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Rationale: Manual ventilation with a bag-valve device (BVD) is a Basic Life Support skill. Prolonged manual ventilation may be required in resource-poor locations and in severe disasters such as hurricanes, pandemics, and chemical events. In such circumstances, trained operators may not be available and lay persons may need to be quickly trained to do the job., Objectives: The current study investigated whether minimally trained operators were able to manually ventilate a simulated endotracheally intubated patient for six hours., Methods: Two groups of 10 volunteers, previously unfamiliar with manual ventilation, received brief, structured BVD-tube ventilation training and performed six hours of manual ventilation on an electronic lung simulator. Operator cardiorespiratory variables and perceived effort, as well as the quality of the delivered ventilation, were recorded. Group One ventilated a "normal lung" (compliance 50cmH2O/L, resistance 5cmH2O/L/min). Group Two ventilated a "moderately injured lung" (compliance 20cmH2O/L, resistance 20cmH2O/L/min)., Results: Volunteers' blood pressure, heart rate (HR), respiratory rate (RR), and peripheral capillary oxygen saturation (SpO2) were stable throughout the study. Perceived effort was minimal. The two groups provided clinically adequate and similar RRs (13.3 [SD = 3.0] and 14.1 [SD = 2.5] breaths/minute, respectively) and minute volume (MV; 7.6 [SD = 2.1] and 7.7 [SD = 1.4] L/minute, respectively)., Conclusions: The results indicate that minimally trained persons can effectively perform six hours of manual BVD-tube ventilation of normal and moderately injured lungs, without undue effort. Quality of delivered ventilation was clinically adequate.

Background: The COVID-19 virus is highly contagious, and thus there is a potential of infecting operating staff when operating on these patients. This case series describes a method of performing open tracheostomy for COVID-19 patients while minimizing potential aerosolization of the virus using typically available equipment and supplies., Methods: This is a case series of 18 patients who were COVID-19-positive and underwent open tracheostomy in the operating room under a negative pressure plastic hood created using readily available equipment and supplies. Patients had to be intubated for at least 14 days, be convalescing from their cytokine storm, and deemed to survive for at least 14 more days. Other indications for tracheostomy were altered mental status, severe deconditioning, respiratory failure and failed extubation attempts., Results: There were 14 men and 4 women with severe SARS-CoV2 infection requiring long-term intubation since March 23 or later. The mean age was 61.7 years, body mass index was 32.6, and the pretracheostomy ventilator day was 20.4 days. The indications for tracheostomy were altered mental status, severe deconditioning and continued respiratory with hypoxia. Failed extubation attempt rate was 16.7% and hemodialysis rate was 38.9%. All patients were hemodynamically stable, without any evidence of accelerating cytokine storm. To date there was one minor bleeding due to postoperative therapeutic anticoagulation., Conclusion: This report describes a method of performing open tracheostomy with minimal aerosolization using readily available equipment and supplies in most hospitals., Level of Evidence: Therapeutic/care management, Level V.

COVID-19 pandemic caused not only many deaths around the world but also made evident technical limitations of hospital and intensive care units (ICU). The growing demand of ICU ventilators in a short lapse of time constitutes one of the main community concerns. The main goal of this communication is to give simple solutions to transform a noninvasive ventilator in an invasive one for intubated patients. The proposal can be applied in two well defined strategies for the COVID-19 pandemic: To replace anesthesia workstations, leaving those machines to be used in patients. To apply this option in COVID-19 patients by way of a therapeutic "bridge", waiting for the release of a ventilator in the ICU., (© 2020 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Published by Elsevier España, S.L.U. All rights reserved.)

Intubated ventilator-dependent patients with high-level spinal cord injury can be managed without tracheostomy tubes provided that they have sufficient cognition to cooperate and that any required surgical procedures are completed and they are medically stable. Intubation for a month or more than extubation to continuous noninvasive ventilatory support (NVS) can be safer long term than resort to tracheotomy. Noninvasive ventilation (NIV) is not conventionally being used for ventilatory support. Noninvasive interfaces include mouthpieces, nasal and oronasal interfaces, and intermittent abdominal pressure ventilators. NIV/NVS should never been used without consideration of mechanical insufflation-exsufflation for airway secretion clearance., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2020 Elsevier Inc. All rights reserved.)

The "iron lung," originally known as the Drinker respirator, was developed in 1928 by Dr Philip Drinker and Dr Louis Agassiz Shaw to improve the respiration of polio patients. In 1931, John Haven Emerson, an inventor from Cambridge, MA, enhanced the design of the Drinker respirator and introduced a new and highly improved model of the iron lung that was cheaper and significantly lighter. Dr Drinker eventually filed a lawsuit against Emerson for alleged patent infringement. In his defense, Emerson argued that devices that help save human lives should be widely accessible to all patients. He also questioned the novelty of Drinker's design, claiming that Drinker's device comprised of patented technology that existed since the late 1800s, and that he therefore did not have full ownership of the machine's intellectual property. Ultimately, the case backfired on Drinker, as he not only lost the court case but also lost the entire panel of patents that were in his possession.

We hypothesized that Ventilator-Associated Event (VAE) within 28 days upon admission to medical intensive care units (ICUs) can be a predictor for poor outcomes in sepsis patients. We aimed to determine the risk factors and associated outcomes of VAE. A total of 453 consecutive mechanically ventilated (MV) sepsis patients were enrolled. Of them, 136 patients had immune profile study. Early VAE (< 7-day MV, n = 33) was associated with a higher mortality (90 days: 81.8% vs. 23.0% [non-VAE], P < 0.01), while late VAE (developed between 7 and 28 days, n = 85) was associated with longer MV day (43.8 days vs. 23.3 days [non-VAE], P < 0.05). The 90-day Kaplan-Meier survival curves showed three lines that separate the groups (non-VAE, early VAE, and late VAE). Cox regression models with time-varying coefficient covariates (adjusted for the number of days from intubation to VAE development) confirmed that VAE which occurred within 28 days upon admission to the medical ICUs can be associated with higher 90-day mortality. The risk factors for VAE development include impaired immune response (lower human leukocyte antigen D-related expression, higher interleukin-10 expression) and sepsis progression with elevated SOFA score (especially in coagulation sub-score).

