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

Feasibility study of the use of a wearable vital sign patch in an intensive care unit setting

Multiple studies and review papers have concluded that early warning systems have a positive effect on clinical outcomes, patient safety and clinical performances. Despite the substantial evidence affirming the efficacy of EWS applications, persistent barriers hinder their seamless integration into clinical practice. Notably, EWS, such as the National Early Warning Score, simplify multifaceted clinical conditions into singular numerical indices, thereby risking the oversight of critical clinical indicators and nuanced fluctuations in patients' health status. Furthermore, the optimal deployment of EWS within clinical contexts remains elusive. Manual assessment of EWS parameters exacts a significant temporal toll on healthcare personnel. Addressing these impediments necessitates innovative approaches. In this regard, wearable medical technologies emerge as promising solutions capable of continual monitoring of hospitalized patients' vital signs. To overcome the barriers of the use of early warning scores, wearable medical technology has the potential to continuously monitor vital signs of hospitalised patients. However, a fundamental inquiry arises regarding the comparability of their reliability to the current used golden standards. This inquiry underscores the imperative for rigorous evaluation and validation of wearable medical technologies to ascertain their efficacy in augmenting extant clinical practices. This prospective, single-center study aimed to evaluate the accuracy of heart rate and respiratory rate measurements obtained from the Vivalink Cardiac patch in comparison to the ECG-based monitoring system utilized at AZ Maria Middelares Hospital in Ghent. Specifically, the study focused on assessing the concordance between the data obtained from the Vivalink Cardiac patch and the established ECG-based monitoring system among a cohort of ten post-surgical intensive care unit (ICU) patients. Of these patients, five were undergoing mechanical ventilation post-surgery, while the remaining five were not. The study proceeded by initially comparing the data recorded by the Vivalink Cardiac patch with that of the ECG-based monitoring system. Subsequently, the data obtained from both the Vivalink Cardiac patch and the ECG-based monitoring system were juxtaposed with the information derived from the ventilation machine, thereby providing a comprehensive analysis of the patch's performance in monitoring vital signs within the ICU setting. For heart rate, the Vivalink Cardiac patch was on average within a 5% error range of the ECG-based monitoring system during 85.11±10.81% of the measured time. For respiratory rate this was during 40.55±17.28% of the measured time. Spearman's correlation coefficient showed a very high correlation of ρ = 0.9 8 for heart rate and a moderate correlation of ρ = 0.66 for respiratory rate. In comparison with the ventilated respiratory rate (ventilation machine) the Vivalink and ECG-based monitoring system both had a moderate correlation of ρ = 0.68 . A very high correlation was found between the heart rate measured by the Vivalink Cardiac patch and that of the ECG-based monitoring system of the hospital. Concerning respiratory rate the correlation between the data from the Vivalink Cardiac patch, the ECG-based monitoring system and the ventilation machine was found to be moderate.

A multi-nudge-based behavioural insight into ward nurses' respiratory rate measurement: An observational study

AIM

This study observed changes in respiratory rate measurement (RRM) and identified barriers and challenges in clinical practice that influence healthcare worker behaviour, aiming to improve RRM in a hospital setting.

DESIGN

An observational study was conducted.

METHODS

We observed and analysed changes in the behaviour of healthcare workers at a hospital where multi-nudges were introduced to improve RRM.

RESULTS

We checked respiration rate using electronic data and discovered that the original measurement rates were low. Measurement rates rapidly increased after posters were added. Barriers such as time constraints and measurement equipment were also noted.

CONCLUSION

RRM was found to be effective in promoting behavioural economics in medical settings. The results show that incorporating behavioural science principles into medical interventions has the potential to positively change behaviour.

IMPLICATIONS FOR THE PROFESSION AND/OR PATIENT CARE

By increasing nurses' awareness of respiratory rate measurement and addressing barriers to it, the measurement rate of respiratory rate can also increase, leading to more accurate patient evaluations and triage.

IMPACT

WHAT PROBLEM DID THE STUDY ADDRESS?: The proportion of respiratory rate measurements leading to rapid response system (RRS) calls was low. WHAT WERE THE MAIN FINDINGS?: The study observed that a multi-nudge approach effectively changes the behaviour of ward nurses, resulting in enhanced quality of medical care. WHERE AND ON WHOM WILL THE RESEARCH HAVE AN IMPACT?: This research can serve as a valuable reference for leaders promoting healthcare quality projects, by offering a method to encourage behavioural change.

REPORTING METHOD

This study complied with the EQUATOR guidelines and its reporting adheres to the STROBE checklist.

PATIENT OR PUBLIC CONTRIBUTION

No patient or public contribution.

Wearable wireless continuous vital signs monitoring on the general ward

PURPOSE OF REVIEW

Wearable wireless sensors for continuous vital signs monitoring (CVSM) offer the potential for early identification of patient deterioration, especially in low-intensity care settings like general wards. This study aims to review advances in wearable CVSM - with a focus on the general ward - highlighting the technological characteristics of CVSM systems, user perspectives and impact on patient outcomes by exploring recent evidence.

RECENT FINDINGS

The accuracy of wearable sensors measuring vital signs exhibits variability, especially notable in ambulatory patients within hospital settings, and standard validation protocols are lacking. Usability of CMVS systems is critical for nurses and patients, highlighting the need for easy-to-use wearable sensors, and expansion of the number of measured vital signs. Current software systems lack integration with hospital IT infrastructures and workflow automation. Imperative enhancements involve nurse-friendly, less intrusive alarm strategies, and advanced decision support systems. Despite observed reductions in ICU admissions and Rapid Response Team calls, the impact on patient outcomes lacks robust statistical significance.

SUMMARY

Widespread implementation of CVSM systems on the general ward and potentially outside the hospital seems inevitable. Despite the theoretical benefits of CVSM systems in improving clinical outcomes, and supporting nursing care by optimizing clinical workflow efficiency, the demonstrated effects in clinical practice are mixed. This review highlights the existing challenges related to data quality, usability, implementation, integration, interpretation, and user perspectives, as well as the need for robust evidence to support their impact on patient outcomes, workflow and cost-effectiveness.

Inherent Bias in Electronic Health Records: A Scoping Review of Sources of Bias

Objectives

1.1Biases inherent in electronic health records (EHRs), and therefore in medical artificial intelligence (AI) models may significantly exacerbate health inequities and challenge the adoption of ethical and responsible AI in healthcare. Biases arise from multiple sources, some of which are not as documented in the literature. Biases are encoded in how the data has been collected and labeled, by implicit and unconscious biases of clinicians, or by the tools used for data processing. These biases and their encoding in healthcare records undermine the reliability of such data and bias clinical judgments and medical outcomes. Moreover, when healthcare records are used to build data-driven solutions, the biases are further exacerbated, resulting in systems that perpetuate biases and induce healthcare disparities. This literature scoping review aims to categorize the main sources of biases inherent in EHRs.

