Rethinking Patient Surveillance on Hospital Wards

Feasibility and Accuracy of Wrist-Worn Sensors for Perioperative Monitoring During and After Major Abdominal Surgery: An Observational Study

INTRODUCTION

Continuous, ambulatory perioperative monitoring using wearable devices has shown promise for earlier detection of physiological deterioration and postoperative complications, preventing 'failure-to-rescue'. This study aimed to compare the accuracy of vital signs measured by wrist-based wearables with gold standard measurements from vital signs monitors or nurse assessments in major abdominal surgery.

METHODS

Adult patients were eligible for inclusion in this prospective observational study validating the Empatica E4 wrist sensor intraoperatively and postoperatively. The primary outcomes were the 95% limits of agreement (LoA) between manual and device recordings of heart rate (HR) and temperature evaluated via Bland-Altman analysis. Secondary analysis was conducted using Clarke-Error grid analysis.

RESULTS

Overall, 31 patients were recruited, and 27 patients completed the study. The median duration of recording per patient was 70.3 h, and a total of 2112 h of data recording were completed. Wrist-based HR measurement was accurate and moderately precise (bias: 0.3 bpm; 95% LoA -15.5 to 17.1), but temperature measurement was neither accurate nor precise (bias -2.2°C; 95% LoA -6.0 to 1.6). On Clarke-Error grid analysis, 74.5% and 29.6% of HR and temperature measurements, respectively, fell within the acceptable range of reference standards.

CONCLUSIONS

Continuous perioperative monitoring of HR and temperature after major abdominal surgery using wrist-based sensors is feasible but was limited in this study by low precision. While wrist-based devices offer promise for the continuous monitoring of high-risk surgical patients, current technology is inadequate. Ongoing device hardware and software innovation with robust validation is required before such technologies can be routinely adopted in clinical practice.

Introducing the Pi-CON Methodology to Overcome Usability Deficits during Remote Patient Monitoring

The adoption of telehealth has soared, and with that the acceptance of Remote Patient Monitoring (RPM) and virtual care. A review of the literature illustrates, however, that poor device usability can impact the generated data when using Patient-Generated Health Data (PGHD) devices, such as wearables or home use medical devices, when used outside a health facility. The Pi-CON methodology is introduced to overcome these challenges and guide the definition of user-friendly and intuitive devices in the future. Pi-CON stands for passive, continuous, and non-contact, and describes the ability to acquire health data, such as vital signs, continuously and passively with limited user interaction and without attaching any sensors to the patient. The paper highlights the advantages of Pi-CON by leveraging various sensors and techniques, such as radar, remote photoplethysmography, and infrared. It illustrates potential concerns and discusses future applications Pi-CON could be used for, including gait and fall monitoring by installing an omnipresent sensor based on the Pi-CON methodology. This would allow automatic data collection once a person is recognized, and could be extended with an integrated gateway so multiple cameras could be installed to enable data feeds to a cloud-based interface, allowing clinicians and family members to monitor patient health status remotely at any time.

Impact of continuous and wireless monitoring of vital signs on clinical outcomes: a propensity-matched observational study of surgical ward patients

BACKGROUND

Continuous and wireless vital sign monitoring is superior to intermittent monitoring in detecting vital sign abnormalities; however, the impact on clinical outcomes has not been established.

METHODS

We performed a propensity-matched analysis of data describing patients admitted to general surgical wards between January 2018 and December 2019 at a single, tertiary medical centre in the USA. The primary outcome was a composite of in-hospital mortality or ICU transfer during hospitalisation. Secondary outcomes were the odds of individual components of the primary outcome, and heart failure, myocardial infarction, acute kidney injury, and rapid response team activations. Data are presented as odds ratios (ORs) with 95% confidence intervals (CIs) and n (%).

