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Sophie Blouet,1 Jasmine Sutter,1 Emeline Fresnel,2 Adrien Kerfourn,2 Antoine Cuvelier,1,3 Maxime Patout1,3 1Department of Pulmonary, Thoracic Oncology and Intensive Respiratory Care, Rouen University Hospital, Rouen, France; 2Kernel Biomedical, Rouen University Hospital, Bois-Guillaume, France; 3Normandie Univ, UNIRouen, EA3830-GRHV, Institute for Research and Innovation in Biomedicine, Rouen, France Introduction: Acute exacerbation of COPD (AECOPD) is associated with poor outcome. Noninvasive ventilation (NIV) is recommended to treat end-stage COPD. We hypothesized that changing breathing pattern of COPD patients on NIV could identify patients with severe AECOPD prior to admission. Methods: This is a prospective monocentric study including all patients with COPD treated with long-term home NIV. Patients were divided in two groups: a stable group in which patients were admitted for the usual respiratory review and an exacerbation group in which patients were admitted for inpatient care of severe AECOPD. Data from the ventilator were downloaded and analyzed over the course of the 10 days that preceded the admission. Results: A total of 62 patients were included: 41 (67%) in the stable group and 21 (33%) in the exacerbation group. Respiratory rate was higher in the exacerbation group than in the stable group over the 10 days preceding inclusion (18.2±0.5 vs 16.3±0.5 breaths/min, respectively) (P=0.034). For 2 consecutive days, a respiratory rate outside the interquartile limit of the respiratory rate calculated over the 4 preceding days was associated with an increased risk of severe AECOPD of 2.8 (95% CI: 1.4–5.5) (P1.0845 was associated with an increased risk of severe AECOPD of 4.0 (95% CI: 1.5–10.5) (P=0.001). This assessment had the sensitivity, specificity, positive predictive, and negative predictive values of 81.0, 63.4, 53.1, and 86.7%, respectively. Conclusion: Data from NIV can identify a change in breathing patterns that predicts severe AECOPD. Keywords: noninvasive ventilation, acute exacerbation of COPD, breathing pattern

Background: Mechanical insufflation-exsufflation (MI-E) is crucial to assist patients with impaired cough, especially those with neuromuscular diseases. Despite recent advancements that enable real-time display of peak expiratory flow (PEF) and inspiratory volume, accurately monitoring these parameters with MI-E devices during treatment can still present challenges., Methods: A bench study that used a mechanical lung connected to 3 MI-E devices (EOVE-70; E-70 and Comfort Cough II) was conducted to evaluate PEF and inspiratory volume monitoring accuracy. Two clinical conditions were tested, low and normal compliance, with 6 different MI-E settings tested: +20/-20, +30/-30, +40/-40, +40/-50, +40/-60, and +40/-70 cm H 2 O. PEF (L/min) and inspiratory volume (mL) displayed on the screen were recorded cycle by cycle, while a pneumotachograph connected to the mechanical lung was used to measure the actual PEF and inspiratory volume for data comparison. Flow bias was assessed by calculating the difference (PEF - peak inspiratory flow) and ratio (PEF to peak inspiratory flow) between flows., Results: All devices systematically underestimated PEF, with device A showing the smallest estimation error (-7.4 [-10.1; -6] %). Devices B and C exhibited larger errors (-26.5 [-29.2; -25.6] and (-29.9 [-30.7; -28.7] %, respectively). All the devices underestimated inspiratory volume, with device B showing the smallest estimation error (-15.1 [-21.2; -12.3] %). Device A exhibited a significantly larger error (-26.9 [-30.3; -24.8] %). The error from device C (-17.7 [-34.5; -13.8] %) was not statistically different from device B. Device type, high pressure settings (> +40/-40 cm H 2 O), and a lung model compliance of 60 mL/cm H 2 O were the main contributors to error in estimating PEF and inspiratory volume. Finally, we observed differences of PEF-to-peak inspiratory flow ratio and PEF minus peak inspiratory flow differences achieved., Conclusions: Our study highlighted consistent underestimation of PEF and inspiratory volume across MI-E devices. Improving device monitoring is essential for guiding MI-E therapy and ensuring patient safety., (Copyright © 2024 by Daedalus Enterprises.)

