Revitalizing a vital sign: improving detection of tachypnea at primary triage

Wearable Solutions Using Physiological Signals for Stress Monitoring on Individuals with Autism Spectrum Disorder (ASD): A Systematic Literature Review

Some previous studies have focused on using physiological signals to detect stress in individuals with ASD through wearable devices, yet few have focused on how to design such solutions. Wearable technology may be a valuable tool to aid parents and caregivers in monitoring the emotional states of individuals with ASD who are at high risk of experiencing very stressful situations. However, effective wearable devices for individuals with ASD may need to differ from solutions for those without ASD. People with ASD often have sensory sensitivity and may, therefore, not tolerate certain types of accessories and experience discomfort when using them. We used the Scopus, PubMed, WoS, and IEEE-Xplore databases to search for studies published from 2014 to 2024 to answer four research questions related to wearable solutions for individuals with ASD, physiological parameters, and techniques/processes used for stress detection. Our review found 31 articles; not all studies considered individuals with ASD, and some were beyond the scope of this review. Most of the studies reviewed are based on cardiac activity for stress monitoring using photoplethysmography (PPG) and electrocardiography (ECG). However, limitations include small sample sizes, variability in study conditions, and the need for customization in stress detection algorithms. In addition, there is a need to customize the stress threshold due to the device's high individual variability and sensitivity. The potential of wearable solutions for stress monitoring in ASD is evident, but challenges include the need for user-friendly and unobtrusive designs and integrating these technologies into comprehensive care plans.

Assessment of respiratory rate monitoring in the emergency department

Objectives

This study aimed to compare the different respiratory rate (RR) monitoring methods used in the emergency department (ED): manual documentation, telemetry, and capnography.

Methods

This is a retrospective study using recorded patient monitoring data. The study population includes patients who presented to a tertiary care ED between January 2020 and December 2022. Inclusion and exclusion criteria were patients with simultaneous recorded RR data from all three methods and less than 10 min of recording, respectively. Linear regression and Bland-Altman analysis were performed between different methods.

Results

A total of 351 patient encounters met study criteria. Linear regression yielded an R-value of 0.06 (95% confidence interval [CI] 0.00-0.12) between manual documentation and telemetry, 0.07 (95% CI 0.01-0.13) between manual documentation and capnography, and 0.82 (95% CI 0.79-0.85) between telemetry and capnography. The Bland-Altman analysis yielded a bias of -0.8 (95% limits of agreement [LOA] -12.2 to 10.6) between manual documentation and telemetry, bias of -0.6 (95% LOA -13.5 to 12.3) between manual documentation and capnography, and bias of 0.2 (95% LOA -6.2 to 6.6) between telemetry and capnography.

Conclusion

There is a poor correlation between manual documentation and both automated methods, while there is relatively good agreement between the automated methods. This finding highlights the need to further investigate the methodology used by the ED staff in monitoring and documenting RR and ways to improve its reliability given that many important clinical decisions are made based on these assessments.

Implementation of a Continuous Patient Monitoring System in the Hospital Setting: A Qualitative Study

BACKGROUND

Technology can improve care delivery, patient outcomes, and staff satisfaction, but integration into the clinical workflow remains challenging. To contribute to this knowledge area, this study examined the implementation continuum of a contact-free, continuous monitoring system (CFCM) in an inpatient setting. CFCM monitors vital signs and uses the information to alert clinicians of important changes, enabling early detection of patient deterioration.

METHODS

Data were collected throughout the entire implementation continuum at a community teaching hospital. Throughout the study, 3 group and 24 individual interviews and five process observations were conducted. Postimplementation alarm response data were collected. Analysis was conducted using triangulation of information sources and two-coder consensus.

RESULTS

Preimplementation perceived barriers were alarm fatigue, questions about accuracy and trust, impact on patient experience, and challenges to the status quo. Stakeholders identified the value of CFCM as preventing deterioration and benefitting patients who are not good candidates for telemetry. Educational materials addressed each barrier and emphasized the shared CFCM values. Mean alarm response times were below the desired target of two minutes. Postimplementation interview analysis themes revealed lessened concerns of alarm fatigue and improved trust in CFCM than anticipated. Postimplementation challenges included insufficient training for secondary users and impact on patient experience.

CONCLUSION

In addition to understanding the preimplementation anticipated barriers to implementation and establishing shared value before implementation, future recommendations include studying strategies for optimal tailoring of education to each user group, identifying and reinforcing positive process changes after implementation, and including patient experience as the overarching element in frameworks for digital tool implementation.

Goulart A, Desuó IC, Gomes G. Application of thermography to estimate respiratory rate in the emergency room: The journal Temperature toolbox

Among the vital signs collected during hospital triage, respiratory rate is an important parameter associated with physiological, pathophysiological, and emotional changes. In recent years, the importance of its verification in emergency centers due to the severe acute respiratory syndrome 2 (SARS2) pandemic has become very clear, although it is still one of the least evaluated and collected vital signs. In this context, infrared imaging has been shown to be a reliable estimator of respiratory rate, with the advantage of not requiring physical contact with patients. The objective of this study was to evaluate the potential of analyzing a sequence of thermal images as an estimator of respiratory rate in the clinical routine of an emergency room. We used an infrared thermal camera (T540, Flir Systems) to obtain the respiratory rate data of 136 patients, based on nostrils' temperature fluctuation, during the peak of the COVID-19 pandemic in Brazil and compared it with the chest incursion count method, commonly employed in the emergency screening procedures. We found a good agreement between both methods, with Bland-Altman limits of agreement ranging from -4 to 4 min-1, no proportional bias (R2 = 0.021, p = 0.095), and a strong correlation between them (r = 0.95, p < 0.001). Our results suggest that infrared thermography has potential to be a good estimator of respiratory rate in the routine of an emergency room.

Vital signs, clinical rules and gut feeling: observational study among fever patients

BACKGROUND

General practitioners (GPs) decide which patients with fever need referral to the emergency department (ED). Vital signs, clinical rules and gut feeling can influence this critical management decision.

AIM

to investigate which vital signs are measured by GPs, and whether referral is associated with vital signs, clinical rules, or gut feeling.

DESIGN & SETTING

prospective observational study at two out-of-hours GP cooperatives METHOD: during two nine-day periods, GPs performed their regular work-up in patients ≥18 y with fever (≥38.0°C). Subsequently, researchers measured missing vital signs for completion of the Systemic Inflammatory Response Syndrome (SIRS) criteria and the quick Sequential Organ Failure Assessment (qSOFA) score. We investigated associations between the number of referrals, positive SIRS/qSOFA scores and GPs' gut feeling.

RESULTS

GPs measured and recorded all vital signs required for SIRS/qSOFA calculation in 24 of 108 (22.2%) assessed patients and referred 45 (41.7%) to the ED. Higher respiratory rates, temperatures, clinical rules and gut feeling were associated with referral. During 7-day follow-up, 9 (14.3%) of 63 initially not referred patients were admitted to hospital.

