Identifying vital sign trajectories to predict 28-day mortality of critically ill elderly patients with acute respiratory distress syndrome.

BACKGROUND: The mortality rate of acute respiratory distress syndrome (ARDS) increases with age (≥ 65 years old) in critically ill patients, and it is necessary to prevent mortality in elderly patients with ARDS in the intensive care unit (ICU). Among the potential risk factors, dynamic subphenotypes of respiratory rate (RR), heart rate (HR), and respiratory rate-oxygenation (ROX) and their associations with 28-day mortality have not been clearly explored. METHODS: Based on the eICU Collaborative Research Database (eICU-CRD), this study used a group-based trajectory model to identify longitudinal subphenotypes of RR, HR, and ROX during the first 72 h of ICU stays. A logistic model was used to evaluate the associations of trajectories with 28-day mortality considering the group with the lowest rate of mortality as a reference. Restricted cubic spline was used to quantify linear and nonlinear effects of static RR-related factors during the first 72 h of ICU stays on 28-day mortality. Receiver operating characteristic (ROC) curves were used to assess the prediction models with the Delong test. RESULTS: A total of 938 critically ill elderly patients with ARDS were involved with five and 5 trajectories of RR and HR, respectively. A total of 204 patients fit 4 ROX trajectories. In the subphenotypes of RR, when compared with group 4, the odds ratios (ORs) and 95% confidence intervals (CIs) of group 3 were 2.74 (1.48-5.07) (P = 0.001). Regarding the HR subphenotypes, in comparison to group 1, the ORs and 95% CIs were 2.20 (1.19-4.08) (P = 0.012) for group 2, 2.70 (1.40-5.23) (P = 0.003) for group 3, 2.16 (1.04-4.49) (P = 0.040) for group 5. Low last ROX had a higher mortality risk (P linear = 0.023, P nonlinear = 0.010). Trajectories of RR and HR improved the predictive ability for 28-day mortality (AUC increased by 2.5%, P = 0.020). CONCLUSIONS: For RR and HR, longitudinal subphenotypes are risk factors for 28-day mortality and have additional predictive enrichment, whereas the last ROX during the first 72 h of ICU stays is associated with 28-day mortality. These findings indicate that maintaining the health dynamic subphenotypes of RR and HR in the ICU and elevating static ROX after initial critical care may have potentially beneficial effects on prognosis in critically ill elderly patients with ARDS.

Associations of Brain Entropy Estimated by Resting State fMRI With Physiological Indices, Body Mass Index, and Cognition.

BACKGROUND: In recent years, resting-state fMRI (rsfMRI)-based brain entropy (BEN) has gained increasing interest as a tool to characterize brain activity. While previous studies indicate that BEN is correlated with cognition, it remains unclear whether BEN is influenced by other factors that typically affect brain activity measured by fMRI. PURPOSE: To investigate the relationship between BEN and physiological indices, including respiratory rate (RR), heart rate (HR), systolic blood pressure (s-BP), and body mass index (BMI), and to investigate whether and to what extent the relationship between BEN and cognition is influenced by physiological variables. STUDY TYPE: Retrospective. SUBJECTS: One thousand two hundred six healthy subjects (mean age: 28.83 ± 3.69 years; 550 male) with rsfMRI datasets selected from the Human Connectome Project (HCP). FIELD STRENGTH/SEQUENCE: Multiband echo planar imaging (EPI) sequence at 3.0 Tesla. ASSESSMENT: Neurocognitive, physical health (RR, HR, s-BP, BMI), and rsfMRI data were retrieved from the HCP datasets. Neurocognition was measured through the total cognition composite (TCC) score provided by HCP. BEN maps were calculated from rsfMRI data. STATISTICAL TESTS: Multiple regression models, pheight-family wise error (FWE) < 0.05 and pcluster-FWE < 0.05 were considered statistically significant. RESULTS: BEN was negatively associated with RR (T-thresholds ranging from 4.75 to 4.8; r-threshold = |0.15|) and positively associated with s-BP and BMI (T-thresholds ranging from 4.75 to 4.8; r-threshold = |0.15|) in areas overlapping with the default mode network. After controlling the physiological effects, BEN still showed regional associations with TCC, including negative associations (T-thresholds = 3.09; r-threshold = |0.1|) in the fronto-parietal cortex and positive associations (T-thresholds = 3.09; r-threshold = |0.1|) in the sensorimotor system (motor network and the limbic system). DATA CONCLUSIONS: RR negatively affects rsfMRI-derived BEN, while s-BP and BMI positively affect BEN. The positive associations between BEN and cognition in the motor network and the limbic system might indicate a facilitation of information processing in the sensorimotor system. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 3.