Background: The driving pressure of the respiratory system is a valuable indicator of global lung stress during passive mechanical ventilation. Monitoring lung stress in assisted ventilation is indispensable, but achieving passive conditions in spontaneously breathing patients to measure driving pressure is challenging. The accuracy of the morphology of airway pressure (Paw) during end-inspiratory occlusion to assure passive conditions during pressure support ventilation has not been examined., Methods: Retrospective analysis of end-inspiratory occlusions obtained from critically ill patients during pressure support ventilation. Flow, airway, esophageal, gastric, and transdiaphragmatic pressures were analyzed. The rise of gastric pressure during occlusion with a constant/decreasing transdiaphragmatic pressure was used to identify and quantify the expiratory muscle activity. The Paw during occlusion was classified in three patterns, based on the differences at three pre-defined points after occlusion (0.3, 1, and 2 s): a "passive-like" decrease followed by plateau, a pattern with "clear plateau," and an "irregular rise" pattern, which included all cases of late or continuous increase, with or without plateau., Results: Data from 40 patients and 227 occlusions were analyzed. Expiratory muscle activity during occlusion was identified in 79% of occlusions, and at all levels of assist. After classifying occlusions according to Paw pattern, expiratory muscle activity was identified in 52%, 67%, and 100% of cases of Paw of passive-like, clear plateau, or irregular rise pattern, respectively. The driving pressure was evaluated in the 133 occlusions having a passive-like or clear plateau pattern in Paw. An increase in gastric pressure was present in 46%, 62%, and 64% of cases at 0.3, 1, and 2 s, respectively, and it was greater than 2 cmH 2 O, in 10%, 20%, and 15% of cases at 0.3, 1, and 2 s, respectively., Conclusions: The pattern of Paw during an end-inspiratory occlusion in pressure support cannot assure the absence of expiratory muscle activity and accurate measurement of driving pressure. Yet, because driving pressure can only be overestimated due to expiratory muscle contraction, in everyday practice, a low driving pressure indicates an absence of global lung over-stretch. A measurement of high driving pressure should prompt further diagnostic workup, such as a measurement of esophageal pressure.

Background: Endotracheal suctioning (ES) provokes a cumulative hemodynamic response by activation of sympathetic and parasympathetic circuits in the central nervous system. In this proof-of-concept study, we aimed to analyze hemodynamic changes during ES in ventilated subarachnoid hemorrhage (SAH) patients and investigated whether the associated hemodynamic changes relate to the time to arousal and functional outcome., Methods: For the current observational study, 191 SAH patients admitted to the neurological intensive care unit of a tertiary hospital requiring mechanical ventilation were included. One thousand eighty ES episodes during the first 72 h of admission were analyzed. Baseline median heart rate (HR) and mean arterial pressure (MAP) were compared to peak HR and MAP during ES based on 5-min averaged data (ΔHR and ΔMAP). Multivariable analysis to assess associations between ΔHR and ΔMAP and time to arousal (time to Richmond Agitation Sedation Scale ≥ 0, RASS) and poor functional outcome (modified Rankin Scale Score > 2, mRS) was performed using generalized estimating equations., Results: Patients were 59 (IQR, 50-70) years old and presented with a median admission H&H grade of 4 (IQR, 3-5). In-hospital mortality was 22% (25% at 3 months) and median time to arousal was 13 (IQR, 4-21) days. HR increased by 2.3 ± 7.1 beats per minute (bpm) from 75.1 ± 14.8 bpm at baseline. MAP increased by 3.2 ± 7.8 mmHg from baseline 80.9 ± 9.8 mmHg. In multivariable analysis, ΔHR (p < 0.001) was significantly lower in patients who regained consciousness at a later time point and a lower ΔHR was associated with poor functional 3-month outcome independent of RASS (adjOR = 0.95; 95% CI = 0.93-0.98) or midazolam dose (adjOR = 0.96; 95% CI = 0.94-0.98). ΔMAP was neither associated with the time to regain consciousness (p = 0.087) nor with functional outcome (p = 0.263)., Conclusion: Augmentation in heart rate may quantify the hemodynamic response during endotracheal suctioning in brain-injured patients. The value as a biomarker to early discriminate the time to arousal and functional outcome in acutely brain-injured patients needs prospective confirmation.

Introduction: In severe asthma, management of life-threatening air trapping that persists despite initiation of standard asthma treatment is difficult in the absence of extracorporeal membranous oxygenation. Case study: Three children with life-threatening asthma could not be adequately ventilated despite maximum conventional treatment because of severe air trapping. A novel method of active expiration by abdominal compression with a standard ventilator was adopted with immediate effect with significant improvement in ventilation. Conclusion: Synchronized abdominal compression is a novel and simple method that allows an effective treatment of severe air trapping in an intubated paralyzed asthma child.

