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• Myotonic dystrophy type 1 patients often present with respiratory insufficiency. • Sleep apnea is very common in myotonic dystrophy type 1 patients. • Home mechanical ventilation is frequently needed in myotonic dystrophy patients. • Low compliance with home mechanical ventilation often occurs in myotonic dystrophy. • Respiratory features cannot predict home mechanical ventilation treatment failure. Chronic respiratory insufficiency is common in patients with myotonic dystrophy type 1 (DM1) and can be treated with noninvasive home mechanical ventilation (HMV). HMV is not always tolerated well resulting in low treatment adherence. We aimed to analyze if baseline respiratory characteristics such as pulmonary function, level of pCO 2 and presence of sleep apnea are associated with HMV treatment adherence in DM1 patients. Pulmonary function testing, polysomnography and blood gas measurement data of DM1 patients were retrospectively collected. Initiation of HMV and treatment adherence after one year was documented. Patients with low treatment adherence (average daily use of HMV <5 h) were grouped with patients that discontinued HMV and compared with patients with high treatment adherence (average daily use of HMV >5 h). HMV was initiated in 101 patients. After one year, 58 patients had low treatment adherence. There were no differences between the low and high treatment adherence group regarding the respiratory characteristics. None of the included predictors (gender, age, body mass index, cytosine-thymine-guanine repeat length, FVC, daytime pCO 2 , bicarbonate, nighttime pCO 2 , nighttime base excess, apnea-hypopnea index and mean saturation during sleep) was able to significantly predict high treatment adherence. In conclusion, the respiratory characteristics are not associated with treatment adherence with HMV in DM1 patients and cannot be used to identify patients at risk for low HMV treatment adherence. [ABSTRACT FROM AUTHOR]

Introduction: Chest compressions during CPR induce oscillations in capnography (ETCO2) waveforms. Studies suggest ETCO2 oscillation characteristics are associated with intrathoracic airflow dependent on airway patency. Oscillations can be quantified by the Airway Opening Index (AOI). We sought to evaluate multiple methods of computing AOI and their association with return of spontaneous circulation (ROSC).Methods: We conducted a retrospective study of 307 out-of-hospital cardiac arrest (OHCA) cases in Seattle, WA during 2019. ETCO2 and chest impedance waveforms were annotated for the presence of intubation and CPR. We developed four methods for computing AOI based on peak ETCO2 and the oscillations in ETCO2 during chest compressions (ΔETCO2). We examined the feasibility of automating ΔETCO2 and AOI calculation and evaluated differences in AOI across the methods using nonparametric testing (α = 0.05).Results: Median [interquartile range] AOI across all cases using Methods 1-4 was 28.0 % [17.9-45.5 %], 20.6 % [13.0-36.6 %], 18.3 % [11.4-30.4 %], and 22.4 % [12.8-38.5 %], respectively (p < 0.001). Cases with ROSC had a higher median AOI than those without ROSC across all methods, though not statistically significant. Cases with ROSC had a significantly higher median [interquartile range] ΔETCO2 of 7.3 mmHg [4.5-13.6 mmHg] compared to those without ROSC (4.8 mmHg [2.6-9.1 mmHg], p < 0.001).Conclusion: We calculated AOI using four proposed methods resulting in significantly different AOI. Additionally, AOI and ΔETCO2 were larger in cases achieving ROSC. Further investigation is required to characterize AOI's ability to predict OHCA outcomes, and whether this information can improve resuscitation care. [ABSTRACT FROM AUTHOR]

