Respiratory Inductive Plethysmography Research Articles

Oxygen saturation and work of breathing indices in preterm infants with bronchopulmonary dysplasia compared to healthy preterm infants at discharge

BACKGROUND: Thoracoabdominal asynchrony (TAA) is commonly seen in preterm infants. Respiratory inductive plethysmography (RIP) is a noninvasive way to objectively assess work of breathing (WOB) indices. The impact of bronchopulmonary dysplasia (BPD) on TAA at discharge has not been established. The aim of this study is to compare WOB indices in premature infants with a diagnosis of BPD to premature infants without a diagnosis of BPD at discharge. METHODS: A prospective, observational study of premature infants (<32 weeks gestation) at discharge during quiet breathing in the supine position. RIP noninvasively measured WOB indices. A high-resolution pulse oximeter collected oxygen saturation and heart rate data. RESULTS: This study included thirty-one infants with BPD and thirty-four infants without BPD. Infants diagnosed with BPD had increased phase angle [BPD Φ = 73 . 90 (8.2) vs NoBPD Φ = 52.6 (8.2), p = 0.039]. Infants diagnosed with BPD had decreased saturations [BPD SpO2 = 96% (0.4) vs NoBPD Sp02 98% (0.3), p=<0.001], increased time with saturations less than 85% [BPD % =2.74 (0.7) vs NoBPD % =0.91 (0.4), p = .018], and increased time with saturations less than 80% [BPD % =1.57 (0.5) vs NoBPD % =0.52 (0.3), p = 0.045]. There was no difference in heart rate or breaths per minute for infants with BPD versus controls. CONCLUSION: Premature infants with BPD demonstrated increased TAA and had lower saturations compared to infants without BPD at discharge despite being chronologically older and being discharged at an older corrected gestational age. The impact of BPD on breathing patterns persists at discharge and suggests these patients may have residual lung and/or respiratory muscle dysfunction.

Validation of Tracheal Sound-Based Respiratory Effort Monitoring for Obstructive Sleep Apnoea Diagnosis.

Background: Respiratory effort is considered important in the context of the diagnosis of obstructive sleep apnoea (OSA), as well as other sleep disorders. However, current monitoring techniques can be obtrusive and interfere with a patient's natural sleep. This study examines the reliability of an unobtrusive tracheal sound-based approach to monitor respiratory effort in the context of OSA, using manually marked respiratory inductance plethysmography (RIP) signals as a gold standard for validation. Methods: In total, 150 patients were trained on the use of type III cardiorespiratory polygraphy, which they took to use at home, alongside a neck-worn AcuPebble system. The respiratory effort channels obtained from the tracheal sound recordings were compared to the effort measured by the RIP bands during automatic and manual marking experiments. A total of 133 central apnoeas, 218 obstructive apnoeas, 263 obstructive hypopneas, and 270 normal breathing randomly selected segments were shuffled and blindly marked by a Registered Polysomnographic Technologist (RPSGT) in both types of channels. The RIP signals had previously also been independently marked by another expert clinician in the context of diagnosing those patients, and without access to the effort channel of AcuPebble. The classification achieved with the acoustically obtained effort was assessed with statistical metrics and the average amplitude distributions per respiratory event type for each of the different channels were also studied to assess the overlap between event types. Results: The performance of the acoustic effort channel was evaluated for the events where both scorers were in agreement in the marking of the gold standard reference channel, showing an average sensitivity of 90.5%, a specificity of 98.6%, and an accuracy of 96.8% against the reference standard with blind expert marking. In addition, a comparison using the Embla Remlogic 4.0 automatic software of the reference standard for classification, as opposed to the expert marking, showed that the acoustic channels outperformed the RIP channels (acoustic sensitivity: 71.9%; acoustic specificity: 97.2%; RIP sensitivity: 70.1%; RIP specificity: 76.1%). The amplitude trends across different event types also showed that the acoustic channels exhibited a better differentiation between the amplitude distributions of different event types, which can help when doing manual interpretation. Conclusions: The results prove that the acoustically obtained effort channel extracted using AcuPebble is an accurate, reliable, and more patient-friendly alternative to RIP in the context of OSA.