Background: The overwhelming demand for mechanical ventilators due to COVID-19 has stimulated interest in using one ventilator for multiple patients (ie, multiplex ventilation). Despite a plethora of information on the internet, there is little supporting evidence and no human studies. The risk of multiplex ventilation is that ventilation and PEEP effects are largely uncontrollable and depend on the difference between patients' resistance and compliance. It is not clear whether volume control ventilation or pressure control ventilation is safer or more effective. We designed a simulation-based study to allow complete control over the relevant variables to determine the effects of various degrees of resistance-compliance imbalance on tidal volume (V T ), end-expiratory lung volume (EELV), and imputed pH., Methods: Two separate breathing simulators were ventilated with a ventilator using pressure control and volume control ventilation modes. Evidence-based lung models simulated a range of differences in resistance and compliance (6 pairs of simulated patients). Differences in V T , EELV, and imputed pH were recorded., Results: Depending on differences in resistance and compliance, differences in V T ranged from 1% (with equal resistance and compliance) to 79%. Differences in EELV ranged from 2% to 109%, whereas differences in pH ranged from 0% to 5%. Failure due to excessive V T (ie, > 8 mL/kg) did not occur, but failure due to excessive EELV difference (ie, > 10%) was evident in 50% of patient pairs. There was no difference in failure rate between volume control and pressure control ventilation modes., Conclusions: These experiments confirmed the potential for markedly different ventilation and oxygenation for patients with uneven respiratory system impedances during multiplex ventilation. Three critical problems must be solved to minimize risk: (1) partitioning of inspiratory flow from the ventilator individually between the 2 patients, (2) measurement of V T delivered to each patient, and (3) provision for individual PEEP. We provide suggestions for solving these problems., Competing Interests: Mr Chatburn has disclosed relationships with IngMar Medical, and Vyaire Medical. Mr Branson has disclosed relationships with Mallinckrodt, Ventec Life Systems, and Zoll Medical Corporation. Dr Hatipoğlu has disclosed no conflicts of interest., (Copyright © 2020 by Daedalus Enterprises.)

Background: The use of shared ventilation, or the simultaneous support of multiple patients connected in parallel to a single mechanical ventilator, is receiving considerable interest for addressing the severe shortage of mechanical ventilators available during the novel coronavirus pandemic (COVID-19). In this paper we highlight the potentially disastrous consequences of naïve shared ventilation, in which patients are simply connected in parallel to a ventilator without any regard to their individual ventilatory requirements. We then examine possible approaches for individualization of mechanical ventilation, using modifications to the breathing circuit that may enable tuning of individual tidal volumes and driving pressures during either volume-controlled ventilation (VCV) or pressure-controlled ventilation (PCV)., Methods: Breathing circuit modifications included a PEEP valve on each expiratory limb for both VCV and PCV, an adjustable constriction and one-way valve on the inspiratory limb for VCV, and a pressure-relief valve for peak inspiratory pressure reduction on the inspiratory limb for PCV. The ability to regulate individual tidal volumes using these breathing circuit modifications was tested both theoretically in computer simulations as well as experimentally in mechanical test lungs., Results: In both the simulations and experimental measurements, naïve shared ventilation resulted in large imbalances across individual tidal volume delivery, dependent on imbalances across patient mechanical properties. The proposed breathing circuit modifications for shared VCV and shared PCV enabled optimization of tidal volume distributions. Individual tidal volume for one patient during shared VCV was sensitive to changes in the mechanical properties of other patients. By contrast, shared PCV enabled independent control of individual patient-received ventilation., Conclusions: Of the shared ventilation strategies considered, shared PCV, with the inclusion of in-line pressure-relief valves in the individual inspiratory and expiratory limbs, offers the greatest degree of safety and lowest risk of catastrophic mechanical interactions between multiple patients connected to a single ventilator., Competing Interests: Dr Kaczka has disclosed relationships with Zoll Medical Corporation and Monitor Mask. Mr Branson has disclosed relationships with Mallinckrodt, Ventec Life Systems, and Zoll Medical Corporation. Drs Herrmann and Kaczka are co-founders and shareholders of OscillaVent, and Dr Hawley is an employee of OscillaVent. The other authors have disclosed no conflicts of interest., (Copyright © 2020 by Daedalus Enterprises.)

Given the rapidly changing nature of COVID-19, clinicians and policy makers require urgent review and summary of the literature, and synthesis of evidence-based guidelines to inform practice. The WHO advocates for rapid reviews in these circumstances. The purpose of this rapid guideline is to provide recommendations on the organizational management of intensive care units caring for patients with COVID-19 including: planning a crisis surge response; crisis surge response strategies; triage, supporting families, and staff.

There are a variety of ventilator options available to the emergency clinician, and decisions on choosing optimal settings will depend on the clinical circumstances. Understanding the latest literature in ventilator management can improve patient outcomes by ensuring optimal oxygenation and ventilation and reducing the potential for ventilator-induced lung injury. This article reviews the most appropriate ventilator settings for a variety of conditions in intubated adult patients presenting to the emergency department, and gives recommendations on monitoring the ventilated patient and making ventilator adjustments. An update on managing COVID-19-associated acute respiratory distress syndrome is also included.

Objective: In the midst of the severe acute respiratory syndrome coronavirus 2 pandemic, which causes coronavirus disease 2019, there is a recognized need to expand critical care services and beds beyond the traditional boundaries. There is considerable concern that widespread infection will result in a surge of critically ill patients that will overwhelm our present adult ICU capacity. In this setting, one proposal to add "surge capacity" has been the use of PICU beds and physicians to care for these critically ill adults., Design: Narrative review/perspective., Setting: Not applicable., Patients: Not applicable., Interventions: None., Measurements and Main Results: The virus's high infectivity and prolonged asymptomatic shedding have resulted in an exponential growth in the number of cases in the United States within the past weeks with many (up to 6%) developing acute respiratory distress syndrome mandating critical care services. Coronavirus disease 2019 critical illness appears to be primarily occurring in adults. Although pediatric intensivists are well versed in the care of acute respiratory distress syndrome from viral pneumonia, the care of differing aged adult populations presents some unique challenges. In this statement, a team of adult and pediatric-trained critical care physicians provides guidance on common "adult" issues that may be encountered in the care of these patients and how they can best be managed in a PICU., Conclusions: This concise scientific statement includes references to the most recent and relevant guidelines and clinical trials that shape management decisions. The intention is to assist PICUs and intensivists in rapidly preparing for care of adult coronavirus disease 2019 patients should the need arise.