Methods

1.2We queried PubMed and Web of Science on January 19th, 2023, for peer-reviewed sources in English, published between 2016 and 2023, using the PRISMA approach to stepwise scoping of the literature. To select the papers that empirically analyze bias in EHR, from the initial yield of 430 papers, 27 duplicates were removed, and 403 studies were screened for eligibility. 196 articles were removed after the title and abstract screening, and 96 articles were excluded after the full-text review resulting in a final selection of 116 articles.

Results

1.3Systematic categorizations of diverse sources of bias are scarce in the literature, while the effects of separate studies are often convoluted and methodologically contestable. Our categorization of published empirical evidence identified the six main sources of bias: a) bias arising from past clinical trials; b) data-related biases arising from missing, incomplete information or poor labeling of data; human-related bias induced by c) implicit clinician bias, d) referral and admission bias; e) diagnosis or risk disparities bias and finally, (f) biases in machinery and algorithms.

Conclusions

1.4Machine learning and data-driven solutions can potentially transform healthcare delivery, but not without limitations. The core inputs in the systems (data and human factors) currently contain several sources of bias that are poorly documented and analyzed for remedies. The current evidence heavily focuses on data-related biases, while other sources are less often analyzed or anecdotal. However, these different sources of biases add to one another exponentially. Therefore, to understand the issues holistically we need to explore these diverse sources of bias. While racial biases in EHR have been often documented, other sources of biases have been less frequently investigated and documented (e.g. gender-related biases, sexual orientation discrimination, socially induced biases, and implicit, often unconscious, human-related cognitive biases). Moreover, some existing studies lack causal evidence, illustrating the different prevalences of disease across groups, which does not per se prove the causality. Our review shows that data-, human- and machine biases are prevalent in healthcare and they significantly impact healthcare outcomes and judgments and exacerbate disparities and differential treatment. Understanding how diverse biases affect AI systems and recommendations is critical. We suggest that researchers and medical personnel should develop safeguards and adopt data-driven solutions with a "bias-in-mind" approach. More empirical evidence is needed to tease out the effects of different sources of bias on health outcomes.

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.

Long-term effects of virtual reality-based therapy in cardiovascular rehabilitation: A longitudinal study

BACKGROUND

In Cardiovascular Rehabilitation (CR), patient adherence to the maintenance phase is a major challenge. Virtual reality-based therapy (VRBT) promotes acute hemodynamic and autonomic repercussions similar to traditional rehabilitation and can increase patient adherence to the program. However, it is unknown whether the combination of VRBT to a traditional CR manages to maintain or even improve clinical and autonomic variables in long term.

OBJECTIVE

To analyze whether VRBT combination in a traditional CR can maintain or improve clinical and autonomic variables in cardiac patients in the maintenance phase of these programs.

METHODS

Twenty-six volunteers (62.04 ± 12.22 years) were evaluated, who underwent an initial assessment and two other assessments (in the sixth and 12th week) of the following outcomes: systolic and diastolic blood pressure, respiratory rate, pulse saturation of oxygen, heart rate, perceived exertion, and cardiac autonomic modulation, using linear and non-linear heart rate variability methods.

RESULTS

Except for the apparent lack of clinical significance observed in Shannon Entropy, LF (nu), and HF (nu), the combination of VRBT as routine in a traditional program did not cause significant changes in the analyzed variables.

CONCLUSION

combination of VRBT was able to maintain the chronic hemodynamic and autonomic repercussions caused by traditional CR.

Implementation of a fast triage score for patients arriving to a low resource hospital in Uganda

Background

The Kitovu Fast Triage (KFT) score predicts imminent mortality from mental status, gait and either respiratory rate or oxygen status. As some non-life-threatening conditions require immediate attention, the South African Triage System (SATS) assigns arbitrary rankings of urgency for specific patient presentations.

Aim

Establish the feasibility of determining and then comparing the KFT score and explicitly defined SATS urgency rankings.

Methods

A computerized proforma used standardized methods of assessing and measuring mental status and gait, and respiratory rate and collected explicitly defined clinical presentations and SATS urgency rankings on 4,842 patients at the time of their arrival to the hospital.

Results

75 % of patients were awake and able to count the months backwards from December to September. Respiratory rates measured by a computer application had no clustering of values or digit preference; however, oximetry failed in 14 % of patients, making the score based on respiratory rate the most practical in our setting. Determining the SATS acuity ranking and both KFT scores usually took <90 s; the commonest complaints were pain, dyspnoea, and fever, which often occurred together; overall 3574 (73.8 %) patients had at least one of these symptoms as did 96.4 % of those with the highest KFT score based on respiratory rate. 12 % of patients with the lowest KFT score based on respiratory rate had one or more very urgent SATS rankings, 52 % of whom had non-severe chest pain. Only 5.7 % of patients complaining of fever had a temperature >38 °C.

Conclusion

Whilst the KFT score based on respiratory rate could be rapidly determined in all patients, it identified some patients as low acuity who had very urgent SATS rankings. However, most of these patients had non-severe chest pain, which may not be a very urgent presentation in our setting as ischaemic heart disease remains uncommon in sub-Saharan Africa.

Society of Critical Care Medicine Guidelines on Recognizing and Responding to Clinical Deterioration Outside the ICU: 2023

RATIONALE

Clinical deterioration of patients hospitalized outside the ICU is a source of potentially reversible morbidity and mortality. To address this, some acute care hospitals have implemented systems aimed at detecting and responding to such patients.

OBJECTIVES

To provide evidence-based recommendations for hospital clinicians and administrators to optimize recognition and response to clinical deterioration in non-ICU patients.

PANEL DESIGN

The 25-member panel included representatives from medicine, nursing, respiratory therapy, pharmacy, patient/family partners, and clinician-methodologists with expertise in developing evidence-based Clinical Practice Guidelines.

METHODS

We generated actionable questions using the Population, Intervention, Control, and Outcomes (PICO) format and performed a systematic review of the literature to identify and synthesize the best available evidence. We used the Grading of Recommendations Assessment, Development, and Evaluation Approach to determine certainty in the evidence and to formulate recommendations and good practice statements (GPSs).

