Respiratory Inductive Plethysmography Research Articles

Mandibular jaw movements as a non-invasive measure of respiratory effort during sleep: application in clinical practice

Assessment of respiratory effort (RE) is key for characterization of respiratory events. The discrimination between central and obstructive events is important because these events are caused by different physio-pathological mechanisms and require different treatment approaches. Many of the currently available options for home sleep apnea testing either do not measure RE, or RE signal recording is not always reliable. This is due to a variety of factors, including for instance wrong placement of the respiratory inductance plethysmography (RIP) sensors leading to artifacts or signal loss. Monitoring of mandibular jaw movements (MJM) provides the ability to accurately measure RE through a single point of contact sensor placed on the patient's chin. The inertial unit included in the capturing technology and overnight positional stability of the sensor provide a robust MJM bio-signal to detect sleep-disordered breathing (SDB). Many of the pharyngeal muscles are attached to the mandible directly, or indirectly via the hyoid bone. The motor trigeminal nerve impulses to contract or relax these muscles generate discrete MJM that reflect changes in RE during sleep. Indeed, the central drive utilizes the lower jaw as a fine-tuning lever to stiffen the upper airway musculature and safeguard the patency of the pharynx. Associations between the MJM bio-signal properties and both physiological and pathological breathing patterns during sleep have been extensively studied. These show a close relationship between changes in the MJM bio-signal as a function of RE that is similar to levels of RE measured simultaneously by the reference bio-signals such as esophageal pressure or crural diaphragmatic electromyography. Specific waveforms, frequencies, and amplitudes of these discrete MJM are seen across a variety of breathing disturbances that are recommended to be scored by the American Academy of Sleep Medicine. Moreover, MJM monitoring provides information about sleep/wake states and arousals, which enables total sleep time measurement for accurate calculation of conventional hourly indices. The MJM bio-signal can be interpreted and its automatic analysis using a dedicated machine learning algorithm delivers a comprehensive and clinically informative study report that provides physicians with the necessary information to aid in the diagnosis of SDB.

Feasibility study of the Nox-T3 device to detect swallowing and respiration pattern in neurologically impaired patients in the acute phase

Dysphagia is a frequent complication in neurologically impaired patients, which can lead to aspiration pneumonia and thus prolonged hospitalization or even death. It is essential therefore, to detect and assess dysphagia early for best patient care. Fiberoptic endoscopic and Videofluoroscopy evaluation of swallowing are the gold standard exams in swallowing studies but neither are perfectly suitable for patients with disorders of consciousness (DOC). In this study, we aimed to find the sensitivity and specificity of the Nox-T3 sleep monitor for detection of swallowing. A combination of submental and peri-laryngeal surface electromyography, nasal cannulas and respiratory inductance plethysmography belts connected to Nox-T 3 allows recording swallowing events and their coordination with breathing, providing time-coordinated patterns of muscular and respiratory activity. We compared Nox-T3 swallowing capture to manual swallowing detection on fourteen DOC patients. The Nox-T3 method identified swallow events with a sensitivity of 95% and a specificity of 99%. In addition, Nox-T3 has qualitative contributions, such as visualization of the swallowing apnea in the respiratory cycle which provide additional information on the swallowing act that is useful to clinicians in the management and rehabilitation of the patient. These results suggest that Nox-T3 could be used for swallowing detection in DOC patients and support its continued clinical use for swallowing disorder investigation.

Comparison of Changes in Chest Wall Mechanics and Respiratory Timing Between Patient-Controlled Epidural Analgesia and Intravenous Patient-Controlled Analgesia After Laparoscopic Gastrectomy: A Randomized Controlled Trial.