The COVID-19 pandemic has brought concerns to managers, healthcare professionals, and the general population related to the potential mechanical ventilators' shortage for severely ill patients. In Brazil, there are several initiatives aimed at producing alternative ventilators to cover this gap. To assist the teams that work in these initiatives, we provide a discussion of some basic concepts on physiology and respiratory mechanics, commonly used mechanical ventilation terms, the differences between triggering and cycling, the basic ventilation modes and other relevant aspects, such as mechanisms of ventilator-induced lung injury, respiratory drive, airway heating and humidification, cross-contamination risks, and aerosol dissemination. After the prototype development phase, preclinical bench-tests and animal model trials are needed to determine the safety and performance of the ventilator, following the minimum technical requirements. Next, it is mandatory going through the regulatory procedures as required by the Brazilian Health Regulatory Agency (Agência Nacional de Vigilância Sanitária - ANVISA). The manufacturing company should be appropriately registered by ANVISA, which also must be notified about the conduction of clinical trials, following the research protocol approval by the Research Ethics Committee. The registration requisition of the ventilator with ANVISA should include a dossier containing the information described in this paper, which is not intended to cover all related matters but to provide guidance on the required procedures.

Rationale: Synchronized positive pressure ventilation is possible using diaphragm electrical activity (EAdi) to control the ventilator. It is unknown whether EAdi can be used to control negative pressure ventilation., Aim: To evaluate the feasibility of using EAdi to control negative pressure ventilation., Methods: Fourteen anesthetized rats were studied (380-590 g) during control, resistive breathing, acute lung injury or CO 2 rebreathing. Positive pressure continuous neurally adjusted ventilatory assist (cNAVA P+ ) was applied via intubation. Negative pressure cNAVA (cNAVA P- ) was applied with the animal placed in a sealed box. In part 1, automatic stepwise increments in cNAVA level by 0.2 cmH 2 O/µV every 30 s was applied for cNAVA P+ , cNAVA P- , and a 50/50 combination of the two (cNAVA P± ). In part 2: During 5-min ventilation with cNAVA P+ or cNAVA P- we measured circuit, box, and esophageal (Pes) pressure, EAdi, blood pressure, and arterial blood gases., Results: Part 1: During cNAVA P+ , pressure in the circuit increased with increasing cNAVA levels, reaching a plateau, and similarly for cNAVA P- , albeit reversed in sign. This was associated with downregulation of the EAdi. Pes swings became less negative with cNAVA P+ but, in contrast, Pes swings were more negative during increasing cNAVA P- levels. Increasing the cNAVA level during cNAVA P± resulted in an intermediate response. Part 2: no significant differences were observed for box/circuit pressures, EAdi, blood pressure, or arterial blood gases. Pes swings during cNAVA P- were significantly more negative than during cNAVA P+ ., Conclusion: Negative pressure ventilation synchronized and proportional to the diaphragm activity is feasible in small animals., (© 2020 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.)

Background: Biofilm formation on endotracheal tubes (ETTs) is an early and frequent event in mechanically ventilated patients. The biofilm is believed to act as a reservoir for infecting microorganisms and thereby contribute to development and relapses of ventilator-associated pneumonia (VAP). Once a biofilm has formed on an ETT surface, it is difficult to eradicate. This clinical study aimed to compare biofilm formation on three widely used ETTs with different surface properties and to explore factors potentially predictive of biofilm formation., Methods: We compared the grade of biofilm formation on ETTs made of uncoated polyvinyl chloride (PVC), silicone-coated PVC, and PVC coated with noble metals after > 24 h of mechanical ventilation in critically ill patients. The comparison was based on scanning electron microscopy of ETT surfaces, biofilm grading, surveillance and biofilm cultures, and occurrence of VAP., Results: High-grade (score ≥ 7) biofilm formation on the ETTs was associated with development of VAP (OR 4.17 [95% CI 1.14-15.3], p = 0.031). Compared to uncoated PVC ETTs, the silicone-coated and noble-metal-coated PVC ETTs were independently associated with reduced high-grade biofilm formation (OR 0.18 [95% CI 0.06-0.59], p = 0.005, and OR 0.34 [95% CI 0.13-0.93], p = 0.036, respectively). No significant difference was observed between silicon-coated ETTs and noble-metal-coated ETTs (OR 0.54 [95% CI 0.17-1.65], p = 0.278). In 60% of the oropharyngeal cultures and 58% of the endotracheal cultures collected at intubation, the same microorganism was found in the ETT biofilm at extubation. In patients who developed VAP, the causative microbe remained in the biofilm in 56% of cases, despite appropriate antibiotic therapy. High-grade biofilm formation on ETTs was not predicted by either colonization with common VAP pathogens in surveillance cultures or duration of invasive ventilation., Conclusion: High-grade biofilm formation on ETTs was associated with development of VAP. Compared to the uncoated PVC ETTs, the silicone-coated and noble-metal-coated PVC ETTs were independently associated with reduced high-grade biofilm formation. Further research on methods to prevent, monitor, and manage biofilm occurrence is needed., Trial Registration: ClinicalTrials.gov NCT02284438 . Retrospectively registered on 21 October 2014.

Background and objectives: It is often challenging even for skilled rescuers to provide adequate positive pressure ventilation consistently. This study aimed to investigate the effectiveness of a newly developed real-time ventilation feedback device (RTVFD) that estimates tidal volume (TV) and ventilation interval (VI) in real time. Materials and methods: We conducted a randomised, crossover, manikin simulation study. A total of 26 medical providers were randomly assigned to the RTVFD-assisted ventilation (RAV) first group ( n = 13) and the non-assisted ventilation (NV) first group ( n = 13). Participants provided ventilation using adult and paediatric bag valves (BVs) for 2 min each. After a washout period, the simulation was repeated by exchanging the participants' groups. Results: The primary outcome was optimal TV in the RAV and NV groups using adult and paediatric BVs. A secondary outcome was optimal VI in the RAV and NV groups using adult and paediatric BVs. The proportions of optimal TV values were higher for the RAVs when using both adult and paediatric BVs (adult BV: 47.29% vs. 18.46%, p < 0.001; paediatric BV: 89.51% vs. 72.66%, p < 0.001) than for the NVs. The proportions of optimal VI were significantly higher in RAVs when using both adult and paediatric BVs than that in NVs (adult BV: 95.64% vs. 50.20%, p < 0.001; paediatric BV: 95.83% vs. 57.14%, p < 0.001). Additionally, we found that with paediatric BVs, the simulation had a higher OR for both optimal TV (13.26; 95% CI, 9.96-17.65; p < 0.001) and VI (1.32; 1.08-1.62, p = 0.007), regardless of RTVFD use. Conclusion: Real-time feedback using RTVFD significantly improves the TV and VI in both adult and paediatric BVs in a manikin simulation study.