Impacts of ocean acidification and hypoxia on cellular immunity, oxygen consumption and antioxidant status in Mediterranean mussel.

There is growing recognition that the hypoxic regions of the ocean are also becoming more acidic due to increasing levels of global carbon dioxide emissions. The impact of water acidification on marine life is largely unknown, as most previous studies have not taken into account the effects of hypoxia, which may affect how organisms respond to low pH levels. In this study, we experimentally examined the consequences of water acidification in combination with normoxic or hypoxic conditions on cellular immune parameters in Mediterranean mussels. We measured total hemocyte counts in hemolymph, the cellular composition of hemolymph, phagocytosis, reactive oxygen species (ROS) production. General response of the organism was evaluated on the basis of the activity of antioxidant enzymes in the hepatopancreas, as well as respiratory rates over an 8-day exposure period. The mussels were exposed to low pH conditions (7.3), either under normoxic conditions (dissolved oxygen concentration of 8 mg/L) or hypoxic conditions (dissolved oxygen concentration of 2 mg/L). The parameters were assessed at days 1, 3, 6, and 8 of the experiment. Experimental acidification under normoxic conditions reduced THC and ROS production by hemocytes during later stages of exposure, but phagocytic activity (PA) only decreased at day 3 and then recovered. Combined acidification and hypoxia suppressed PA in hemocytes at the beginning of exposure, while hemocyte ROS production and THC decreased by the end of the experiment. The hemolymph cellular composition and activity of antioxidant enzymes were unaffected by acidified conditions under different oxygen regimes, but mussel respiratory rate (RR) decreased with a more significant reduction in oxygen consumption under hypoxia. Mussels showed a relatively high tolerance to acidification in combination with various dissolved oxygen levels, although prolonged acidification exposure led to increased detrimental effects on immunity and metabolism.

Comparison emergence of sedation, using dexmedetomidine and remimazolam, in spinal anaesthesia - double blinded randomized controlled trial.

Background: Continuous intravenous infusion of remimazolam may be suitable for sedation in patients undergoing regional anaesthesia. However, there have been no studies comparing remimazolam and dexmedetomidine for this purpose. This study compared emergence from sedation between dexmedetomidine and remimazolam following continuous intravenous infusion in patients undergoing spinal anaesthesia. Methods: This double-blinded, randomised controlled trial assessed the sedative effects of dexmedetomidine and remimazolam. Following spinal anaesthesia, patients were sedated using continuous intravenous infusion of either dexmedetomidine (D group) or remimazolam (R group).The D group received dexmedetomidine administered at 6 mL/kg/h (6 µg/kg/h) for 10 minutes, followed by 1 mL/kg/h (1 µg/kg/h). The R group received remimazolam administered at 6 mL/kg/h (6 mg/kg/h) for 10 minutes, followed by 1 mL/kg/h (1 mg/kg/h). Sedation levels were evaluated using the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale. The time to reach MOAA/S ≤ 3 from the start of drug infusion and the time to reach MOAA/S = 5 from the end of infusion were recorded. Hemodynamic parameters and respiratory rate were also monitored. Results: The R group reached MOAA/S ≤ 3 significantly faster than the D group during induction of sedation (4 ± 1 minutes and 11 ± 3 minutes, respectively, p < 0.001). The R group also reached MOAA/S = 5 significantly faster than the D group during emergence from sedation (11 ± 3 minutes and 16 ± 5 minutes, respectively, p < 0.001). Both groups maintained stable hemodynamic parameters and respiratory rate without any significant differences, although the mean heart rate was significantly lower in the D group than in the R group after the start of infusion. Conclusion: Remimazolam demonstrated significantly faster induction of and emergence from sedation compared to dexmedetomidine, with no significant differences in haemodynamics or respiratory depression.