Upper abdominal surgery is associated with postoperative diaphragmatic dysfunction. Whether patient-controlled epidural analgesia (PCEA) is superior to intravenous patient-controlled analgesia (IV-PCA) in preventing postoperative diaphragmatic dysfunction is still unclear in laparoscopic gastric surgery. Sixteen patients undergoing laparoscopic gastrectomy randomly received either PCEA or IV-PCA. The primary outcomes were the change in chest wall mechanics and respiratory timing, measured by respiratory inductive plethysmography(Respitrace; Ambulatory Monitoring Inc., Ardsley, New York, United States) before and after surgery, and analyzed by a data acquisition system (PowerLab; ADInstruments, Dunedin, New Zealand). Inspiratory time (Ti), expiratory time (Te), total respiratory cycle time (Ttot), proportion of inspiratory time over total respiratory cycle time (Ti/Ttot), respiratory rate (RR), and abdominal contribution to tidal volume (AB/VT [%]) were calculated from the stored data. AB/VT, relative volume contribution of diaphragm to tidal breathing, represents an index of diaphragmatic function.Because the diaphragm is the main contributor to tidal volume, decreases in AB/VT indicate diaphragm dysfunction. Changes in outcomes over time between the two groups were analyzed using a linear mixed model, and two-sided p values < 0.05 were considered statistically significant. The secondary outcomes were postoperative pain score(visual analog scale (VAS)), bowel function recovery, and hospital stay duration. Postoperative AB/VT in the IV-PCA group was significantly decreased compared to preoperative levels. AB/VT in the PCEA group was significantly higher than the IV-PCA group on postoperative day (POD) 1. Change in AB/VT over time between the PCEA group and the IV-PCA group differed significantly (p = 0.01). A decrease of AB/VT during POD 1 to 3 was observed in the IV-PCA group but not in the PCEA group. As for respiratory timing, there were significant increases in RR with a reduction of Te and Ttot compared to preoperative levels on POD 1 in the PCEA group. There were significant decreases in RR and Ti/Ttot with an increase of Te and Ttot compared to preoperative levels on POD 1 in the IV-PCA group. There was a significant difference in the change of the Ttot over time between the two groups (p = 0.046). There were no significant differences in the changes of Te, Ti/Ttot, Ti, and RR over time between the two groups. There was no significant difference in VAS over time at rest and mobilization, recovery of bowel function, and hospital stay between the two groups. Continuous ropivacaine infusion with PCEA partially attenuated diaphragmatic dysfunction after laparoscopic gastrectomy, while pain relief by continuous intravenous administration of fentanyl could not attenuate diaphragmatic dysfunction. This suggests that PCEA might ameliorate postoperative diaphragmatic dysfunction after laparoscopic gastrectomy.

Effort and work-of-breathing parameters strongly correlate with increased resistance in an animal model.

Effort of Breathing (EOB) calculations may be a reliable alternative to Work of Breathing (WOB) calculations in which Respiratory Inductance Plethysmography (RIP) replaces spirometry. We sought to compare EOB and WOB measurements in a nonhuman primate model of increasing extrathoracic inspiratory resistance simulating upper airway obstruction (UAO). RIP, spirometry, and esophageal manometry were measured in spontaneously breathing, intubated Rhesus monkeys utilizing 11 calibrated resistors randomly applied for 2-min. EOB was calculated breath-by-breath as Pressure Rate Product (PRP) and Pressure Time Product (PTP). WOB was calculated from the Pressure-Volume curve based on spirometry (WOBSPIR) or RIP flow (WOBRIP). WOB, PRP and PTP showed similar linear increases when exposed to higher levels of resistive loads. When comparing WOBSPIR to WOBRIP, a similar strong correlation was seen for both signals as resistance increased and there were no statistically significant differences. EOB and WOB parameters utilizing esophageal manometry and RIP, independent of spirometry, showed a strong correlation as a function of increasing inspiratory resistance in nonhuman primates. This allows several potential monitoring possibilities for non-invasively ventilated patients or situations where spirometry is not available. EOB and WOB parameters showed a strong correlation as a function of increasing inspiratory resistance in nonhuman primates. There was a strong correlation between spirometry-based WOB versus RIP-based WOB. To date, it has remained untested as to whether EOB is a reliable alternative for WOB and if RIP can replace spirometry in these measurements. Our results enable additional potential monitoring possibilities for non-invasively ventilated patients or situations where spirometry is not available. Where spirometry is not available, there is no need to apply a facemask post extubation to a spontaneously breathing, non-intubated infant to make objective EOB measurements.