The coronavirus disease 2019 (COVID-19) pandemic has rapidly exposed health care system inadequacies. Hospital ventilator shortages in Italy compelled US physicians to consider creative solutions, such as using Y-pieces or T-pieces, to preclude the need to make decisions of life or death based on medical equipment availability. We add to current knowledge and testing capacity for ventilator splitters by reporting the ability to examine the functionality of ventilator splitters by using 2 high-fidelity lung simulators. Data obtained by the high-fidelity lung simulators included: tidal volume, respiratory rate, minute ventilation, peak inspiratory pressure, peak plateau pressure, and positive end-expiratory pressure.

Importance: During the coronavirus disease 2019 pandemic, there may be too few ventilators to meet medical demands. It is unknown how many US states have ventilator allocation guidelines and how these state guidelines compare with one another., Objective: To evaluate the number of publicly available US state guidelines for ventilator allocation and the variation in state recommendations for how ventilator allocation decisions should occur and to assess whether unique criteria exist for pediatric patients., Evidence Review: This systematic review evaluated publicly available guidelines about ventilator allocation for all states in the US and in the District of Columbia using department of health websites for each state and internet searches. Documents with any discussion of a process to triage mechanical ventilatory support during a public health emergency were screened for inclusion. Articles were excluded if they did not include specific ventilator allocation recommendations, were in draft status, did not include their state department of health, or were not the most up-to-date guideline. All documents were individually assessed and reassessed by 2 independent reviewers from March 30 to April 2 and May 8 to 10, 2020., Findings: As of May 10, 2020, 26 states had publicly available ventilator guidelines, and 14 states had pediatric guidelines. Use of the Sequential Organ Failure Assessment score in the initial rank of adult patients was recommended in 15 state guidelines (58%), and assessment of limited life expectancy from underlying conditions or comorbidities was included in 6 state guidelines (23%). Priority was recommended for specific groups in the initial evaluation of patients in 6 states (23%) (ie, Illinois, Maryland, Massachusetts, Michigan, Pennsylvania, and Utah). Many states recommended exclusion criteria in adult (11 of 26 states [42%]) and pediatric (10 of 14 states [71%]) ventilator allocation. Withdrawal of mechanical ventilation from a patient to give to another if a shortage occurs was discussed in 22 of 26 adult guidelines (85%) and 9 of 14 pediatric guidelines (64%)., Conclusions and Relevance: These findings suggest that although allocation guidelines for mechanical ventilatory support are essential in a public health emergency, only 26 US states provided public guidance on how this allocation should occur. Guidelines among states, including adjacent states, varied significantly and could cause inequity in the allocation of mechanical ventilatory support during a public health emergency, such as the coronavirus disease 2019 pandemic.

Background: To determine the level of inspiratory pressure minimizing the risk of gastric insufflation while providing adequate pulmonary ventilation., Methods: In this prospective, randomized, double-blind study, patients were allocated to one of the two groups (P10, P15) defined by the inspiratory pressure applied during controlled-pressure ventilation: 10 and 15 cm H 2 O. Anesthesia was induced using propofol and sufentanil; no neuromuscular-blocking agent was administered. Once loss of eyelash reflex occurred, facemask ventilation was started for a 2-min period. The cross-sectional antral area was measured using ultrasonography before and after facemask ventilation. Respiratory parameters were recorded., Results: Forty patients were analyzed. Mean tidal volume was about 7 ml/kg in group P10, and was >11 ml/kg in group P15 in the same period. As indicated by ultrasonography test, the antral area in P15 group was markedly incresed compared with P10 group., Conclusion: Inspiratory pressure of 10 cm H 2 O allowed for reduced occurrence of gastric insufflation with proper lung ventilation during induction of anesthesia with sufentanil and propofol in nonparalyzed and nonobese patients., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2019. Published by Elsevier Inc.)

Competing Interests: Competing interests: None declared.

Competing Interests: Competing interests: We have read and understood BMJ policy on declaration of interests and declare that JK is a site principal investigator for clinical trials with Eli Lilly and Novartis.

Objective: Flow-controlled expiration (FLEX) and flow-controlled ventilation (FCV) imply a linearized expiration, and were suggested as new approaches for lung-protective ventilation, especially in the case of an inhomogeneous lung. We hypothesized that a linearized expiration homogenizes the pressure distribution between compartments during expiration, compared to volume-controlled (VCV) and pressure-controlled (PCV) ventilation., Approach: We investigated the expiratory pressure decays in a physical model of an inhomogeneous respiratory system. The model contained four compartments of which two had a high (25 ml cmH 2 O -1 ) and two a low compliance (10 ml cmH 2 O -1 ). These were combined with either a high (6.5 cmH 2 O s l -1 ) or low resistance (2.8 cmH 2 O s l -1 ), respectively. The model was ventilated in all modes at various tidal volumes and peak pressures, and we determined in each compartment the expiratory time at which the pressure declined to 50% (t 50 ) of the end-inspiratory pressure, and the maximal differences of t 50 (Δt 50 ) and pressure (Δp max ) between all compartments., Main Results: During FLEX and FCV, t 50 was 6- to 7-fold higher compared to VCV and PCV (all P < 0.001). During VCV and PCV, Δt 50 was higher (128 ± 18 ms) compared to FLEX and FCV (49 ± 19 ms; all P < 0.001). Δp max reached up to 3.8 ± 0.2 cmH 2 O during VCV and PCV, but only 0.6 ± 0.1 cmH 2 O during FLEX and FCV (P < 0.001)., Significance: FLEX and FCV provide a more homogeneous expiratory pressure distribution between compartments with different mechanical properties compared with VCV and PCV. This may reduce shear stress within inhomogeneous lung tissue.