Modulatory effects of dietary saturated fatty acids on platelet mitochondrial function following short-term exposure to ambient Particulate Matter (PM2.5).

Exposure to ambient fine particulate matter (PM2.5) was found to produce vascular injury, possibly by activating platelets within days after exposure. The aim of this study was to investigate the modulatory effects of dietary saturated fatty acids on platelet mitochondrial respiratory parameters following short-term inhalational exposure to PM2.5. A total of 22 healthy male volunteers were recruited from the Research Triangle area of North Carolina. Platelets were isolated from fresh whole blood samples and mitochondrial respiratory parameters were measured using an extracellular flux analyzer. Intake of saturated fat was averaged from multiple 24-hr dietary recalls. Daily ambient PM2.5 concentrations were obtained from ambient air quality monitoring stations. Correlation and ANOVA were used in data analyses, along with the pick-a-point method and the Johnson-Neyman technique for probing moderation. After controlling for age and omega-3 index, the intake of dietary saturated fatty acids after reaching 9.3% or higher of the total caloric intake significantly moderated the associations between PM2.5 exposure and several platelet mitochondrial respiratory parameters. In conclusion, dietary saturated fatty acids above 9.3% of total caloric intake influenced the relationship between short-term PM2.5 exposure and platelet mitochondrial respiration. Further research is needed to understand these associations and their implications for cardiovascular health.

For a clinical application of optical triangulation to assess respiratory rate using an RGB camera and a line laser.

This paper presents a non-contact and unrestrained respiration monitoring system based on the optical triangulation technique. The proposed system consists of a red-green-blue (RGB) camera and a line laser installed to face the frontal thorax of a human body. The underlying idea of the work is that the camera and line laser are mounted in opposite directions, unlike other research. By applying the proposed image processing algorithm to the camera image, laser coordinates are extracted and converted to world coordinates using the optical triangulation method. These converted world coordinates represent the height of the thorax of a person. The respiratory rate is measured by analyzing changes of the thorax surface depth. To verify system performance, the camera and the line laser are installed on the head and foot sides of a bed, respectively, facing toward the center of the bed. Twenty healthy volunteers were enrolled and underwent measurement for 100s. Evaluation results show that the optical triangulation-based image processing method demonstrates non-inferior performance to a commercial patient monitoring system with a root-mean-squared error of 0.30rpm and a maximum error of 1rpm ( p > 0.05 ), which implies the proposed non-contact system can be a useful alternative to the conventional healthcare method.

A pilot study using the LASCA technique to analyze stress using heart rate variability.

In the quest to uncover biological cues that help explain organic changes brought on by an external stimulus, like stress, new technologies have become necessary. The Laser Speckle Contrast Analysis (LASCA) approach is one of these technologies that may be used to analyze biological data, including respiratory rate (RR) intervals, and then use the results to determine heart rate variability (HRV Thus, to evaluate the stress brought on by physical activity, this study used the LASCA approach. A stress induction procedure involving physical exertion was employed, and the results were compared to other established techniques (cortisol analysis and ECG signal) to verify the LASCA methodology as a tool for measuring HRV and stress. The study sample comprised 27 willing participants. The technique involving LASCA allowed for the non-invasive (non-contact) acquisition of HRV and the study of stress. Furthermore, it made it possible to gather pertinent data, such as recognizing modifications to the thermoregulation, peripheral vasomotor tonus, and renin-angiotensin-aldosterone systems that were brought on by elevated stress and, as a result, variations in HRV readings.

Mitochondrial coding genes mediate insecticide tolerance in the oriental fruit fly, Bactrocera dorsalis (Hendel).

