyzed the impact of the four factors using a multiple linear regression (MLR) analysis. The results show that compared with the ABP-derived PPV, finger-derived PAV had an agreement of 3.2 ± 5.1%, whereas forehead-PAV had an agreement of 12.0 ± 9.1%. From the MLR analysis, we found that baseline variation was a factor significantly affecting the agreement between PPV and PAV. After correcting for respiration-induced baseline variation, the agreements for finger- and forehead-derived PAV were improved to reach an agreement of − 1.2 ± 3.8% and 3.3 ± 4.8%, respectively. To conclude, finger-derived PAV showed better agreement with ABP-derived PPV compared to forehead-derived PAV. Baseline variation was a factor that significantly affected the agreement between PPV and PAV. By correcting for the baseline variation, improved agreements were obtained for both the finger and forehead, and the difference between these two agreements was diminished. The tracking abilities for both finger- and forehead-derived PAV still warrant improvement for wide use in clinical practice. Overall, our results show that baseline-corrected finger- and forehead-derived PAV may provide a non-invasive alternative for PPV.
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Affiliation(s)
- Shaoxiong Sun
- Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
- Philips Research, Eindhoven, The Netherlands.
| | | | | | - Xi Long
- Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Philips Research, Eindhoven, The Netherlands
| | - Igor Paulussen
- Philips Research, Eindhoven, The Netherlands
- Elisabeth-Tweesteden Hospital, Tilburg, The Netherlands
| | - Ronald M Aarts
- Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Philips Research, Eindhoven, The Netherlands
| | - Gerrit J Noordergraaf
- Philips Research, Eindhoven, The Netherlands
- Elisabeth-Tweesteden Hospital, Tilburg, The Netherlands
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Addison PS, Jacquel D, Foo DMH, Antunes A, Borg UR. Video-Based Physiologic Monitoring During an Acute Hypoxic Challenge: Heart Rate, Respiratory Rate, and Oxygen Saturation. Anesth Analg 2017; 125:860-873. [PMID: 28333706 DOI: 10.1213/ane.0000000000001989] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND The physiologic information contained in the video photoplethysmogram is well documented. However, extracting this information during challenging conditions requires new analysis techniques to capture and process the video image streams to extract clinically useful physiologic parameters. We hypothesized that heart rate, respiratory rate, and oxygen saturation trending can be evaluated accurately from video information during acute hypoxia. METHODS Video footage was acquired from multiple desaturation episodes during a porcine model of acute hypoxia using a standard visible light camera. A novel in-house algorithm was used to extract photoplethysmographic cardiac pulse and respiratory information from the video image streams and process it to extract a continuously reported video-based heart rate (HRvid), respiratory rate (RRvid), and oxygen saturation (SvidO2). This information was then compared with HR and oxygen saturation references from commercial pulse oximetry and the known rate of respiration from the ventilator. RESULTS Eighty-eight minutes of data were acquired during 16 hypoxic episodes in 8 animals. A linear mixed-effects regression showed excellent responses relative to a nonhypoxic reference signal with slopes of 0.976 (95% confidence interval [CI], 0.973-0.979) for HRvid; 1.135 (95% CI, 1.101-1.168) for RRvid, and 0.913 (95% CI, 0.905-0.920) for video-based oxygen saturation. These results were obtained while maintaining continuous uninterrupted vital sign monitoring for the entire study period. CONCLUSIONS Video-based monitoring of HR, RR, and oxygen saturation may be performed with reasonable accuracy during acute hypoxic conditions in an anesthetized porcine hypoxia model using standard visible light camera equipment. However, the study was conducted during relatively low motion. A better understanding of the effect of motion and the effect of ambient light on the video photoplethysmogram may help refine this monitoring technology for use in the clinical environment.
