Pulse oximetry respiratory monitoring for assessment of acute childhood wheeze.

OBJECTIVE: There is a lack of objective measures to assess children with acute wheezing episodes. Increased respiratory rate (RR) and pulsus paradoxus (PP) are recognised markers, but poorly recorded in practice. We examined whether they can be reliably assessed from a pulse oximeter plethysmogram ('pleth') trace and predict clinical outcome. PATIENTS AND METHODS: We studied 44 children aged 1-7 years attending hospital with acute wheeze, following initial 'burst' bronchodilator therapy (BT), and used custom software to measure RR and assess PP from oximeter pleth traces. Traces were examined for quality, and the accuracy of the RR measurement was validated against simultaneous respiratory inductive plethysmography (RIP). RR and PP at 1 hour after BT were compared with clinical outcomes. RESULTS: RR from pleth and RIP showed excellent agreement, with a mean difference (RIP minus pleth) of -0.5 breaths per minute (limits of agreement -3.4 to +2.3). 52% of 1 min epochs contained 10 s or more of pleth artefact. At 1 hour after BT, children who subsequently required intravenous bronchodilators had significantly higher RR (median (IQR) 63 (62-66) vs 43 (37-51) breaths per minute) than those who did not, but their heart rate and oxygen saturation were similar. Children with RR ≥55 per minute spent longer in hospital: median (IQR) 30 (22-45) vs 10 (7-21) hours. All children who subsequently required hospital admission had PP-analogous pleth waveforms 1 hour after BT. CONCLUSION: RR can be reliably measured and PP detected from the pulse oximeter pleth trace in children with acute wheeze and both markers predict clinical outcome. TRIAL REGISTRATION NUMBER: UKCRN15742.

Assessment of neonatal respiratory rate variability.

Accurate measurement of respiratory rate (RR) in neonates is challenging due to high neonatal RR variability (RRV). There is growing evidence that RRV measurement could inform and guide neonatal care. We sought to quantify neonatal RRV during a clinical study in which we compared multiparameter continuous physiological monitoring (MCPM) devices. Measurements of capnography-recorded exhaled carbon dioxide across 60-s epochs were collected from neonates admitted to the neonatal unit at Aga Khan University-Nairobi hospital. Breaths were manually counted from capnograms and using an automated signal detection algorithm which also calculated mean and median RR for each epoch. Outcome measures were between- and within-neonate RRV, between- and within-epoch RRV, and 95% limits of agreement, bias, and root-mean-square deviation. Twenty-seven neonates were included, with 130 epochs analysed. Mean manual breath count (MBC) was 48 breaths per minute. Median RRV ranged from 11.5% (interquartile range (IQR) 6.8-18.9%) to 28.1% (IQR 23.5-36.7%). Bias and limits of agreement for MBC vs algorithm-derived breath count, MBC vs algorithm-derived median breath rate, MBC vs algorithm-derived mean breath rate were - 0.5 (- 2.7, 1.66), - 3.16 (- 12.12, 5.8), and - 3.99 (- 11.3, 3.32), respectively. The marked RRV highlights the challenge of performing accurate RR measurements in neonates. More research is required to optimize the use of RRV to improve care. When evaluating MCPM devices, accuracy thresholds should be less stringent in newborns due to increased RRV. Lastly, median RR, which discounts the impact of extreme outliers, may be more reflective of the underlying physiological control of breathing.

Bioinspired Self-Powered Piezoresistive Sensors for Simultaneous Monitoring of Human Health and Outdoor UV Light Intensity.