The oriental fruit fly, Bactrocera dorsalis (Hendel), an invasive insect pest infesting fruits and vegetables, possesses a remarkable capacity for environmental adaptation. The investigation of behind mechanisms of the stress adaptability in B. dorsalis holds significantly practical relevance. Previous studies on the molecular mechanism underlying stress resistance in B. dorsalis have predominantly focused on nuclear-coding genes, with limited exploration on organelle-coding genes. In this study, we assessed alterations in the mitochondrial physiological parameters of B. dorsalis under exposure to malathion, avermectin, and beta-cypermethrin at LD50 dosages. The results showed that all three insecticides were capable of reducing mitochondrial complex IV activity and ATP content. Expression patterns of mitochondrial coding genes across different developmental stages, tissues and insecticide exposures were analyzed by RT-qPCR. The results revealed that these mitochondrial coding genes were expressed in various tissues and at different developmental stages. Particularly noteworthy, atp6, cox2, and cytb exhibited substantial up-regulation in response to malathion and avermectin treatment. Furthermore, RNAi-mediated knockdown of atp6 and cox2 resulted in the increased toxicity of malathion and avermectin against B. dorsalis, and cox2 silencing was also associated with the decreased complex IV activity. These findings suggest that atp6 and cox2 most likely play pivotal roles in mediating tolerance or resistance to malathion and avermectin in B. dorsalis. Our results provide novel insights into the role of mitochondrial coding genes in conferring tolerance to insecticides in B. dorsalis, with practical implications for controlling this pest in the field.

Unobtrusive Sensors for Synchronous Monitoring of Different Breathing Parameters in Care Environments.

Respiratory problems are common amongst older people. The rapid increase in the ageing population has led to a need for developing technologies that can monitor such conditions unobtrusively. This paper presents a novel study that investigates Wi-Fi and ultra-wideband (UWB) antenna sensors to simultaneously monitor two different breathing parameters: respiratory rate, and exhaled breath. Experiments were carried out with two subjects undergoing three breathing cases in breaths per minute (BPM): (1) slow breathing (12 BPM), (2) moderate breathing (20 BPM), and (3) fast breathing (28 BPM). Respiratory rates were captured by Wi-Fi sensors, and the data were processed to extract the respiration rates and compared with a metronome that controlled the subjects' breathing. On the other hand, exhaled breath data were captured by a UWB antenna using a vector network analyser (VNA). Corresponding reflection coefficient data (S11) were obtained from the subjects at the time of exhalation and compared with S11 in free space. The exhaled breath data from the UWB antenna were compared with relative humidity, which was measured with a digital psychrometer during the breathing exercises to determine whether a correlation existed between the exhaled breath's water vapour content and recorded S11 data. Finally, captured respiratory rate and exhaled breath data from the antenna sensors were compared to determine whether a correlation existed between the two parameters. The results showed that the antenna sensors were capable of capturing both parameters simultaneously. However, it was found that the two parameters were uncorrelated and independent of one another.

An Inertial-Based Wearable System for Monitoring Vital Signs during Sleep.

This study explores the feasibility of a wearable system to monitor vital signs during sleep. The system incorporates five inertial measurement units (IMUs) located on the waist, the arms, and the legs. To evaluate the performance of a novel framework, twenty-three participants underwent a sleep study, and vital signs, including respiratory rate (RR) and heart rate (HR), were monitored via polysomnography (PSG). The dataset comprises individuals with varying severity of sleep-disordered breathing (SDB). Using a single IMU sensor positioned at the waist, strong correlations of more than 0.95 with the PSG-derived vital signs were obtained. Low inter-participant mean absolute errors of about 0.66 breaths/min and 1.32 beats/min were achieved, for RR and HR, respectively. The percentage of data available for analysis, representing the time coverage, was 98.3% for RR estimation and 78.3% for HR estimation. Nevertheless, the fusion of data from IMUs positioned at the arms and legs enhanced the inter-participant time coverage of HR estimation by over 15%. These findings imply that the proposed methodology can be used for vital sign monitoring during sleep, paving the way for a comprehensive understanding of sleep quality in individuals with SDB.

Energy-Efficient PPG-Based Respiratory Rate Estimation Using Spiking Neural Networks.