The impact of chronic liver disease on outcomes in patients with COVID-19 is uncertain. Hence, we aimed to explore this association. We explored the outcomes of all adult inpatients with COVID-19 in France, in 2020. We computed adjusted odds ratios to measure the associations between chronic liver disease, alcohol use disorders, mechanical ventilation and day-30 in-hospital mortality. The sample comprised 259,110 patients (median [IQR] age 70 (54–83) years; 52% men), including 15,476 (6.0%) and 10,006 (3.9%) patients with chronic liver disease and alcohol use disorders, respectively. Death occurred in 38,203 (15%) patients, including 7,475 (28%) after mechanical ventilation, and 2,941 (19%) with chronic liver disease. The adjusted odds ratios for mechanical ventilation and day-30 mortality were 1.54 (95% CI 1.44–1.64, p < 0.001) and 1.79 (1.71–1.87, p < 0.001) for chronic liver disease; 0.55 (0.47–0.64, p < 0.001) and 0.54 (0.48–0.61, p < 0.001) for mild liver disease; 0.64 (0.53–0.76; p < 0.001) and 0.71 (0.63–0.80, p < 0.001) for compensated cirrhosis; 0.65 (0.52–0.81, p < 0.001) and 2.21 (1.94–2.51, p < 0.001) for decompensated cirrhosis; 0.34 (0.24–0.50; p < 0.001) and 1.38 (1.17–1.62, p < 0.001) for primary liver cancer; and 0.82 (0.76–0.89; p < 0.001) and 1.11 (1.05–1.17; p < 0.001) for alcohol use disorders. Chronic viral hepatitis; non-viral, non-alcoholic chronic hepatitis; organ, including liver, transplantation, and acquired immunodeficiency syndrome were not associated with COVID-19-related death. Chronic liver disease increased the risk of COVID-19-related death in France in 2020. Therapeutic effort limitation may have contributed to COVID-19-related death in French residents with a liver-related complication or an alcohol use disorder. We studied the outcomes, including mechanical ventilation and day-30 mortality, of all adults with COVID-19 who were discharged from acute and post-acute care in France in 2020 (N = 259,110). Patients with mild liver disease; compensated cirrhosis; organ, including liver, transplantation; or acquired immunodepression syndrome were not at increased risk of COVID-19-related mortality. Patients with alcohol use disorders, decompensated cirrhosis, or primary liver cancer were at increased risk of COVID-19-related mortality but were less likely to receive mechanical ventilation. Our results suggest that therapeutic effort limitation may have contributed to the excess mortality in French residents with a liver-related complication or an alcohol use disorder. [Display omitted] • We assessed the association between chronic liver disease and clinical outcomes of in-patients with COVID-19. • Chronic liver disease increased the risk of COVID-19-related death. • Therapeutic effort limitations may have contributed to death of patients with decompensated cirrhosis, primary liver cancer, or with an alcohol use disorder. [ABSTRACT FROM AUTHOR]

Objectives: To describe the frequency of neonatal resuscitation interventions implemented for newborn babies in the state of Queensland over a 10-year period and determine if these changes suggest adherence to changes in Australian guidelines.Study Design: A population-based retrospective cohort study utilising the Queensland Perinatal Data Collection dataset. All liveborn babies ≥23 + 0 weeks + days gestation born between 1 July 2007 and 30 June 2017 were included except those for whom resuscitation was not attempted and those babies <25 + 0 weeks for whom it was unsuccessful. Trends in resuscitation were demonstrated using Loess regression.Results: Of 618,589 eligible newborns,182,260 received any resuscitation manoeuvre (29.5%). The proportion receiving oxygen without assisted ventilation declined from 19.3% in 2007-08 to 5.6% in 2016-17. Upper airway suctioning also decreased. Assisted ventilation increased from 7.9% to 10.0% of all babies with the largest contribution from late preterm and term babies. The rate of endotracheal suctioning for meconium and the rate of narcotic antagonist use also declined. A greater proportion of babies received chest compressions (1.9-3.2 per 1000 babies) and adrenaline (epinephrine). Mortality decreased from 1.9 to 1.5 per 1000 babies in the cohort.Conclusion: Ten-year trends showed reduced use of oxygen or upper airway suctioning without assisted ventilation, reduced intubation to suction meconium, reduced use of narcotic antagonists and greater use of assisted ventilation suggesting appropriate practice change in response to Australian neonatal resuscitation guidelines. The increase in the use of chest compressions and adrenaline was unexpected and the reasons for it are unclear. [ABSTRACT FROM AUTHOR]