CONCLUSION

GPs measured and recorded all vital signs for SIRS and qSOFA in 1 in 5 patients with fever and referred half of 63 SIRS positive and almost all of 22 qSOFA positive patients. Some vital signs and gut feeling were associated with referral, but none were consistently present in all referred patients. The vast majority of patients who were not initially referred remained at home during follow-up.

Initial assessment in emergency departments by chief complaint and respiratory rate

BACKGROUND

Understanding heterogeneity of the respiratory rate (RR) as a risk stratification marker across chief complaints is important to reduce misinterpretation of the risk posed by outcome events and to build accurate risk stratification tools. This study was conducted to investigate the associations between RR and clinical outcomes according to the five most frequent chief complaints in an emergency department (ED): fever, shortness of breath, altered mental status, chest pain, and abdominal pain.

METHODS

This retrospective cohort study examined ED data of all adult patients who visited the ED of a tertiary medical center during April 2018-September 2019. The primary exposure was RR at the ED visit. Outcome measures were hospitalization and mechanical ventilation use. We used restrictive cubic spline and logistic regression models to assess the association of interest.

RESULTS

Of 16 956 eligible ED patients, 4926 (29%) required hospitalization; 448 (3%) required mechanical ventilation. Overall, U-shaped associations were found between RR and the risk of hospitalization (eg, using RR = 16 as the reference, the odds ratio [OR] of RR = 32, 6.57 [95% CI 5.87-7.37]) and between RR and the risk of mechanical ventilation. This U-shaped association was driven by patients' association with altered mental status (eg, OR of RR = 12, 2.63 [95% CI 1.25-5.53]). For patients who have fever or shortness of breath, the risk of hospitalization increased monotonously with increased RR.

CONCLUSIONS

U-shaped associations of RR with the risk of overall clinical outcomes were found. These associations varied across chief complaints.

Classifying signals from a wearable accelerometer device to measure respiratory rate

Background

Automatic measurement of respiratory rate in general hospital patients is difficult. Patient movement degrades the signal and variation of the breathing cycle means that accurate observation for ≥60 s is needed for adequate precision.

Methods

We studied acutely ill patients recently admitted to a teaching hospital. Breath duration was measured from a triaxial accelerometer attached to the chest wall and compared with a signal from a nasal cannula. We randomly divided the patient records into a training (n=54) and a test set (n=7). We used machine learning to train a neural network to select reliable signals, automatically identifying signal features associated with accurate measurement of respiratory rate. We used the test records to assess the accuracy of the device, indicated by the median absolute difference between respiratory rates, provided by the accelerometer and by the nasal cannula.

Results

In the test set of patients, machine classification of the respiratory signal reduced the median absolute difference (interquartile range) from 1.25 (0.56–2.18) to 0.48 (0.30–0.78) breaths per min. 50% of the recording periods were rejected as unreliable and in one patient, only 10% of the signal time was classified as reliable. However, even only 10% of observation time would allow accurate measurement for 6 min in an hour of recording, giving greater reliability than nurse charting, which is based on much less observation time.

Conclusion

Signals from a body-mounted accelerometer yield accurate measures of respiratory rate, which could improve automatic illness scoring in adult hospital patients.

A machine learning method was developed to classify sections of breathing records from acutely ill patients wearing a small wireless motion sensor. This would allow accurate and automatic measurement, recording, and charting of respiratory rate.https://bit.ly/301P8XW

Quantitative systematic review: Sources of inaccuracy in manually measured adult respiratory rate data

AIMS

To identify the potential sources of inaccuracy in manually measured adult respiratory rate (RR) data and quantify their effects.

DESIGN

Quantitative systematic review with meta-analyses where appropriate.

DATA SOURCES

Medline, CINAHL, and Cochrane Library (from database inception to 31 July 2019).

REVIEW METHODS

Studies presenting data on individual sources of inaccuracy in the manual measurement of adult RR were analysed, assessed for quality, and grouped according to the source of inaccuracy investigated. Quantitative data were extracted and synthesized and meta-analyses performed where appropriate.

RESULTS

Included studies (N = 49) identified five sources of inaccuracy. The awareness effect creates an artefactual reduction in actual RR, and observation methods involving shorter counts cause systematic underscoring. Individual RR measurements can differ substantially in either direction between observations due to inter- or intra-observer variability. Value bias, where particular RRs are over-represented (suggesting estimation), is a widespread problem. Recording omission is also widespread, with higher average rates in inpatient versus triage/admission contexts.

CONCLUSION

This review demonstrates that manually measured RR data are subject to several potential sources of inaccuracy.

IMPACT

RR is an important indicator of clinical deterioration and commonly included in track-and-trigger systems. However, the usefulness of RR data depends on the accuracy of the observations and documentation, which are subject to five potential sources of inaccuracy identified in this review. A single measurement may be affected by several factors. Hence, clinicians should interpret recorded RR data cautiously unless systems are in place to ensure its accuracy. For nurses, this includes counting rather than estimating RRs, employing 60-s counts whenever possible, ensuring patients are unaware that their RR is being measured, and documenting the resulting value. For any given site, interventions to improve measurement should take into account the local organizational and cultural context, available resources, and the specific measurement issues that need to be addressed.

A hierarchical logistic regression predicting rapid respiratory rates from post-exertional malaise

BACKGROUND

Past research has found high rates of hyperventilation in patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), but hyperventilation can be influenced by psychological factors. Clinical respiratory rates have been less frequently assessed.

AIM

This study aimed to identify the predictors of rapid respiratory rates in patients referred to an outpatient clinic specializing in ME/CFS.

METHODS

Adults (n = 216) referred to an outpatient clinic specializing in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) participated in a two-day cardiopulmonary exercise test. As part of that evaluation, subjects had resting respiratory rates measured on two consecutive days. The current study used questionnaires to assess the relationship between tachypnea (rapid respiratory rates) and a variety of domains including post-exertional malaise (PEM), a common complaint in patients with ME/CFS, and psychiatric/somatic symptoms, using hierarchical logistic regression analysis.

RESULTS

PEM was a significant predictor of tachypnea, while psychological/somatic assessments and sedentary behaviors were not significantly predictive of tachypnea.

CONCLUSIONS

These findings suggest that respiratory rate may be useful as an objective clinical metric of PEM, and potentially ME/CFS.