Introduction: A wide range of recent ventilators, dedicated or not, is available for non-invasive ventilation (NIV) in respiratory or intensive care units (ICU). We conducted a bench study to compare their technical performances., Methods: Ventilators, including five ICU ventilators with NIV mode on, two dedicated NIV ventilators and one transport ventilator, were evaluated on a test bench for NIV, consisting of a 3D manikin head connected to an ASL 5000 lung model via a non-vented mask. Ventilators were tested according to three simulated lung profiles (normal, obstructive, restrictive), three levels of simulated air leakage (0, 15, 30 L/min), two levels of pressure support (8, 14 cmH 2 O) and two respiratory rates (15, 25 cycles/min)., Results: The global median Asynchrony Index (AI) was higher with ICU ventilators than with dedicated NIV ventilators (4% (0; 76) vs 0% (0; 15), respectively; p<0.05) and different between all ventilators (p<0.001). The AI was higher with ICU ventilators for the normal and restrictive profiles (p<0.01) and not different between ventilators for the obstructive profile. Auto-triggering represented 43% of all patient-ventilator asynchrony. Triggering delay, cycling delay, inspiratory pressure-time product, pressure rise time and pressure at mask were different between all ventilators (p<0.01). Dedicated NIV ventilators induced a lower pressure-time product than ICU and transport ventilators (p<0.01). There was no difference between ventilators for minute ventilation and peak flow., Conclusion: Despite the integration of NIV algorithms, most recent ICU ventilators appear to be less efficient than dedicated NIV ventilators. Technical performances could change, however, according to the underlying respiratory disease and the level of air leakage., Competing Interests: Competing interests: Christian Caillard reports non-financial support from Asten. Christophe Girault reports grants and non-financial support from Fischer & Paykel Healthcare, Resmed Ltd., Loweinstein Medical, Asten, outside the submitted work. Antoine Cuvelier, Maxime Patout, Emeline Fresnel, Fabienne Tamion and Elise Artaud-Macari have nothing to disclose., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: In patients with chronic respiratory failure, home non-invasive ventilation (NIV) is delivered through nasal or oronasal masks. Masks are a cornerstone for NIV success but can be associated with side effects. However, the type, the frequency and the consequences of these side effects are unknown. Here, we aimed to study the prevalence, nature, and impact of mask-related adverse events in a cohort of stable patients. We then investigated differences between oronasal and nasal masks both in our cohort and in a bench study., Methods: Prospective observational cohort including patients established on long-term non-invasive ventilation admitted for their elective review. Data regarding mask-related side effects were assessed using a structured questionnaire. Our bench study was performed using a 3-D printed head connected to an artificial lung., Results: Eight hundred patients were included of whom, 84% had a oronasal mask. Moderate to very severe mask-related side effects occurred in 47% of patients and severe to very severe side effects occurred in 18%. Side effects were associated to a poorer daytime PaCO 2 (p=0.005), poorer subjective sleep quality (p=0.003), poorer quality of life (p<0.001). Mask-related side effects were more frequently reported with the use of oronasal masks as compared to nasal masks (p=0.023). Our bench study showed that nasal masks were more stable than oronasal masks (p<0.001)., Conclusion: Mask-related side effects are frequent and associated with poorer outcome. Our data suggest that nasal masks may have a better tolerance profile and should be used as a first-line interface., (Copyright ©The authors 2024. For reproduction rights and permissions contact permissions@ersnet.org.)