RESULTS

The panel issued 10 statements on recognizing and responding to non-ICU patients with critical illness. Healthcare personnel and institutions should ensure that all vital sign acquisition is timely and accurate (GPS). We make no recommendation on the use of continuous vital sign monitoring among unselected patients. We suggest focused education for bedside clinicians in signs of clinical deterioration, and we also suggest that patient/family/care partners' concerns be included in decisions to obtain additional opinions and help (both conditional recommendations). We recommend hospital-wide deployment of a rapid response team or medical emergency team (RRT/MET) with explicit activation criteria (strong recommendation). We make no recommendation about RRT/MET professional composition or inclusion of palliative care members on the responding team but suggest that the skill set of responders should include eliciting patients' goals of care (conditional recommendation). Finally, quality improvement processes should be part of a rapid response system.

CONCLUSIONS

The panel provided guidance to inform clinicians and administrators on effective processes to improve the care of patients at-risk for developing critical illness outside the ICU.

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.

Predicting ICU admission and death in the Emergency Department: A comparison of six early warning scores

AIM

To compare the ability of the most used Early Warning Scores (EWS) to identify adult patients at risk of poor outcomes in the emergency department (ED).

METHODS

Single-center, retrospective observational study. We evaluated the digital records of consecutive ED admissions in patients ≥ 18 years from 2010 to 2019 and calculated NEWS, NEWS2, MEWS, RAPS, REMS, and SEWS based on parameters measured on ED arrival. We assessed the discrimination and calibration performance of each EWS in predicting death/ICU admission within 24 hours using ROC analysis and visual calibration. We also measured the relative weight of clinical and physiological derangements that identified patients missed by EWS risk stratification using neural network analysis.

RESULTS

Among 225,369 patients assessed in the ED during the study period, 1941 (0.9%) were admitted to ICU or died within 24 hours. NEWS was the most accurate predictor (area under the receiver operating characteristic [AUROC] curve 0.904 [95% CI 0.805-0.913]), followed by NEWS2 (AUROC 0.901). NEWS was also well calibrated. In patients judged at low risk (NEWS < 2), 359 events occurred (18.5% of the total). Neural network analysis revealed that age, systolic BP, and temperature had the highest relative weight for these NEWS-unpredicted events.

CONCLUSIONS

NEWS is the most accurate EWS for predicting the risk of death/ICU admission within 24 h from ED arrival. The score also had a fair calibration with few events occurring in patients classified at low risk. Neural network analysis suggests the need for further improvements by focusing on the prompt diagnosis of sepsis and the development of practical tools for the measurement of the respiratory rate.

The reverse shock index multiplied by the Glasgow Coma Scale score can predict the need for initial resuscitation in patients suspected of sepsis

For patients suspected of sepsis, early recognition of the need for initial resuscitation is key in management. This study evaluated the ability of a modified shock index - the reverse shock index multiplied by the Glasgow Coma Scale score (rSIG) - to predict the need for initial resuscitation in patients with sepsis. This retrospective study involved adults with infection who were admitted to a Japanese tertiary care hospital from an emergency department between January and November 2020. The rSIG, modified Early Warning Score (MEWS), quick Sequential Organ Failure Assessment (qSOFA), and original shock index (SI) values were recorded using initial vital signs. The primary outcome was the area under the receiver-operating characteristic curve (AUROC) for the composite outcome consisting of vasopressor use, mechanical ventilation, and 72-h mortality. Secondary outcomes were the AUROCs for each component of the primary outcome and 28-day mortality. As a result, the primary outcome was met by 67 of the 724 patients (9%). The AUROC was significantly higher for the rSIG than for the other tools (rSIG 0.84 [0.78 - 0.88]; MEWS 0.78 [0.71 - 0.84]; qSOFA 0.72 [0.65 - 0.79]; SI 0.80 [0.74 - 0.85]). Compared with MEWS and qSOFA, the rSIG also had a higher AUROC for vasopressor use and mechanical ventilation, but not for 72-h mortality or in-hospital mortality. The rSIG could be a simple and reliable predictor of the need for initial resuscitation in patients suspected of sepsis.

Use of high flow nasal cannula oxygen therapy for patients infected with SARS-CoV-2 outside intensive care setting

BACKGROUND

In early 2022, there was a sudden surge of patients infected by the Omicron variant of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in Hong Kong (HK), resulting in 9,163 deaths as of 29 May 2022. Many of the local population had not been vaccinated before this wave. The number of patients who developed coronavirus disease 2019 (COVID-19) related respiratory failure outnumbered the capacity of intensive care unit (ICU) beds. Some of these patients had to be supported with high flow nasal cannula (HFNC) therapy outside ICU setting. HK was in crisis situation. The primary objective of this study is to assess the 28-day mortality of this group of patients. The secondary objective is to explore any predictors of non-survivors to help clinical decision-making in future crisis.

METHODS

This is a retrospective observational study of patients suffering from COVID-19 related respiratory failure who received HFNC therapy in general medical wards of two hospitals during the period of 17 Mar to 30 Apr 2022. Survival and risk factors were reviewed.

RESULTS

Forty-nine patients were recruited. Twenty-six patients (53%) survived at 28-day after initiation of HFNC support. Three clinical parameters were found to be significantly associated with mortality at 28-day: (I) SpO2/FiO2 (SF) ratio <160 at 48 hours; (II) SF ratio <191 at 72 hours; (III) serial SF ratio at 48 or 72 hours showing no improvement over that at the time of initiation of HFNC therapy.

CONCLUSIONS

Use of HFNC outside ICU setting showed benefit to patients suffering from COVID-19 related acute hypoxemic respiratory failure (AHRF). Serial SF ratio monitoring at 48 and 72 hours after therapy initiation might serve as predictors of outcome and thus guide clinical decision-making for medical resource allocation in outbreak situation.

Biomarker-Based Assessment Model for Detecting Sepsis: A Retrospective Cohort Study

The concept of the quick sequential organ failure assessment (qSOFA) simplifies sepsis detection, and the next SOFA should be analyzed subsequently to diagnose sepsis. However, it does not include the concept of suspected infection. Thus, we simply developed a biomarker-based assessment model for detecting sepsis (BADS). We retrospectively reviewed the electronic health records of patients admitted to the intensive care unit (ICU) of a 2000-bed university tertiary referral hospital in South Korea. A total of 989 patients were enrolled, with 77.4% (n = 765) of them having sepsis. The patients were divided into a ratio of 8:2 and assigned to a training and a validation set. We used logistic regression analysis and the Hosmer-Lemeshow test to derive the BADS and assess the model. BADS was developed by analyzing the variables and then assigning weights to the selected variables: mean arterial pressure, shock index, lactate, and procalcitonin. The area under the curve was 0.754, 0.615, 0.763, and 0.668 for BADS, qSOFA, SOFA, and acute physiology and chronic health evaluation (APACHE) II, respectively, showing that BADS is not inferior in sepsis prediction compared with SOFA. BADS could be a simple scoring method to detect sepsis in critically ill patients quickly at the bedside.