The Importance of Respiratory Rate Monitoring: From Healthcare to Sport and Exercise

Respiratory rate is a fundamental vital sign that is sensitive to different pathological conditions (e.g., adverse cardiac events, pneumonia, and clinical deterioration) and stressors, including emotional stress, cognitive load, heat, cold, physical effort, and exercise-induced fatigue. The sensitivity of respiratory rate to these conditions is superior compared to that of most of the other vital signs, and the abundance of suitable technological solutions measuring respiratory rate has important implications for healthcare, occupational settings, and sport. However, respiratory rate is still too often not routinely monitored in these fields of use. This review presents a multidisciplinary approach to respiratory monitoring, with the aim to improve the development and efficacy of respiratory monitoring services. We have identified thirteen monitoring goals where the use of the respiratory rate is invaluable, and for each of them we have described suitable sensors and techniques to monitor respiratory rate in specific measurement scenarios. We have also provided a physiological rationale corroborating the importance of respiratory rate monitoring and an original multidisciplinary framework for the development of respiratory monitoring services. This review is expected to advance the field of respiratory monitoring and favor synergies between different disciplines to accomplish this goal.

Current clinical methods of measurement of respiratory rate give imprecise values

Background

Respiratory rate is a basic clinical measurement used for illness assessment. Errors in measuring respiratory rate are attributed to observer and equipment problems. Previous studies commonly report rate differences ranging from 2 to 6 breaths·min^-1 between observers.

Methods

To study why repeated observations should vary so much, we conducted a virtual experiment, using continuous recordings of breathing from acutely ill patients. These records allowed each breathing cycle to be precisely timed. We made repeated random measures of respiratory rate using different sample durations of 30, 60 and 120 s. We express the variation in these repeated rate measurements for the different sample durations as the interquartile range of the values obtained for each subject. We predicted what values would be found if a single measure, taken from any patient, were repeated and inspected boundary values of 12, 20 or 25 breaths·min^-1, used by the UK National Early Warning Score, for possible mis-scoring.

Results

When the sample duration was nominally 30 s, the mean interquartile range of repeated estimates was 3.4 breaths·min^-1. For the 60 s samples, the mean interquartile range was 3 breaths·min^-1, and for the 120 s samples it was 2.5 breaths·min^-1. Thus, repeat clinical counts of respiratory rate often differ by >3 breaths·min^-1. For 30 s samples, up to 40% of National Early Warning Scores could be misclassified.

Conclusions

Early warning scores will be unreliable when short sample durations are used to measure respiratory rate. Precision improves with longer sample duration, but this may be impractical unless better measurement methods are used.

Contrasting characters of quick methods to measure respiratory rate in a clinical setting

INTRODUCTION

Many medical professionals unofficially use quick methods for saving time. However, the evidence of such assessments is limited. The main aim of this article is verifying the agreement of these methods.

OBJECTIVES

Overall, 106 out-patients were simultaneously evaluated with respect to the respiratory time measurement (RTM; 60 divided by the single respiratory time), 15 seconds period quadruple respiratory rate (15secRR; 15 seconds respiratory rate multiplied by 4), and 1-min respiratory rate (1minRR; gold standard respiratory rate).

METHOD

We assessed the correlation, Bland-Altman plot, kappa value, and normalized root mean square error of the quick methods for the respiratory rate, with 1minRR as the gold standard.

RESULTS

The mean ± SD of 1minRR, RTM, and 15secRR are 20.4 ± 5.6, 19.1 ± 5.7, and 21.4 ± 6.5 breathes per minute, respectively. The correlation between RTM and 1minRR was 0.85 (95% confidence interval [95% CI]: 0.79-0.90), while that between 15secRR and 1minRR was 0.81 (95% CI: 0.74-0.87). The kappa coefficients between RTM and 1minRR, between 15secRR and 1minRR, and between RTM and 15secRR were 0.57 (95% CI: 0.41-0.72), 0.59 (95% CI: 0.43-0.74), and 0.37 (95% CI: 0.20-0.53), respectively. The normalized root mean square error between RTM and 1minRR was 16.9% and that between 15secRR and 1minRR was 15.0%. The Bland Altman plot demonstrated that RTM and 15secRR showed contrasting characteristics.

CONCLUSION

Compared to the gold standard, RTM tends to underestimate, while 15secRR tends to overestimate the respiratory rate. Therefore, health care professionals should be aware of this methodological tendency to assess vital signs properly.

A Novel, Contactless, Portable “Spot-Check” Device Accurately Measures Respiratory Rate

Respiratory rate (RR) is an important vital sign used in the initial and ongoing assessment of acutely ill patients. It is also used as a predictor of serious deterioration in a patient's clinical condition. Convenient electronic devices exist for measurement of pulse, blood pressure, oxygen saturation, and temperature. Although devices which measure RR exist, none has entered everyday clinical practice. We have developed a contactless portable respiratory rate monitor (CPRM) and evaluated the agreement in respiratory rate measurements between existing methods and our new device. The CPRM uses thermal anemometry to measure breath signals during inspiration and expiration. RR data were collected from 52 healthy adult volunteers using respiratory inductance plethysmography (RIP) bands (established contact method), visual counting of chest movements (established noncontact method), and the CPRM (new method), simultaneously. Two differently shaped funnel attachments to the CPRM were evaluated for each volunteer. Data showed a good agreement between measurements from the CPRM and the gold standard RIP, with intraclass correlation coefficient (ICC): 0.836, mean difference 0.46 and 95% limits of agreement of −5.90 to 6.83. When separate air inlet funnels of the CPRM were analyzed, stronger agreement was seen with an elliptical air inlet; ICC 0.908, mean difference 0.37 with 95% limits of agreement −4.35 to 5.08. A contactless device for accurately and quickly measuring respiratory rate will be an important triage tool in the clinical assessment of patients. More testing is needed to explore the reasons for outlying measurements and to evaluate in the clinical setting.

Wearable Devices for Precision Medicine and Health State Monitoring

Wearable technologies will play an important role in advancing precision medicine by enabling measurement of clinically-relevant parameters describing an individual's health state. The lifestyle and fitness markets have provided the driving force for the development of a broad range of wearable technologies that can be adapted for use in healthcare. Here we review existing technologies currently used for measurement of the four primary vital signs: temperature, heart rate, respiration rate, and blood pressure, along with physical activity, sweat, and emotion. We review the relevant physiology that defines the measurement needs and evaluate the different methods of signal transduction and measurement modalities for the use of wearables in healthcare.

Wearable devices for remote vital signs monitoring in the outpatient setting: an overview of the field

Early detection of physiological deterioration has been shown to improve patient outcomes. Due to recent improvements in technology, comprehensive outpatient vital signs monitoring is now possible. This is the first review to collate information on all wearable devices on the market for outpatient physiological monitoring.

A scoping review was undertaken. The monitors reviewed were limited to those that can function in the outpatient setting with minimal restrictions on the patient’s normal lifestyle, while measuring any or all of the vital signs: heart rate, ECG, oxygen saturation, respiration rate, blood pressure and temperature.

A total of 270 papers were included in the review. Thirty wearable monitors were examined: 6 patches, 3 clothing-based monitors, 4 chest straps, 2 upper arm bands and 15 wristbands. The monitoring of vital signs in the outpatient setting is a developing field with differing levels of evidence for each monitor. The most common clinical application was heart rate monitoring. Blood pressure and oxygen saturation measurements were the least common applications. There is a need for clinical validation studies in the outpatient setting to prove the potential of many of the monitors identified.