The exact fabrication of precise three-dimensional structures for piezoresistive sensors necessitates superior manufacturing methods or tooling, which are accompanied by time-consuming processes and the potential for environmental harm. Herein, we demonstrated a method for in situ synthesis of zinc oxide nanorod (ZnO NR) arrays on graphene-treated cotton and paper substrates and constructed highly sensitive, flexible, wearable, and chemically stable strain sensors. Based on the structure of pine trees and needles in nature, the hybrid sensing layer consisted of graphene-attached cotton or paper fibers and ZnO NRs, and the results showed a high sensitivity of 0.389, 0.095, and 0.029 kPa-1 and an ultra-wide linear range of 0-100 kPa of this sensor under optimal conditions. Our study found that water absorption and swelling of graphene fibers and the associated reduction of pore size and growth of zinc oxide were detrimental to pressure sensor performance. A random line model was developed to examine the effects of different hydrothermal times on sensor performance. Meanwhile, pulse detection, respiration detection, speech recognition, and motion detection, including finger movements, walking, and throat movements, were used to show their practical application in human health activity monitoring. In addition, monolithically grown ZnO NRs on graphene cotton sheets had been integrated into a flexible sensing platform for outdoor UV photo-indication, which is, to our knowledge, the first successful case of an integrated UV photo-detector and motion sensor. Due to its excellent strain detection and UV detection abilities, these strategies are a step forward in developing wearable sensors that are cost-controllable and high-performance.

Role of ROX index in the first assessment of COVID-19 patients in the emergency department.

During the first outbreak of Coronavirus disease 2019 (COVID-19) Emergency Departments (EDs) were overcrowded. Hence, the need for a rapid and simple tool to support clinical decisions, such as the ROX index (Respiratory rate - OXygenation), defined as the ratio of peripheral oxygen saturation and fraction of inspired oxygen, to respiratory rate. The aim of the study was to evaluate the accuracy of the ROX index in predicting hospitalization and mortality in patients with a diagnosis of COVID-19 in the ED. The secondary outcomes were to assess the number of readmissions and the variations in the ROX index between the first and the second admission. This was an observational prospective monocentric study, carried out in the ED of Sant'Orsola-Malpighi Hospital in Bologna, Italy. Five hundred and fifty-four consecutive patients with COVID-19 were enrolled and the ROX index was calculated. Patients were followed until hospital discharge or death. A ROX index value < 25.7 was associated with hospitalization (area under the curve [AUC] = 0.737, 95% CI 0.696-0.779, p < 0.001). The ROX index < 22.3 was statistically related to higher 30-day mortality (AUC = 0.764, 95% CI 0.708-0.820, p < 0.001). Eight patients were discharged and returned to the ED within the subsequent 7 days, their mean ROX index was 30.3 (6.2; range 21.9-39.4) at the first assessment and 24.6 (5.5; 14.5-29.5) at the second assessment, (p = 0.012). The ROX index, together with laboratory, imaging and clinical findings, correlated with the need for hospital admission, mechanical ventilation and mortality risk in COVID-19 patients.

Assessment of aerobic fitness in individuals with and without nonspecific chronic low back pain: a pilot study.

Aerobic fitness assessment in patients with low back pain (LBP) may help clinicians to plan how to progress the aerobic training. This was a pilot study designed to evaluate the performance of people with LBP on two different aerobic fitness tests performed on a treadmill and to compare the measure of aerobic fitness between people with LBP and healthy individuals. Ten people with LBP and 10 healthy individuals underwent two aerobic fitness protocols, the modified Bruce and maximum incremental test protocols, performed on a treadmill. Data collected during the protocols were: oxygen consumption, heart rate (HR), blood lactate concentration, respiratory quotient, rating of perceived exertion response, and pain intensity. Independent t-test and two-way analysis of variance were used respectively to assess difference between groups characteristics and physiological responses to the protocols. Our results showed that both groups were similar with regards to age (P = 0.839) or HRrest (P = 0.730) but the LBP group showed higher BMI compared to the healthy group (P = 0.031). Regarding the performance of both groups on the aerobic fitness tests, the only significant difference was reported for respiratory quotient which showed a main effect of test (P = 0.015) with higher values favoring the modified Bruce over the incremental test. Our study showed that most people with LBP are able to perform and tolerate both aerobic fitness tests but no significant differences between people with LBP and healthy individuals on both protocols were reported.