Internet of medical things. Measurement of respiratory dynamics using wearable sensors in post-COVID-19 patients

Nowadays, the measurement of respiratory dynamics is underrated at clinical setting and in the daily life of a subject and it still represents a challenge from a technical and medical point of view. In this article we propose a concept to measure some of its parameters, such as the respiratory rate (RR), using four inertial sensors. Two different experiments were performed to validate the concept. We analyzed the most suitable placement of each sensor to assess those features and we studied the reliability of the system to measure abnormal parameters of respiration (tachypnea, bradypnea and breath holding). Finally, we measured post-COVID-19 patients, some of them with breath alterations after more than a year of the diagnosis. Experimental results showed that the proposed system could be potentially used to measure the respiratory dynamics at clinical setting. Moreover, while RR can be easily calculated by any sensor, other parameters need to be measured with a sensor in a particular position.

NURSE-LED proactive rounding and automatic early-warning score systems to prevent resuscitation incidences among Adults in ward-based Hospitalised patients

Objectives

In this study, we investigated the impact of critical care outreach implemented to overcome the problem of rapid response system (RRS) activation. The aim was to evaluate the impact of nurse-led proactive rounding on the rate of adverse events in a hospital setting using an automatic early-warning score system, without a call-activated team.

Methods

This observational study was conducted at a university hospital in Japan. Beginning in September 2019, critical care outreach via nurse-led proactive rounding of the general ward was conducted, using an automatic early-warning score system. We retrospectively assessed the computerised records of all inpatient days (N = 497,284) of adult inpatients admitted to the hospital from September 2017 to 2020. We compared the adverse event occurrences before and after implementation of the critical care outreach program. The main outcome measures were: unexpected death in the general ward, code blue (an in-hospital resuscitation request code directed towards all staff via broadcast) for non-intensive care unit inpatients and unexpected intensive care unit admissions from the general ward. The secondary outcome was the proportion of patients who received respiratory rate measurement.

Results

The incidence rate ratios of the occurrence of unexpected deaths (0.19, 95% confidence interval: 0.04-0.57) and code blue in the general ward (0.15, 95% confidence interval: 0.025-0.50) decreased. There was no change in unexpected intensive care unit admissions from the general ward (1.25, confidence interval: 0.84-1.82). The proportion of patients who received respiratory rate measurement increased (10.2% vs 16.2%).

Conclusion

Our results suggest that in RRSs, drastic control of the failure of the mechanism to activate a response team may produce positive outcomes. Proactive rounding that bypasses the mechanism to activate a response team component of RRSs may relieve ward nurses of activation failure responsibility and help them overcome the hierarchical hospital structure.

The quality of vital signs measurements and value preferences in electronic medical records varies by hospital, specialty, and patient demographics

We aimed to assess the frequency of value preferences in recording of vital signs in electronic healthcare records (EHRs) and associated patient and hospital factors. We used EHR data from Oxford University Hospitals, UK, between 01-January-2016 and 30-June-2019 and a maximum likelihood estimator to determine the prevalence of value preferences in measurements of systolic and diastolic blood pressure (SBP/DBP), heart rate (HR) (readings ending in zero), respiratory rate (multiples of 2 or 4), and temperature (readings of 36.0 °C). We used multivariable logistic regression to investigate associations between value preferences and patient age, sex, ethnicity, deprivation, comorbidities, calendar time, hour of day, days into admission, hospital, day of week and speciality. In 4,375,654 records from 135,173 patients, there was an excess of temperature readings of 36.0 °C above that expected from the underlying distribution that affected 11.3% (95% CI 10.6-12.1%) of measurements, i.e. these observations were likely inappropriately recorded as 36.0 °C instead of the true value. SBP, DBP and HR were rounded to the nearest 10 in 2.2% (1.4-2.8%) and 2.0% (1.3-5.1%) and 2.4% (1.7-3.1%) of measurements. RR was also more commonly recorded as multiples of 2. BP digit preference and an excess of temperature recordings of 36.0 °C were more common in older and male patients, as length of stay increased, following a previous normal set of vital signs and typically more common in medical vs. surgical specialities. Differences were seen between hospitals, however, digit preference reduced over calendar time. Vital signs may not always be accurately documented, and this may vary by patient groups and hospital settings. Allowances and adjustments may be needed in delivering care to patients and in observational analyses and predictive tools using these factors as outcomes or exposures.

Frequency Comb-Based Ground-Penetrating Bioradar: System Implementation and Signal Processing

Radars can be used as sensors to detect the breathing of victims trapped under layers of building materials in catastrophes like earthquakes or gas explosions. In this contribution, we present the implementation of a novel frequency comb continuous wave (FCCW) bioradar module using a commercial software-defined radio (SDR). The FCCW radar transmits multiple equally spaced frequency components simultaneously. The data acquisition of the received combs is frequency domain-based. Hence, it does not require synchronization between the transmit and receive channels, as time domain-based broadband radars, such as ultra wideband (UWB) pulse radar and frequency-modulated CW (FMCW) radar, do. Since a frequency comb has an instantaneous wide bandwidth, the effective scan rate is much higher than that of a step frequency CW (SFCW) radar. This FCCW radar is particularly suitable for small motion detection. Using inverse fast Fourier transform (IFFT), we can decompose the received frequency comb into different ranges and remove ghost signals and interference of further range intervals. The frequency comb we use in this report has a bandwidth of only 60 MHz, resulting in a range resolution of up to 2.5 m, much larger than respiration-induced chest wall motions. However, we demonstrate that in the centimeter range, motions can be detected and evaluated by processing the received comb signals. We want to integrate the bioradar into an unmanned aircraft system for fast and safe search and rescue operations. As a trade-off between ground penetrability and the size and weight of the antenna and the radar module, we use 1.3 GHz as the center frequency. Field measurements show that the proposed FCCW bioradar can detect an alive person through different nonmetallic building materials.

Noncontact Longitudinal Respiratory Rate Measurements in Healthy Adults Using Radar-Based Sleep Monitor (Somnofy): Validation Study

BACKGROUND

Respiratory rate (RR) is arguably the most important vital sign to detect clinical deterioration. Change in RR can also, for example, be associated with the onset of different diseases, opioid overdoses, intense workouts, or mood. However, unlike for most other vital parameters, an easy and accurate measuring method is lacking.

OBJECTIVE

This study aims to validate the radar-based sleep monitor, Somnofy, for measuring RRs and investigate whether events affecting RR can be detected from personalized baselines calculated from nightly averages.