Research in this area is in its infancy. Future research should look at aggregating the results of validity and reliability and patient outcome studies for each monitor and between different devices. This would provide a more holistic overview of the potential for the clinical use of each device.

Accuracy and interobserver-agreement of respiratory rate measurements by healthcare professionals, and its effect on the outcomes of clinical prediction/diagnostic rules

Objective

In clinical prediction/diagnostic rules aimed at early detection of critically ill patients, the respiratory rate plays an important role. We investigated the accuracy and interobserver-agreement of respiratory rate measurements by healthcare professionals, and the potential effect of incorrect measurements on the scores of 4 common clinical prediction/diagnostic rules: Systemic Inflammatory Response Syndrome (SIRS) criteria, quick Sepsis-related Organ Failure Assessment (qSOFA), National Early Warning Score (NEWS), and Modified Early Warning Score (MEWS).

Methods

Using an online questionnaire, we showed 5 videos with a healthy volunteer, breathing at a fixed (true) rate (13–28 breaths/minute). Respondents measured the respiratory rate, and categorized it as low, normal, or high. We analysed how accurate the measurements were using descriptive statistics, and calculated interobserver-agreement using the intraclass correlation coefficient (ICC), and agreement between measurements and categorical judgments using Cohen’s Kappa. Finally, we analysed how often incorrect measurements led to under/overestimation in the selected clinical rules.

Results

In total, 448 healthcare professionals participated. Median measurements were slightly higher (1-3/min) than the true respiratory rate, and 78.2% of measurements were within 4/min of the true rate. ICC was moderate (0.64, 95% CI 0.39–0.94). When comparing the measured respiratory rates with the categorical judgments, 14.5% were inconsistent. Incorrect measurements influenced the 4 rules in 8.8% (SIRS) to 37.1% (NEWS). Both underestimation (4.5–7.1%) and overestimation (3.9–32.2%) occurred.

Conclusions

The accuracy and interobserver-agreement of respiratory rate measurements by healthcare professionals are suboptimal. This leads to both over- and underestimation of scores of four clinical prediction/diagnostic rules. The clinically most important effect could be a delay in diagnosis and treatment of (critically) ill patients.

Remote Pediatric Critical Care Telephone Consultations: Quality and Outcomes

There are no studies describing the nature and quality of telephone consultations for critically ill children despite being an important part of pediatric intensive care. We described pediatric telephone consultations to a PICU in Ontario, Canada in 2011 and 2012. Of 203 consultations, 104 patients (51.2%) were admitted to the PICU; this was associated with weekend consultations ( p  = 0.005) and referral hospital location ( p  = 0.036). Frequency of interruptions was 1 in every 3.2 (2.0, 5.7) minutes and not associated with call content. Twenty-one percent of consults had limited discussion of vital signs. Our study described our center's remote critical care consultation program and outcomes.

Reliability of Zephyr Bioharness and Fitbit Charge Measures of Heart Rate and Activity at Rest, During the Modified Canadian Aerobic Fitness Test, and Recovery

Nazari, G, MacDermid, JC, Sinden, KE, Richardson, J, and Tang, A. Reliability of Zephyr Bioharness and Fitbit Charge measures of heart rate and activity at rest, during the modified Canadian Aerobic Fitness Test, and recovery. J Strength Cond Res 33(2): 559-571, 2019-The purpose of this study was to determine the intrasession and intersession reliability of Zephyr Bioharness (ZB) and Fitbit Charge variables in both healthy men and women at rest, during the Modified Canadian Aerobic Fitness Test (mCAFT), and throughout recovery. Stratified convenience and snowball sampling were used to recruit 60 participants (30 women, 48 ± 15 years) and (30 men, 48 ± 15 years) from McMaster University student, staff, and faculty population. At rest, intrasession average heart rate (b·min). Intraclass correlation coefficients (ICCs) and Standard Error of Measurement [SEM] for Zephyr ranged from (0.94-0.97) [1.17-1.70] to (0.92-0.97) [1.45-2.10] for Fitbit Charge. During the mCAFT, the Zephyr ICCs and (SEM) ranged from 0.31-0.99 (1.28-8.10) to 0.45-0.99 (1.45-8.71) for the Fitbit Charge. Throughout the recovery, the ICCs and (SEM) ranged from 0.44-0.98 (1.26-10.47) to 0.45-0.98 (1.15-11.90) for Zephyr and Fitbit devices, respectively. At rest, intersession ICCs (SEM) for Zephyr and Fitbit ranged from 0.90-0.94 (1.73-2.37) to 0.88-0.94 (1.83-2.67), respectively. At mCAFT, the Zephyr ICCs (SEM) ranged from 0.91-0.97 (3.12-4.64) to 0.85-0.98 (3.28-4.88) for the Fitbit. Throughout the recovery, the ICCs (SEM) ranged from 0.93-0.97 (2.65-4.66) to 0.76-0.91 (3.17-4.67) for Zephyr and Fitbit devices, respectively. To conclude, both the ZB and Fitbit Charge devices demonstrated excellent reliability measures throughout the 3 phases. The findings from our study add to the existing pool of literature regarding the reliability parameters of wearable devices and suggest that stable and consistent measures of heart rate and physical activity can be obtained using ZB and Fitbit Charge devices among healthy male and female participants at rest, during a standardized submaximal fitness test (mCAFT), and throughout recovery.

Recent development of respiratory rate measurement technologies

Respiratory rate (RR) is an important physiological parameter whose abnormality has been regarded as an important indicator of serious illness. In order to make RR monitoring simple to perform, reliable and accurate, many different methods have been proposed for such automatic monitoring. According to the theory of respiratory rate extraction, methods are categorized into three modalities: extracting RR from other physiological signals, RR measurement based on respiratory movements, and RR measurement based on airflow. The merits and limitations of each method are highlighted and discussed. In addition, current works are summarized to suggest key directions for the development of future RR monitoring methodologies.

Postoperative ward monitoring - Why and what now?

The postoperative ward is considered an ideal nursing environment for stable patients transitioning out of the hospital. However, approximately half of all in-hospital cardiorespiratory arrests occur here and are associated with poor outcomes. Current monitoring practices on the hospital ward mandate intermittent vital sign checks. Subtle changes in vital signs often occur at least 8-12 h before an acute event, and continuous monitoring of vital signs would allow for effective therapeutic interventions and potentially avoid an imminent cardiorespiratory arrest event. It seems tempting to apply continuous monitoring to every patient on the ward, but inherent challenges such as artifacts and alarm fatigue need to be considered. This review looks to the future where a continuous, smarter, and portable platform for monitoring of vital signs on the hospital ward will be accompanied with a central monitoring platform and machine learning-based pattern detection solutions to improve safety for hospitalized patients.