Background: Positive end-expiratory pressure (PEEP) is widely used to improve oxygenation and prevent alveolar collapse in mechanically ventilated patients with the acute respiratory distress syndrome (ARDS). Although PEEP improves arterial oxygenation predictably, high-PEEP strategies have demonstrated equivocal improvements in ARDS-related mortality. The effect of PEEP on tissue oxygen delivery is poorly understood and is difficult to quantify or investigate in the clinical environment.Methods: We investigated the effects of PEEP on tissue oxygen delivery in ARDS using a new, high-fidelity, computational model with highly integrated respiratory and cardiovascular systems. The model was configured to replicate published clinical trial data on the responses of 12 individual ARDS patients to changes in PEEP. These virtual patients were subjected to increasing PEEP levels during a lung-protective ventilation strategy (0-20 cm H2O). Measured variables included arterial oxygenation, cardiac output, peripheral oxygen delivery, and alveolar strain.Results: As PEEP increased, tissue oxygen delivery decreased in all subjects (mean reduction of 25% at 20 cm H2O PEEP), despite an increase in arterial oxygen tension (mean increase 6.7 kPa at 20 cm H2O PEEP). Changes in arterial oxygenation and tissue oxygen delivery differed between subjects but showed a consistent pattern. Static and dynamic alveolar strain decreased in all patients as PEEP increased.Conclusions: Incremental PEEP in ARDS appears to protect alveoli and improve arterial oxygenation, but also appears to impair tissue oxygen delivery significantly because of reduced cardiac output. We propose that this trade-off may explain the poor improvements in mortality associated with high-PEEP ventilation strategies. [ABSTRACT FROM AUTHOR]

Background: Transtracheal jet ventilation (TTJV) is recommended in several airway guidelines as a potentially life-saving procedure during the 'Can't Intubate Can't Oxygenate' (CICO) emergency. Some studies have questioned its effectiveness.Methods: Our goal was to determine the complication rates of TTJV in the CICO emergency compared with the emergency setting where CICO is not described (non-CICO emergency) or elective surgical setting. Several databases of published and unpublished literature were searched systematically for studies describing TTJV in human subjects. Complications were categorized as device failure, barotrauma (including subcutaneous emphysema), and miscellaneous. Device failure was defined by the inability to place and/or use the TTJV device, not patient survival.Results: Forty-four studies (428 procedures) met the inclusion criteria. Four studies included both emergency and elective procedures. Thirty studies described 132 emergency TTJV procedures; 90 were CICO emergencies. Eighteen studies described 296 elective TTJV procedures. Device failure occurred in 42% of CICO emergency vs 0% of non-CICO emergency (P<0.001) and 0.3% of elective procedures (P<0.001). Barotrauma occurred in 32% of CICO emergency vs 7% of non-CICO emergency (P<0.001) and 8% of elective procedures (P<0.001). The total number of procedures with any complication was 51% of CICO emergency vs 7% of non-CICO emergency (P<0.001) and 8% of elective procedures (P<0.001). Several reports described TTJV-related subcutaneous emphysema hampering subsequent attempts at surgical airway or tracheal intubation.Conclusions: TTJV is associated with a high risk of device failure and barotrauma in the CICO emergency. Guidelines and recommendations supporting the use of TTJV in CICO should be reconsidered. [ABSTRACT FROM AUTHOR]

Background: Lung-protective ventilation is claimed to be beneficial not only in critically ill patients, but also in pulmonary healthy patients undergoing general anaesthesia. We report the use of electrical impedance tomography for assessing regional changes in ventilation, during both spontaneous breathing and mechanical ventilation, in patients undergoing robot-assisted radical prostatectomy.Methods: We performed electrical impedance tomography measurements in 39 patients before induction of anaesthesia in the sitting (M1) and supine position (M2), after the start of mechanical ventilation (M3), during capnoperitoneum and Trendelenburg positioning (M4), and finally, in the supine position after release of capnoperitoneum (M5). To quantify regional changes in lung ventilation, we calculated the centre of ventilation and 'silent spaces' in the ventral and dorsal lung regions that did not show major impedance changes.Results: Compared with the awake supine position [2.3% (2.3)], anaesthesia and mechanical ventilation induced a significant increase in silent spaces in the dorsal dependent lung [9.2% (6.3); P<0.05]. Capnoperitoneum and the Trendelenburg position led to a significant increase in such spaces [11.5% (8.9)]. Silent space in the ventral lung remained constant throughout anaesthesia.Conclusion: Electrical impedance tomography was able to identify and quantify on a breath-by-breath basis circumscribed areas, so-called silent spaces, within healthy lungs that received little or no ventilation during general anaesthesia, capnoperitoneum, and different body positions. As these silent spaces are suggestive of atelectasis on the one hand and overdistension on the other, they might become useful to guide individualized protective ventilation strategies to mitigate the side-effects of anaesthesia and surgery on the lungs. [ABSTRACT FROM AUTHOR]