RESULTS

We initially screened a population of 34,636 patients (mean age 58.3 (Range 18-101) yr, 16,456 (47.5%) women. After propensity matching, intermittent monitoring (n=12 345) was associated with increased risk of a composite of mortality or ICU admission (OR 3.42, 95% CI 3.19-3.67; P<0.001), and heart failure (OR 1.48, 95% CI 1.21-1.81; P<0.001), myocardial infarction (OR 3.87, 95% CI 2.71-5.71; P<0.001), and acute kidney injury (OR 1.32, 95% CI 1.09-1.57; P<0.001) compared with continuous wireless monitoring (n=7955). The odds of rapid response team intervention were similar in both groups (OR 0.86, 95% CI 0.79-1.06; P=0.726).

CONCLUSIONS

Patients who received continuous ward monitoring were less likely to die or be admitted to ICU than those who received intermittent monitoring. These findings should be confirmed in prospective randomised trials.

Surveillance of high-risk early postsurgical patients for real-time detection of complications using wireless monitoring (SHEPHERD study): results of a randomized multicenter stepped wedge cluster trial

Background

Vital signs measurements on the ward are performed intermittently. This could lead to failure to rapidly detect patients with deteriorating vital signs and worsens long-term outcome. The aim of this study was to test the hypothesis that continuous wireless monitoring of vital signs on the postsurgical ward improves patient outcome.

Methods

In this prospective, multicenter, stepped-wedge cluster randomized study, patients in the control group received standard monitoring. The intervention group received continuous wireless monitoring of heart rate, respiratory rate and temperature on top of standard care. Automated alerts indicating vital signs deviation from baseline were sent to ward nurses, triggering the calculation of a full early warning score followed. The primary outcome was the occurrence of new disability three months after surgery.

Results

The study was terminated early (at 57% inclusion) due to COVID-19 restrictions. Therefore, only descriptive statistics are presented. A total of 747 patients were enrolled in this study and eligible for statistical analyses, 517 patients in the control group and 230 patients in the intervention group, the latter only from one hospital. New disability at three months after surgery occurred in 43.7% in the control group and in 39.1% in the intervention group (absolute difference 4.6%).

Conclusion

This is the largest randomized controlled trial investigating continuous wireless monitoring in postoperative patients. While patients in the intervention group seemed to experience less (new) disability than patients in the control group, results remain inconclusive with regard to postoperative patient outcome due to premature study termination.

Clinical trial registration

ClinicalTrials.gov, ID: NCT02957825.

Initiatives to detect and prevent death from perioperative deterioration

PURPOSE OF REVIEW

This study indicates that there are differences between hospitals in detection, as well as in adequate management of postsurgical complications, a phenomenon that is described as 'failure-to-rescue'.In this review, recent initiatives to reduce failure-to-rescue in the perioperative period are described.

RECENT FINDINGS

Use of cognitive aids, emergency manuals, family participation as well as remote monitoring systems are measures to reduce failure-to-rescue situations. Postoperative visit of an anaesthesiologist on the ward was not shown to improve outcome, but there is still room for improvement of postoperative care.

SUMMARY

Improving the complete emergency chain, including monitoring, recognition and response in the afferent limb, as well as diagnostic and treatment in the efferent limb, should lead to reduced failure-to-rescue situations in the perioperative period.

The effect of technical filtering and clinical criteria on alert rates from continuous vital sign monitoring in the general ward

OBJECTIVES

Continuous vital sign monitoring at the general hospital ward has major potential advantages over intermittent monitoring but generates many alerts with risk of alert fatigue. We hypothesized that the number of alerts would decrease using different filters.

METHODS

This study was an exploratory analysis of the alert reducing effect from adding two different filters to continuously collected vital sign data (peripheral oxygen saturation, blood pressure, heart rate, and respiratory rate) in patients admitted after major surgery or severe medical disease. Filtered data were compared to data without artifact removal. Filter one consists of artifact removal, filter two consists of artifact removal plus duration criteria adjusted for severity of vital sign deviation. Alert thresholds were based on the National Early Warning Score (NEWS) threshold.