Purpose: Tracheostomized patients often present with muscle weakness, altered consciousness, or swallowing difficulties. Hence, the literature is scarce regarding the challenging management of tracheostomy weaning. There is a need to strengthen the understanding of respiratory mechanisms with the different tracheostomy tube modalities that compose this weaning pathway. We aimed to evaluate the impact of these modalities on the work of breathing (WOB), total positive end-expiratory pressure (PEEPtot), and tidal volume (V T )., Methods: With a three-dimensional (3D) printed head mimicking human upper airways, we added a tracheal extension, and pierced to allow insertion of a size 7.0 tracheostomy cannula. The whole was connected to an artificial lung. Three lung mechanics were simulated (normal, obstructive and restrictive). We compared five different tracheostomy tube modalities to a control scenario in which the tube was capped and the cuff was deflated., Results: A marginal difference was observed on the WOB within conditions with a slight increase + 0.004 [95% CI (0.003-0.004); p < 0.001] when the cuff was inflated in the normal and restrictive models and a slight decrease in the obstructive model. The highest PEEPtot that was reached was + 1 cmH 2 O [95% CI (1-1.1); p < 0.001] with high-flow therapy (HFT) with the cuff inflated in the obstructive model. We observed a statistically significant reduction in V T [up to - 57 mL 95% CI (- 60 to - 54); p < 0.001] when the cuff was inflated, in both the normal and obstructive models., Conclusions: Our results support the use of conditions that involve cuff deflation. Intermediate modalities with the cuff deflated produced similar results than cannula capping., (© 2024. The Author(s).)

Background: There is a lack of bench systems permitting to evaluate ventilation devices in the specific context of cardiac arrest., Objectives: The objective of the study is to assess if a new physiological manikin may permit to evaluate the performances of medical devices dedicated to ventilation during cardiopulmonary resuscitation (CPR)., Methods: Specific CPR-related features required to reproduce realistic ventilation were implemented into the SAM (Sarthe Anjou Mayenne) manikin. In the first place, the manikin ability to mimic ventilation during CPR was assessed and compared to real-life tracings of airway pressure, flow and capnogram from three out of hospital cardiac arrest (OHCA) patients. In addition, to illustrate the interest of this manikin, ventilation was evaluated during mechanical continuous chest compressions with two devices dedicated to CPR: the Boussignac cardiac arrest device (B-card - Vygon; Ecouen France) and the Impedance Threshold Device (ITD - Zoll; Chelmsford, MA)., Results: The SAM manikin enabled precise replication of ventilation tracings as observed in three OHCA patients during CPR, and it allowed for comparison between two distinct ventilation devices. B-card generated a mean, maximum and minimum intrathoracic pressure of 6.3 (±0.1) cmH 2 O, 18.9 (±1.1) cmH 2 O and -0.3 (±0.2) cmH 2 O respectively; while ITD generated a mean, maximum and minimum intrathoracic pressure of -1.6 (±0.0) cmH 2 O, 5.7 (±0.1) cmH 2 O and -4.8 (±0.1) cmH 2 O respectively during CPR. B-card allowed to increase passive ventilation compared to the ITD which resulted in a dramatic limitation of passive ventilation., Conclusion: The SAM manikin is an innovative model integrating specific physiological features that permit to accurately evaluate and compare ventilation devices during CPR., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: ‘EF is the co-founder of KerNel Biomedical society who received part of the study fund allocated to this manikin development. AL and LP are medical engineers in the Med2Lab funded by Air Liquide Medical Systems. RC is a physician working for Air Liquide Medical Systems. ML reports part time salary with Air Liquide Medical Systems and KerNel Biomedical. JCR reports part time salary for research activities (Med2Lab) from Air Liquide Medical Systems. FB reports personal consulting fees from Löwenstein Medical and Air Liquide Medical Systems, travel fees from Draeger and Air Liquide Medical Systems and research support from Covidien and GE Healthcare outside this work. FM and DS reports Grants from Fisher and Paykel and travel fees from Air Liquide Medical Systems outside this work. AM reports personal fees from Draeger, Faron Pharmaceuticals, Air Liquide Medical Systems, Pfizer, ResMed and Draeger and grants and personal fees from Fisher & Paykel and Covidien, outside this work. None of the other authors have competing interests related to this topic.’., (© 2024 The Authors.)