Background Positive pressure ventilation in patients with a bronchopleural fistula (BPF) is associated with variable, unpredictable gas leaks that can impair gas exchange. The optimum settings for high-frequency jet ventilation in this scenario are unclear. We investigated flow dynamics with BPFs of 2 and 10 mm, at various positions and with different jet ventilator settings in a bench-top model. Methods A 2 or 10 mm length fistula was created at proximal, middle, or distal sites in standard artificial ventilator ‘test’ lungs and cadaveric porcine lungs. The effects of alterations in frequency, applied pressure, and on entrained, expired, and leak volumes were determined using gauge and differential pressure sensors. Results Entrained, delivered, and leak volumes were affected markedly by ventilator settings, particularly frequency: leaks were much greater at frequencies <100 min−1. The leak/expired volume ratio varied between 0% and 92%. Leak and entrained volumes increased progressively with more proximally situated fistulae, whereas the measured expired volume decreased. Leak volumes with a 2 mm fistula were approximately half that of a 10 mm fistula across all ventilator frequencies. All volumes increased with increased driving pressure. The optimum injection time varied depending on BPF position and the accepted compromise between leak and expired volumes. Entrained volume contributed up to 50% of the total tidal volume. Conclusions These data suggest that gas leak will be minimized and ventilator volumes maintained during jet ventilation using frequencies >200 min−1 and lower driving pressures, but confirmatory clinical studies are required. Values displayed by the jet ventilator are unreliable. [ABSTRACT FROM AUTHOR]

Background Superimposed high-frequency jet ventilation (SHFJV) has proved to be safe and effective in clinical practice. However, it is unclear which frequency range optimizes ventilation and gas exchange. The aim of this study was to systematically compare high-frequency jet ventilation (HFJV) with HFJV by assessing chest wall volume variations (ΔEEVCW) and gas exchange in relation to variable high frequency. Methods SHFJV or HFJV were used alternatively to ventilate the lungs of 10 anaesthetized pigs (21–25 kg). The low-frequency component was kept at 16 min−1 in SHFJV. In both modes, high frequencies ranging from 100 to 1000 min−1 were applied in random order and ventilation was maintained for 5 min in all modalities. Chest wall volume variations were obtained using opto-electronic plethysmography. Airway pressures and arterial blood gases were measured repeatedly. Results SHFJV increased ΔEEVCW compared with HFJV; the difference ranged from 43 to 68 ml. Tidal volume (VT) was always >240 ml during SHFJV whereas during HFJV ranged from 92 ml at the ventilation frequency of 100 min−1 to negligible values at frequencies >300 min−1. We observed similar patterns for and . SHFJV provided generally higher, frequency-independent oxygenation ( at least 32.0 kPa) and CO2 removal (∼5.5 kPa), whereas HFJV led to hypoxia and hypercarbia at higher rates (<10 kPa and >10 kPa at fHF>300 min−1). Conclusions In a porcine model, SHFJV was more effective in increasing end-expiratory volume than single-frequency HFJV, but both modes may provide adequate ventilation in the absence of airway obstruction and respiratory disease, except for HFJV at frequencies ≥300 min−1. [ABSTRACT FROM PUBLISHER]