The impact of kangaroo mother care on work of breathing and oxygen saturation in very low birth weight infants with respiratory insufficiency.

Kangaroo mother care (KMC) is defined as prolonged skin to skin care between a mother and infant with the infant lying in prone position on mom's chest. KMC decreases morbidity and mortality and promotes physiologic stability. The aim of this study is to measure work of breathing (WOB) during KMC in very low birth weight (VLBW) infants on non-invasive respiratory support. A prospective observational pilot study was conducted comparing WOB indices during standard care (SC) and KMC. Respiratory inductive plethysmography (RIP) measured WOB indices non-invasively: phase angle and labored breathing index. VLBW infants who were stable on non-invasive respiratory support were randomized to receive RIP measurements during KMC or during SC first. Summary statistics and mixed linear models were used to compare WOB and vital signs. A total of 32 infants were consented for the study, data collection and analysis was completed on 28 infants. There were no significant differences in mean phase angle during KMC or SC (73.5±4.6 SE deg vs 66.8±3.9 SE deg, p = 0.25). No differences in WOB and vital signs were detected. Controlling for respiratory support or randomization/first location did not change the results. In this pilot cohort, infants demonstrated no differences in work of breathing indices or oxygen saturation during KMC or SC while receiving non-invasive respiratory support. KMC appears to be safe and well tolerated with no worsened WOB. Larger studies should be performed to confirm our findings.

Ventilatory response and stability of oxygen saturation during a hypoxic challenge in very preterm infants.

Preterm infants have immature control of breathing and impaired pulmonary gas exchange. We hypothesized that infants with bronchopulmonary dysplasia (BPD) have a blunted ventilatory response and peripheral oxygen saturation (SpO2 ) instability during a hypoxic challenge. We evaluated the response to hypoxia in 57 very preterm infants (38 no BPD, 10 mild BPD, 9 moderate-to-severe BPD) at 36 weeks' postmenstrual age. The fraction of inspired oxygen (FI O2 ) was reduced stepwise at 5-min intervals to achieve peripheral SpO2 between 86% and 95%. The lowest permissible FI O2 and SpO2 were 0.14% and 86%. We recorded SpO2 , FI O2 , and the respiratory signal (respiratory inductive plethysmography). We calculated respiratory rate (RR), tidal volume (VT ), minute ventilation (VE ), and respiratory drive (ratio between VT and inspiratory time, VT /TI ). SpO2 variability was expressed as the interquartile range (IQR). FI O2 was reduced from a median (Q1, Q3) of 0.21 (0.21, 0.21) to 0.17 (0.17, 0.18). We observed a marked individual variability in the ventilatory response to the hypoxic challenge, regardless of BPD severity. At the lowest permissible FI O2 , 37(65%) infants reduced their VE , and 20 (35%) increased minute ventilation; 20infants (35%) developed periodic breathing associated with increased SpO2 IQR and lower SpO2 minima, and 16 (28%) exhibited an oscillatory pattern in VE and SpO2 without end-expiratory pauses, regardless of BPD severity. In very preterm infants, a mild hypoxic challenge reduced ventilation, increased SpO2 variability and periodic breathing regardless of BPD severity.

Do differences in abdominal movement patterns during coughing and forced expiration affect cranioventral bladder neck displacement in healthy nulliparous subjects?