Respiratory rates observed over 15 and 30 s compared with rates measured over 60 s: practice-based evidence from an observational study of acutely ill adult medical patients during hospital admission

BACKGROUND

Respiratory rate is often measured over a period shorter than 1 min and then multiplied to produce a rate per minute. There are few reports of the performance of such estimates compared with rates measured over a full minute.

AIM

Compare performance of respiratory rates calculated from 15 and 30 s of observations with measurements over 1 min.

DESIGN

A prospective single center observational study.

METHODS

The respiratory rates calculated from observations for 15 and 30 s were compared with simultaneous respiratory rates measured for a full minute on acutely ill medical patients during their admission to a resource poor hospital in sub-Saharan Africa using a novel respiratory rate tap counting software app.

RESULTS

There were 770 respiratory rates recorded on 321 patients while they were in the hospital. The bias (limits of agreement) between the rate derived from 15 s of observations and the full minute was -1.22 breaths per minute (bpm) (-7.16 to 4.72 bpm), and between the rate derived from 30 s and the full minute was -0.46 bpm (-3.89 to 2.97 bpm). Rates observed over 1 min that scored 3 National Early Warning Score points were not identified by half the rates derived from 15 s and a quarter of the rates derived from 30 s.

CONCLUSION

Practice-based evidence shows that abnormal respiratory rates are more reliably detected with measurements made over a full minute, and respiratory rate measurement 'short-cuts' often fail to identify sick patients.

Vital signs and impaired cognition in older emergency department patients: The APOP study

BACKGROUND/OBJECTIVES

Cognitive impairment is a frequent problem among older patients attending the Emergency Department (ED) and can be the result of pre-existing cognitive impairment, delirium, or neurologic disorders. Another cause can also be acute disturbance of brain perfusion and oxygenation, which may be reversed by optimal resuscitation. This study aimed to assess the relationship between vital signs, as a measure of acute hemodynamic changes, and cognitive impairment in older ED patients.

DESIGN

Prospective cohort study.

SETTING

ED's of two tertiary care and two secondary care hospitals in the Netherlands.

PARTICIPANTS

2629 patients aged 70-years and older.

MEASUREMENTS

Vital signs were measured at the moment of ED arrival as part of routine clinical care. Cognition was measured using the Six-Item Cognitive Impairment Test (6-CIT).

RESULTS

The median age of patients was 78 years (IQR 74-84). Cognitive impairment was present in 738 patients (28.1%). When comparing lowest with highest quartiles, a systolic blood pressure of <129 mmHg (OR 1.30, 95% confidence interval (95%CI) 0.98-1.73)was associated with increased risk of cognitive impairment. A higher respiratory rate (>21/min) was associated with increased risk of impaired cognition (OR 2.16, 95% CI 1.58-2.95) as well as oxygen saturation of <95% (OR 1.64, 95%CI 1.24-2.19).

CONCLUSION

Abnormal vital signs associated with decreased brain perfusion and oxygenation are also associated with cognitive impairment in older ED patients. This may partially be explained by the association between disease severity and delirium, but also by acute disturbance of brain perfusion and oxygenation. Future studies should establish whether normalization of vital signs will also acutely improve cognition.

Clinical Audit on the Practice of Documentation at Preanesthetic Evaluation in a Specialized University Hospital

Background:

Performing preanesthetic evaluation, documenting, and keeping readily accessible record are responsibilities of anesthetists. Documentation can improve overall patient outcome. It also has an irreplaceable role in medico-legal aspects. Documentation is one of the challenges of providing quality care.

Aim:

The aim of this study was to evaluate the quality of documentation practice during preanesthetic visits.

Materials and Methods:

This clinical audit was conducted in the University of Gondar Hospital. Predefined 22 practice quality indicators were prepared according to modified global quality index.

Statistical Analysis:

Descriptive statistics was performed using SPSS version 20.

Results:

A total of 122 preanesthetic evaluation tools (PAETs) were reviewed. None of PAETs found fully completed according to the indicators. Trends differ between elective and emergency conditions. Indicators with high completion rate (>90%) were signed a consent, medical history, history of medication, allergy, anesthesia and surgery, cardiopulmonary examination, airway examination, preoperative diagnosis, and planned procedure. Anesthetic plan, vital signs, a name, per-oral status, premedication, and age were found with below average (<50%) completion rate.

Conclusions:

Documentation practice during the preanesthetic visit was below the standard. Unclear instructions should be replaced with standardized contents. Providing regular trainings on clinical documentation for students and staffs, and introducing modern electronic-based documentation system and preanesthetic clinics may improve the practice.

Frequency of vital sign measurement among intubated patients in the general ward and nurses' attitudes toward vital sign measurement

Purpose

The lack of recognition of respiratory distress may result in emergency tracheal intubation in the general ward. However, few studies have examined the differences in the frequency of vital sign measurement between patients with and without emergency tracheal intubation in the general ward. Thus, this study aimed to investigate the differences in the frequency of vital sign measurements between patients with and without emergency tracheal intubation.

Patients and methods

This is a single-center, retrospective, observational study of unplanned intensive care unit (ICU) admissions from the general wards between December 2015 and February 2017. This study included patients with emergency medical intubations in the general ward who were then transferred to the ICU. Vital signs measured within 24 hours prior to ICU admission were compared between patients who did and did not require emergency tracheal intubation in the general ward. A survey was also conducted to explore the nurses' attitudes toward vital sign measurements.

Results

Compared with other vital signs, the respiratory rate was significantly less frequently measured. Moreover, the frequency of respiratory rate measurement was lower in the 38 patients who were intubated than in the 102 patients who were not intubated in the general ward (P=0.07). The survey revealed that 54% of the participating nurses considered assessment of the respiratory rate as the most troublesome nursing task and ~15% of nurses did not routinely measure respiratory rates.

Conclusion

Respiratory rate was less frequently assessed in deteriorating patients in the general ward, possibly because it was considered a troublesome task.

Factors Associated With Discharge Home After Transfer to a Pediatric Emergency Department

OBJECTIVES

The transfer of children from community emergency departments (EDs) to tertiary care pediatric EDs for investigations, interventions, or a second opinion is common. In order to improve health care system efficiency, we must have a better understanding of this population and identify areas for education and capacity building.

METHODS

We conducted a retrospective chart review of all patients (aged 0-17 years) who were transferred from community ED to a pediatric ED from November 2013 to November 2014. The primary outcome was the frequency of referred patients who were discharged home from the pediatric ED.