Introduction: Chronic Critical Illness (chronic CI) is a condition associated to patients surviving an episode of acute respiratory failure (ARF). The prevalence and the factors associated with the development of chronic CI in the population admitted to a Respiratory Intensive Care Unit (RICU) have not yet been clarified., Methods: An observational prospective cohort study was undertaken at the RICU of the University Hospital of Modena (Italy). Patients mechanically ventilated with ARF in RICU were enrolled. Demographics, severity scores (APACHEII, SOFA, SAPSII), and clinical condition (septic shock, pneumonia, ARDS) were recorded on admission. Respiratory mechanics and inflammatory-metabolic blood parameters were measured both on admission and over the first week of stay. All variables were tested as predictors of chronic CI through univariate and multivariate analysis., Results: Chronic CI occurred in 33 out of 100 patients observed. Higher APACHEII, the presence of septic shock, diaphragmatic dysfunction (DD) at sonography, multidrug-resistant (MDR) bacterial infection, the occurrence of a second infection during stay, and a C-reactive protein (CRP) serum level inceasing 7 days over admission were associated with chronic CI. Septic shock was the strongest predictor of chronic CI (AUC = 0.92 p < 0.0001)., Conclusions: Chronic CI is frequent in patients admitted to RICU and mechanically ventilated due to ARF. Infection-related factors seem to play a major role as predictors of this syndrome., (Copyright © 2019. Published by Elsevier España, S.L.U.)

The current coronavirus disease 2019 (Covid-19) pandemia is a highly dynamic situation characterized by therapeutic and logistic uncertainties. Depending on the effectiveness of social distancing, a shortage of intensive care respirators must be expected. Concomitantly, many physicians and nursing staff are unaware of the capabilities of alternative types of ventilators, hence being unsure if they can be used in intensive care patients. Intensive care respirators were specifically developed for the use in patients with pathological lung mechanics. Nevertheless, modern anesthesia machines offer similar technical capabilities including a number of different modes. However, conceptual differences must be accounted for, requiring close monitoring and the presence of trained personnel. Modern transport ventilators are mainly for bridging purposes as they can only be used with 100% oxygen in contaminated surroundings. Unconventional methods, such as "ventilator-splitting", which have recently received increasing attention on social media, cannot be recommended. This review intends to provide an overview of the conceptual and technical differences of different types of mechanical ventilators.

Endotracheal intubation is a vital component of many rat in vivo experiments to secure the airway and allow controlled ventilation. Even in the hands of experienced researchers, however, the procedure remains technically challenging. The safest and most reliable way for human intubation is by video laryngoscopy. Previous attempts to apply this technique in rodents have been complicated and expensive. We, hereby, describe a novel, noninvasive method to safely intubate rats orally by video laryngoscopy, thus avoiding the need for a surgical tracheostomy. By repurposing a commercially available ear wax removal device, visualization of the rat larynx can be significantly enhanced. Because of its small diameter, integrated illumination, and a powerful camera with adequate focal length, the device has all of the necessary properties for exploring the upper airway of a rat. After identifying the vocal cords by video laryngoscopy, the insertion of an endotracheal tube (a 14G intravenous catheter) into the trachea under constant visual control is facilitated by using PE50 polyethylene tubing as a stylet (Seldinger technique). The procedure has been performed more than 60 times in our laboratory; all intubations were successful on the first attempt, and no adverse events were observed. We conclude that the described procedure is a simple and effective way to intubate a rat noninvasively, using inexpensive and commercially available equipment.

Objective: To investigate the effects of a heat and moisture exchanger (HME) on the temperature and humidity of inhaled gas in isoflurane-anesthetized dogs., Study Design: Prospective, interventional study., Animals: A total of four experimental dogs and four client-owned dogs weighing 13.9 ± 7.4 kg (mean ± standard deviation)., Methods: The four experimental dogs were anesthetized on two occasions with and without an intact HME at least 1 week apart. The four client-owned dogs were anesthetized once only for a surgical procedure and assigned to the HME group or no-HME group in alternate order, resulting in six dogs for each group. All dogs were premedicated, anesthetized with propofol and intubated. The HME was connected to the endotracheal tube. Anesthesia was maintained with isoflurane. A digital thermo-hygrometer was placed between the endotracheal tube and HME. The temperature and relative humidity of the inhaled gas were measured every 5 minutes for 60 minutes and the absolute humidity was calculated at each time point., Results: The temperature and absolute humidity of the inhaled gas was significantly higher at 5-60 minutes after intubation in the HME group than in the no-HME group. Absolute humidity was maintained above 29 mg H 2 O L -1 in the HME group. No significant time-dependent effects on temperature, relative humidity or absolute humidity of the inhaled gas were observed., Conclusions and Clinical Relevance: The temperature and absolute humidity of the inhaled gas were higher when an HME was used during isoflurane anesthesia in dogs. The use of an HME may reduce the risk of dehydration and dysfunction of the airway mucosal epithelium., (Copyright © 2020 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Purpose: The present study was designed to assess the immediate effects of the semi-occluded ventilation mask (SOVM) in subjects with functional dysphonia and subjects with normal voice., Methods: Sixty-four participants were included in this study (48 women and 16 men). Thirty-one of them were diagnosed with functional dysphonia and 33 with normal voice. All subjects were randomly assigned to one of two conditions: an experimental condition using the SOVM (n = 33) and a control condition with participants not using the SOVM (n = 31). Thus, within both conditions, participants could be either dysphonic or normal-voiced. This produced a total of four different groups: (1) subjects with normal voice with SOVM (n = 17), (2) subjects with normal voice without SOVM (n = 16), (3) dysphonic subjects with SOVM (n = 16), and (4) dysphonic subjects without SOVM (n = 15). All participants underwent aerodynamic, electroglottographic (EGG), and acoustic assessments, and were also asked to assess their own voice, before and after voice exercises., Results: Significant differences were found for aerodynamic, EGG, and acoustic variables when comparing SOVM conditions (dysphonic and normal) against control. Cepstral peak prominence and EGG contact quotient showed an increase among dysphonic participants with SOVM. L1-L0 showed an increase for all participants in SOVM condition (dysphonic and normal). Self-perceived resonant voice quality showed an increase for both groups in SOVM condition. Glottal airflow showed a decrease for the dysphonic participants in SOVM condition. Phonation threshold pressure and subglottic pressure showed a decrease for both groups in SOVM condition., Conclusion: The present study suggests that immediate positive effect could be produced by connected speech phonatory tasks using the SOVM in both dysphonic subjects and subjects with normal voice, the change being greater among the former. SOVM seems to promote an easy voice production and a more efficient phonation., (Copyright © 2018 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