Aims:Abdominal movement patterns during coughing and forced expiration (FE) fall into two categories: abdominal inward movement (AIM) and abdominal outward movement (AOM). These abdominal movement patterns are thought to affect cranioventral (CV) bladder neck displacement differently. However, many studies have described an absent or altered PFM response during coughing, assuming PFM dysfunction, without considering the impact of abdominal movement pattern differences. The aim of this study was to observe abdominal movement patterns during coughing and FE and compare the associated (CV) bladder neck displacement patterns. Method:Participants performed three maximal expulsive coughs, followed by three FEs, during which the respiratory inductive plethysmography (RIP) method was used to identify abdominal movement patterns. Concurrently, perineal 2D ultrasound was applied to assess CV bladder neck displacement. All measurements were done in the standing and crook lying position. Descriptive statistics were computed for abdominal movement patterns and bladder neck displacement. Chi-squared tests were used to compare abdominal movement patterns and CV bladder neck displacement. Results:One hundred and forty-nine healthy nulliparous women without PFM dysfunction participated in the study. During both coughing and FE in the standing position, women who displayed an AIM pattern had a significantly higher occurrence of CV bladder neck displacement compared to those presenting AOM. In the crook lying position, there was a significantly higher occurrence of bladder neck displacement during coughing in subjects showing AIM compared to those with AOM. Conclusion:Significant differences were found in abdominal movement patterns during coughing and FE in healthy nulliparous subjects in standing and crook lying positions. Most of the subjects showed AOM during coughing or FE in both standing and lying positions. This is contrary to the existing literature and needs further investigation. Abdominal movement patterns impacted CV bladder neck displacement during coughing and FE while standing and during coughing in the crook lying position. Clinicians should be aware of different abdominal movement patterns, which should be considered for diagnosis and treatment.

A plethysmography investigation comparing respiration rate before onset and after the end of central sleep apnoea episodes

The study explored possible changes in respiration rate immediately before onset and after end of central sleep apnoea (CSA) episodes using respiratory inductive plethysmography (RIP). RIP signals were recorded simultaneously from the chest and abdomen of 31 paediatric patients (mean age 7.12 years, standard deviation 4.40 years, 20 females, 11 males) attending a children’s hospital for overnight sleep disorder monitoring. The patients were also monitored for electrocardiogram, electroencephalogram, electrooculogram, electromyograph, CO2, body position, SpO2 and if they tolerated, their respiratory airflow using a thermistor (placed under the nose) and nasal prongs (placed in the nostrils). An experienced clinical physiologist scored the recorded data by indicating the time point of each respiratory pause, its duration and type (i.e., apnoea or hypopnoea; central or obstructive). The RIP signals from the chest and abdomen were summed and converted to a respiration rate signal by determining the time points they crossed the time axis. Events were scored using standard paediatric sleep and breathing scoring rules. Statistical analysis indicated significant differences between the skewness and kurtosis of respiratory rate values immediately before the onset and after the end of CSA episodes, however the mean respiration rate did not change significantly. This indicates possible changes in the pattern of respiration rate immediately after the end of CSA episodes. It may be possible to use these results to predict the onset of a CSA episode, however, to confirm the finding a larger study will be needed.

Benchtop Characterization of Wearable Respiratory Monitors for Assessing Feasibility of Measuring Lung Volume

Abstract Objective: This study characterizes three commercially available wearable respiratory monitors (WRMs): (1) Hexoskin Smart Garment, (2) Smartex WWS, and (3) Equivital EQ02 LifeMonitor, each with a unique chest motion sensor technology: respiratory inductance plethysmography, piezoresistor, and strain gauge, respectively. WRMs comprise of a body garment with embedded sensors that measure ambulatory chest motion in real-time. Once calibrated, chest motion waveforms from WRMs can be converted to lung volume waveform, which is then used to derive respiratory topography. The aim of this study is to assess and compare these WRMs in terms of: (i) their response signal to chest motion linearity, which is necessary for successful calibration, and (ii) their ability to measure breath-hold, which is a parameter of interest for lung deposition modeling. Methods: A benchtop test setup was built to simulate chest motion in a controlled way to facilitate comparison across the three devices. A staircase square-wave chest motion profile was used to simultaneously assess both signal linearity and ability to measure breath-hold. The respiratory response from the sensors was compared to the simulated chest motion. Results: The Hexoskin showed the best performance in both metrics, whereas the Equivital had the worst performance in both. The Smartex showed moderate ability to measure breath-hold but poor signal linearity. Conclusion: Of the three WRMs tested, the Hexoskin appears to be the best choice for ambulatory lung volume measurement. Significance: This study demonstrates the feasibility of adapting current technology to observe respiratory behavior valuable in many research domains, including tobacco research.