RESULTS

Two hundred four patients were transferred from community EDs in the study period. One hundred thirteen children (55.4%) were discharged home from the pediatric ED. Presence of inpatient pediatric services (P = 0.04) at the referral hospital and a respiratory diagnosis (P = 0.03) were independently associated with admission to the children's hospital. In addition, 74 patients (36.5%) had no critically abnormal vital signs at the referral hospital and did not require any special tests, interventions, consultations, or admission to the children's hospital. Younger age (P = 0.03), lack of inpatient pediatric services (P = 0.04), and a diagnosis change (P = 0.03) were independently associated with this outcome.

CONCLUSIONS

More than half of patients transferred to the pediatric tertiary care ED did not require admission, and more than one third did not require special tests, interventions, consults, or admission. Many of these patients were likely transferred for a second opinion from a pediatric emergency medicine specialist. Education and real-time videoconferencing consultations using telemedicine may help to reduce the frequency of transfers for a second opinion and contribute to cost savings over the long term.

Manual centile-based early warning scores derived from statistical distributions of observational vital-sign data

AIMS OF STUDY

To develop and validate a centile-based early warning score using manually-recorded data (mCEWS). To compare mCEWS performance with a centile-based early warning score derived from continuously-acquired data (from bedside monitors, cCEWS), and with other published early warning scores.

MATERIALS AND METHODS

We used an unsupervised approach to investigate the statistical properties of vital signs in an in-hospital patient population and construct an early-warning score from a "development" dataset. We evaluated scoring systems on a separate "validation" dataset. We assessed the ability of scores to discriminate patients at risk of cardiac arrest, unanticipated intensive care unit admission, or death, each within 24 h of a given vital-sign observation, using metrics including the area under the receiver-operating characteristic curve (AUC).

RESULTS

The development dataset contained 301,644 vital sign observations from 12,153 admissions (median age (IQR): 63 (49-73); 49.2% females) March 2014-September 2015. The validation dataset contained 1,459,422 vital-sign observations from 53,395 admissions (median age (IQR): 68 (48-81), 51.4% females) October 2015-May 2017. The AUC (95% CI) for the mCEWS was 0.868 (0.864-0.872), comparable with the National EWS, 0.867 (0.863-0.871), and other recently proposed scores. The AUC for cCEWS was 0.808 (95% CI, 0.804-0.812). The improvement in performance in comparison to the continuous CEWS was mainly explained by respiratory rate threshold differences.

CONCLUSIONS

Performance of an EWS is highly dependent on the database from which itis derived. Our unsupervised statistical approach provides a straightforward, reproducible method to enable the rapid development of candidate EWS systems.

Psychometric properties of the Zephyr bioharness device: a systematic review

BACKGROUND

Technological development and improvements in Wearable Physiological Monitoring devices, have facilitated the wireless and continuous field-based monitoring/capturing of physiologic measures in healthy, clinical or athletic populations. These devices have many applications for prevention and rehabilitation of musculoskeletal disorders, assuming reliable and valid data is collected. The purpose of this study was to appraise the quality and synthesize findings from published studies on psychometric properties of heart rate measurements taken with the Zephyr Bioharness device.

METHODS

We searched the Embase, Medline, PsycInfo, PuMed and Google Scholar databases to identify articles. Articles were appraised for quality using a structured clinical measurement specific appraisal tool. Two raters evaluated the quality and conducted data extraction. We extracted data on the reliability (intra-class correlation coefficients and standard error of measurement) and validity measures (Pearson/Spearman's correlation coefficients) along with mean differences. Agreement parameters were summarised by the average biases and 95% limits of agreement.

RESULTS

A total of ten studies were included: quality ratings ranged from 54 to 92%. The intra-class correlation coefficients reported ranged from 0.85-0.98. The construct validity coefficients compared against gold standard calibrations or other commercially used devices, ranged from 0.74-0.99 and 0.67-0.98 respectively. Zephyr Bioharness agreement error ranged from - 4.81 (under-estimation) to 3.00 (over-estimation) beats per minute, with varying 95% limits of agreement, when compared with gold standard measures.

CONCLUSION

Good to excellent quality evidence from ten studies suggested that the Zephyr Bioharness device can provide reliable and valid measurements of heart rate across multiple contexts, and that it displayed good agreements vs. gold standard comparators - supporting criterion validity.

Make vital signs great again - A call for action

Vital signs are the simplest, cheapest and probably the most important information gathered on patients in hospital. In this narrative review we present a large amount of evidence that vital signs are currently little valued, not regularly or accurately recorded, and frequently not acted on appropriately. It is probable that few hospitals would keep their accreditation with regulatory bodies if they collected and acted on their laboratory results in the same way that they collect and act on vital signs. Professional societies and regulatory bodies need to address this issue: if vital signs were more accurately and frequently measured, and acted on promptly and appropriately hospital care would be safer, better and cheaper.

The effects of awareness and count duration on adult respiratory rate measurements: An experimental study

AIMS AND OBJECTIVES

To investigate whether awareness of manual respiratory rate monitoring affects respiratory rate in adults, and whether count duration influences respiratory rate estimates.

BACKGROUND

Nursing textbooks typically suggest that the patient should ideally be unaware of respiratory rate observations; however, there is little published evidence of the effect of awareness on respiratory rate, and none specific to manual measurement. In addition, recommendations about the length of the respiratory rate count vary from text to text, and the relevant empirical evidence is scant, inconsistent and subject to substantial methodological limitations.

DESIGN

Experimental study with awareness of respiration monitoring (aware, unaware; randomised between-subjects) and count duration (60 s, 30 s, 15 s; within-subjects) as the independent variables. Respiratory rate (breaths/minute) was the dependent variable.

METHODS

Eighty-two adult volunteers were randomly assigned to aware and unaware conditions. In the baseline block, no live monitoring occurred. In the subsequent experimental block, the researcher informed aware participants that their respiratory rate would be counted, and did so. Respirations were captured throughout via video recording, and counted by blind raters viewing 60-, 30- and 15-s extracts. The data were collected in 2015.

RESULTS

There was no baseline difference between the groups. During the experimental block, the respiratory rates of participants in the aware condition were an average of 2.13 breaths/minute lower compared to unaware participants. Reducing the count duration from 1 min to 15 s caused respiratory rate to be underestimated by an average of 2.19 breaths/minute (and 0.95 breaths/minute for 30-s counts). The awareness effect did not depend on count duration.

CONCLUSIONS

Awareness of monitoring appears to reduce respiratory rate, and shorter monitoring durations yield systematically lower respiratory rate estimates.

RELEVANCE TO CLINICAL PRACTICE

When interpreting and acting upon respiratory rate data, clinicians should consider the potential influence of these factors, including cumulative effects.

Is everyone really breathing 20 times a minute? Assessing epidemiology and variation in recorded respiratory rate in hospitalised adults

BACKGROUND

Respiratory rate (RR) is an independent predictor of adverse outcomes and an integral component of many risk prediction scores for hospitalised adults. Yet, it is unclear if RR is recorded accurately. We sought to assess the potential accuracy of RR by analysing the distribution and variation as a proxy, since RR should be normally distributed if recorded accurately.