Artificial Intelligence-Based Algorithms and Healthcare Applications of Respiratory Inductance Plethysmography: A Systematic Review

Artificial Intelligence-Based Algorithms and Healthcare Applications of Respiratory Inductance Plethysmography: A Systematic Review

Diagnosing OSA and Insomnia at Home Based Only on an Actigraphy Total Sleep Time and RIP Belts an Algorithm "Nox Body Sleep™".

The COVID-19 pandemic has influenced clinical sleep protocols with stricter hospital disinfection requirements. Facing these new rules, we tested if a new artificial intelligence (AI) algorithm: The Nox BodySleep™ (NBS) developed without airflow signals for the analysis of sleep might assess pertinently sleep in patients with Obstructive Sleep Apnea (OSA) and chronic insomnia (CI) as a control group, compared to polysomnography (PSG) manual scoring. NBS is a recurrent neural network model that estimates Wake, NREM, and REM states, given features extracted from activity and respiratory inductance plethysmography (RIP) belt signals (Nox A1 PSG). Sleep states from 139 PSG studies (CI N = 72; OSA N = 67) were analyzed by NBS and compared to manually scored PSG using positive percentage agreement, negative percentage agreement, and overall agreement metrics. Similarly, we compared common sleep parameters and OSA severity using sleep states estimated by NBS for each recording and compared to manual scoring using Bland-Altman analysis and intra-class correlation coefficient. For 127,170 sleep epochs, an overall agreement of 83% was reached for Wake, NREM and REM states (92% for REM states in CI patients) between NBS and manually scored PSG. Overall agreement for estimating OSA severity was 100% for moderate-severe OSA and 91% for minimal OSA. The absolute errors of the apnea-hypopnea index (AHI) and total sleep time (TST) were significantly lower for the NBS compared to no scoring of sleep. The intra-class correlation was higher for AHI and significantly higher for TST using the NBS compared to no scoring of sleep. NBS gives sleep states, parameters and AHI with a good positive and negative percentage agreement, compared with manually scored PSG.

Cardiorespiratory Response to Workload Volume and Ergonomic Risk: Automotive Assembly Line Operators’ Adaptations

Repetitive tasks can lead to long-term cardiovascular problems due to continuous strain and inadequate recovery. The automobile operators on the assembly line are exposed to these risks when workload volume changes according to the workstation type. However, the current ergonomic assessments focus primarily on observational and, in some cases, biomechanical methods that are subjective and time-consuming, overlooking cardiorespiratory adaptations. This study aimed to analyze the cardiorespiratory response to distinct workload volumes and ergonomic risk (ER) scores for an automotive assembly line. Sixteen male operators (age = 38 ± 8 years; BMI = 25 ± 3 kg·m2) volunteered from three workstations (H1, H2, and H3) with specific work cycle duration (1, 3, and 5 min respectively). Electrocardiogram (ECG), respiratory inductance plethysmography (RIP), and accelerometer (ACC) data were collected during their shift. The results showed significant differences from the first to the last 10 min, where H3 had its SDRRi reduced (p = 0.014), H1’s phase synchrony and H2’s coordination between thoracic and abdominal movements decreased (p < 0.001, p = 0.039). In terms of ergonomic risk, the moderate-high rank showed a reduction in SDRRi (p = 0.037) and moderate-risk activities had diminished phase synchrony (p = 0.018) and correlation (p = 0.004). Thus, the explored parameters could have the potential to develop personalized workplace adaptation and risk assessment systems.