RESULTS

A population of 716 patients admitted for severe medical disease or major surgery with continuous wireless vital sign monitoring at the general ward with a mean monitoring time of 75.8 h, were included for the analysis. Without artifact removal, we found a median of 137 [IQR: 87-188] alerts per patient/day, artifact removal resulted in a median of 101 [IQR: 56-160] alerts per patient/day and with artifact removal combined with a duration-severity criterion, we found a median of 19 [IQR: 9-34] alerts per patient/day. Reduction of alerts was 86.4% (p < 0.001) for values without artifact removal (137 alerts) vs. the duration criteria and a reduction (19 alerts) of 81.5% (p < 0.001) for the criteria with artifact removal (101 alerts) vs. the duration criteria (19 alerts).

CONCLUSION

We conclude that a combination of artifact removal and duration-severity criteria approach substantially reduces alerts generated by continuous vital sign monitoring.

Missing data imputation techniques for wireless continuous vital signs monitoring

Wireless vital signs sensors are increasingly used for remote patient monitoring, but data analysis is often challenged by missing data periods. This study explored the performance of various imputation techniques for continuous vital signs measurements. Wireless vital signs measurements (heart rate, respiratory rate, blood oxygen saturation, axillary temperature) from surgical ward patients were used for repeated random simulation of missing data periods (gaps) of 5-60 min in two-hour windows. Gaps were imputed using linear interpolation, spline interpolation, last observation- and mean carried forwards technique, and cluster-based prognosis. Imputation performance was evaluated using the mean absolute error (MAE) between original and imputed gap samples. Besides, effects on signal features (window's slope, mean) and early warning scores (EWS) were explored. Gaps were simulated in 1743 data windows, obtained from 52 patients. Although MAE ranges overlapped, median MAE was structurally lowest for linear interpolation (heart rate: 0.9-2.6 beats/min, respiratory rate: 0.8-1.8 breaths/min, temperature: 0.04-0.17 °C, oxygen saturation: 0.3-0.7% for 5-60 min gaps) but up to twice as high for other techniques. Three techniques resulted in larger ranges of signal feature bias compared to no imputation. Imputation led to EWS misclassification in 1-8% of all simulations. Imputation error ranges vary between imputation techniques and increase with gap length. Imputation may result in larger signal feature bias compared to performing no imputation, and can affect patient risk assessment as illustrated by the EWS. Accordingly, careful implementation and selection of imputation techniques is warranted.

Rapid Response Team Activation Triggers in Adults and Children: An Integrative Review

PURPOSE

This integrative review aims to identify the triggers for rapid response team (RRT) activation and their outcomes in pediatric patients and to compare them with those of adult patients. In addition, this integrative review synthesizes the outcomes of cardiopulmonary resuscitation (CPR), intensive care unit (ICU) admission, length of hospital stay, and mortality following RRT activation.

METHOD

An integrative review using the Whittemore and Knafl methodology was undertaken with a search of three large databases (PubMed, Ovid MEDLINE, and CINAHL) and found 25 relevant studies published in the years 2017 through 2022.

RESULTS

Tachypnea, decreased oxygen saturation, tachycardia, changes in blood pressure, and level of consciousness were the most common triggers in both populations. However, specific activation triggers differed between children and adults.

CONCLUSIONS

The most common triggers for RRT are detectable through vital signs monitoring; therefore, vigilant tracking of patients' vital signs is critical and can provide early clues to clinical deterioration.