Different Settings of Nonsynchronized Bilevel Nasal Continuous Positive Airway Pressure and Respiratory Function in Preterm Infants: A Pilot Study.

With this study, we evaluated the short-term effects of different modes and settings of noninvasive respiratory support on gas exchange, breathing parameters, and thoracoabdominal synchrony in preterm infants in the acute phase of moderate respiratory distress syndrome. A feasibility crossover trial was conducted in neonates < 32 weeks' gestation on nasal continuous positive airway pressure (n-CPAP) or bilevel n-CPAP. Infants were delivered the following settings in consecutive order for 10 minutes each: • n-CPAP (5 cm H2O) • bilevel n-CPAP 1 (Pres low = 5 cm H2O, Pres high = 7 cm H2O, T-high = 1 second, rate = 30/min) • n-CPAP (5 cm H2O) • bilevel n-CPAP 2 (Pres low = 5 cm H2O, Pres high = 7 cm H2O, T-high = 2 second, rate = 15/min) • n-CPAP (5 cm H2O). During each phase, physiologic parameters were recorded; the thoracoabdominal synchrony expressed by the phase angle (Φ) and other respiratory patterns were monitored by noncalibrated respiratory inductance plethysmography. Fourteen preterm infants were analyzed. The mean CPAP level was significantly lower in the n-CPAP period compared with bilevel n-CPAP 1 and 2 (p = 0.03). Higher values were achieved with bilevel n-CPAP 2 (6.2 ± 0.6 vs. 5.7 ± 0.5 cm H2O, respectively; p < 0.05). No statistical difference in the Φ was detected, nor between the three settings. Our study did not show any superiority of bilevel n-CPAP over n-CPAP. However, nonsynchronized bilevel n-CPAP might be helpful when additional pressure is needed. · There is currently a high degree of uncertainty about the superiority of one modality and setting of noninvasive respiratory over another.. · Our study confirmed that non-synchronized bilevel n-CPAP might be helpful when additional pressure is needed for recruitment.. · A T-high of 1 second could possibly be better tolerated in this population, but further research is needed..

Estimation of respiratory rate and exhale duration using audio signals recorded by smartphone microphones

Monitoring respiration using mobile technology has potential to contribute to the clinical management of patients with infectious diseases or chronic respiratory conditions in the home. In this study, a new method to estimate respiratory rate and exhale duration from audio data recorded using smartphone microphones was developed. The method first determines the fundamental frequency of the audio signal, which guides an adaptive thresholding method to detect individual exhales. Exhale boundary times were refined using adaptive physiological thresholds. To control for environmental noise in remote audio recordings, a method to classify audio signals as acceptable or unacceptable for accurate respiration monitoring was developed. Estimated respiratory rates and audio exhale durations were validated against respiratory inductance plethysmography (RIP) in 27 healthy participants. A further 217 audio recordings were collected remotely by 210 healthy and COVID-19 participants, with results compared with researcher annotations. Compared to RIP in the laboratory, respiratory rate was estimated with a mean absolute error (MAE) of 0.2 ± 0.27 bpm, and within 1 bpm for 96 % of recordings (r = 0.99). Compared to researcher annotations for remote recordings, respiratory rate was estimated with a MAE of 0.79 ± 2.44 bpm, and within 1 bpm for 87.5 % of recordings (r = 0.92), while audio exhale duration was estimated with a MAE of 0.21 ± 0.23 s. Audio signal quality was classified with an area under the receiver operating characteristic of 0.81 ±. This method offers the potential for accurate remote monitoring of respiratory rate and breathing patterns in individuals with COVID-19 and other chronic respiratory conditions.