Quantitative validation of the suprasternal pressure signal to assess respiratory effort during sleep

Objective. Intra-esophageal pressure (Pes) measurement is the recommended gold standard to quantify respiratory effort during sleep, but used to limited extent in clinical practice due to multiple practical drawbacks. Respiratory inductance plethysmography belts (RIP) in conjunction with oronasal airflow are the accepted substitute in polysomnographic systems (PSG) thanks to a better usability, although they are partial views on tidal volume and flow rather than true respiratory effort and are often used without calibration. In their place, the pressure variations measured non-invasively at the suprasternal notch (SSP) may provide a better measure of effort. However, this type of sensor has been validated only for respiratory events in the context of obstructive sleep apnea syndrome (OSA). We aim to provide an extensive verification of the suprasternal pressure signal against RIP belts and Pes, covering both normal breathing and respiratory events. Approach. We simultaneously acquired suprasternal (207) and esophageal pressure (20) signals along with RIP belts during a clinical PSG of 207 participants. In each signal, we detected breaths with a custom algorithm, and evaluated the SSP in terms of detection quality, breathing rate estimation, and similarity of breathing patterns against RIP and Pes. Additionally, we examined how the SSP signal may diverge from RIP and Pes in presence of respiratory events scored by a sleep technician. Main results. The SSP signal proved to be a reliable substitute for both esophageal pressure (Pes) and respiratory inductance plethysmography (RIP) in terms of breath detection, with sensitivity and positive predictive value exceeding 75%, and low error in breathing rate estimation. The SSP was also consistent with Pes (correlation of 0.72, similarity 80.8%) in patterns of increasing pressure amplitude that are common in OSA. Significance. This work provides a quantitative analysis of suprasternal pressure sensors for respiratory effort measurements.

Lung behavior during a staircase high-frequency oscillatory ventilation recruitment maneuver

BackgroundLung volume optimization maneuvers (LVOM) are necessary to make physiologic use of high-frequency oscillatory ventilation (HFOV), but lung behavior during such maneuvers has not been studied to determine lung volume changes after initiation of HFOV, to quantify recruitment versus derecruitment during the LVOM and to calculate the time to stabilization after a pressure change.MethodsWe performed a secondary analysis of prospectively collected data in subjects < 18 years on HFOV. Uncalibrated respiratory inductance plethysmography (RIP) tracings were used to quantify lung recruitment and derecruitment during the LVOM inflation and deflation. The time constant was calculated according to the Niemann model.ResultsRIP data of 51 subjects (median age 3.5 [1.7–13.3] months) with moderate-to-severe pediatric acute respiratory distress syndrome (PARDS) in 85.4% were analyzed. Lung recruitment and derecruitment occurred during the LVOM inflation phase upon start of HFOV and between and within pressure changes. At 90% of maximum inflation pressure, lung derecruitment already started during the deflation phase. Time to stable lung volume (time constant) could only be calculated in 26.2% of all pressure changes during the inflation and in 21.4% during the deflation phase, independent of continuous distending pressure (CDP). Inability to calculate the time constant was due to lack of stabilization of the RIP signal or no change in any direction.ConclusionsSignificant heterogeneity in lung behavior during a staircase incremental–decremental LVOM occurred, underscoring the need for higher initial inflation pressures when transitioning from conventional mechanical ventilation (CMV) and a longer time between pressure changes to allow for equilibration.

Measurement of thoraco-abdominal synchrony using respiratory inductance plethysmography: technical aspects and a proposal to overcome its limitations

ABSTRACT Background Thoraco-abdominal asynchrony (TAA) is usually assessed by respiratory inductance plethysmography. The main parameter used for its assessment is the calculation of the phase angle based on Lissajous plots. However, there are some mathematical limitations to its use. Research design and methods Sequences of five breaths were selected from a) normal subjects, b) COPD patients, both at rest and during exercise, and c) patients with obstructive apnea syndrome. Automated analysis was performed calculating phase angle, loop rotation (clockwise or counterclockwise), global phase delay and loop area. TAA severity was estimated quantitatively and in subgroups. Results 2290 cycles were analyzed (55% clockwise rotation). Phase angle ranged from −86.90 to + 88.4 degrees, while global phase delay ranged from −179.75 to + 178.54. Despite a good correlation with global phase delay (p < 0.01, ANOVA test), phase angle and loop area were not able to correctly classify breaths with severe deviation and paradoxical movements (p=ns, Bonferroni post hoc test). Conclusions Global phase delay covers the whole spectrum of TAA situations in a single value. It may be a relevant parameter for diagnosis and follow-up of clinical conditions leading to TAA. Clinical trial registration The trial from which the traces were obtained was registered at ClinicalTrials.gov ;(identifier: NCT04597606).