Leakage is a common issue with PAP therapy and may contribute to short-term non-compliance with treatment. PAP manufacturers use different methods to estimate and report air leaks (median, mean, p90, p95, % of important air leak, time spent on major leaks), which makes the analysis and comparisons challenging. Leak intensity is a well-known parameter of major importance as it can significantly affect the performance of PAP devices. However, there is a lack of knowledge regarding another leakage parameter, namely the leakage pattern. As of now, there is no standard classification for leak patterns in real-life settings. Our objective was to develop and propose a comprehensive nomenclature for leakage patterns observed during nasal auto-PAP therapy. We examined 50 ventilatory polygraphy recordings conducted with auto-PAP, based on data from a prior study in which the unintentional leak flow was precisely measured over time. We have categorized leaks into two main types: continuous leaks, which appear and persist for an extended period, and discontinuous leaks, which vanish more rapidly. Continuous leaks can have both abrupt or gradual apparitions and terminations. Their "shape" can be either interrupted or constant. Discontinuous leaks can have both abrupt or gradual apparitions and terminations. Due to the relatively short observation scale (less than 5 min minutes), this type of leakage is not characterized by a specific shape between apparition and termination. This nomenclature could be a valuable tool that facilitates comparative bench tests or clinical studies. This tool could support manufacturers in developing precise algorithms for leak compensation, residual AHI estimation and the accuracy of CPAP monitoring data. Lastly, establishing a standardized approach for describing and categorizing air leakage patterns could assist clinicians in identifying device-related issues, such as patient discomfort arising from specific types of leakage., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Lebret Marius reports a relationship with Air Liquide Medical Systems and KerNel Biomedical that includes: employment., (Copyright © 2023. Published by Elsevier B.V.)

Background: Little is known about the use of long-term non-invasive ventilation (NIV) in the elderly. We aimed to assess if the effectiveness of long-term NIV of patients ≥ 80 years (older) was not greatly inferior to that of patients < 75 years (younger)., Methods: This retrospective exposed/unexposed cohort study included all patients established on long-term NIV treated at Rouen University Hospital between 2017 and 2019. Follow-up data were collected at the first visit following NIV initiation. The primary outcome was daytime PaCO2 with a non-inferiority margin of 50% of the improvement of PaCO2 for older patients compared to younger patients., Results: We included 55 older patients and 88 younger patients. After adjustment on the baseline PaCO2, the mean daytime PaCO2 was reduced by 0.95 (95% CI: 0.67; 1.23) kPa in older patients compared to1.03 (95% CI: 0.81; 1.24) kPa in younger patients for a ratio of improvements estimated at 0.95/1.03 = 0.93 (95% CI: 0.59; 1.27, one-sided p = 0.007 for non-inferiority to 0.50). Median (interquartile range) daily use was 6 (4; 8.1) hours in older versus 7.3 (5; 8.4) hours in younger patients. No significant differences were seen in the quality of sleep and NIV safety. The 24-months survival was 63.6% in older and 87.2% in younger patients., Conclusions: effectiveness and safety seemed acceptable in older patients, with a life expectancy long enough to expect a mid-term benefit, suggesting that initiation of long-term NIV should not be refused only based on age. Prospective studies are needed., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Masson SAS.)

Background: Home CPAP and noninvasive ventilation (NIV) are increasingly used in children. An appropriate choice of the CPAP/NIV device, according to the manufacturer recommendations, should guarantee accurate data collection software. However, not all devices display accurate patient data. We hypothesized that the detection of patient breathing may be expressed as a minimal tidal volume (V T min ) rather than a minimal weight. The aim of the study was to estimate the V T min detected by home ventilators when set on CPAP., Methods: Twelve level I-III devices were analyzed using a bench test. Pediatric profiles were simulated with increasing V T values to determine the V T min that the ventilator may detect. The duration of CPAP use and the presence/absence of waveform tracings on the built-in software were also gathered., Results: V T min varied according to the device, ranging from 16-84 mL, independent of level category. The duration of CPAP use was underestimated in all level I devices, which were either not able to display any waveform or only intermittently, until V T min was reached. The duration of CPAP use was overestimated for the level II and III devices, with the display of different waveforms according to the device as soon as the device was switched on., Conclusions: Based on the V T min detected, some level I and II devices may be suitable for infants. A careful testing of the device should be done at CPAP initiation, with a review of data generated from ventilator software., Competing Interests: Dr Lebret is a part-time employee of Air Liquide Medical Systems. The remaining authors have disclosed no conflicts of interest., (Copyright © 2023 by Daedalus Enterprises.)