The effect of hyperoxia on ventilation during recovery from general anesthesia: A randomized pilot study for a parallel randomized controlled trial

Study objectiveWhile supplemental O2 inhalation corrects hypoxemia, its effect on post-anesthesia ventilation remains unknown. This pilot trial tested the hypothesis that hyperoxia increases the time spent with a transcutaneous PCO2 (TcPCO2) > 45 mmHg, compared with standard O2 supplementation. DesignSingle-blinded, parallel two-arm randomized pilot trial. SettingUniversity hospital. Patients20 patients undergoing robotic-assisted laparoscopic nephrectomy. MeasurementsAfter institutional approval and informed consent, patients were randomized to receive O2 titrated to arterial saturation (SpO2): 90–94% (Conservative O2, N =10), or to SpO2 > 96% (Liberal O2, N = 10) for up to 90 min after anesthesia. Continuous TcPCO2, respiratory inductance plethysmography (RIP), and SpO2, were recorded. We calculated the percentage of time at TcPCO2 > 45 mmHg for each patient and compared the two groups using analysis of covariance, adjusting for sex, age, and body mass index. We also estimated the sample size required to detect the between-group difference observed in this pilot trial. RIP signals were used to calculate apnea/hypopnea index (AHI), which was then compared between two groups. Main resultsThe mean percentage of time with a TcPCO2 > 45 mmHg was 80.6% for the Conservative O2 (N=9) and 61.2% for the Liberal O2 (N=10) group [between-group difference of 19.4% (95% CI: −18.7% to 57.6%), P = 0.140]. With an observed effect size of 0.73, we estimated that 30 participants per group are required, to demonstrate this difference with a power of 80% at a two-sided alpha of 5%. Means SpO2 were 94.5% and 99.9% for the Conservative O2 and the Liberal O2 groups, respectively. AHI was significantly higher in the Conservative O2, compared with the Liberal O2 group (median AHI: 16 vs. 3; P = 0.0014). ConclusionsHyperoxia in the post-anesthesia period reduced the time spent at TcPCO2 > 45 mmHg and significantly decreased AHI, while mean SpO2 ranged inside the a priori defined limits. Trial registrationClinicalTrials.gov identifier: NCT04723433

Respiratory and articulatory influences on inhalation noise during speech

During speech production, individuals inhale more deeply and rapidly compared to non-speaking inspiration. Such inspirations are also more frequently audible than their non-speech counterparts. To what extent do the acoustic characteristics of inhalation noise reflect respiratory contributions versus other articulatory mechanisms? To gain insight into this question, here we relate acoustics, captured using a head-mounted microphone, with kinematic data collected via respiratory inductance plethysmography (RIP) and optopalatography (OPG). The OPG system permits measurement of lip movements (displacement and velocity), tongue-palate contacts, and midsagittal distance when the tongue has no contact with the palate. Custom-made palates, including both contact sensors as well as optical sensors, were obtained for eight typical female speakers of German. Speech was recorded in normal and loud conditions. In this exploratory analysis, we anticipate that (a) louder speech will be accompanied by deeper, more rapid inhalations; and (b) greater articulatory opening during the inhalation phase; (c) the magnitude of lip aperture will be correlated with inspiration-excited first formant values; and (d) both supralaryngeal and respiratory displacements and velocities will be reflected in the inhalation noise characteristics. That is, speech inspiration, like speech itself, will demonstrate regular correspondences between physiological actions and the acoustic output.

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

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. 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. 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. 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. 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.

Pulse oximetry respiratory monitoring for assessment of acute childhood wheeze

ObjectiveThere 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....