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Affiliation(s)
- Paul S Addison
- From the *Video Biosignals Group, Medtronic Respiratory & Monitoring Solutions, Technopole Centre, Edinburgh, United Kingdom; and †Medical Affairs, Medtronic Respiratory & Monitoring Solutions, Boulder, Colorado
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Scheeren TWL, Saugel B. Journal of clinical monitoring and computing 2016 end of year summary: monitoring cerebral oxygenation and autoregulation. J Clin Monit Comput 2017; 31:241-246. [PMID: 28120178 PMCID: PMC5346134 DOI: 10.1007/s10877-017-9980-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 01/03/2017] [Indexed: 11/24/2022]
Abstract
In the perioperative and critical care setting, monitoring of cerebral oxygenation (ScO2) and cerebral autoregulation enjoy increasing popularity in recent years, particularly in patients undergoing cardiac surgery. Monitoring ScO2 is based on near infrared spectroscopy, and attempts to early detect cerebral hypoperfusion and thereby prevent cerebral dysfunction and postoperative neurologic complications. Autoregulation of cerebral blood flow provides a steady flow of blood towards the brain despite variations in mean arterial blood pressure (MAP) and cerebral perfusion pressure, and is effective in a MAP range between approximately 50–150 mmHg. This range of intact autoregulation may, however, vary considerably between individuals, and shifts to higher thresholds have been observed in elderly and hypertensive patients. As a consequence, intraoperative hypotension will be poorly tolerated, and might cause ischemic events and postoperative neurological complications. This article summarizes research investigating technologies for the assessment of ScO2 and cerebral autoregulation published in the Journal of Clinical Monitoring and Computing in 2016.
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Affiliation(s)
- Thomas W L Scheeren
- Department of Anesthesiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
| | - Bernd Saugel
- Department of Anesthesiology, Centre of Anesthesiology and Intensive Care Medicine, University Medical Centre Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
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Addison PS. Respiratory effort from the photoplethysmogram. Med Eng Phys 2017; 41:9-18. [PMID: 28126420 DOI: 10.1016/j.medengphy.2016.12.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 12/19/2016] [Accepted: 12/21/2016] [Indexed: 11/17/2022]
Abstract
The potential for a simple, non-invasive measure of respiratory effort based on the pulse oximeter signal - the photoplethysmogram or 'pleth' - was investigated in a pilot study. Several parameters were developed based on a variety of manifestations of respiratory effort in the signal, including modulation changes in amplitude, baseline, frequency and pulse transit times, as well as distinct baseline signal shifts. Thirteen candidate parameters were investigated using data from healthy volunteers. Each volunteer underwent a series of controlled respiratory effort maneuvers at various set flow resistances and respiratory rates. Six oximeter probes were tested at various body sites. In all, over three thousand pleth-based effort-airway pressure (EP) curves were generated across the various airway constrictions, respiratory efforts, respiratory rates, subjects, probe sites, and the candidate parameters considered. Regression analysis was performed to determine the existence of positive monotonic relationships between the respiratory effort parameters and resulting airway pressures. Six of the candidate parameters investigated exhibited a distinct positive relationship (p<0.001 across all probes tested) with increasing upper airway pressure repeatable across the range of respiratory rates and flow constrictions studied. These were: the three fundamental modulations in amplitude (AM-Effort), baseline (BM-Effort) and respiratory sinus arrhythmia (RSA-Effort); two pulse transit time modulations - one using a pulse oximeter probe and an ECG (P2E-Effort) and the other using two pulse oximeter probes placed at different peripheral body sites (P2-Effort); and baseline shifts in heart rate, (BL-HR-Effort). In conclusion, a clear monotonic relationship was found between several pleth-based parameters and imposed respiratory loadings at the mouth across a range of respiratory rates and flow constrictions. The results suggest that the pleth may provide a measure of changing upper airway dynamics indicative of the effort to breathe.
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Affiliation(s)
- Paul S Addison
- Minimally Invasive Therapies Group, Medtronic, The Technopole Centre, Edinburgh EH26 0PJ, Scotland, United Kingdom .
