Should Transport Ventilators Be Used in Times of Crisis? The Use of Emergency Authorized Nonconventional Ventilators Is Associated With Mortality Among Patients With COVID-19 Acute Respiratory Distress Syndrome.

OBJECTIVES: Nonconventional ventilators (NCVs), defined here as transport ventilators and certain noninvasive positive pressure devices, were used extensively as crisis-time ventilators for intubated patients with COVID-19. We assessed whether there was an association between the use of NCV and higher mortality, independent of other factors. DESIGN: This is a multicenter retrospective observational study. SETTING: The sample was recruited from a single healthcare system in New York. The recruitment period spanned from March 1, 2020, to April 30, 2020. PATIENTS: The sample includes patients who were intubated for COVID-19 acute respiratory distress syndrome (ARDS). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The primary outcome was 28-day in-hospital mortality. Multivariable logistic regression was used to derive the odds of mortality among patients managed exclusively with NCV throughout their ventilation period compared with the remainder of the sample while adjusting for other factors. A secondary analysis was also done, in which the mortality of a subset of the sample exclusively ventilated with NCV was compared with that of a propensity score-matched subset of the control group. Exclusive use of NCV was associated with a higher 28-day in-hospital mortality while adjusting for confounders in the regression analysis (odds ratio, 1.41; 95% CI [1.07-1.86]). In the propensity score matching analysis, the mortality of patients exclusively ventilated with NCV was 68.9%, and that of the control was 60.7% ( p = 0.02). CONCLUSIONS: Use of NCV was associated with increased mortality among patients with COVID-19 ARDS. More lives may be saved during future ventilator shortages if more full-feature ICU ventilators, rather than NCVs, are reserved in national and local stockpiles.

Fluid Balance and Ventilator-Associated Events Among Patients Admitted to ICUs in China: A Nested Case-Control Study.

OBJECTIVES: Fluid therapy is an important component of intensive care management, however, optimal fluid management is unknown. The relationship between fluid balance and ventilator-associated events has not been well established. This study investigated the dose-response relationship between fluid balance and ventilator-associated events. DESIGN: Nested case-control study. SETTING: The study was based on a well-established, research-oriented registry of healthcare-associated infections at ICUs of West China Hospital system (Chengdu, China). PATIENTS: A total of 1,528 ventilator-associated event cases with 3,038 matched controls, who consistently underwent mechanical ventilation for at least 4 days from April 1, 2015, to December 31, 2018, were included. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We calculated cumulative fluid balance within 4 days prior to ventilator-associated event occurrence. A weighted Cox proportional hazards model with restricted cubic splines was used to evaluate the dose-response relationship. A nonlinear relationship between fluid balance and all three tiers of ventilator-associated events, patients with fluid balance between -1 and 0 L had the lowest risk (p < 0.05 for nonlinear test). The risk of ventilator-associated event was significantly higher in patients with positive fluid balance (4 d cumulative fluid balance: 1 L: 1.19; 3 L: 1.92; 5 L: 2.58; 7 L: 3.24), but not in those with negative fluid balance (-5 L: 1.34; -3 L: 1.14; -1 L: 0.98). CONCLUSIONS: There was nonlinear relationship between fluid balance and all three tiers of ventilator-associated event, with an fluid balance between -1 and 0 L corresponding to the lowest risk. Positive but not negative fluid balance increased the risk of ventilator-associated events, with higher positive fluid balance more likely to lead to ventilator-associated events.

Performance and impact of disposable and reusable respirators for healthcare workers during pandemic respiratory disease: a rapid evidence review.

OBJECTIVES: To synthesise evidence concerning the range of filtering respirators suitable for patient care and guide the selection and use of different respirator types. DESIGN: Comparative analysis of international standards for respirators and rapid review of their performance and impact in healthcare. DATA SOURCES: Websites of international standards organisations, Medline and Embase, hand-searching of references and citations. STUDY SELECTION: Studies of healthcare workers (including students) using disposable or reusable respirators with a range of designs. We examined respirator performance, clinician adherence and performance, comfort and impact, and perceptions of use. RESULTS: We included standards from eight authorities across Europe, North and South America, Asia and Australasia and 39 research studies. There were four main findings. First, international standards for respirators apply across workplace settings and are broadly comparable across jurisdictions. Second, effective and safe respirator use depends on proper fitting and fit testing. Third, all respirator types carry a burden to the user of discomfort and interference with communication which may limit their safe use over long periods; studies suggest that they have little impact on specific clinical skills in the short term but there is limited evidence on the impact of prolonged wearing. Finally, some clinical activities, particularly chest compressions, reduce the performance of filtering facepiece respirators. CONCLUSION: A wide range of respirator types and models is available for use in patient care during respiratory pandemics. Careful consideration of performance and impact of respirators is needed to maximise protection of healthcare workers and minimise disruption to care.

Impact of Social Distancing Measures on Coronavirus Disease Healthcare Demand, Central Texas, USA.