Respiratory analysis during sleep using a chest-worn accelerometer: A machine learning approach

Objective:There is a great interest in observing breathing patterns during sleep, as sleep disturbances can be caused by respiratory irregularity and cessations. In this paper, we introduce the first steps to an accelerometer-based screening tool for respiratory rate estimation and a novel approach towards detecting breathing cessations such as apnea/hypopnea, by extending and combining established signal processing routines with machine learning. Methods:From a single chest-worn accelerometer, we estimate the respiratory rate based on the inhalation/exhalation movements of the chest and carry out a full overnight validation. On this basis, we build a set of features customized to detect irregular respiratory activity, including a novel feature: the respiratory peak variance (RPV). From thirteen healthy subjects, a classification model was trained, validated, and tested with over 98 h of PSG-labeled accelerometer data. Results:The algorithm estimated the respiratory rate with a mean difference of 1.8 breaths per minute compared to respiratory inductance plethysmography during overnight PSGs. The machine learning classifier detected respiratory cessations with a sensitivity and specificity of 76.05% and 70.05% respectively, with an overall accuracy of 70.95%. Conclusion:We successfully demonstrated the potential of a novel respiratory feature set in a preliminary application with young healthy volunteers for respiratory rate estimation and in identifying apnea/hypopnea events during overnight sleep. Significance:We present a simple and unobtrusive wearable system that can serve as a home screening tool for sleep-related breathing disorders.

Pilot Study of Respiratory-Swallow Coordination in Amyotrophic Lateral Sclerosis.

Amyotrophic lateral sclerosis (ALS) impacts bulbar and respiratory musculature, which may contribute to impaired swallow function (dysphagia) and respiratory-swallow coordination. The purpose of this pilot study was to examine if respiratory-swallow coordination in individuals with ALS was perturbed compared to healthy controls. We further explored relationships between measures of respiratory function and self-reported swallowing outcomes on respiratory-swallow coordination. We employed a cross-sectional design with eight participants with ALS and eight age- and sex-matched healthy participants. Respiratory inductance plethysmography and a nasal cannula were used to capture respiratory-swallow phase patterns during a standardized clinical swallow examination. The advantageous respiratory-swallow phase pattern was defined if exhalation surrounded the swallow (E-E). Spirometry was used to capture indices of respiratory function (forced vital capacity % predicted, peak cough flow [PCF]). Validated questionnaires were used to collect information regarding ALS-related bulbar functional status and swallowing-related concerns. Compared to the matched healthy cohort, individuals with ALS demonstrated higher rates of non-E-E respiratory-swallow phase patterning and worse bulbar/swallow dysfunction. Group (ALS), swallow tasks, and PCF were significantly associated with respiratory-swallow phase pattern. These preliminary findings support altered respiratory-swallow phase patterning in ALS. Future work should employ an instrumental assessment to quantify swallowing physiology and elucidate the relationship between perturbed respiratory-swallow coordination and swallowing function.

Effect of pediatric ventilation weaning technique on work of breathing

BackgroundVentilator liberation is one of the most challenging aspects in patients with respiratory failure. Most patients are weaned through a transition from full to partial respiratory support, whereas some advocate using a continuous spontaneous ventilation (CSV). However, there is little scientific evidence supporting the practice of pediatric ventilator liberation, including the timing of onset of and the approach to weaning mode. We sought to explore differences in patient effort between a pressure controlled continuous mode of ventilation (PC-CMV) [in this cohort PC assist/control (PC-A/C)] with a reduced ventilator rate and CSV, and to study changes in patient effort with decreasing PS.MethodsIn this prospective physiology cross-over study, we randomized children < 5 years to first PC-A/C with a 25% reduction in ventilator rate, or CSV (continuous positive airway pressure [CPAP] + PS). Patients were then crossed over to the other arm. Patient effort was measured by calculating inspiratory work of breathing (WOB) using the Campbell diagram (WOBCampbell), and by pressure–rate-product (PRP) and pressure–time-product (PTP). Respiratory inductance plethysmography (RIP) was used to calculate the phase angle. Measurements were obtained at baseline, during PC-A/C and CPAP + PS, and during decreasing set PS (maximum -6 cmH2O).ResultsThirty-six subjects with a median age of 4.4 (IQR 1.5–11.9) months and median ventilation time of 4.9 (IQR 3.4–7.0) days were included. Nearly all patients (94.4%) were admitted with primary respiratory failure. WOBCampbell during baseline [0.67 (IQR 0.38–1.07) Joules/L] did not differ between CSV [0.49 (IQR 0.17–0.83) Joules/L] or PC-A/C [0.47 (IQR 0.17–1.15) Joules/L]. Neither PRP, PTP, ∆Pes nor phase angle was different between the two ventilator modes. Reducing pressure support resulted in a statistically significant increase in patient effort, albeit that these differences were clinically negligible.ConclusionsPatient effort during pediatric ventilation liberation was not increased when patients were in a CSV mode of ventilation compared to a ventilator mode with a ventilator back-up rate. Reducing the level of PS did not lead to clinically relevant increases in patient effort. These data may aid in a better approach to pediatric ventilation liberation.Trial registration clinicaltrials.gov NCT05254691. Registered 24 February 2022