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Addison PS. Slope Transit Time (STT): A Pulse Transit Time Proxy requiring Only a Single Signal Fiducial Point. IEEE Trans Biomed Eng 2016; 63:2441-2444. [DOI: 10.1109/tbme.2016.2528507] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Predicting stroke volume and arterial pressure fluid responsiveness in liver cirrhosis patients using dynamic preload variables. Eur J Anaesthesiol 2016; 33:645-52. [DOI: 10.1097/eja.0000000000000479] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Garde A, Zhou G, Raihana S, Dunsmuir D, Karlen W, Dekhordi P, Huda T, Arifeen SE, Larson C, Kissoon N, Dumont GA, Ansermino JM. Respiratory rate and pulse oximetry derived information as predictors of hospital admission in young children in Bangladesh: a prospective observational study. BMJ Open 2016; 6:e011094. [PMID: 27534987 PMCID: PMC5013424 DOI: 10.1136/bmjopen-2016-011094] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
OBJECTIVE Hypoxaemia is a strong predictor of mortality in children. Early detection of deteriorating condition is vital to timely intervention. We hypothesise that measures of pulse oximetry dynamics may identify children requiring hospitalisation. Our aim was to develop a predictive tool using only objective data derived from pulse oximetry and observed respiratory rate to identify children at increased risk of hospital admission. SETTING Tertiary-level hospital emergency department in Bangladesh. PARTICIPANTS Children under 5 years (n=3374) presenting at the facility (October 2012-April 2013) without documented chronic diseases were recruited. 1-minute segments of pulse oximetry (photoplethysmogram (PPG), blood oxygen saturation (SpO2) and heart rate (HR)) and respiratory rate were collected with a mobile app. PRIMARY OUTCOME The need for hospitalisation based on expert physician review and follow-up. METHODS Pulse rate variability (PRV) using pulse peak intervals of the PPG signal and features extracted from the SpO2 signal, all derived from pulse oximetry recordings, were studied. A univariate age-adjusted logistic regression was applied to evaluate differences between admitted and non-admitted children. A multivariate logistic regression model was developed using a stepwise selection of predictors and was internally validated using bootstrapping. RESULTS Children admitted to hospital showed significantly (p<0.01) decreased PRV and higher SpO2 variability compared to non-admitted children. The strongest predictors of hospitalisation were reduced PRV-power in the low frequency band (OR associated with a 0.01 unit increase, 0.93; 95% CI 0.89 to 0.98), greater time spent below an SpO2 of 98% and 94% (OR associated with 10 s increase, 1.4; 95% CI 1.3 to 1.4 and 1.5; 95% CI 1.4 to 1.6, respectively), high respiratory rate, high HR, low SpO2, young age and male sex. These variables provided a bootstrap-corrected AUC of the receiver operating characteristic of 0.76. CONCLUSIONS Objective measurements, easily obtained using a mobile device in low-resource settings, can predict the need for hospitalisation. External validation will be required before clinical adoption.
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Affiliation(s)
- Ainara Garde
- Department of Electrical & Computer Engineering, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Guohai Zhou
- Department of Statistics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Shahreen Raihana
- Centre for Child and Adolescent Health, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Dustin Dunsmuir
- Department of Anesthesiology, Pharmacology & Therapeutics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Walter Karlen
- Department of Health Sciences and Technology, ETH Zurich, Zürich, Switzerland
| | - Parastoo Dekhordi
- Department of Electrical & Computer Engineering, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Tanvir Huda
- Centre for Child and Adolescent Health, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
- School of Public Health, Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Shams El Arifeen
- Centre for Child and Adolescent Health, International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Charles Larson
- Department of Pediatrics, British Columbia Children's Hospital and The University of British Columbia, Vancouver, British Columbia, Canada
| | - Niranjan Kissoon
- Department of Pediatrics, British Columbia Children's Hospital and The University of British Columbia, Vancouver, British Columbia, Canada
| | - Guy A Dumont
- Department of Electrical & Computer Engineering, The University of British Columbia, Vancouver, British Columbia, Canada
| | - J Mark Ansermino
- Department of Anesthesiology, Pharmacology & Therapeutics, The University of British Columbia, Vancouver, British Columbia, Canada
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Addison PS, Foo DMH, Jacquel D, Borg U. Video monitoring of oxygen saturation during controlled episodes of acute hypoxia. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2016:4747-4750. [PMID: 28269331 DOI: 10.1109/embc.2016.7591788] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A method for extracting video photoplethysmographic information from an RGB video stream is tested on data acquired during a porcine model of acute hypoxia. Cardiac pulsatile information was extracted from the acquired signals and processed to determine a continuously reported oxygen saturation (SvidO2). A high degree of correlation was found to exist between the video and a reference from a pulse oximeter. The calculated mean bias and accuracy across all eight desaturation episodes were -0.03% (range: -0.21% to 0.24%) and accuracy 4.90% (range: 3.80% to 6.19%) respectively. The results support the hypothesis that oxygen saturation trending can be evaluated accurately from a video system during acute hypoxia.