Increasing ventilator surge capacity in COVID 19 pandemic: design, manufacture and in vitro-in vivo testing in anaesthetized healthy pigs of a rapid prototyped mechanical ventilator.

OBJECTIVE: The advent of new technologies has made it possible to explore alternative ventilator manufacturing to meet the worldwide shortfall for mechanical ventilators especially in pandemics. We describe a method using rapid prototyping technologies to create an electro-mechanical ventilator in a cost effective, timely manner and provide results of testing using an in vitro-in vivo testing model. RESULTS: Rapid prototyping technologies (3D printing and 2D cutting) were used to create a modular ventilator. The artificial manual breathing unit (AMBU) bag connected to wall oxygen source using a flow meter was used as air reservoir. Controlled variables include respiratory rate, tidal volume and inspiratory: expiratory (I:E) ratio. In vitro testing and In vivo testing in the pig model demonstrated comparable mechanical efficiency of the test ventilator to that of standard ventilator but showed the material limits of 3D printed gears. Improved gear design resulted in better ventilator durability whilst reducing manufacturing time (< 2-h). The entire cost of manufacture of ventilator was estimated at 300 Australian dollars. A cost-effective novel rapid prototyped ventilator for use in patients with respiratory failure was developed in < 2-h and was effective in anesthetized, healthy pig model.

Evaluating the Impact of Freespira on Panic Disorder Patients' Health Outcomes and Healthcare Costs within the Allegheny Health Network.

Panic disorder (PD) is a debilitating condition that drives medical spending at least twice as high as medically matched controls. Excessive utilization of healthcare resources comes from emergency department (ED), medications, diagnostic testing, and physician visits. Freespira is an FDA-cleared digital therapeutic that treats PD and panic attacks (PA) by correcting underlying abnormal respiratory physiology. Efficacy of Freespira has been established in prior studies. This paper reports on a quality improvement program that investigated whether treating PD patients with Freespira would reduce medical costs and improve outcomes over 12-months. Panic symptoms were assessed using the Panic Disorder Severity Scale (PDSS). Pre-and post-treatment insurance claims determined costs. At baseline, mean Clinician Global Impression (CGI-S) was 4.4 (moderately/markedly ill), mean PDSS was 14.4 and mean PA frequency/week was 2 (range 0-5). Immediately post-treatment (week 5) mean CGI-S, PDSS and weekly PA frequency declined to 2.8 (borderline/mildly ill, 4.9 (remission) and 0.2 (range 0-2) respectively, p < 0.001. 82% reported PDSS decrease of ≥ 40% (clinically significant), 86% were PA-free. One-year post treatment mean CGI-S, PDSS and PA remained low at 2.1, 4.4, and 0.3 (range 0-1) respectively. 91% had PDSS decrease of ≥ 40%, 73% were PA-free. The majority of patients were panic attack free and/or reduced their symptoms and avoidance behaviors 1-year post Freespira treatment. Mean overall medical costs were reduced by 35% from $548 to $358 PMPM (per member per month) or an annual reduction of $2280. at 12 months post-treatment. There was a 65% reduction in ED costs from $87 to $30 PMPM. Median pharmacy costs were reduced by 68% from $73 to $23 PMPM.

Unobtrusive Health Monitoring in Private Spaces: The Smart Vehicle.

Unobtrusive in-vehicle health monitoring has the potential to use the driving time to perform regular medical check-ups. This work intends to provide a guide to currently proposed sensor systems for in-vehicle monitoring and to answer, in particular, the questions: (1) Which sensors are suitable for in-vehicle data collection? (2) Where should the sensors be placed? (3) Which biosignals or vital signs can be monitored in the vehicle? (4) Which purposes can be supported with the health data? We reviewed retrospective literature systematically and summarized the up-to-date research on leveraging sensor technology for unobtrusive in-vehicle health monitoring. PubMed, IEEE Xplore, and Scopus delivered 959 articles. We firstly screened titles and abstracts for relevance. Thereafter, we assessed the entire articles. Finally, 46 papers were included and analyzed. A guide is provided to the currently proposed sensor systems. Through this guide, potential sensor information can be derived from the biomedical data needed for respective purposes. The suggested locations for the corresponding sensors are also linked. Fifteen types of sensors were found. Driver-centered locations, such as steering wheel, car seat, and windscreen, are frequently used for mounting unobtrusive sensors, through which some typical biosignals like heart rate and respiration rate are measured. To date, most research focuses on sensor technology development, and most application-driven research aims at driving safety. Health-oriented research on the medical use of sensor-derived physiological parameters is still of interest.