Background: Several noninvasive ventilatory supports rely in their design on high oxygen consumption which may precipitate oxygen shortage, as experienced during the COVID-19 pandemic. In this bench-to-bedside study, we assessed the performance of a new continuous positive airway pressure (CPAP) device integrating a large reservoir ("Bag-CPAP") designed to minimize oxygen consumption, and compared it with other CPAP devices., Methods: First, a bench study compared the performances of Bag-CPAP and four CPAP devices with an intensive care unit ventilator. Two FiO 2 targets (40-60% and 80-100%) at a predefined positive end expiratory pressure (PEEP) level between 5 and 10 cm H 2 O were tested and fraction of inspired oxygen (FiO 2 ) and oxygen consumption were measured. Device-imposed work of breathing (WOB) was also evaluated. Second, an observational clinical study evaluated the new CPAP in 20 adult patients with acute respiratory failure in two hospitals in France. Actual FiO 2 , PEEP, peripheral oxygen saturation, respiratory rate, and dyspnea score were assessed., Results: All six systems tested in the bench study reached the minimal FiO 2 target of 40% and four reached at least 80% FiO 2 while maintaining PEEP in the predefined range. Device-delivered FiO 2 /consumed oxygen ratio was the highest with the new reservoir-based CPAP irrespective of FiO 2 target. WOB induced by the device was higher with Bag-CPAP. In the clinical study, Bag-CPAP was well tolerated and could reach high (> 90%) and moderate (> 50%) FiO 2 with an oxygen flow rate of 15 [15-16] and 8 [7-9] L/min, respectively. Dyspnea score improved significantly after introduction of Bag-CPAP, and SpO 2 increased., Conclusions: In vitro, Bag-CPAP exhibited the highest oxygen saving properties albeit had increased WOB. It was well accepted clinically and reduced dyspnea. Bag-CPAP may be useful to treat patients with acute respiratory failure in the field, especially when facing constraints in oxygen delivery., (© 2023. The Author(s).)

Background: The impact of leaks has mainly been assessed in bench models using continuous leak patterns which did not reflect real-life leakage. We aimed to assess the impact of the pattern and intensity of unintentional leakage (UL) using several respiratory models., Methods: An active artificial lung (ASL 5000) was connected to three bilevel-ventilators set in pressure mode; the experiments were carried out with three lung mechanics (COPD, OHS and NMD) with and without upper airway obstruction. Triggering delay, work of breathing, pressure rise time, inspiratory pressure, tidal volume, cycling delay and the asynchrony index were measured at 0, 6, 24 and 36 L/min of UL. We generated continuous and inspiratory UL., Results: Compared to 0 L/min of UL, triggering delays were significantly higher with 36 L/min of UL (+27 ms) and pressure rise times were longer (+71 ms). Cycling delays increased from -4 [-250-169] ms to 150 [-173-207] ms at, respectively 0 L/min and 36 L/min of UL and work of breathing increased from 0.15 [0.12-0.29] J/L to 0.19 [0.16-0.36] J/L. Inspiratory leakage pattern significantly increased triggering delays (+35 ms) and cycling delays (+263 ms) but decreased delivered pressure (-0.94 cmH 2 O) compared to continuous leakage pattern. Simulated upper airway obstruction significantly increased triggering delay (+199 ms), cycling delays (+371 ms), and decreased tidal volume (-407 mL) and pressure rise times (-56 ms)., Conclusions: The pattern of leakage impacted more the device performances than the magnitude of the leakage per se. Flow limitation negatively reduced all ventilator performances.