Respiratory rate (RR) is a vital indicator for assessing the bodily functions and health status of patients. RR is a prominent parameter in the field of biomedical signal processing and is strongly associated with other vital signs such as blood pressure, heart rate, and heart rate variability. Various physiological signals, such as photoplethysmogram (PPG) signals, are used to extract respiratory information. RR is also estimated by detecting peak patterns and cycles in the signals through signal processing and deep-learning approaches. In this study, we propose an end-to-end RR estimation approach based on a third-generation artificial neural network model-spiking neural network. The proposed model employs PPG segments as inputs, and directly converts them into sequential spike events. This design aims to reduce information loss during the conversion of the input data into spike events. In addition, we use feedback-based integrate-and-fire neurons as the activation functions, which effectively transmit temporal information. The network is evaluated using the BIDMC respiratory dataset with three different window sizes (16, 32, and 64 s). The proposed model achieves mean absolute errors of 1.37 ± 0.04, 1.23 ± 0.03, and 1.15 ± 0.07 for the 16, 32, and 64 s window sizes, respectively. Furthermore, it demonstrates superior energy efficiency compared with other deep learning models. This study demonstrates the potential of the spiking neural networks for RR monitoring, offering a novel approach for RR estimation from the PPG signal.

A Wearable Sandwich Heterostructure Multimode Fiber Optic Microbend Sensor for Vital Signal Monitoring.

This work proposes a highly sensitive sandwich heterostructure multimode optical fiber microbend sensor for heart rate (HR), respiratory rate (RR), and ballistocardiography (BCG) monitoring, which is fabricated by combining a sandwich heterostructure multimode fiber Mach-Zehnder interferometer (SHMF-MZI) with a microbend deformer. The parameters of the SHMF-MZI sensor and the microbend deformer were analyzed and optimized in detail, and then the new encapsulated method of the wearable device was put forward. The proposed wearable sensor could greatly enhance the response to the HR signal. The performances for HR, RR, and BCG monitoring were as good as those of the medically approved commercial monitors. The sensor has the advantages of high sensitivity, easy fabrication, and good stability, providing the potential for application in the field of daily supervision and health monitoring.

Breathing Monitoring in Soccer: Part I-Validity of Commercial Wearable Sensors.

Growing evidence suggests that respiratory frequency (fR) is a valid marker of effort during high-intensity exercise, including sports of an intermittent nature, like soccer. However, very few attempts have been made so far to monitor fR in soccer with unobtrusive devices. This study assessed the validity of three strain-based commercial wearable devices measuring fR during soccer-specific movements. On two separate visits to the soccer pitch, 15 players performed a 30 min validation protocol wearing either a ComfTech® (CT) vest or a BioharnessTM (BH) 3.0 strap and a Tyme WearTM (TW) vest. fR was extracted from the respiratory waveform of the three commercial devices with custom-made algorithms and compared with that recorded with a reference face mask. The fR time course of the commercial devices generally resembled that of the reference system. The mean absolute percentage error was, on average, 7.03% for CT, 8.65% for TW, and 14.60% for BH for the breath-by-breath comparison and 1.85% for CT, 3.27% for TW, and 7.30% for BH when comparison with the reference system was made in 30 s windows. Despite the challenging measurement scenario, our findings show that some of the currently available wearable sensors are indeed suitable to unobtrusively measure fR in soccer.

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.

Strategies to alleviate heat stress on performance and physiological parameters in feedlot-finished cattle under heat stress conditions. A systematic review-meta-analysis.

Strategies to alleviate heat stress on live performance - dry matter intake (DMI), average daily gain (ADG), and feed conversion efficiency (FCE) - and on physiological parameters - respiratory rate (RR) and panting score (PS) - of feedlot-finished cattle were evaluated by systematic review-meta-analysis. Using the PICO framework were identified 3813 records, with 31 publications and 6729 cattle being considered in the meta-analysis (MA). The comparison most reported was sun vs. shade (n = 24 publications), followed by shade vs. shade (area per animal and effectivity in reduce solar load) (n = 7 publications) and sun vs. sprinkling (n = 4 publications). Cattle with access to shade with total reduction in solar load improved ADG (p = 0.008) and FCE (p = 0.024), and reduced RR (p < 0.001) compared to unshaded animals. Cattle with access to shade with a height between 3 and 4 m increased ADG (p < 0.001), tended to improve FCE (p = 0.054), and reduced RR (p < 0.001) compared to unshaded animals. An area of shade from 2 to 4 m2/animal increased ADG (p = 0.002), and higher than 4 m2/animal reduced RR (p < 0.001) compared to unshaded animals. Animals that received sprinkling volume below 1 L/animal/min improved ADG (p = 0.008) compared to unshaded animals. Cattle with access to shade with a high area per animal improved DMI (p = 0.023) and ADG (p < 0.001) compared to animals with a low area. In univariate meta-regression, it was observed that the variables significantly (P < 0.05) influencing DMI were THI category; influencing ADG were cattle gender, THI category, and coat color; influencing FCE were cattle age and hemisphere; and influencing RR were country, THI category and climate. Performance and physiological parameters of feedlot-finished cattle under heat stress depend on animal and environmental characteristics.