METHODS

First, RRs from Somnofy for 37 healthy adults during full nights of sleep were extensively validated against respiratory inductance plethysmography. Then, the night-to-night consistency of a proposed filtered average RR was analyzed for 6 healthy participants in a pilot study in which they used Somnofy at home for 3 months.

RESULTS

Somnofy measured RR 84% of the time, with mean absolute error of 0.18 (SD 0.05) respirations per minute, and Bland-Altman 95% limits of agreement adjusted for repeated measurements ranged from -0.99 to 0.85. The accuracy and coverage were substantially higher in deep and light sleep than in rapid eye movement sleep and wake. The results were independent of age, sex, and BMI, but dependent on supine sleeping position for some radar orientations. For nightly filtered averages, the 95% limits of agreement ranged from -0.07 to -0.04 respirations per minute. In the longitudinal part of the study, the nightly average was consistent from night to night, and all substantial deviations coincided with self-reported illnesses.

CONCLUSIONS

RRs from Somnofy were more accurate than those from any other alternative method suitable for longitudinal measurements. Moreover, the nightly averages were consistent from night to night. Thus, several factors affecting RR should be detectable as anomalies from personalized baselines, enabling a range of applications. More studies are necessary to investigate its potential in children and older adults or in a clinical setting.

The clinical neglect of vital signs' assessment: an emerging patient safety issue?

OBJECTIVE

Vital signs assessment is a critical component of acute clinical care. Despite this, research has consistently found that the assessment of these signs is often neglected in clinical practice. This paper highlights three recent cases in the media where the neglect of vital signs assessment resulted in patient mortality.

RESULTS

Recent media reports highlighted the potentially devastating consequences of vital signs not being rigorously assessed including avoidable death. The public needs to be confident they will receive safe, quality health care when admitted to hospital.

CONCLUSION

The neglect of vital signs assessment places patients at risk of poor outcomes. Early detection of clinical deterioration via the assessment of vital signs facilitates prompt medical intervention. Factors contributing to the neglect of vital signs assessment need to be identified and corrective action taken to improve the safety of clinical care.

Aerosol capture and coronavirus spike protein deactivation by enzyme functionalized antiviral membranes

The airborne nature of coronavirus transmission makes it critical to develop new barrier technologies that can simultaneously reduce aerosol and viral spread. Here, we report nanostructured membranes with tunable thickness and porosity for filtering coronavirus-sized aerosols, combined with antiviral enzyme functionalization that can denature spike glycoproteins of the SARS-CoV-2 virus in low-hydration environments. Thin, asymmetric membranes with subtilisin enzyme and methacrylic functionalization show more than 98.90% filtration efficiency for 100-nm unfunctionalized and protein-functionalized polystyrene latex aerosol particles. Unfunctionalized membranes provided a protection factor of 540 ± 380 for coronavirus-sized particle, above the Occupational Safety and Health Administration's standard of 10 for N95 masks. SARS-CoV-2 spike glycoprotein on the surface of coronavirus-sized particles was denatured in 30 s by subtilisin enzyme-functionalized membranes with 0.02-0.2% water content on the membrane surface.

[Hemodynamic Monitoring 2.0 - What is Possible on Normal Wards?]

Life threatening events after surgery often occur on the ward. These events could be prevented by early detection of clinical deterioration of patients' health status during ward care. Therefore, an adequate monitoring could help to identify patients at risk, since there is an imbalance of monitoring intensity and the occurrence of life-threatening events during hospital stay.Additional monitoring on the general ward could lead to more patient safety. The practicability of additional monitoring needs to be considered, and therefore the use of available monitoring systems on the ward is limited. Capillary refill time (CRT) and the passive leg raise test (PLR) seem to be usable intermittent monitoring techniques.Continuous monitoring systems ensure a better detection of unwanted events and hemodynamic trends. However, the increased workload for the nursing staff and tethered monitors are unfavorable. Future trends of developing wireless monitoring systems are of paramount importance in this respect. Controlling artefacts is crucial for the successful balance between false alarms and "missed events". An adequate reaction is needed when detecting adverse events to avoid a "failure to rescue".

Respiratory rate monitoring in healthy volunteers by central photoplethysmography compared to capnography

Monitoring of respiration is a central task in clinical medicine, crucial to patient safety. Despite the uncontroversial role of altered respiratory frequency as an important sign of impending or manifest deterioration, reliable measurement methods are mostly lacking outside of intensive care units and operating theaters. Photoplethysmography targeting the central blood circulation in the sternum could offer accurate and inexpensive monitoring of respiration. Changes in blood flow related to the different parts of the respiratory cycle are used to identify the respiratory pattern. The aim of this observational study was to compare photoplethysmography at the sternum to standard capnography in healthy volunteers. Bland Altman analysis showed good agreement (bias -0.21, SD 1.6, 95% limits of agreement -3.4 to 2.9) in respiratory rate values. Photoplethysmography provided high-quality measurements of respiratory rate comparable to capnographic measurements. This suggests that photoplethysmography may become a precise, cost-effective alternative for respiratory monitoring.

Validation of Respiratory Rate-Oxygenation Index in Patients With COVID-19-Related Respiratory Failure

OBJECTIVES:

The respiratory rate-oxygenation (ROX) index is a fraction of oxygen saturation, Fio₂, and respiratory rate that has been validated to predict receipt of invasive mechanical ventilation in patients receiving high-flow nasal cannula (HFNC). This study aimed to validate ROX in a cohort of inpatients with COVID-19–related respiratory failure.

DESIGN:

Retrospective validation of the ROX index. We calculated sensitivity, specificity, positive predictive value, negative predictive value, and 95% CIs of ROX for invasive mechanical ventilation any time during hospitalization.

SETTING:

Twenty-one hospitals of Kaiser Permanente Northern California, an integrated healthcare delivery system.

PATIENTS:

We identified adults with positive severe acute respiratory syndrome coronavirus 2 polymerase chain reaction test within 3 weeks of, or during, hospitalization between February 1, 2020, and December 31, 2020. We calculated ROX at 12 hours after HFNC initiation. We grouped patients as low (≥ 4.88), intermediate (< 4.88 and ≥ 3.85), or high (< 3.85) risk using previously published thresholds.

INTERVENTIONS:

None.

MEASUREMENTS AND MAIN RESULTS:

We identified 1,847 patients who had no limitation of life support. Of these, 525 (31.7%) received invasive mechanical ventilation any time during hospitalization and 511 died (27.7%). The sensitivity, specificity, positive predictive value, and negative predictive value of 12-hour ROX threshold (< 3.85) predicting invasive mechanical ventilation were 32.3% (95% CI, 28.5–36.3%), 89.8% (95% CI, 88.0–91.4%), 59.4% (95% CI, 53.8–64.9%), and 74.1% (95% CI, 71.8–76.3%), respectively.