The coronavirus disease 2019 (COVID-19) pandemic created an unprecedented need for mechanical ventilation in critically ill patients. To meet this increased demand, some facilities were forced to use anesthesia gas machines (AGMs) as intensive care unit (ICU) ventilators. While an off-label use, AGM manufacturers, the Anesthesia Patient Safety Foundation, and the American Society of Anesthesiologists have guidelines for AGM use in the ICU, however, there is scant literature describing their use. This article describes our experiences at New York University Langone Medical Center using AGMs in the ICU for ventilating critically ill COVID-19 patients.

Introduction: A bag valve mask (BVM) is a life saving device used by all levels of health care professionals during resuscitative care. We focus most of our time optimizing the patient's position, firmly securing the mask, and frequency of ventilations. However, despite our best efforts to control these factors, we may still be precipitating harm to the patient. Multiple studies have shown the tidal volumes typically delivered by the adult BVM are often higher than recommended for lung-protective ventilation protocols. In this study we measure and compare the ventilation parameters delivered by the adult and pediatric BVM ventilators., Methods: A RespiTrainer Advance® adult mannequin was used to simulate a patient. Healthcare providers were directed to manually ventilate an intubated mannequin for two minutes using adult and pediatric sized BVMs. Tidal volume, minute ventilation, peak pressure, and respiration rate was recorded., Results: The adult BVM provided a mean tidal volume of 807.7mL versus the pediatric BVM providing 630.7mL, both of which exceeded the upper threshold of 560mL of tidal volume necessary for lung protective ventilation of an adult male with an ideal body weight of 70kg. The adult BVM exceeded this threshold by 44.2% versus the pediatric BVM's 12.6% with 93% of participants exceeding the maximum threshold with the adult BVM and 82.3% exceeding it with the pediatric BVM., Conclusion: The pediatric BVM in our study provided far more consistent and appropriate ventilation parameters for adult patients compared to an adult BVM, but still exceeded the upper limits of lung protective ventilation parameters. The results of this study highlight the potential dangers in using an adult BVM due to increased risk of pulmonary barotrauma. These higher tidal volumes can contribute to lung injury. This study confirms that smaller BVMs may provide safer ventilatory parameters. Future studies should focus on patient-centered outcomes with BVM.

Competing Interests: Competing interests: Sandy Buchman is the president and a member of the Board of Directors of the Canadian Medical Association. He has received speaker fees from the University of Toronto and Cancer Care Ontario, and nonfinancial support from the Israel National Institute for Health Policy Research. James Downar has received consultant fees from Joule and honoraria from Boehringer Ingelheim (Canada). Amit Arya has received honoraria from Pallium Canada for peer review activities for LEAP course materials. No other competing interests were declared.

Background: Limited information is available regarding intraoperative ventilator settings and the incidence of postoperative pulmonary complications (PPCs) in patients undergoing neurosurgical procedures. The aim of this post-hoc analysis of the 'Multicentre Local ASsessment of VEntilatory management during General Anaesthesia for Surgery' (LAS VEGAS) study was to examine the ventilator settings of patients undergoing neurosurgical procedures, and to explore the association between perioperative variables and the development of PPCs in neurosurgical patients., Methods: Post-hoc analysis of LAS VEGAS study, restricted to patients undergoing neurosurgery. Patients were stratified into groups based on the type of surgery (brain and spine), the occurrence of PPCs and the assess respiratory risk in surgical patients in Catalonia (ARISCAT) score risk for PPCs., Results: Seven hundred eighty-four patients were included in the analysis; 408 patients (52%) underwent spine surgery and 376 patients (48%) brain surgery. Median tidal volume (V T ) was 8 ml [Interquartile Range, IQR = 7.3-9] per predicted body weight; median positive end-expiratory pressure (PEEP) was 5 [3 to 5] cmH 2 0. Planned recruitment manoeuvres were used in the 6.9% of patients. No differences in ventilator settings were found among the sub-groups. PPCs occurred in 81 patients (10.3%). Duration of anaesthesia (odds ratio, 1.295 [95% confidence interval 1.067 to 1.572]; p = 0.009) and higher age for the brain group (odds ratio, 0.000 [0.000 to 0.189]; p = 0.031), but not intraoperative ventilator settings were independently associated with development of PPCs., Conclusions: Neurosurgical patients are ventilated with low V T and low PEEP, while recruitment manoeuvres are seldom applied. Intraoperative ventilator settings are not associated with PPCs.