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Respiratory modulations in the photoplethysmogram (DPOP) as a measure of respiratory effort. J Clin Monit Comput 2015; 30:595-602. [PMID: 26377021 PMCID: PMC5023749 DOI: 10.1007/s10877-015-9763-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 08/28/2015] [Indexed: 12/03/2022]
Abstract
DPOP is a measure of the strength of respiratory modulations present in the pulse oximetry photoplethysmogram (pleth) waveform. It has been proposed as a non-invasive parameter for the prediction of the response to volume expansion in hypovolemic patients. The effect of resistive breathing on the DPOP parameter was studied to determine whether it may have an adjunct use as a measure of respiratory effort. Healthy volunteers were tasked to breathe at fixed respiratory rates over a range of airway resistances generated by a flow resistor inserted within a mouthpiece. Changes in respiratory efforts, effected by the subjects and measured as airway pressures at the mouth, were compared to DPOP values derived from a finger pulse oximeter probe. It was found that the increased effort to breathe manifests itself as an associated increase in DPOP. Further, a relationship between DPOP and percent modulation of the pleth waveform was observed. A version of the DPOP algorithm that corrects for low perfusion was implemented which resulted in an improved relationship between DPOP and PPV. Although a limited cohort of seven volunteers was used, the results suggest that DPOP may be useful as a respiratory effort parameter, given that the fluid level of the patient is maintained at a constant level over the period of analysis.
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Respiratory variations in the photoplethysmographic waveform amplitude depend on type of pulse oximetry device. J Clin Monit Comput 2015; 30:317-25. [DOI: 10.1007/s10877-015-9720-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 06/05/2015] [Indexed: 10/23/2022]
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On better estimating and normalizing the relationship between clinical parameters: comparing respiratory modulations in the photoplethysmogram and blood pressure signal (DPOP versus PPV). COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2015; 2015:576340. [PMID: 25691912 PMCID: PMC4322304 DOI: 10.1155/2015/576340] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 12/11/2014] [Indexed: 12/02/2022]
Abstract
DPOP (ΔPOP or Delta-POP) is a noninvasive parameter which measures the strength of respiratory modulations present in the pulse oximeter waveform. It has been proposed as a noninvasive alternative to pulse pressure variation (PPV) used in the prediction of the response to volume expansion in hypovolemic patients. We considered a number of simple techniques for better determining the underlying relationship between the two parameters. It was shown numerically that baseline-induced signal errors were asymmetric in nature, which corresponded to observation, and we proposed a method which combines a least-median-of-squares estimator with the requirement that the relationship passes through the origin (the LMSO method). We further developed a method of normalization of the parameters through rescaling DPOP using the inverse gradient of the linear fitted relationship. We propose that this normalization method (LMSO-N) is applicable to the matching of a wide range of clinical parameters. It is also generally applicable to the self-normalizing of parameters whose behaviour may change slightly due to algorithmic improvements.
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Addison PS, Wang R, Uribe AA, Bergese SD. Increasing signal processing sophistication in the calculation of the respiratory modulation of the photoplethysmogram (DPOP). J Clin Monit Comput 2014; 29:363-72. [PMID: 25209132 PMCID: PMC4420848 DOI: 10.1007/s10877-014-9613-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 08/27/2014] [Indexed: 11/07/2022]
Abstract
DPOP (∆POP or Delta-POP) is a non-invasive parameter which measures the strength of respiratory modulations present in the pulse oximetry photoplethysmogram (pleth) waveform. It has been proposed as a non-invasive surrogate parameter for pulse pressure variation (PPV) used in the prediction of the response to volume expansion in hypovolemic patients. Many groups have reported on the DPOP parameter and its correlation with PPV using various semi-automated algorithmic implementations. The study reported here demonstrates the performance gains made by adding increasingly sophisticated signal processing components to a fully automated DPOP algorithm. A DPOP algorithm was coded and its performance systematically enhanced through a series of code module alterations and additions. Each algorithm iteration was tested on data from 20 mechanically ventilated OR patients. Correlation coefficients and ROC curve statistics were computed at each stage. For the purposes of the analysis we split the data into a manually selected ‘stable’ region subset of the data containing relatively noise free segments and a ‘global’ set incorporating the whole data record. Performance gains were measured in terms of correlation against PPV measurements in OR patients undergoing controlled mechanical ventilation. Through increasingly advanced pre-processing and post-processing enhancements to the algorithm, the correlation coefficient between DPOP and PPV improved from a baseline value of R = 0.347 to R = 0.852 for the stable data set, and, correspondingly, R = 0.225 to R = 0.728 for the more challenging global data set. Marked gains in algorithm performance are achievable for manually selected stable regions of the signals using relatively simple algorithm enhancements. Significant additional algorithm enhancements, including a correction for low perfusion values, were required before similar gains were realised for the more challenging global data set.
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Affiliation(s)
- Paul S Addison
- Advanced Research Group, Covidien Respiratory and Monitoring Solutions, The Technopole Centre, Edinburgh, EH26 0PJ, Scotland, UK,
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