METHODS

We conducted a descriptive observational study of electronic health record data from consecutive hospitalisations from 2009 to 2010 from six diverse hospitals. We assessed the distribution of the maximum RR on admission, using heart rate (HR) as a comparison since this is objectively measured. We assessed RR patterns among selected subgroups expected to have greater physiological variation using the coefficient of variation (CV=SD/mean).

RESULTS

Among 36 966 hospitalisations, recorded RR was not normally distributed (p<0.001), but right skewed (skewness=3.99) with values clustered at 18 and 20 (kurtosis=23.9). In contrast, HR was relatively normally distributed. Patients with a cardiopulmonary diagnosis or hypoxia only had modestly greater variation (CV increase of 2%-6%). Among 1318 patients transferred from the ward to the intensive care unit (n=1318), RR variation the day preceding transfer was similar to that observed on admission (CV 0.24 vs 0.26), even for those transferred with respiratory failure (CV 0.25).

CONCLUSIONS

The observed patterns suggest that RR is inaccurately recorded, even among those with cardiopulmonary compromise, and represents a 'spot' estimate with values of 18 and 20 breaths per minute representing 'normal.' While spot estimates may potentially be adequate to indicate clinical stability, inaccurate RR may alternatively lead to misclassification of disease severity, potentially jeopardising patient safety. Thus, we recommend greater training for hospital personnel to accurately record RR.

A review of wearable technology in medicine

With rapid advances in technology, wearable devices have evolved and been adopted for various uses, ranging from simple devices used in aiding fitness to more complex devices used in assisting surgery. Wearable technology is broadly divided into head-mounted displays and body sensors. A broad search of the current literature revealed a total of 13 different body sensors and 11 head-mounted display devices. The latter have been reported for use in surgery (n = 7), imaging (n = 3), simulation and education (n = 2) and as navigation tools (n = 1). Body sensors have been used as vital signs monitors (n = 9) and for posture-related devices for posture and fitness (n = 4). Body sensors were found to have excellent functionality in aiding patient posture and rehabilitation while head-mounted displays can provide information to surgeons to while maintaining sterility during operative procedures. There is a potential role for head-mounted wearable technology and body sensors in medicine and patient care. However, there is little scientific evidence available proving that the application of such technologies improves patient satisfaction or care. Further studies need to be conducted prior to a clear conclusion.

Treadmill exercise improves fitness and reduces craving and use of cocaine in individuals with concurrent cocaine and tobacco-use disorder

Exercise may be a useful treatment for substance use disorders. Participants (N=24) included treatment-seeking individuals with concurrent cocaine and tobacco-use disorder (cigarette smokers). Participants were randomized to either running or walking (30min per session, 3 times per week) or sitting (control condition) for 4 consecutive weeks. Several metrics indicated significant differences among runners, walkers, and sitters during sessions, including mean distance covered and calories burned. In addition, remote physiological monitoring showed that the groups differed significantly according to mean maximum heart rate (HR), respiration, and locomotor activity. Across the 4-week study, exercise improved fitness measures including significantly decreasing resting HR. Though not statistically significant, exercise improved abstinence from cocaine and increased self-reports of no cocaine use in last 24h. In general, reductions in tobacco use and craving were not as robust. To our knowledge, this is the first study to evaluate the effects of a multi-week exercise program in individuals with concurrent cocaine and tobacco-use disorder. The data clearly show significant improvements in basic fitness measures and several indices reveal that exercise improved both self-report and biochemically verified reports of cocaine abstinence. Taken together, the data from this study provide preliminary evidence for the efficacy of exercise for improving fitness and reducing cocaine use.

Remotely Delivered Exercise-Based Cardiac Rehabilitation: Design and Content Development of a Novel mHealth Platform

Background

Participation in traditional center-based cardiac rehabilitation exercise programs (exCR) is limited by accessibility barriers. Mobile health (mHealth) technologies can overcome these barriers while preserving critical attributes of center-based exCR monitoring and coaching, but these opportunities have not yet been capitalized on.

Objective

We aimed to design and develop an evidence- and theory-based mHealth platform for remote delivery of exCR to any geographical location.

Methods

An iterative process was used to design and develop an evidence- and theory-based mHealth platform (REMOTE-CR) that provides real-time remote exercise monitoring and coaching, behavior change education, and social support.

Results

The REMOTE-CR platform comprises a commercially available smartphone and wearable sensor, custom smartphone and Web-based applications (apps), and a custom middleware. The platform allows exCR specialists to monitor patients’ exercise and provide individualized coaching in real-time, from almost any location, and provide behavior change education and social support. Intervention content incorporates Social Cognitive Theory, Self-determination Theory, and a taxonomy of behavior change techniques. Exercise components are based on guidelines for clinical exercise prescription.

Conclusions

The REMOTE-CR platform extends the capabilities of previous telehealth exCR platforms and narrows the gap between existing center- and home-based exCR services. REMOTE-CR can complement center-based exCR by providing an alternative option for patients whose needs are not being met. Remotely monitored exCR may be more cost-effective than establishing additional center-based programs. The effectiveness and acceptability of REMOTE-CR are now being evaluated in a noninferiority randomized controlled trial.

A noncontact RF-based respiratory sensor: results of a clinical trial

BACKGROUND

Respiratory rate (RR) is a critical vital signs monitored in health care setting. Current monitors suffer from sensor-contact failure, inaccurate data, and limited patient mobility. There is a critical need for an accurate and reliable and noncontact system to monitor RR. We developed a contact-free radio frequency (RF)-based system that measures movement using WiFi signal diffraction, which is converted into interpretable data using a Fourier transform. Here, we investigate the system's ability to measure fine movements associated with human respiration.

MATERIALS AND METHODS

Testing was conducted on subjects using visual cue, fixed-tempo instruction to breath at standard RRs. Blinded instruction-based RRs were compared to RF-acquired data to determine measurement accuracy. The RF-based technology was studied on postoperative ventilator-dependent patients. Blinded ventilator capnographic RR data were collected for each patient and compared to RF-acquired data to determine measurement accuracy.

RESULTS

Respiratory rate data collected from 10 subjects breathing at a fixed RR (14, 16, 18, or 20) demonstrated 95.5% measurement accuracy between the patient's actual rate and that measured by our RF technology. Ten patients were enrolled into the clinical trial. Blinded ventilator capnographic RR data were compared to RF-based acquired data. The RF-based data showed 88.8% measurement accuracy with ventilator capnography.

CONCLUSIONS

Initial clinical pilot trials with our contact-free RF-based monitoring system demonstrate a high degree of RR measurement accuracy when compared to capnographic data. Based on these results, we believe RF-based systems present a promising noninvasive, inexpensive, and accurate tool for continuous RR monitoring.