CONCLUSIONS:

The 12-hour ROX index has a positive predictive value (59.4%) using threshold of less than 3.85 for COVID-19 patients needing invasive mechanical ventilation. Our health system has embedded ROX into the electronic health record to prioritize rounding during periods of inpatient surge.

Developing real-world evidence from real-world data: Transforming raw data into analytical datasets

Development of evidence-based practice requires practice-based evidence, which can be acquired through analysis of real-world data from electronic health records (EHRs). The EHR contains volumes of information about patients-physical measurements, diagnoses, exposures, and markers of health behavior-that can be used to create algorithms for risk stratification or to gain insight into associations between exposures, interventions, and outcomes. But to transform real-world data into reliable real-world evidence, one must not only choose the correct analytical methods but also have an understanding of the quality, detail, provenance, and organization of the underlying source data and address the differences in these characteristics across sites when conducting analyses that span institutions. This manuscript explores the idiosyncrasies inherent in the capture, formatting, and standardization of EHR data and discusses the clinical domain and informatics competencies required to transform the raw clinical, real-world data into high-quality, fit-for-purpose analytical data sets used to generate real-world evidence.

Comparison of hemodynamic responses between conventional and virtual reality therapies in patients with heart failure admitted to an emergency room

ABSTRACT This study aimed to evaluate and to compare the acute response, due to semi-immersive virtual reality (VR) and conventional therapies (CT), of hemodynamic parameters in hospitalized individuals admitted to an emergency unity for heart failure (HF). This is a viability study with 11 individuals subjected to sessions with and without VR. At CT, stretching, active or active-assisted exercises, and fractional inspiration were performed. In VR therapy (VRT), VR box glasses were used to promote VR relaxation associated with CT. The hemodynamic parameters evaluated were heart rate, systolic and diastolic blood pressure, oxygen saturation, and double product. To analyze them, Student’s t- and Mann Whitney tests were used (p<0.05). Comparing baseline and final evaluations showed no significant differences in the hemodynamic parameters of both groups (p>0.05). Comparing absolute variations between CT and VRT also produced no significant differences between hemodynamic responses (p>0.05). Results showed that administering VRT and CT promoted physiological changes in the responses of hemodynamic parameters in individuals with HF hospitalized in an emergency unit without significant differences between the two interventions. This study suggests that VRT is a hemodynamically safe method for treating patients in emergency units.

OUP accepted manuscript

Background

Wearable devices have been proposed as a novel method for monitoring patients after surgery to track recovery, identify complications early, and improve surgical safety. Previous studies have used a heterogeneous range of devices, methods, and analyses. This review aimed to examine current methods and wearable devices used for monitoring after abdominal surgery and identify knowledge gaps requiring further investigation.

Methods

A scoping review was conducted given the heterogeneous nature of the evidence. MEDLINE, EMBASE, and Scopus databases were systematically searched. Studies of wearable devices for monitoring of adult patients within 30 days after abdominal surgery were eligible for inclusion.

Results

A total of 78 articles from 65 study cohorts, with 5153 patients were included. Thirty-one different wearable devices were used to measure vital signs, physiological measurements, or physical activity. The duration of postoperative wearable device use ranged from 15 h to 3 months after surgery. Studies mostly focused on physical activity metrics (71.8 per cent). Continuous vital sign measurement and physical activity tracking both showed promise for detecting postoperative complications earlier than usual care, but conclusions were limited by poor device precision, adherence, occurrence of false alarms, data transmission problems, and retrospective data analysis. Devices were generally well accepted by patients, with high levels of acceptance, comfort, and safety.

Conclusion

Wearable technology has not yet realized its potential to improve postoperative monitoring. Further work is needed to overcome technical limitations, improve precision, and reduce false alarms. Prospective assessment of efficacy, using an intention-to-treat approach should be the focus of further studies.

Comparação da resposta hemodinâmica entre terapia convencional e realidade virtual em pacientes com insuficiência cardíaca internados na unidade de emergência

RESUMO O objetivo deste estudo foi avaliar e comparar a resposta aguda de parâmetros hemodinâmicos de acordo com o uso de realidade virtual (RV) semi-imersiva e terapia convencional (TC) em indivíduos internados no serviço hospitalar de emergência por insuficiência cardíaca (IC). Trata-se de estudo de viabilidade com 11 indivíduos submetidos a sessões de terapia com e sem o uso da RV. Na TC, os participantes realizaram alongamentos, exercícios ativos ou ativo-assistidos e inspiração fracionada. Já na terapia com realidade virtual (TRV) utilizou-se os óculos VR box - virtual reality glasses aplicando VR relax associado à TC. Os parâmetros hemodinâmicos avaliados foram: frequência cardíaca, pressão arterial sistólica e diastólica e saturação de oxigênio. Para análise, foram utilizados os testes t de Student e de Mann-Whitney (p<0,05). Ao avaliar os parâmetros hemodinâmicos basal e final em ambos os grupos, não foi verificada diferença significativa entre os momentos (p>0,05). Com relação à comparação das variações absolutas entre a TC e a TRV, não foi observada diferença significativa entre as respostas hemodinâmicas (p>0,05). Os resultados demonstraram que a implementação da TRV e da TC promoveram alterações fisiológicas nas respostas dos parâmetros hemodinâmicos em indivíduos com IC hospitalizados em uma unidade de emergência, não havendo diferenças significativas entre as duas intervenções. O estudo sugere que a RV é um método hemodinamicamente seguro para aplicação em unidade de emergência.

Assessing and managing post-operative haemorrhage and haemorrhagic shock

Improved surgical outcomes have been achieved as a result of preoperative risk assessments and developments in surgical and anaesthetic techniques. However, post-operative haemorrhage remains a life-threatening complication requiring swift recognition and management. This article explores the compensatory mechanisms the body employs during haemorrhage and how these may present as altered observations that can aid early recognition. It also describes the rapid assessment of patients using the ABCDE (airway, breathing, circulation, disability, exposure) approach and outlines the management interventions used to halt the bleeding and restore intravascular volume.

Single-sided and integrated polyaniline/ poly(vinylidene fluoride) flexible membrane with micro/nanostructures as breathable, nontoxic and fast response wearable humidity sensor

Harmless and breathable flexible humidity sensor has important applications in continuous and real-time detection of human physiological activities. In this work, with hydrophobic poly (vinylidene fluoride) (PVDF) membrane as both the template and substrate and cetyltrimethylammonium bromide as a structure regulator, polyaniline (PANI) was unilaterally deposited on a PVDF microporous membrane to facilely fabricate a single-sided integrated flexible humidity sensor (IFHS). Such IFHS is featured with unique micro/nano structure and good air permeability. Moreover, it exhibits good humidity sensing properties at room temperature including fast response, small hysteresis and stable response even under bending deformation. The flexible sensor could realize non-contact monitoring of human respiration and speaking activities. Unilateral deposition of PANI and good breathability of IFHS avoids direct contact between PANI and human skin, thus averting harms to human and minimizing the deterioration of humidity sensing properties of PANI layer. The simple method is universal to the preparation of single-sided, integrated, breathable, nontoxic and fast response wearable humidity sensors based on PANI and hydrophobic microporous polymer membranes, offering useful references for the construction of advanced flexible sensors.