Social distancing orders have been enacted worldwide to slow the coronavirus disease (COVID-19) pandemic, reduce strain on healthcare systems, and prevent deaths. To estimate the impact of the timing and intensity of such measures, we built a mathematical model of COVID-19 transmission that incorporates age-stratified risks and contact patterns and projects numbers of hospitalizations, patients in intensive care units, ventilator needs, and deaths within US cities. Focusing on the Austin metropolitan area of Texas, we found that immediate and extensive social distancing measures were required to ensure that COVID-19 cases did not exceed local hospital capacity by early May 2020. School closures alone hardly changed the epidemic curve. A 2-week delay in implementation was projected to accelerate the timing of peak healthcare needs by 4 weeks and cause a bed shortage in intensive care units. This analysis informed the Stay Home-Work Safe order enacted by Austin on March 24, 2020.

Effect of Endotracheal Tube Size, Respiratory System Mechanics, and Ventilator Settings on Driving Pressure.

OBJECTIVES: We sought to investigate factors that affect the difference between the peak inspiratory pressure measured at the Y-piece under dynamic flow conditions and plateau pressure measured under zero-flow conditions (resistive pressure) during pressure controlled ventilation across a range of endotracheal tube sizes, respiratory mechanics, and ventilator settings. DESIGN: In vitro study. SETTING: Research laboratory. PATIENTS: None. INTERVENTIONS: An in vitro bench model of the intubated respiratory system during pressure controlled ventilation was used to obtain the difference between peak inspiratory pressure measured at the Y-piece under dynamic flow conditions and plateau pressure measured under zero-flow conditions across a range of endotracheal tubes sizes (3.0-8.0 mm). Measurements were taken at combinations of pressure above positive end-expiratory pressure (10, 15, and 20 cm H2O), airway resistance (no, low, high), respiratory system compliance (ranging from normal to extremely severe), and inspiratory time at constant positive end-expiratory pressure (5 cm H2O). Multiple regression analysis was used to construct models predicting resistive pressure stratified by endotracheal tube size. MEASUREMENTS AND MAIN RESULTS: On univariate regression analysis, respiratory system compliance (ß -1.5; 95% CI, -1.7 to -1.4; p < 0.001), respiratory system resistance (ß 1.7; 95% CI, 1.5-2.0; p < 0.001), pressure above positive end-expiratory pressure (ß 1.7; 95% CI, 1.4-2.0; p < 0.001), and inspiratory time (ß -0.7; 95% CI, -1.0 to -0.4; p < 0.001) were associated with resistive pressure. Multiple linear regression analysis showed the independent association between increasing respiratory system compliance, increasing airway resistance, increasing pressure above positive end-expiratory pressure, and decreasing inspiratory time and resistive pressure across all endotracheal tube sizes. Inspiratory time was the strongest variable associated with a proportional increase in resistive pressure. The contribution of airway resistance became more prominent with increasing endotracheal tube size. CONCLUSIONS: Peak inspiratory pressures measured during pressure controlled ventilation overestimated plateau pressure irrespective of endotracheal tube size, especially with decreased inspiratory time or increased airway resistance.

Risk Factors for Mortality and Respiratory Support in Elderly Patients Hospitalized with COVID-19 in Korea.

BACKGROUND: The mortality risk of coronavirus disease 2019 (COVID-19) is higher in patients with older age, and many elderly patients are reported to require advanced respiratory support. METHODS: We reviewed medical records of 98 patients aged ≥ 65 years who were hospitalized with COVID-19 during a regional outbreak in Daegu/Gyeongsangbuk-do province of Korea. The outcome measures were in-hospital mortality and the treatment with mechanical ventilation (MV) or high-flow nasal cannula (HFNC). RESULTS: The median age of the patients was 72 years; 55.1% were female. Most (74.5%) had at least one underlying condition. Overall case fatality rate (CFR) was 20.4%, and median time to death after admission was 8 days. The CFR was 6.1% among patients aged 65-69 years, 22.7% among those aged 70-79 years, and 38.1% among those aged ≥ 80 years. The CFR among patients who required MV was 43.8%, and the proportion of patients received MV/HFNC was 28.6%. Nosocomial acquisition, diabetes, chronic lung diseases, and chronic neurologic diseases were significant risk factors for both death and MV/HFNC. Hypotension, hypoxia, and altered mental status on admission were also associated with poor outcome. CRP > 8.0 mg/dL was strongly associated with MV/HFNC (odds ratio, 26.31; 95% confidence interval, 7.78-88.92; P < 0.001), and showed better diagnostic characteristics compared to commonly used clinical scores. CONCLUSION: Patients aged ≥ 80 years had a high risk of requiring MV/HFNC, and mortality among those severe patients was very high. Severe initial presentation and laboratory abnormalities, especially high CRP, were identified as risk factors for mortality and severe hospital course.

Accuracy of Reported Tidal Volume During Neonatal Ventilation With Airway Leak: A Lung Model Study.