Running economy and effort after cycling: Effect of methodological choices.

Prior exercise can negatively affect movement economy of a subsequent task. However, the impact of cycling exercise on the energy cost of subsequent running is difficult to ascertain, possibly because of the use of different methods of calculating economy. We examined the influence of a simulated cycling bout on running physiological cost (running economy, heart rate and ventilation rates) and perceptual responses (ratings of perceived exertion and effort) by comparing two running bouts, performed before and after cycling using different running economy calculation methods. Seventeen competitive male triathletes ran at race pace before and after a simulated Olympic-distance cycling bout. Running economy was calculated as V̇O2 (mL∙kg-1∙min-1), oxygen cost (EO2, mL∙kg-1∙m-1) and aerobic energy cost (Eaer, J∙kg-1∙m-1). All measures of running economy and perceptual responses indicated significant alterations imposed by prior cycling. Despite a good level of agreement with minimal bias between calculation methods, differences (p < 0.05) were observed between Eaer and both V̇O2 and EO2. The results confirmed that prior cycling increased physiological cost and perceptual responses in a subsequent running bout. It is recommended that Eaer be calculated as a more valid measure of running economy alongside perceptual responses to assist in the identification of individual responses in running economy following cycling.

Health assessment of Conolophus subcristatus, Conolophus pallidus, and C. subcristatus X Amblyrhynchus cristatus hybrid (Galápagos land iguanas).

The land iguanas, Conolophus pallidus and Conolophus subcristatu are large and charismatic lizards endemic to the Galápagos archipelago, but little information exists on their normal health parameters. The former is restricted to Santa Fe island, while C. subcristatus inhabits the islands of the central and western region of the archipelago. Both species are classified as vulnerable by the IUCN Red List of Threatened Species. As part of a population health assessment authorized by the Galápagos National Park, wild adult iguanas from three islands (North Seymour, South Plazas, and Santa Fe) were captured in July 2018. Data from a single C. subcristatus X Amblyrhynchus cristatus hybrid captured on South Plazas is also included. We analyzed blood samples drawn from 52 healthy wild adult land iguanas captured on three islands. An iSTAT portable blood analyzer was used to obtain values for pH, lactate, pO2, pCO2, HCO3-, sO2%, hematocrit, packed cell volume (PCV), hemoglobin Na, K, iCa, and glucose. Standard laboratory hematology techniques were employed for PCV determination; resulting values were also compared to the hematocrit values generated by the iSTAT. Body temperature, heart rate, respiratory rate, and body measurements were also recorded and compared to previously published data for the marine iguana (Amblyrhynchus cristatus), which shares a common ancestor with the land iguana. The data reported here provide preliminary baseline values that may be useful in comparisons between captive and wild populations, between wild populations, and in detecting changes in health status among Galápagos land iguanas affected by anthropogenic threats, climate change, or natural disturbances.

The Sequential Clinical Assessment of Respiratory Function (SCARF) score: A dynamic pulmonary physiologic score that predicts adverse outcomes in critically ill rib fracture patients.