A review of infant apnea monitor design

Apnea detection is critical to the management of infant apnea. Effective monitoring and management of apnea using apnea monitors is known to reduce complications and possible fatalities in infants. There is a need to determine the critical design considerations in apnea monitors. This article reviews the design and development of infant apnea monitors. We conducted a targeted literature review from different databases, including PubMed, ScienceDirect, and Google Scholar. We reviewed articles published between January 1995 and February 2023. The search was done using combinations of key terms, namely, “apnea,” “apnea monitors,” and “apnea monitor design.” Articles that met the inclusion criteria were extracted and analyzed. The review investigated common physiological parameters, sensor types, and validation results of apnea monitors. The review revealed important design considerations adopted in the literature as well as the different sensor types and methods of apnea detection. It was found that thoracic impedance pneumography, thermistors, respiratory inductance plethysmography, pneumotachograph, and MEMS accelerometer are the most common sensor types used to design apnea monitors. The review revealed that most apnea monitors were designed to measure multiple physiological parameters. Device validation results varied from one device to another, with sensitivity and specificity metrics ranging between 80% and 96%. With the high burden of infant apnea in developing countries and its associated mortality and morbidity, the design of functional infant apnea monitors has become increasingly important to complement the expensive and complex polysomnography technique. Therefore, we must use appropriate sensors and design approaches for effective detection of infant apnea.

Rib cage contributions to inspiratory capacity in patients with cervical spinal cord injury

BackgroundCervical spinal cord injury (CSI) often leads to impaired respiratory function, affecting the overall well-being of patients. This study aimed to investigate the influence of rib cage motion on inspiratory capacity in CSI patients. MethodsWe conducted a study with 11 CSI patients, utilising respiratory inductance plethysmography (RIP). We measured ventilatory volume by spirometry concurrently with RIP. Participants were instructed to perform maximal inspiratory efforts. Inspiratory capacity (IC) was calculated from spirometry waveforms. We converted the respiratory waveforms of the chest and abdomen into inspiratory volume measured by a spirometer. The inspiratory volume measured by the chest sensor was defined as VRIP-rib cage (VRIP-rc), and the inspiratory volume measured by the abdominal sensor was defined as VRIP-abdomen (VRIP-ab). Subsequently, the relationships of IC with VRIP-rc and VRIPab were assessed. ResultsThe mean IC was 1.828 ± 0.459 L, with the mean VRIP-rc at 1.343 ± 0.568 L and the mean VRIP-ab at 0.485 ± 0.427 L. A significant correlation was observed between IC and VRIP-rc (r = 0.67, p = 0.02), indicating that rib cage motion significantly influences IC in CSI patients. ConclusionThis study highlights the importance of rib cage motion in assessing inspiratory capacity in patients with CSI.

Use of Intrinsic Entropy to Assess the Instantaneous Complexity of Thoracoabdominal Movement Patterns to Indicate the Effect of the Iso-Volume Maneuver Trial on the Performance of the Step Test.

The recent surge in interest surrounds the analysis of physiological signals with a non-linear dynamic approach. The measurement of entropy serves as a renowned method for indicating the complexity of a signal. However, there is a dearth of research concerning the non-linear dynamic analysis of respiratory signals. Therefore, this study employs a novel method known as intrinsic entropy (IE) to assess the short-term dynamic changes in thoracoabdominal movement patterns, as measured by respiratory inductance plethysmography (RIP), during various states such as resting, step test, recovery, and iso-volume maneuver (IVM) trials. The findings reveal a decrease in IE of thoracic wall movement (TWM) and an increase in IE of abdominal wall movement (AWM) following the IVM trial. This suggests that AWM may dominate the breathing exercise after the IVM trial. Moreover, due to the high temporal resolution of IE, it proves to be a suitable measure for assessing the complexity of thoracoabdominal movement patterns under non-stationary states such as the step test and recovery. The results also demonstrate that the instantaneous complexity of TWM and AWM can effectively capture instantaneous changes during non-stationary states, which may prove valuable in understanding the respiratory mechanism for healthcare purposes in daily life.