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.

A review of the literature on the accuracy, strengths, and limitations of visual, thoracic impedance, and electrocardiographic methods used to measure respiratory rate in hospitalized patients

Background

Respiratory rate (RR) is one of the most important indicators of a patient's health. In critically ill patients, unrecognized changes in RR are associated with poorer outcomes. Visual assessment (VA), impedance pneumography (IP), and electrocardiographic‐derived respiration (EDR) are the three most commonly used methods to assess RR. While VA and IP are widely used in hospitals, the EDR method has not been validated for use in hospitalized patients. Additionally, little is known about their accuracy compared with one another. The purpose of this systematic review was to compare the accuracy, strengths, and limitations of VA of RR to two methods that use physiologic data, namely IP and EDR.

Methods

A systematic review of the literature was undertaken using prespecified inclusion and exclusion criteria. Each of the studies was evaluated using standardized criteria.

Results

Full manuscripts for 23 studies were reviewed, and four studies were included in this review. Three studies compared VA to IP and one study compared VA to EDR. In terms of accuracy, when Bland–Altman analyses were performed, the upper and lower levels of agreement were extremely poor for both the VA and IP and VA and EDR comparisons.

Conclusion

Given the paucity of research and the fact that no studies have compared all three methods, no definitive conclusions can be drawn about the accuracy of these three methods. The clinical importance of accurate assessment of RR warrants new research with rigorous designs to determine the accuracy, and clinically meaningful levels of agreement of these methods.

Understanding the principles of non-invasive positive pressure ventilation

Non-invasive positive pressure ventilation (NPPV) provides respiratory support to patients without the need for invasive intubation. Although it has been used for several years in critical care, NPPV has come to prominence as a management option for certain patients with respiratory complications of coronavirus disease 2019 (COVID-19). This has led to increased care provision by nurses with little or no experience and expertise in critical care and NPPV. This article provides an overview of the principles of NPPV and its use in type 1 and type 2 respiratory failure. It explains the pathophysiology of several conditions that often lead to respiratory failure and how NPPV can mitigate respiratory failure and improve gas exchange. An individualised assessment of the patient's suitability for NPPV and an evaluation of the effectiveness of the therapy are crucial to ensure its safe and effective use. Nurses also have an important role in providing explanations and support to patients.

The effectiveness of continuous respiratory rate monitoring in predicting hypoxic and pyrexic events: a retrospective cohort study

Respiratory rate (RR) is routinely used to monitor patients with infectious, cardiac and respiratory diseases and is a component of early warning scores used to predict patient deterioration. However, it is often measured visually with considerable bias and inaccuracy.Objectives. Firstly, to compare distribution and accuracy of electronically measured RR (EMRR) and visually measured RR (VMRR). Secondly, to determine whether, and how far in advance, continuous electronic RR monitoring can predict oncoming hypoxic and pyrexic episodes in infectious respiratory disease.Approach.A retrospective cohort study analysing the difference between EMRR and VMRR was conducted using patient data from a large tertiary hospital. Cox proportional hazards models were used to determine whether continuous, EMRR measurements could predict oncoming hypoxic (SpO₂ < 92%) and pyrexic (temperature >38 °C) episodes.Main results.Data were gathered from 34 COVID-19 patients, from which a total of 3445 observations of VMRR (independent of Hawthorne effect), peripheral oxygen saturation and temperature and 729 117 observations of EMRR were collected. VMRR had peaks in distribution at 18 and 20 breaths per minute. 70.9% of patients would have had a change of treatment during their admission based on the UK's National Early Warning System if EMRR was used in place of VMRR. An elevated EMRR was predictive of hypoxic (hazard ratio: 1.8 (1.05-3.07)) and pyrexic (hazard ratio: 9.7 (3.8-25)) episodes over the following 12 h.Significance.Continuous EMRR values are systematically different to VMRR values, and results suggest it is a better indicator of true RR as it has lower kurtosis, higher variance, a lack of peaks at expected values (18 and 20) and it measures a physiological component of breathing directly (abdominal movement). Results suggest EMRR is a strong marker of oncoming hypoxia and is highly predictive of oncoming pyrexic events in the following 12 h. In many diseases, this could provide an early window to escalate care prior to deterioration, potentially preventing morbidity and mortality.

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

An Analysis on the Performance of a Mobile Platform with Gas Sensors for Real Time Victim Localization

This work concerns the performance analysis of the sensors contained in a victim detection system. The system is a mobile platform with gas sensors utilized for real time victim localization in urban environments after a disaster has caused the entrapment of people in partially collapsed building structures. The operating principle of the platform is the sampling of air from potential survival spaces (voids) and the measurement of the sampled air's temperature and concentration of CO₂ and O₂. Humans in a survival space are modelled as sources of CO₂ and heat and sinks of O₂. The physical openings of a survival space are modelled as sources of fresh air and sinks of the internal air. These sources and sinks dynamically affect the monitored properties of the air inside a survival space. In this paper, the effects of fresh air sources and internal air sinks are first examined in relation to local weather conditions. Then, the effect of human sources of CO₂ and sinks of O₂ in the space are examined. A model is formulated in order to reliably estimate the concentration of CO₂ and O₂ as a function of time for given reasonable entrapment scenarios. The input parameters are the local weather conditions, the openings of the survival space, and the number and type of entrapped humans. Three different tests successfully verified the presented theoretical estimations. A detection system with gas sensors of specified or measured capabilities, by utilizing this model and based on the expected concentrations, may inform the operator of the minimum required presence of humans in a survival space that can be detected after "some time".

Derivation of a Clinical Risk Score to Predict 14-Day Occurrence of Hypoxia, ICU Admission, and Death Among Patients with Coronavirus Disease 2019

BACKGROUND

Uncertainty surrounding COVID-19 regarding rapid progression to acute respiratory distress syndrome and unusual clinical characteristics make discharge from a monitored setting challenging. A clinical risk score to predict 14-day occurrence of hypoxia, ICU admission, and death is unavailable.

OBJECTIVE

Derive and validate a risk score to predict suitability for discharge from a monitored setting among an early cohort of patients with COVID-19.