BACKGROUND: Rib fracture scoring systems are limited by a lack of serial pulmonary physiologic variables. We created the Sequential Clinical Assessment of Respiratory Function (SCARF) score and hypothesized that admission, maximum, and rising scores predict adverse outcomes among critically ill rib fracture patients. METHODS: Prospective cohort study of rib fracture patients admitted to the surgical intensive care unit (ICU) at a Level I trauma center from August 2017 to June 2018. The SCARF score was developed a priori and validated using the cohort. One point was assigned for: <50% predicted, respiratory rate >20, numeric pain score ≥5, and inadequate cough. Demographics, injury patterns, analgesics, and adverse pulmonary outcomes were abstracted. Performance characteristics of the score were assessed using the receiver operator curve area under the curve. RESULTS: Three hundred forty scores were available from 100 patients. Median admission and maximum SCARF score was 2 (range 0-4). Likelihood of pneumonia (p = 0.04), high oxygen requirement (p < 0.01), and prolonged ICU length of stay (p < 0.01) were significantly associated with admission and maximum scores. The receiver operator curve area under the curve for the maximum SCARF score for these outcomes were 0.86, 0.76, and 0.79, respectively. In 10 patients, the SCARF score worsened from admission to day 2; these patients demonstrated increased likelihood of pneumonia (p = 0.04) and prolonged ICU length of stay (p = 0.07). Patients who developed complications maintained a SCARF score one point higher throughout ICU stay compared with patients who did not (p = 0.04). The SCARF score was significantly associated with both narcotic (p = 0.03) and locoregional anesthesia (p = 0.03) usage. CONCLUSION: Admission, maximum, daily, and rising scores were associated with utilization of pain control therapies and development of adverse outcomes. The SCARF score may be used to guide therapies for critically ill rib fracture patients, with a proposed threshold greater than 2. LEVEL OF EVIDENCE: Prognostic study, level II.

Nesting box imager: Contact-free, real-time measurement of activity, surface body temperature, and respiratory rate applied to hibernating mouse models.

Noncontact methods to measure animal activity and physiology are necessary to monitor undisturbed states such as hibernation. Although some noncontact measurement systems are commercially available, they are often incompatible with realistic habitats, which feature freely moving animals in small, cluttered environments. A growing market of single-board computers, microcontrollers, and inexpensive sensors has made it possible to assemble bespoke integrated sensor systems at significantly lower price points. Herein, we describe a custom-built nesting box imager (NBI) that uses a single-board computer (Raspberry Pi) with a passive infrared (IR) motion sensor, silicon charge-coupled device (CCD), and IR camera CCD to monitor the activity, surface body temperature, and respiratory rate of the meadow jumping mouse during hibernation cycles. The data are logged up to 12 samples per minute and postprocessed using custom Matlab scripts. The entire unit can be built at a price point below US$400, which will be drastically reduced as IR (thermal) arrays are integrated into more consumer electronics and become less expensive.

Quantitative Assessment of Autonomic Regulation of the Cardiac System.

Autonomic neural system (ANS) regulates the circulation to provide optimal perfusion of every organ in accordance with its metabolic needs, and the quantitative assessment of autonomic regulation is crucial for personalized medicine in cardiovascular diseases. In this paper, we propose the Dystatis to quantitatively evaluate autonomic regulation of the human cardiac system, based on homeostatis and probabilistic graphic model, where homeostatis explains ANS regulation while the probability graphic model systematically defines the regulation process for quantitative assessment. The indices and measurement methods for three well-designed scenarios are also illustrated to evaluate the proposed Dystatis: (1) heart rate variability (HRV), blood pressure variability (BPV), and respiration synchronization (Synch) in resting situation; (2) chronotropic competence indices (CCI) in graded exercise testing; and (3) baroreflex sensitivity (BRS), sympathetic nerve activity (SNA), and parasympathetic nerve activity (PNA) in orthostatic testing. The previous clinical results have shown that the proposed method and indices for autonomic cardiac system regulation have great potential in prediction, diagnosis, and rehabilitation of cardiovascular diseases, hypertension, and diabetes.

Assessment of Signal Processing Methods for Measuring the Respiratory Rate in the Neonatal Intensive Care Unit.