Clinical evaluation of a smart wristband for monitoring oxygen saturation, pulse rate, and respiratory rate.

Recently, photoplethysmography-based vital parameter measurements have increased in popularity. However, clinical evaluation of these measurements is lacking. The objective of this study was to rigorously evaluate the clinical accuracy and reliability of a novel photoplethysmography-based wristband for measuring key vital parameters-oxygen saturation (SpO2), respiratory rate (RR), and pulse rate (PR)-during heart catheterisations. Vital parameters obtained during heart catheterisations by means of a photoplethysmography-based wristband (CardioWatch 287-2, Corsano Health) were compared to reference measurements performed by a Nellcor fingerclip (SpO2, PR) as well as a 5-lead ECG (RR) (QMAPP Haemodynamic Monitoring module, Fysicon B.V.) by means of correlation coefficients and root means squared error (RMSE). Effects of skin colour and arm hair density were additionally evaluated. In total, 945 samples from a total of 100 patients were included in the analysis. The correlation coefficients and RSME obtained for the difference between reference and photoplethysmography-based wristband measurements were r = 0.815 and 1.6% for SpO2, r = 0.976 and 0.9 brpm for RR, and r = 0.995 and 1.3 bpm for PR. Similar results were obtained across all skin colour and arm hair density subcategories. This study shows that photoplethysmography-based SpO2, RR, and PR measurements can be accurate during heart catheterisations. Future investigations are required to evaluate the wristband's performance under dynamic circumstances as well as over an extended time period. Trial registration: www.clinicaltrials.gov, NCT05566886.

Video plethysmography for contactless measurement of respiratory rate in surgical patients.

The accurate recording of respiratory rate (RR) without contact is important for patient care. The current methods for RR measurement such as capnography, pneumography, and plethysmography require patient contact, are cumbersome, or not accurate for widespread clinical use. Video Plethysmography (VPPG) is a novel automated technology that measures RR using a facial video without contact. The objective of our study was to determine whether VPPG can feasibly and accurately measure RR without contact in surgical patients at a clinical setting. After research ethics approval, 216 patients undergoing ambulatory surgery consented to the study. Patients had a 1.5 min video of their faces taken via an iPad preoperatively, which was analyzed using VPPG to obtain RR information. The RR prediction by VPPG was compared to 60-s manual counting of breathing by research assistants. We found that VPPG predicted RR with 88.8% accuracy and a bias of 1.40 ± 1.96 breaths per minute. A significant and high correlation (0.87) was observed between VPPG-predicted and manually recorded RR. These results did not change with the ethnicity of patients. The success rate of the VPPG technology was 99.1%. Contactless RR monitoring of surgical patients at a hospital setting using VPPG is accurate and feasible, making this technology an attractive alternative to the current approaches to RR monitoring. Future developments should focus on improving reliability of the technology.

Measurement accuracy of a microwave doppler sensor beneath the mattress as a continuous respiratory rate monitor: a method comparison study.