The influence of receiving real-time visual feedback on breathing during treadmill running to exhaustion.

Breathing plays a vital role in everyday life, and specifically during exercise it provides working muscles with the oxygen necessary for optimal performance. Respiratory inductance plethysmography (RIP) monitors breathing through elastic belts around the chest and abdomen, with efficient breathing defined by synchronous chest and abdomen movement. This study examined if providing runners with visual feedback through RIP could increase breathing efficiency and thereby time to exhaustion. Thirteen recreational runners (8F, 5M) ran to exhaustion on an inclined treadmill on two days, with visual feedback provided on one randomly chosen day. Phase angle was calculated as a measure of thoraco-abdominal coordination. Time to exhaustion was not significantly increased when visual feedback was provided (p = 1). Phase angle was not significantly predicted by visual feedback (p = 0.667). Six participants improved phase angle when visual feedback was provided, four of whom increased time to exhaustion. Four participants improved phase angle by 9° or more, three of whom increased time to exhaustion. Participants who improved phase angle with visual feedback highlight that improving phase angle could increase time to exhaustion. Greater familiarization with breathing techniques and visual feedback and a different paradigm to induce running fatigue are needed to support future studies of breathing in runners.

Pre-gelled Electrode Grid for Self-Applied EEG Sleep Monitoring at Home.

The need for diagnostic capabilities for sleep disorders such as sleep apnea and insomnia far exceeds the capacity of inpatient sleep laboratories. Some home monitoring systems omit electroencephalography (EEG) because trained personnel may be needed to apply EEG sensors. Since EEG is essential for the detailed evaluation of sleep, better systems supporting the convenient and robust recording of sleep EEG at home are desirable. Recent advances in EEG acquisition with flex-printed sensors promise easier application of EEG sensor arrays for chronic recordings, yet these sensor arrays were not designed for sleep EEG. Here we explored the self-applicability of a new sleep EEG sensor array (trEEGrid) without prior training. We developed a prototype with pre-gelled neonatal ECG electrodes placed on a self-adhesive grid shape that guided the fast and correct positioning of a total of nine electrodes on the face and around the ear. Positioning of the sensors was based on the results of a previous ear-EEG sleep study (da Silva Souto et al., 2021), and included electrodes around the ear, one eye, and the chin. For comparison, EEG and electrooculogram channels placed according to the American Academy of Sleep Medicine criteria, as well as respiratory inductance plethysmography on thorax and abdomen, oxygen saturation, pulse and body position were included with a mobile polysomnography (PSG) system. Two studies with 32 individuals were conducted to compare the signal quality of the proposed flex-printed grid with PSG signals and to explore self-application of the new grid at home. Results indicate that the new array is self-applicable by healthy participants without on-site hands-on support. A comparison of the hypnogram annotations obtained from the data of both systems revealed an overall substantial agreement on a group level (Cohen’s κ = 0.70 ± 0.01). These results suggest that flex-printed pre-gelled sensor arrays designed for sleep EEG acquisition can facilitate self-recording at home.