Remote physiological monitoring of acute cocaine exposure

Cocaine exposure results in predictable cardiovascular changes. The current study evaluated the utility of BioHarness for assessing cardiovascular and respiratory changes following cocaine exposure (0 and 40 mg, IV) under controlled laboratory conditions. Participants (n = 28) included non-treatment-seeking, cocaine-dependent volunteers. Results showed that BioHarness was able to detect a significant increase in heart rate following cocaine exposure, in comparison to placebo, (p < 0.0001). Additionally, heart rate values obtained using BioHarness were significantly correlated with those obtained from standard hospital equipment (p < 0.001). Significantly greater peak effects in breathing rate were also observed (p = 0.04). BioHarness is a promising remote physiological monitoring device that can accurately assess exposure to cocaine in the laboratory and may provide additional advantages when compared to standard hospital equipment.

High reliability in respiratory rate assessment in children with respiratory symptomatology in a rural area in Mozambique

Early recognition of severe medical conditions is often based on clinical scores and vital sign measurements such as the respiratory rate (RR) count. We designed this study to determine the reliability of RR assessment counted three times during a full minute by independent observers in children in a developing country setting. A total of 55 participants were enrolled in the study. Participant ages ranged from 10 days to 7 years (median 22 months). Agreement for RR count was high (intraclass correlation coefficient of 0.95; 95% confidence interval: 0.93-0.97). Agreement for presence of tachypnea was also high (Kappa coefficient of 0.83, p < 0.001). However, a single reading would have misclassified 5-11% of the participants as non-tachypneic. Repeated RR counts offer reliable results if done during a full minute. Patients not fulfilling tachypnea criterion but with a high RR count should have the measurement repeated.

Evaluation of a wearable physiological status monitor during simulated fire fighting activities

A physiological status monitor (PSM) has been embedded in a fire-resistant shirt. The purpose of this research study was to examine the ability of the PSM-shirt to accurately detect heart rate (HR) and respiratory rate (RR) when worn under structural fire fighting personal protective equipment (PPE) during the performance of various activities relevant to fire fighting. Eleven healthy, college-aged men completed three activities (walking, searching/crawling, and ascending/descending stairs) that are routinely performed during fire fighting operations while wearing the PSM-shirt under structural fire fighting PPE. Heart rate and RR recorded by the PSM-shirt were compared to criterion values measured concurrently with an ECG and portable metabolic measurement system, respectively. For all activities combined (overall) and for each activity, small differences were found between the PSM-shirt and ECG (mean difference [95% CI]: overall: -0.4 beats/min [-0.8, -0.1]; treadmill: -0.4 beats/min [-0.7, -0.1]; search: -1.7 beats/min [-3.1, -.04]; stairs: 0.4 beats/min [0.04, 0.7]). Standard error of the estimate was 3.5 beats/min for all tasks combined and 1.9, 5.9, and 1.9 beats/min for the treadmill walk, search, and stair ascent/descent, respectively. Correlations between the PSM-shirt and criterion heart rates were high (r = 0.95 to r = 0.99). The mean difference between RR recorded by the PSM-shirt and criterion overall was 1.1 breaths/min (95% CI: -1.9 to -0.4). The standard error of the estimate for RR ranged from 4.2 breaths/min (treadmill) to 8.2 breaths/min (search), with an overall value of 6.2 breaths/min. These findings suggest that the PSM-shirt provides valid measures of HR and useful approximations of RR when worn during fire fighting duties.

Validation of heart rate derived from a physiological status monitor-embedded compression shirt against criterion ECG

Firefighters are subject to extreme environments and high physical demands when performing duty-related tasks. Recently, physiological status monitors (PSM) have been embedded into a compression shirt to enable firefighters to measure, visualize, log, and transmit vital metrics such as heart rate (HR) to aid in cardiovascular risk identification and mitigation, thereby attempting to improve the health, fitness, and safety of this population. The purpose of this study was to validate HR recorded by the PSM-embedded compression shirt against a criterion standard laboratory ECG-derived HR when worn concurrently with structural firefighting personal protective equipment (PPE) during four simulated firefighting activities. Ten healthy, college-age men (mean ± SD: age: 21 ± 1 yr; body mass: 91 ± 10 kg; body mass index: 26.9 ± 3.1 kg/m(2)) completed four tasks that are routinely performed during firefighting operations: outdoor fast-paced walking (FW), treadmill walking (TW), searching/crawling (SC), and ascending/descending stairs (AD). They wore the PSM-embedded compression shirt under structural firefighting PPE. HR was recorded concurrently by the PSM-embedded compression shirt and a portable metabolic measurement system accompanied with a standard 12-lead electrocardiograph that was used to provide criterion measures of HR. For all four tasks combined there was very high correlation of PSM and ECG HR (r > 0.99; SEE 0.84 /min) with a mean difference (bias) of -0.02 /min and limits of agreement of -0.07 to 0.02 /min. For individual tasks, the correlations were also high (r-values = 0.99; SEE 0.81-0.89). The mean bias (limits of agreement) was: FW 0.03 (-0.09 to 0.14); TW 0.04 (-0.05 to 0.12); SC -0.01 (-0.12 to 0.10); AD -0.13 (-0.21 to -0.04) /min. These findings demonstrate that the PSM-embedded compression shirt provides a valid measure of HR during simulated firefighting activities when compared with a standard 12-lead ECG.

Level of agreement between prehospital and emergency department vital signs in trauma patients

OBJECTIVES

Describe the level of agreement between prehospital (emergency medical service [EMS]) and ED vital signs in a group of trauma patients transported to an inner city Major Trauma Centre. We also sought to determine factors associated with differences in recorded vital sign measurements.

METHODS

All adult patients meeting trauma triage criteria and transported directly from scene of injury by New South Wales Ambulance to our institution were included. The primary outcome was the difference in vital signs: heart rate (HR), systolic blood pressure (SBP), respiratory rate (RR) and Glasgow Coma Scale (GCS), between ED and EMS recorded measurements. Agreement was assessed using intraclass correlation coefficients and enhanced Bland-Altman plots. Multivariable linear regression models were used to determine factors associated with vital sign differences.

RESULTS

The 1181 trauma patients met inclusion criteria. Intraclass correlation coefficients were as follows: GCS 0.74 (95% confidence interval [CI], 0.37, 1.12); HR 0.41 (95% CI, 0.30, 0.53); SBP 0.37 (95% CI, 0.27, 0.46); and RR 0.29 (95% CI, 0.06, 0.51). Bland-Altman derived 95% limits of agreement lay outside a priori limits of clinical agreement for SBP and RR and were within limits of clinical agreement for GCS and HR. SBP and HR differences were associated with prehospital airway and fluid intervention.

CONCLUSIONS

Agreement was demonstrated between EMS and ED GCS scores but not RR and SBP recordings. Discrepancies appeared to reflect physiological changes in response to EMS initiated interventions. Trauma triage algorithms and risk models might need to take these measurement differences, and factors associated with them, into account.