The association between vital signs abnormalities during postanaesthesia care unit stay and deterioration in the general ward following major abdominal cancer surgery assessed by continuous wireless monitoring

Objective: Vital signs abnormalities in the post-anaesthesia care unit (PACU) may identify patients at risk of severe postoperative complications in the general ward, but are sparsely investigated by continuous monitoring. We aimed to assess if the severity of vital signs abnormalities in the PACU was correlated to the duration of severe vital signs abnormalities and serious adverse events (SAEs) in the general ward. Design: Prospective cohort study. Primary exposure was PACU vital signs abnormalities assessed by a standardised PACU recovery score. Participants: Adult patients, aged ≥ 60 years, who underwent major abdominal cancer surgery. Main outcome measures: The duration of severe vital signs abnormalities were assessed by continuous wireless vital signs monitoring and, secondly, by any SAE within the first 96 hours in the general ward. Results: One-hundred patients were included, and 92 patients with a median of 91 hours (interquartile range, 71-95 hours) of vital signs recording were analysed. The maximum vital signs abnormalities in the PACU were not significantly correlated to overall vital signs abnormalities in the general ward (R = 0.13; P = 0.22). Severe circulatory abnormalities in the overall PACU stay and at discharge were significantly correlated to the duration of circulatory vital signs abnormalities on the ward (R = 0.32 [P = 0.00021] and R = 0.26 [P = 0.014], respectively). Seventeen patients (18%) experienced SAEs, without significant association to the PACU stay (area under the receiver operating characteristic [AUROC], 0.59; 95% CI, 0.46-0.73). Conclusion: Vital signs abnormalities in the PACU did not show a tendency towards predicting overall severe vital signs abnormalities or SAEs during the first days in the general ward. Circulatory abnormalities in the PACU showed a tendency towards predicting circulatory complications in the ward.

Tele-Rapid Response Team (Tele-RRT): The effect of implementing patient safety network system on outcomes of medical patients-A before and after cohort study

BACKGROUND

Rapid Response Teams were developed to provide interventions for deteriorating patients. Their activation depends on timely detection of deterioration. Automated calculation of warning scores may lead to early recognition, and improvement of RRT effectiveness.

METHOD

This was a "Before" and "After" study, in the "Before" period ward nurses activated RRT after manually recording vital signs and calculating warning scores. In the "After" period, vital signs and warning calculations were automatically relayed to RRT through a wireless monitoring network.

RESULTS

When compared to the before group, the after group had significantly lower incidence and rate of cardiopulmonary resuscitation (CPR) (2.3 / 1000 inpatient days versus 3.8 / 1000 inpatient days respectively, p = 0.01), significantly shorter length of hospital stay and lower hospital mortality, but significantly higher number of RRT activations. In multivariable logistic regression model, being in the "After" group decreases odds of CPR by 33% (OR = 0.67 [95% CI: 0.46-0.99]; p = 0.04). There was no difference between groups in ICU admission.

CONCLUSION

Automated activation of the RRT significantly reduced CPR events and rates, improved CPR success rate, reduced hospital length of stay and mortality, but increased the number of RRT activations. There were no differences in unplanned ICU admission or readmission.

Contactless Heartbeat Measurement Using Speckle Vibrometry

Monitoring of heart rate in patients in the general ward is necessary to assess the clinical situation of the patient. Currently, this is done via spot-checks on pulse rate manually or on heart rate using Electrocardiogram (ECG) by nurses. More frequent measurements would allow early detection of adverse cardiac events. In this work, we investigate a contactless measurement setup combined with a signal processing pipeline, which is based on speckle vibrometry (SV), to perform contactless heart rate monitoring of human subjects in a supine position, mimicking a resting scenario in the general ward. Our results demonstrate the feasibility of extracting heart rate with SV through varying textile thicknesses (i.e., 8 mm, 32 mm and 64 mm), with an error smaller than 3 beats per minute on average compared to the ground-truth heart rate derived from ECG.

Early diagnosis of sepsis using an E-health application for a clinical early warning system outside of the intensive care unit: a case report

Background

Elderly and frail patients who are unable to call for help in case of vital distress can develop complications during their hospitalization. As a supplement to clinical monitoring by the nursing staff, these patients can also be monitored in real time, with the Sensium E-health technology. An application notifies clinical staff of any change in their vital signs (heart rate, respiratory rate, temperature) outside of normal ranges, suggestive of physiological decline. Nurses and physicians are notified of these abnormal changes by email and also via mobile application (iPhone or iPad), allowing early intervention to prevent further deterioration.