Abstract: Aim This study investigates if a n impedance threshold valve (ITV) might improve survival after cardiac arrest by increasing vital organ blood flow. The combination of ITV and supraglottic airway devices (SADs) has not been previously studied. This simulation study in a manikin aimed at analysing differences in ventilation with different SADs without and with an ITV. Methods: In a resuscitation manikin, cardiopulmonary resuscitation (CPR) was performed with interrupted (30:2) and continuous chest compressions using facemask, tracheal tube and 10 SADs (six different laryngeal masks, LT-D, LTS-D, Combitube® and Easy Tube®). Ventilation was performed with and without an ITV. A total of 550 CPR cycles of 3-min duration were performed with chest compressions and ventilation standardised by use of a mechanical thumper device and an emergency ventilator. Results: Sufficient ventilation was possible with all devices tested. For ventilation during continuous chest compressions, there were significantly reduced tidal volumes for all airway devices with ITV use. By contrast, during interrupted chest compressions, no differences in tidal volumes with the ITV occurred in the majority of devices. The maximum reduction of tidal volume for any device was 7.8% of the volume reached without the ITV. Conclusion: Based on the findings of this manikin trial, the use of an ITV for ventilation during CPR is possible in combination with supraglottic airway devices. Merging these two strategies warrants further clinical evaluation to judge the relevance of tidal volume reduction found in this trial. [ABSTRACT FROM AUTHOR]

Summary: Aim of the study: Endotracheal intubation is the preferred method to ensure proper artificial ventilation. Early detection of esophageal intubation is important for an individual patient''s outcome. The aim of the study was to see if impedance measurements can be used to detect esophageal intubation, using the impedance measurement system of an experimental defibrillator. Materials and methods: Patients who died at the emergency department of a tertiary care hospital were eligible to be studied. After death was declared, patients were ventilated with a predefined tidal volume alternately via the conventional tracheal tube and via an additionally tube placed into the esophagus. The lowest and respectively highest median impedance amplitude for the first three ventilations was used as cut-off to calculate predictive values. Results: We enrolled 10 patients (mean age 65 years (S.D. 14), 7 male) of whom 9 underwent CPR prior to death, 30% of the patients had a BMI>30. Severe lung-edema was present in 2 cases. The lowest tracheal impedance value was 0.736Ω and the highest esophageal was 0.496Ω. A ROC curve for this individualised approach gave an area under the curve of 1 (95% CI 0.001, 0.249). Conclusion: There is a large and significant reduction in transthoracic impedance when the tube is malpositioned in the esophagus. It may therefore be feasible to detect malintubation via thoracic impedance changes as an aid to improve the survival of critical ill patients. Further investigations on a larger population are needed. [Copyright &y& Elsevier]

Abstract: The “Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care – International Consensus on Science” recommend a tidal ventilation volume of 10ml/kg body-weight without the use of supplemental oxygen during two-rescuer adult cardiopulmonary resuscitation (CPR). This relates to a ventilation volume of about 6.4l/min. Additionally, the first aid provider ventilating the victim will breathe for him/herself during the external chest compression period adding another 3.2l/min of ventilation. Finally, a deep breath is recommended before each ventilation to increase the end-expiratory oxygen concentration of the air exhaled. To investigate the effects of these recommendations, 20 healthy volunteers were asked to perform two-rescuer CPR in a lung model connected to a BLS-manikin. End-tidal carbon dioxide, oxygen saturation, and heart rate were recorded continuously. Capillary blood gas samples were collected and non-invasive blood pressure was recorded prior to the start of external chest compressions and immediately after the end of each measurment period. Furthermore, hyperventilation related symptoms reported by the volunteers were also recorded. The data reveal a significant decrease in capillary and end-tidal carbon dioxide pressure in the volunteers (P &#60;0.001). Additionally, in 75% of test persons multiple hyperventilation associated symptoms occurred. Ventilation during two-rescuer CPR performed according to the Guidelines 2000 may cause injury to the health of first aid providers. To minimize hyperventilation, both rescuers should exchange their positions at intervals of 3–5min. These data challenge the recommendation to take a deep breath prior to each ventilation. [Copyright &y& Elsevier]