Background and Objective: When home non-invasive ventilation (NIV) is initiated, five goals need to be achieved: a daily use >4 h/day, an improvement in gas exchange, health-related quality of life (HRQL) and sleep quality without side effects. Our aim was to assess how frequently these five goals were reached and the factors predictive of achievement., Methods: We conducted a monocentric cohort study that included patients electively established on home NIV over 2 years. HRQL was assessed at baseline and follow-up by the Severe Respiratory Insufficiency questionnaire. Adequate initiation was defined as the achievement of at least three of five goals and successful initiation as the achievement of all., Results: Two-hundred and fifty patients were included at baseline. NIV was initiated for: obesity hypoventilation syndrome (n = 95; 38%), neuromuscular disease (n = 70; 28%), chronic obstructive pulmonary disease (n = 66; 26%) and chest wall disease (n = 19; 8%). At follow-up, measures of all five goals were available in 141 (56%) patients. NIV initiation was adequate for 96 (68%) patients and successful for 12 (9%) patients. In multivariate analysis, a tidal volume ≥ 7.8 ml/kg of ideal body weight was associated with an increased likelihood of adequate NIV initiation (hazard ratio: 5.765 [95% CI:1.824-18.223], p = 0.006]. Improvement in daytime partial arterial carbon dioxide pressure (PaCO 2 ) was not correlated to improvement in HRQL or sleep quality. Severe to very severe NIV-related side effects occurred in 114 (47%) patients and were associated with higher daytime PaCO 2 (6.35 ± 1.08 vs. 5.92 ± 0.79 kPa, p < 0.001)., Conclusion: Successful home NIV initiation is rarely achieved in real life. HRQL and NIV tolerance should be assessed to improve patient-centred outcomes., (© 2021 Asian Pacific Society of Respirology.)

BACKGROUND: Aerobatic pilots must withstand high and sudden acceleration forces (G z ) up to 10 G z . The physiological consequences of such a succession of high and abrupt positive and negative G z on the human body over time remain mostly unknown. This case report emphasizes changes in physiological factors such as cerebral oxygenation and heart rate dynamics collected in real aerobatic flights. CASE REPORT: A 37-yr-old man, experienced in aerobatic flying, voluntarily took part in this study. During two flight runs (1520 min), the pilot performed aerobatic maneuvers with multiple high (10 G z ) positive and negative accelerations. During the flights he wore a Polar heart rate sensor while cerebral oxygenation was measured continuously over his prefrontal cortex via near-infrared spectroscopy (NIRS). NIRS allows for measurement of the relative concentration changes of oxygenated hemoglobin (O₂Hb) and deoxygenated hemoglobin (HHb), making it possible to determine cerebral oxygenation and hemodynamic status. DISCUSSION: The continuous in-flight monitoring of O₂Hb and HHb revealed the large effects of successive positive and negative G z exposures on cerebral hemodynamics alterations. The results showed a significant and positive correlation between changes in G z exposures and O₂Hb concentration. This case report highlights that NIRS provides some valuable and sensitive indicators for the monitoring of cerebral hemodynamics during aerobatic flights exposed to multiple and high acceleration forces. To our knowledge, this first study quantifying cerebral oxygenation changes in aerobatics opens the way for the assessment of individual physiological responses and tolerance in pilots to repeated high G z during real flights. Fresnel E, Dray G, Pla S, Jean P, Belda G, Perrey S. Cerebral oxygenation responses to aerobatic flight . Aerosp Med Hum Perform. 2021; 92(10):838842 .

Background: SARS-CoV-2 aerosolization during noninvasive positive-pressure ventilation may endanger health care professionals. Various circuit setups have been described to reduce virus aerosolization. However, these setups may alter ventilator performance., Research Question: What are the consequences of the various suggested circuit setups on ventilator efficacy during CPAP and noninvasive ventilation (NIV)?, Study Design and Methods: Eight circuit setups were evaluated on a bench test model that consisted of a three-dimensional printed head and an artificial lung. Setups included a dual-limb circuit with an oronasal mask, a dual-limb circuit with a helmet interface, a single-limb circuit with a passive exhalation valve, three single-limb circuits with custom-made additional leaks, and two single-limb circuits with active exhalation valves. All setups were evaluated during NIV and CPAP. The following variables were recorded: the inspiratory flow preceding triggering of the ventilator, the inspiratory effort required to trigger the ventilator, the triggering delay, the maximal inspiratory pressure delivered by the ventilator, the tidal volume generated to the artificial lung, the total work of breathing, and the pressure-time product needed to trigger the ventilator., Results: With NIV, the type of circuit setup had a significant impact on inspiratory flow preceding triggering of the ventilator (P < .0001), the inspiratory effort required to trigger the ventilator (P < .0001), the triggering delay (P < .0001), the maximal inspiratory pressure (P < .0001), the tidal volume (P = .0008), the work of breathing (P < .0001), and the pressure-time product needed to trigger the ventilator (P < .0001). Similar differences and consequences were seen with CPAP as well as with the addition of bacterial filters. Best performance was achieved with a dual-limb circuit with an oronasal mask. Worst performance was achieved with a dual-limb circuit with a helmet interface., Interpretation: Ventilator performance is significantly impacted by the circuit setup. A dual-limb circuit with oronasal mask should be used preferentially., (Copyright © 2021 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