Case presentation

An 86-year-old Caucasian female, with chronic kidney disease, was hospitalized in our medical unit for pyelonephritis associated with a moderate deterioration of serum creatinine. Remote continuous monitoring allowed us to diagnose clinical deterioration early and adjust her treatment. The treatment improved her clinical condition and amended the secondary sepsis with circulation failure in 2 days.

Conclusions

The prognosis for patients with acute complicated pyelonephritis is much worse than for those with uncomplicated pyelonephritis. Remote continuous monitoring might be helpful to early diagnose urosepsis. This technology leads to improved prognosis of patients without initial vital distress, allowing early treatment and admission to intensive care unit.

Wireless wearables for postoperative surveillance on surgical wards: a survey of 1158 anaesthesiologists in Western Europe and the USA

Background

Several continuous monitoring solutions, including wireless wearable sensors, are available or being developed to improve patient surveillance on surgical wards. We designed a survey to understand the current perception and expectations of anaesthesiologists who, as perioperative physicians, are increasingly involved in postoperative care.

Methods

The survey was shared in 40 university hospitals from Western Europe and the USA.

Results

From 5744 anaesthesiologists who received the survey link, there were 1158 valid questionnaires available for analysis. Current postoperative surveillance was mainly based on intermittent spot-checks of vital signs every 4-6 h in the USA (72%) and every 8-12 h in Europe (53%). A majority of respondents (91%) considered that continuous monitoring of vital signs should be available on surgical wards and that wireless sensors are preferable to tethered systems (86%). Most respondents indicated that oxygen saturation (93%), heart rate (80%), and blood pressure (71%) should be continuously monitored with wrist devices (71%) or skin adhesive patches (54%). They believed it may help detect clinical deterioration earlier (90%), decrease rescue interventions (59%), and decrease hospital mortality (54%). Opinions diverged regarding the impact on nurse workload (increase 46%, decrease 39%), and most respondents considered that the biggest implementation challenges are economic (79%) and connectivity issues (64%).

Conclusion

Continuous monitoring of vital signs with wireless sensors is wanted by most anaesthesiologists from university hospitals in Western Europe and in the USA. They believe it may improve patient safety and outcome, but may also be challenging to implement because of cost and connectivity issues.

[Development of clinical risk management in German hospitals]

Clinical risk management supports healthcare workers in recognizing, reducing, and managing risks in patient care. It is mandatory for all outpatient and inpatient facilities in the German healthcare system. The contents of the clinical risk management are regulated in the Social Code (Title 5), the guidelines of the Federal Joint Committee, the Patients' Rights Act, and the norms and recommendations of the Patient Safety Alliance. The Federal Joint Committee explicitly points out that minimum standards of risk management, error management, error reporting systems, complaint management in hospitals, and the use of checklists for surgical interventions must be implemented.The legislator requires that the effectiveness of the clinical risk management be checked regularly. Questionnaire surveys on clinical risk management in Germany show an overall positive development. However, the data are not sufficient for a comprehensive assessment. Methodologically reliable procedures should therefore be developed that check the status of the clinical risk management much more frequently and regularly. The data measuring structure, process, and outcome should be collected systematically and presented in a comparative manner in relation to the facilities.Opportunities for clinical risk management arise from the World Health Organization's Global Action Safety Plan, advances in digitization, the integration of clinical risk management into organizational risk management, and the improvement of structural quality. Clinical risk management must be given even more space in the daily routine of doctors and nurses. This requires competence and human resources in this area. These are not sufficiently available in German hospitals.