Background: Acute lung injury (ALI) is a frequent complication after severe trauma. Lung-protective ventilation strategies and damage control resuscitation have been proposed for the prevention of ALI; however, there are no clinical or laboratory parameters to predict who is at risk of developing ALI after trauma. In the present study, we explored pulmonary inflammatory markers as a potential predictor of ALI using a porcine model of hemorrhagic shock., Materials and Methods: Female swine were randomized to mechanical ventilation with low tidal volume (V T ) (6 mL/kg) or high V T (12 mL/kg). After equilibration, animals underwent pressure-controlled hemorrhage (mean arterial pressure [MAP] 35 ± 5 mmHg) for 1 h, followed by resuscitation with fresh whole blood or Hextend. They were maintained at MAP of 50 ± 5 mmHg for 3 h in the postresuscitation phase. Bronchoalveolar lavage fluids were collected hourly and analyzed for inflammatory markers. Lung samples were taken, and porcine neutrophil antibody staining was used to evaluate the presence of neutrophils. ELISA evaluated serum porcine surfactant protein D levels. Sham animals were used as negative controls., Results: Pigs that underwent hemorrhagic shock had higher heart rates, lower cardiac output, lower MAPs, and worse acidosis compared with sham at the early time points (P < 0.05 each). There were no significant differences in central venous pressure or pulmonary capillary wedge pressure between groups. Pulmonary neutrophil infiltration, as defined by neutrophil antibody staining on lung samples, was greater in the shock groups regardless of resuscitation fluid (P < 0.05 each). Bronchoalveolar lavage fluid neutrophil levels were not different between groups. There were no differences in levels of porcine surfactant protein D between groups at any time points, and the levels did not change over time in each respective group., Conclusions: Our study demonstrates the reproducibility of a porcine model of hemorrhagic shock that is consistent with physiologic changes in humans in hemorrhagic shock. Pulmonary neutrophil infiltration may serve as an early marker for ALI; however, the practicality of this finding has yet to be determined., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Long-term home mechanical ventilation is increasingly used by patients with chronic respiratory failure. Storage of medical data in the cloud is expanding, and ventilation can be monitored remotely. The aim of this bench study was to determine whether tidal volume (V T ) can be affected by the location of supplemental oxygen placement., Methods: We tested 4 home ventilators in a bench test using a dual-chamber test lung to test the addition of supplemental oxygen placement via a connector in the circuit (ie, front intake port) versus via the manufacturer's rear intake port, with different oxygen supply flows of 2, 4, 6, and 8 L/min. We compared the effectively delivered V T as measured with a pneumotachograph (ie, measured V T ) versus the V T reported by each home ventilator (ie, monitored V T )., Results: For all of the home ventilators, the monitored V T and measured V T were comparable when the rear oxygen intake was used, regardless of oxygen flow. However, when the front oxygen intake was used, the monitored V T as measured by the ventilators was significantly lower than the measured V T , with the greatest difference reaching 29% for the highest oxygen flow tested (8 L/min)., Conclusions: The monitored V T may be inaccurate if oxygen is added with a connector in the circuit, which may have consequences on both the individual level and collective level (ie, big data analysis). Physicians who analyze data from home ventilators should be aware of the site of oxygen supplementation and promote use of only the rear oxygen intake., Competing Interests: The authors have disclosed no conflicts of interest., (Copyright © 2020 by Daedalus Enterprises.)

Background: To assess the arterial oxygen partial pressure (PaO2) at defined time points during preoxygenation and to compare high-flow heated humidified nasal oxygenation with standard preoxygenation using oxygen insufflation via a facemask for at least 5 minutes, before intubation during induction of general anesthesia., Methods: This randomized, single-blinded, prospective study will be conducted in patients undergoing head and neck surgery. After standard monitoring, the artery catheter at the radial artery or dorsalis pedis artery will be placed and arterial blood gas analysis (ABGA) for baseline values will be performed simultaneously. Each group will be subjected to 1 of 2 preoxygenation methods (high-flow nasal cannula or simple facemask) for 5 minutes, and ABGA will be performed twice. After confirming intubation, we will start mechanical ventilation and check the vital signs and perform the final ABGA., Discussion: This trial aims to examine the trajectory of PaO2 levels during the whole preoxygenation procedure and after intubation. We hypothesize that preoxygenation with the high-flow nasal cannula will be superior to that with the face mask., Study Registration: This trial was registered with the Clinical Trial Registry (NCT03896906; ClinicalTrials.gov).

Background: The effect of alternative spontaneous breathing trial (SBT) techniques on extubation success and other clinically important outcomes is uncertain. A systematic review and meta-analysis was performed to clarify the preferable SBT (T-piece or pressure support ventilation [PSV])., Methods: We searched the PubMed, Cochrane, and Embase databases for randomized controlled trials (RCTs) from inception to the 31st of July 2019. We included RCTs involving adult patients (> 18 years) who underwent at least two different SBT methods. All authors reported our primary outcome of successful extubation rate and clearly compared PS versus T-piece with clinically relevant secondary outcomes (rate of reintubation, ICU and hospital length of stay, and ICU and hospital mortality). Results were expressed as odds ratio (OR) and mean difference (MD) with accompanying 95% confidence interval (CI)., Results: Ten RCTs including 3165 patients were included. The results of this meta-analysis showed that there was no significant difference in the successful extubation rate between the T-piece group and PS group (odds ratio [OR] = 0.91; 95% CI, 0.78-1.07; P = 0.27; I 2  = 79%). In addition, compared with the PS group, the T-piece group showed no significant difference in the rate of reintubation (odds ratio [OR] = 0.99; 95% CI, 0.78-1.26; P = 0.95; I 2  = 5%), ICU mortality (odds ratio [OR] = 1.22; 95% CI, 0.83-1.80; P = 0.30; I 2  = 0%), hospital mortality (odds ratio [OR] = 1.36; 95% CI, 0.99-1.87; P = 0.06; I 2  = 19%), ICU length of stay (mean difference = - 0.10; 95% CI, - 0.59 to 0.39; P = 0.69; I 2  = 13%), and hospital length of stay (mean difference = - 0.82;95% CI, - 2.2 to 0.55; P = 0.24; I 2  = 0%)., Conclusions: T-piece and PSV as SBTs are considered to have comparable predictive power of successful extubation in critically ill patients. The analysis of secondary outcomes also shows no significant difference in the rate of reintubation, ICU and hospital length of stay, and ICU and hospital mortality between the two groups. Further randomized controlled studies of SBTs are still required.