PURPOSE: Non-contact continuous respiratory rate monitoring is preferred for early detection of patient deterioration. However, this technique is under development; a gold standard respiratory monitor has not been established. Therefore, this prospective observational method comparison study aimed to compare the measurement accuracy of a non-contact continuous respiratory rate monitor, a microwave Doppler sensor positioned beneath the mattress, with that of other monitors. METHODS: The respiratory rate of intensive care unit patients was simultaneously measured using a microwave Doppler sensor, capnography, thoracic impedance pneumography, and a piezoelectric sensor beneath the mattress. Bias and 95% limits of agreement between the respiratory rate measured using capnography (standard reference) and that measured using the other three methods were calculated using Bland-Altman analysis for repeated measures. Clarke error grid (CEG) analysis evaluated the sensor's ability to assist in correct clinical decision-making. RESULTS: Eighteen participants were included, and 2,307 data points were analyzed. The bias values (95% limits of agreement) of the microwave Doppler sensor, thoracic impedance pneumography, and piezoelectric sensor were 0.2 (- 4.8 to 5.2), 1.5 (- 4.4 to 7.4), and 0.4 (- 4.0 to 4.8) breaths per minute, respectively. Clinical decisions evaluated using CEG analyses were correct 98.1% of the time for the microwave Doppler sensor, which was similar to the performance of the other devices. CONCLUSION: The microwave Doppler sensor had a small bias but relatively low precision, similar to other devices. In CEG analyses, the risk of each monitor leading to inadequate clinical decision-making was low. TRIAL REGISTRATION NUMBER: UMIN000038900, February 1, 2020.

Thermoregulatory responses and ingestive behavior of sheep subjected to water restriction and high- and low-energy diets in a semi-arid environment.

The aim of the study was to evaluate the effect of water restriction and low- and high-energy diets on sheep's thermoregulatory responses and ingestive behavior. Forty sheep, non-castrated, with an average body weight of 18.85 kg (SD = 2.80 kg) and an average age of 5 months were assigned to a 2 × 2 factorial arrangement, comprising 2 diets (high- and low-energy) and 2 water offers (ad libitum and 50% water restriction), with 10 replicates. Thermoregulatory responses were evaluated in two periods (morning and afternoon). There was an interaction effect of Diet x Water supply x Periods on respiratory rate (P < 0.05). High-energy diets resulted in increased heart rate, idleness, dry matter feeding and rumination efficiency, and water intake. Low-energy diets increased feeding time, rumination time, the number of ruminal cuds, chews per day, total chewing time, neutral detergent fiber intake and rumination efficiency, number of ruminations per day, average duration of rumination, and defecation frequency. Water supply affected heart rate and idleness (P < 0.05). Sheep had higher values of heart rate and rectal and surface temperatures during the afternoon (P < 0.05). Water restriction combined with a low-energy diet and high environmental temperature leads to a reduction in the respiratory rate of Santa Inês crossbred sheep. Regardless of the dietary energy value, water restriction by 50% of the daily requirement of sheep reduces dry matter intake and increases idleness.

Respiratory rate measurement by pressure variation in the high flow nasal cannula-system in healthy volunteers.

PURPOSE: This study tests if the pressure variation in the HFNC-system may allow for monitoring of respiratory rate and the pressure difference during breathing may be a marker of respiratory effort. METHODS: A HFNC system (Fisher & Paykel Optiflow Thrive 950) was modified by adding a GE Healthcare D-Lite spirometry sensor attached to a respiratory module and a pressure transducer. Participants were instructed to breathe regularly, quickly and slowly during 4 different conditions (HFNC flow 30 l/min and 70 l/min and with an open and closed mouth). Respiratory rate was counted based on pressure variation shown on the monitor graphs and compared with the count by observation of the participant. The pressure difference between inspiration and expiration was tested for correlation with the respiratory rate, as a surrogate marker for respiratory effort. RESULTS: Twenty five participants were included in this study. False detection of apnea in pressure-based measurements occurred in 10% and 11% of the measurements with open mouth position at 30 l/min and 70 l/min HFNC-flow, respectively, but not with a closed mouth. The 95% Limits of Agreement were - 1.85;1.91, -13.72;9,88, -2.25;2.47, -30.32;19.93 for the conditions of 30 l/min -closed mouth, 30 l/min - open mouth, 70 l/min - closed mouth and 70 l/min - open mouth, respectively. There was a correlation between pressure difference and respiratory effort, except for the condition of 30 l/min with open mouth. CONCLUSIONS: The pressure variation in the HFNC system allows for respiratory rate and effort monitoring, but requires further development to increase precision. TRIAL REGISTRATION: ClinicalTrials.gov (NCT05991843).