Economics of implementing an early deterioration detection solution for general care patients at a US hospital

Aim: This study estimates the costs and outcomes pre- versus post-implementation of an early deterioration detection solution (EDDS), which assists in identifying patients at risk of clinical decline. Materials & methods: A retrospective database analysis was conducted to assess average costs per discharge, length of stay (LOS), complications, in-hospital mortality and 30-day all-cause re-admissions pre- versus post-implementation of an EDDS. Results: Average costs per discharge were significantly reduced by 18% (US$16,201 vs $13,304; p = 0.007). Average LOS was also significantly reduced (6 vs 5 days; p = 0.033), driven by a reduction in general care LOS of 1 day (p = 0.042). Complications, in-hospital mortality and 30-day all-cause re-admissions were similar. Conclusion: Costs and LOS were lower after implementation of an EDDS for general care patients.

Continuous vital sign monitoring using a wearable patch sensor in obese patients: a validation study in a clinical setting

Our aim was to determine the agreement of heart rate (HR) and respiratory rate (RR) measurements by the Philips Biosensor with a reference monitor (General Electric Carescape B650) in severely obese patients during and after bariatric surgery. Additionally, sensor reliability was assessed. Ninety-four severely obese patients were monitored with both the Biosensor and reference monitor during and after bariatric surgery. Agreement was defined as the mean absolute difference between both monitoring devices. Bland Altman plots and Clarke Error Grid analysis (CEG) were used to visualise differences. Sensor reliability was reflected by the amount, duration and causes of data loss. The mean absolute difference for HR was 1.26 beats per minute (bpm) (SD 0.84) during surgery and 1.84 bpm (SD 1.22) during recovery, and never exceeded the 8 bpm limit of agreement. The mean absolute difference for RR was 1.78 breaths per minute (brpm) (SD 1.90) during surgery and 4.24 brpm (SD 2.75) during recovery. The Biosensor's RR measurements exceeded the 2 brpm limit of agreement in 58% of the compared measurements. Averaging 15 min of measurements for both devices improved agreement. CEG showed that 99% of averaged RR measurements resulted in adequate treatment. Data loss was limited to 4.5% of the total duration of measurements for RR. No clear causes for data loss were found. The Biosensor is suitable for remote monitoring of HR, but not RR in morbidly obese patients. Future research should focus on improving RR measurements, the interpretation of continuous data, and development of smart alarm systems.

Outpatient surgery for the inpatient: an introduction to postacute care

PURPOSE OF REVIEW

This article considers how postacute care (PAC) facilities such as skilled nursing facilities, inpatient rehabilitation facilities and long-term care hospitals could represent an opportunity for outpatient surgical facilities to improve patient care. In order to understand how these facilities interact with outpatient surgical services, it is first necessary to understand the types of facilities that provide PAC.

RECENT FINDINGS

The significant costs associated with PAC have led to some proposed regulatory changes. Evidence examining postacute costs following total joint replacement has indicated that these costs may be decreased with cooperative efforts between perioperative physicians and PAC facilities. However, the lack of currently published data on the interaction between outpatient surgery and inpatient PAC facilities creates a need to explore how greater cooperation between these types of facilities could lead to improvements in patient care.

SUMMARY

PAC facilities are inpatient facilities focused on the rehabilitation of patients recovering from an acute illness or surgical intervention. This article seeks to provide ambulatory practitioners a fundamental understanding of PAC as a starting point for future collaborative efforts with PAC facilities; improving care for patients referred to and from PAC facilities for outpatient surgical care.

Remote transmission monitoring for postoperative perineural analgesia after major orthopedic surgery: A multicenter, randomized, parallel-group, controlled trial

STUDY OBJECTIVE

After surgery, patients reported the delay in receiving help as the primary factor for poorly controlled pain. This study aimed to compare the effectiveness of patient management through two communication modalities: remote transmission (RT) versus bedside control (BC). We hypothesized that using remote technology for pump programming may provide the best postoperative infusion regimen for the patient's self-assessment of pain and adverse events.

DESIGN

A multicenter, randomized, parallel-group, controlled trial.

SETTING

Anesthesiology department and orthopedic surgery ward at three university hospitals.