Knowledge of the pathological instabilities in the breathing pattern can provide valuable insights into the cardiorespiratory status of the critically-ill infant as well as their maturation level. This paper is concerned with the measurement of respiratory rate in premature infants. We compare the rates estimated from the chest impedance pneumogram, the ECG-derived respiratory rhythms, and the PPG-derived respiratory rhythms against those measured in the reference standard of breath detection provided by attending clinical staff during 165 manual breath counts. We demonstrate that accurate RR estimates can be produced from all sources for RR in the 40-80 bpm (breaths per min) range. We also conclude that the use of indirect methods based on the ECG or the PPG poses a fundamental challenge in this population due to their poor behavior at fast breathing rates (upward of 80 bpm).

Vital signs on hospital discharge and re admission rates.

BACKGROUND: Assessing the stability of a patient's vital signs in the 24 hours before discharge has been suggested as an objective and inexpensive way to determine safety for discharge. AIM: To determine the association between unstable vital signs at the time of discharge with the readmission rate over a one-year period. DESIGN: An observational cohort multi-center study at three urban community hospitals using electronic health record data collected from November 1, 2016, to October 30, 2017. METHODS: A total of 29322 hospitalizations to medical floors with complete sets of vital signs were included. The final vital signs collected on the day of discharge were used for analysis. The readmission rates were compared using different variables such as age, sex, insurance payer (Medicare or Medicaid), discharge time, discharge disposition, length of stay at the hospital, the number, and type of abnormal vital signs at discharge. RESULTS: Unstable vital signs at discharge were found in 2862 patients (9.8%). The readmission rate was highest in patients with two (11.3%) unstable vital signs compared to those with one (8.5%) and three or more (0%) instabilities. Patients with a combination of heart rate >100 beats/min and respiratory rate >20 breaths/min at discharge had a 14.1% seven-day readmission rate (P = 0.0057, Odds Ratio = 1.87, Confidence Interval = 1.19-2.95). CONCLUSIONS: Vital sign instabilities in the 24 hours before discharge are associated with increased seven-day readmission rate.

Physiological Monitoring During Augmented Reality Exercise Confirms Advantages to Health and Well-Being.

Augmented reality (AR) is a versatile tool that is changing the way we interact with the world. One way is through exergaming, integrating AR, and gaming with traditional exercise programs. This study aimed to test three different AR systems to determine their ability to elicit physiological responses similar to those experienced while exercising or performing rehabilitation exercises. The systems tested included a head-mounted display experience (Teapots), a Sony EyeToy game (Slap Stream), and a prototype of a PC-camera-based system (Drums). Physiological recordings show that Slap Stream and Drums produced significant increases (p < 0.05) in heart rate (HR) and skin conductance, and all three games produced nonsignificant increase in respiratory rate. Of the three games, Slap Stream produced the highest rates of low- (∼28 percent), moderate- (17 percent), and high-intensity (∼22 percent) HRs. This study successfully showed that inexpensive easy-to-use AR systems can effectively contribute to exercise programs. Future game design recommendations, including feedback, mixed reality, and stress tracking, are discussed.

Assessment of vibration exposure and physiological responses of crew members during Infantry Combat Vehicle (ICV) operation: a pilot study.

BACKGROUND: Operation of infantry combat vehicle (ICV) influences the cardiorespiratory responses as well as the risk of vibration exposure on the crew members which adversely affect their performance and health. AIM: To assess the effect of stress factors, that is, ICV's compartmental temperature, relative humidity (RH) and vehicular vibration on the physiological parameters (heart rate (HR), respiratory frequency (RF), estimated core body temperature (ECT)) of the crew members during the ICV operation. METHODS: A 1 hour run trial of the ICV operation was conducted with its crew members at their respective positions. Compartmental temperature and RH were monitored at an interval of every 15 min during the run trial. Physiological parameters were monitored continuously during the run trial. Whole body vibration (WBV) and hand-arm vibration (HAV) of the crew members were also measured during the run trial time. RESULTS: The findings showed a strong positive correlation (p<0.05) between the increasing compartmental temperature and RH with its run trial time. Significant changes were observed in the physiological parameters (p<0.05) along with the increasing run trial time. Additionally, the physiological parameters showed a strong positive correlation with compartmental temperature and RH, respectively (p<0.05). Also, a significant increase (p<0.05) in the muscle strength was recorded after their exposure to ICV operation. The study also confirmed high level of WBV exposure of the crew members during the ICV operation. CONCLUSION: Increase in HR, RF and ECT along with increase in temperature and RH is a predictive indicator of physiological stress. Moreover, high levels of vibration exposure of various operations may bring deleterious effect on soldiers' health as well as their performance. Proper ergonomic intervention can reduce exposure to vibration, physiological stress and increase comfort which may ultimately ensure an optimum performance of soldiers and successful completion of mission.