Noninvasive ventilation (NIV) during exercise has been suggested to sustain higher training intensity but the type of NIV interface, patient-ventilator asynchronies (PVA) or technological limitation of the ventilator may interfere with exercise. We assessed whether these parameters affect endurance exercise capacity in severe COPD patients. In total, 21 patients with severe COPD not eligible to home NIV performed three constant workload tests. The first test was carried out on spontaneous breathing (SB) and the following ones with NIV and a nasal or oronasal mask in a randomized order. PVA and indicators of ventilator performance were assessed through a comprehensive analysis of the flow pressure tracing raw data from the ventilator. The time limit was significantly reduced with both masks (406 s (197-666), 240 s (131-385) and 189 s (115-545), p < 0.01 for tests in SB, with oronasal and nasal mask, respectively). There were few PVA with an oronasal mask (median: 3.4% (1.7-5.2)) but the ventilator reached its maximal generating capacity (median flowmax: 208.0 L/s (189.5-224.8) while inspiratory pressure dropped throughout exercise (from 10.1 (9.4-11.4) to 8.8 cmH2O (8.6-10.8), p < 0.01). PVA were more frequent with nasal mask (median: 12.8% (3.2-31.6), p < 0.01). Particularly, the proportion of patients with ineffective efforts > 10% was significantly higher with nasal interface (0% versus 33.3%, p < 0.01). NIV did not effectively improve endurance capacity in COPD patients not acclimated to home NIV. This was due to a technological limitation of the ventilator for the oronasal mask and the consequence either of an insufficient pressure support or a technological limitation for the nasal mask.

Heart rate variability analysis using 24-h Holter monitoring is frequently performed to assess the cardiovascular status of a patient. The present retrospective study is based on the beat-to-beat interval variations or ΔRR, which offer a better view of the underlying structures governing the cardiodynamics than the common RR-intervals. By investigating data for three groups of adults (with normal sinus rhythm, congestive heart failure, and atrial fibrillation, respectively), we showed that the first-return maps built on ΔRR can be classified according to three structures: (i) a moderate central disk, (ii) a reduced central disk with well-defined segments, and (iii) a large triangular shape. These three very different structures can be distinguished by computing a Shannon entropy based on a symbolic dynamics and an asymmetry coefficient, here introduced to quantify the balance between accelerations and decelerations in the cardiac rhythm. The probability P111111 of successive heart beats without large beat-to-beat fluctuations allows to assess the regularity of the cardiodynamics. A characteristic time scale, corresponding to the partition inducing the largest Shannon entropy, was also introduced to quantify the ability of the heart to modulate its rhythm: it was significantly different for the three structures of first-return maps. A blind validation was performed to validate the technique.

Objectives: A prospective study was performed to assess the intermediate and long-term efficacy of intralesional cidofovir therapy associated with surgical excision in laryngeal papillomatosis in adults., Methods: Endoscopy with intralesional injection of cidofovir 5 mg/mL was performed 3 times at 4-week intervals. The concentration was later increased to 7.5 mg/mL and the interval between injections shortened to 2 weeks. Further treatment was performed at 3 or 6 months, depending on the evolution of the papillomas. After complete remission, the treatment was stopped and the patients were reviewed every 6 months., Results: Nineteen patients completed the protocol, with a mean of 4.5 injections each. Complete remission was obtained in 17 cases (89%) after a mean of 3.8 procedures. Remission was stable after a mean follow-up of 24 months (range, 8 to 57 months). With higher cidofovir concentrations at shorter intervals, patients needed fewer injections to achieve remission (mean, 2.1 versus 4.7 injections)., Conclusions: The effectiveness of intralesional cidofovir therapy in adult-onset recurrent respiratory papillomatosis was impressive. Once obtained, complete remission was stable on intermediate or long-term follow-up. The concentration and the interval between injections seemed to influence the number of injections necessary to achieve remission.