PATIENTS

Eighty patients undergoing orthopedic surgery with postoperative perineural patient-controlled analgesia were included.

INTERVENTIONS

Two groups (n = 40 for each group) were formed by randomization. In the postoperative period, perineural analgesia was followed up via an RT system or BC for 72 h.

MEASUREMENTS

A nurse assessed daily pain, sensory and motor blocks and adverse events. Patients completed a questionnaire three times a day and alerted for any problem according to the group (RT system or nurses' follow-up). On the third postoperative day, the nurse removed the catheter, completed the final assessment, and collected the historical data from the pump. A physician's shorter response time to change the patient control analgesia (PCA) program was the primary endpoint.

RESULTS

Of the 80 patients, 71 were analyzed (34 were randomized to the RT group and 37 to the BC group). Fifty-eight pump setting changes were noted. Analysis of repeated evaluations shows that mean time (SD) to change the PCA pump settings was significantly lower in the RT group (20 min (22.3 min)) than in the BC group (55.9 min (71.1 min)); mean difference [95% CI], -35.9 min [-74.3 to 2.4]); β estimation [95% CI], -34 [-63 to -6], p = 0.011). Pain relief, sensory and motor blocks did not differ between the groups: β estimation [95% CI], 0.1 [-0.4 to 0.6], p = 0.753; 0.5 [-0.4 to 1.4], p = 0.255; 0.9 [-0.04 to 1.8], p = 0.687, respectively. β = -34 [-63 to -6], p = 0.011). The consumption of ropivacaine, nurse workload and the cost of the analgesia regimen decreased in the RT group. No differences were noted in satisfaction scores or complication rates.

CONCLUSIONS

The response time for the physician to change the PCA program when necessary was shorter for patients using RT and alerts to the physician were more frequent compared with spot checks by nurses. RT helps to decrease nurses' workload, ropivacaine consumption, and costs but did not affect postoperative pain relief, complication rate, or patient-reported satisfaction score.

IRB CONTACT INFORMATION

Comité de Protection des Personnes, Sud Méditerranée III, Montpellier-Nîmes, France, registration number EudraCT A01698-35.

CLINICAL TRIAL NUMBER

ClinicalTrials.gov ID:NCT02018068 PROTOCOL: The full trial protocol can be accessed at Department of Anesthesiology and Critical Care Medicine, Medical Research and Statistics Unit, Lapeyronie University Hospital, Avenue Doten G Giraud, Montpellier, France. s-bringuierbranchereau@chu-montpellier.fr.

Clinical evaluation of a wearable sensor for mobile monitoring of respiratory rate on hospital wards

A wireless and wearable system was recently developed for mobile monitoring of respiratory rate (RR). The present study was designed to compare RR mobile measurements with reference capnographic measurements on a medical-surgical ward. The wearable sensor measures impedance variations of the chest from two thoracic and one abdominal electrode. Simultaneous measurements of RR from the wearable sensor and from the capnographic sensor (1 measure/minute) were compared in 36 ward patients. Patients were monitored for a period of 182 ± 56 min (range 68–331). Artifact-free RR measurements were available 81% of the monitoring time for capnography and 92% for the wearable monitoring system (p < 0.001). A total of 4836 pairs of simultaneous measurements were available for analysis. The average reference RR was 19 ± 5 breaths/min (range 6–36). The average difference between the wearable and capnography RR measurements was − 0.6 ± 2.5 breaths/min. Error grid analysis showed that the proportions of RR measurements done with the wearable system were 89.7% in zone A (no risk), 9.6% in zone B (low risk) and < 1% in zones C, D and E (moderate, significant and dangerous risk). The wearable method detected RR values > 20 (tachypnea) with a sensitivity of 81% and a specificity of 93%. In ward patients, the wearable sensor enabled accurate and precise measurements of RR within a relatively broad range (6–36 b/min) and the detection of tachypnea with high sensitivity and specificity.