DESIGN

Model derivation and validation in a retrospective cohort. We built a manual forward stepwise logistic regression model to identify variables associated with suitability for discharge and assigned points to each variable. Event-free patients were included after at least 14 days of follow-up.

PARTICIPANTS

All adult patients with a COVID-19 diagnosis between March 1, 2020, and April 12, 2020, in 10 hospitals in Massachusetts, USA.

MAIN MEASURES

Fourteen-day composite predicting hypoxia, ICU admission, and death. We calculated a risk score for each patient as a predictor of suitability for discharge evaluated by area under the curve.

KEY RESULTS

Of 2059 patients with COVID-19, 1326 met inclusion. The 1014-patient training cohort had a mean age of 58 years, was 56% female, and 65% had at least one comorbidity. A total of 255 (25%) patients were suitable for discharge. Variables associated with suitability for discharge were age, oxygen saturation, and albumin level, yielding a risk score between 0 and 55. At a cut point of 30, the score had a sensitivity of 83% and specificity of 82%. The respective c-statistic for the derivation and validation cohorts were 0.8939 (95% CI, 0.8687 to 0.9192) and 0.8685 (95% CI, 0.8095 to 0.9275). The score performed similarly for inpatients and emergency department patients.

CONCLUSIONS

A 3-item risk score for patients with COVID-19 consisting of age, oxygen saturation, and an acute phase reactant (albumin) using point of care data predicts suitability for discharge and may optimize scarce resources.

Use of wireless respiratory rate sensor monitoring during opioid patient-controlled analgesia after gynaecological surgery: A prospective cohort study

Background and Aims:

Respiratory depression is a rare but serious complication during opioid administration. Therefore, early detection of signs of deterioration is paramount. The current standard of care of using manual intermittent respiratory rate (RR) measurement is labour intensive and inefficient. We evaluated a wireless sensor monitor, Aingeal (Renew Health Ltd, Ireland), to continuously monitor RR, heart rate (HR) and temperature compared to standard clinical measurements.

Methods:

Patients who underwent major gynaecological operations and received postoperative opioid patient-controlled analgesia were recruited. Patients were connected to the sensor monitor via a central station software platform. The primary outcome was comparison of RR between sensor and nursing monitoring, with secondary outcomes being HR and temperature between two methods. Feedback from patients and healthcare providers was also collected. Bland-Altman analyses were used to compare the vital signs recorded in sensor against those in patient's electronic record.

Results:

A total of 1121 hours of vital signs data were analysed. Bias for RR was -0.90 (95% confidence interval (CI): -9.39, 7.60) breaths/min between nursing and averaged sensor readings. Bias for heart rate was -1.12 (95% CI: -26.27, 24.03) and bias for temperature was 1.45 (95% CI: -5.67, 2.76) between the two methods.

Conclusion:

There is satisfactory agreement of RR measurements, as well as HR and temperature measurements, by the wireless sensor monitor with standard clinical intermittent monitoring with overall good user experience.

[Postoperative remote monitoring]

During the course of surgical interventions, complications mostly occur in the postoperative period. Slight clinical indications can be observed, which precede a significant deterioration of the patient's condition. On the general ward vital parameters, such as heart and breathing frequencies are measured every 4-8 h. Even if the monitoring of critically ill patients is increased to every 2 h and the measurement of vital functions takes 10 min, the patient is only monitored for 120 min in a 24 h period and remains postoperatively on the general ward without monitoring for 22 out of 24 h. New wireless monitoring systems are available to continuously register some vital functions with the aid of wearable sensors. These systems can alert and alarm ward personnel if the patient's condition deteriorates. Although the optimal monitoring system does not yet exist and implementation of these new wireless monitoring systems might involve some risks, these new methods offer a great opportunity to optimize surveillance of postoperative patients on the general ward.

An evaluation of a video magnification-based system for respiratory rate monitoring in an acute mental health setting

CONTEXT

One of the most important goals of inpatient psychiatric care is to provide a safe and therapeutic environment for both patients and staff. A small number of aggressive or agitated patients are difficult to sedate, even after multiple doses of sedating antipsychotics. Adverse effects can result in harm to the patient and staff and that observations are conducted without touching the patient.

AIM

This study aims to determine if motion magnification can improve the feasibility of non-contact respirations monitoring over a video feed.

METHODS

Registered nurses were invited to view seven pairs of pre-recorded footage of healthy volunteers and count the number of breaths that they observe over a period of one minute for each. One of the paired videos was unprocessed and the other magnified the motion of chest rise and fall.

RESULTS

Nursing observation of respirations showed an improvement in reduction of count error from 15.7 % to 1.5 % after video magnification of respiratory movement. Nurses also stated that viewing the processed video was much easier to make their observations from.

CONCLUSION

It is possible to use magnified video to monitor respirations of patients during circumstances where it is potentially difficult to obtain. Further observational studies should be conducted on a larger scale with this type of technique and is urgently needed to inform practice.

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.

Patterns of behaviour in nursing staff actioning the afferent limb of the rapid response system (RRS): A focused ethnography

AIM

To improve understanding of afferent limb behaviour in acute hospital ward settings, to define and specify who needs to do what differently and to report what afferent limb behaviours should be targeted in a subsequent multi-phase, theory-based, intervention development process.

DESIGN

Focused ethnography was used including direct observation of nursing staff enacting afferent limb behaviours and review of vital signs charts.

METHODS

An observation guide focused observation on "key moments" of the afferent limb. Descriptions of observations from between 7 January 2019-18 December 2019 were recorded in a field journal alongside reflexive notes. Vital signs and early warning scores from charts were reviewed and recorded. Field notes were analysed using structured content analysis. Observed behaviour was compared with expected (policy-specified) behaviour.

RESULTS

Observation was conducted for 300 hr. Four hundred and ninety-nine items of data (e.g., an episode of observation or a set of vital signs) were collected. Two hundred and eighty-nine (58%) items of data were associated with expected (i.e. policy-specified) afferent limb behaviour; 210 (42%) items of data were associated with unexpected afferent limb behaviour (i.e. alternative behaviour or no behaviour). Ten specific behaviours were identified where the behaviour observed deviated (negatively) from policy or where no action was taken when it should have been. One further behaviour was seen to expedite the assessment of a deteriorating patient by an appropriate responder and was therefore considered a positive deviance.

CONCLUSION

Afferent limb failure has been described as a problem of inconsistent staff behaviour. Eleven potential target behaviours for change are reported and specified using a published framework.

IMPACT

Clear specification of target behaviour will allow further enquiry into the determinants of these behaviours and the development of a theory-based intervention that is more likely to result in behaviour change and can be tested empirically in future research.

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.