P045 Noxturnal cRIP: A Comparative Analysis of Sensors for the Identification of Respiratory Events in Polysomnography

Abstract Introduction AASM recommends the use of nasal pressure (NP), oronasal thermal flow (TF), and respiratory inductance plethysmography (RIP) for detecting and characterising respiratory events in polysomnography. The use of both NP and TF sensors is reported to be more accurate in respiratory event identification than either alone. However, these sensors can be unreliable if dislodged and cause discomfort. Noxturnal calibrated RIP flow (cRIPflow), derived from RIP, may provide a non-invasive alternative method for flow measurement in identification of respiratory events. Method Respiratory scoring was performed manually by a single experienced scorer on 10 diagnostic sleep studies under AASM standards. Scoring was repeated using three different measurements for each study: cRIPflow only, Thermistor (Th) only and both Th+NP (AASM recommendation). Apnoea hypopnoea index (AHI), central apnoea index (CAI), obstructive apnoea index (OAI), mixed apnoea index (MAI) and hypopnoea index (HI) were calculated and paired t-test analysis utilised for comparison between measurements. Results No statistical differences were identified in comparison of cRIPflow with Th or Th+NP in respiratory event identification: CAI (cRIPflow 3.2/hr±7.1, Th 3.9/hr±8.9, Th+NP 3.1/hr±7.5), OAI (cRIPflow 6.1/hr±6.8, Th 5.3/hr±8.2, Th+NP 6.7/hr±8.9), MAI (cRIPflow 5.2/hr±9.7, Th 4.3/hr±8.7, Th+NP 4.7/hr±9.2), or HI (cRIPflow 12.5/hr±13.9, Th 11.1/hr±10.5, Th+NP 10.4/hr±10.7). There was a statistical difference for AHI (cRIPflow 26.9/hr±26.6, Th 24.5/hr±26.4, Th+NP 25.0/hr±26.5). Discussion This study suggests cRIPflow may provide an alternative measurement in the detection and characterisation of respiratory events, however further analysis with larger sample size would provide more insight into sensitivity and specificity of this method.

Etiology and Mechanism of Intermittent Hypoxemia Episodes in Spontaneously Breathing Extremely Premature Infants

To evaluate the mechanisms leading to intermittent hypoxemia (IH) episodes in spontaneously breathing extremely premature infants at 32 weeks and 36weeks postmenstrual age (PMA). We studied spontaneously breathing premature infants born at 23-28weeks of gestational age who presented with IH episodes while on noninvasive respiratory support at 32 or 36weeks PMA. Daytime recordings of arterial oxygen saturation (SpO2), esophageal pressure, respiratory inductive plethysmography of the abdomen, chest wall, and their sum were obtained during 4hours at 32 weeks and 36 weeks PMA. IH episodes (SpO2<90% for ≥5seconds) and severe IH episodes (SpO2<80% for ≥5seconds) were classified as resulting from apnea, active exhalation and breath holding, reduced tidal volume (VT), or reduced respiratory rate (RR) during the preceding 60seconds. Fifty-one infants with a mean gestational age of 25.9 ±1.5weeks and a mean birth weight of 846± 185g were included. Of these, 31 and 41 were included in the analysis at 32 weeks and 36weeks PMA, respectively. At both 32 weeks and 36weeks PMA, greater proportions of all IH episodes and severe IH episodes were associated with active exhalation and breath holding than with apnea, reduced RR, or reduced VT. The severity and duration of the IH episodes did not differ between mechanisms. In this group of premature infants, the predominant mechanism associated with daytime IH was active exhalation and breath holding. This etiology is more closely associated with behavioral factors than abnormal respiratory control and can have implications for prevention.

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.