Minute ventilation assessment in the PACU is useful to predict postoperative respiratory depression following discharge to the floor: A prospective cohort study.

STUDY OBJECTIVE: Reliably identifying patients at risk for postoperative respiratory depression (RD) remains an unmet need. We hypothesized that defined low minute ventilation events (LMVe) near the end of the post-anesthesia care unit (PACU) stay identifies patients at RD risk on the general hospital floor (GHF). DESIGN: Prospective observational study. SETTING: Tertiary care, urban academic medical center. PACU and GHF during the first postoperative night. PATIENTS: One hundred-and-nineteen adult, ASA I - III patients undergoing elective surgery under general anesthesia completed the study. INTERVENTIONS: Data collection from a non-invasive respiratory volume monitor and the patients' medical record perioperatively through the first postoperative night. MEASUREMENTS: Minute ventilation (MV), tidal volume (TV) and respiratory rate (RR) were measured continuously in the PACU and on the GHF. MV was counted as the percent of individual predicted MV (MVPRED), and RD was defined as ≥1 LMVe/h on the GHF. Based on the number of LMVes within 30 min before PACU discharge, patients were grouped into A, 'Not-At-Risk': 0 LMVe and B, 'At-Risk': ≥1 LMVes. Unpaired t-test, Mann-Whitney U test, ANOVA, Kruskal-Wallis test, Fisher's exact test, sensitivity and specificity and ROC curve analyses were applied as appropriate. MAIN RESULTS: One hundred-and-six (89%) and 13 (11%) patients met Group A and B criteria respectively. The latter had more LMVe/h on the GHF (median 0.81 vs 0, p ≤ 0.001), and their MVPRED was significantly less. Following opioid administration, the LMVe likelihood was 43% in Group B and 5.6% in Group A. As a predictor for RD on the GHF, the number of LMVe in the last 30 min of PACU, had positive and negative predictive values of 61.5% and 90.6%, respectively. CONCLUSION: Minute ventilation assessment in the PACU as described in this study can be useful to identify patients at risk for postoperative respiratory depression.

Use of respiratory rates and heart rate variability in the assessment and treatment of children and adolescents with functional somatic symptoms.

Functional somatic symptoms (FSS) emerge when the stress system is activated in response to physical or emotional stress that is either chronic or especially intense. In such cases, the heightened state of physiological arousal and motor activation can be measured through biological markers. Our team have integrated the use of biological markers of body state - respiratory rate, heart rate (HR) and heart rate variability (HRV) measurements - as a way of helping families to understand how physical symptoms can signal activation of the body's stress systems. This study measured respiratory rates, HR and HRV in children and adolescents with FSS (and healthy controls) during baseline assessment to determine whether these biological markers were effective at differentiating patients with FSS. The study also implemented a biofeedback intervention during the assessment to determine whether patients with FSS were able to slow their respiratory rates and increase HRV. Patients with FSS had faster respiratory rates, faster HR, and lower HRV, suggesting activation of the autonomic nervous system coupled with activation of the respiratory motor system. Like controls, patients were able to slow their respiratory rates, but in contrast to controls, they were unable to increase their HRV. Our findings suggest that patients with FSS present in a state of physiological activation and struggle to regulate their body state. Patients with FSS are likely to need ongoing training and practice to regulate body state coupled with interventions that target regulatory capacity across multiple systems.