OBJECTIVES: To determine the accuracy of tidal volume reported by neonatal ventilators, with and without leak compensation, in invasive and noninvasive ventilation modes in the presence of airway leak; and, to determine what factors have a significant effect on the accuracy of tidal volume reported by ventilators with leak compensation in the presence of airway leak. We hypothesized that ventilators with a leak compensation function that includes estimation of tidal volume could accurately report tidal volume in the presence of airway leak, but that the accuracy of reported tidal volume may be affected by variables such as the identity of the ventilator, lung mechanics, leak size, positive end-expiratory pressure level, and body size. DESIGN: In vitro assessment of ventilator volume delivery was conducted for seven acute care ventilators using a passive lung simulator. SETTING: Laboratory-based measurements. INTERVENTIONS: The error of reported tidal volume was calculated under three ventilation modes (noninvasive-pressure-control, invasive-pressure-control, and invasive-dual-control ventilation), three models of lung mechanics (normal and restrictive and obstructive lung disease), a range of airway leak values, two positive end-expiratory pressure values, and two body weights for each ventilator. Ventilators with and without leak compensation were studied. MEASUREMENTS AND MAIN RESULTS: In the absence of airway leak, all ventilators reported tidal volume accurately. In the presence of airway leak, the error of reported tidal volume increased for all ventilators without a leak compensation algorithm while ventilators with leak compensation that included estimation of tidal volume accurately reported tidal volume. In the presence of airway leak, clinically significant effects on the error of reported tidal volume by ventilators with leak compensation were associated with the choice of ventilator in all modes and with lung mechanics in invasive ventilation modes. CONCLUSIONS: Reported tidal volume is affected by the presence of airway leak, but in many ventilators a leak compensation algorithm that includes estimation of tidal volume can correct for the discrepancy between actual and reported tidal volume. However, even in ventilators with leak compensation, choice of ventilator and lung mechanics in invasive ventilation modes have a significant effect on error of reported tidal volume.

First responder communication in CBRN environments: FIRCOM-CBRN study.

INTRODUCTION: Recent terror attacks and assassinations involving highly toxic chemical weapons have stressed the importance of sufficient respiratory protection of medical first responders and receivers. As full-face respirators cause perceptual-motor impairment, they not only impair vision but also significantly reduce speech intelligibility. The recent introduction of electronic voice projection units (VPUs), attached to a respirator, may improve communication while wearing personal respiratory protection. OBJECTIVE: To determine the influence of currently used respirators and VPUs on medical communication and speech intelligibility. METHODS: 37 trauma anaesthetists carried out an evaluation exercise of six different respirators and VPUs including one control. Participants had to listen to audio clips of a variety of sentences dealing with scenarios of emergency triage and medical history taking. RESULTS: In the questionnaire, operators stated that speech intelligibility of the Avon C50 respirator scored the highest (mean 3.9, ±SD 1.0) and that the Respirex Powered Respiratory Protective Suit (PRPS) NHS-suit scored lowest (1.6, 0.9). Regarding loudness the C50 plus the Avon VPU scored highest (4.1, 0.7), followed by the Draeger FPS-7000-com-plus (3.4, 1.0) and the Respirex PRPS NHS-suit scored lowest (2.3, 0.8). CONCLUSIONS: We found that the Avon C50 is the preferred model among the tested respirators. In our model, electronic voice projection modules improved loudness but not speech intelligibility. The Respirex PRPS NHS-suit was rated significantly less favourably in respect of medical communication and speech intelligibility.

Neural Breathing Pattern and Patient-Ventilator Interaction During Neurally Adjusted Ventilatory Assist and Conventional Ventilation in Newborns.

OBJECTIVE: To compare neurally adjusted ventilatory assist and conventional ventilation on patient-ventilator interaction and neural breathing patterns, with a focus on central apnea in preterm infants. DESIGN: Prospective, observational cross-over study of intubated and ventilated newborns. Data were collected while infants were successively ventilated with three different ventilator conditions (30 min each period): 1) synchronized intermittent mandatory ventilation (SIMV) combined with pressure support at the clinically prescribed, SIMV with baseline settings (SIMVBL), 2) neurally adjusted ventilatory assist, 3) same as SIMVBL, but with an adjustment of the inspiratory time of the mandatory breaths (SIMV with adjusted settings [SIMVADJ]) using feedback from the electrical activity of the diaphragm). SETTING: Regional perinatal center neonatal ICU. PATIENTS: Neonates admitted in the neonatal ICU requiring invasive mechanical ventilation. MEASUREMENTS AND MAIN RESULTS: Twenty-three infants were studied, with median (range) gestational age at birth 27 weeks (24-41 wk), birth weight 780 g (490-3,610 g), and 7 days old (1-87 d old). Patient ventilator asynchrony, as quantified by the NeuroSync index, was lower during neurally adjusted ventilatory assist (18.3% ± 6.3%) compared with SIMVBL (46.5% ±11.7%; p < 0.05) and SIMVADJ (45.8% ± 9.4%; p < 0.05). There were no significant differences in neural breathing parameters, or vital signs, except for the end-expiratory electrical activity of the diaphragm, which was lower during neurally adjusted ventilatory assist. Central apnea, defined as a flat electrical activity of the diaphragm more than 5 seconds, was significantly reduced during neurally adjusted ventilatory assist compared with both SIMV periods. These results were comparable for term and preterm infants. CONCLUSIONS: Patient-ventilator interaction appears to be improved with neurally adjusted ventilatory assist. Analysis of the neural breathing pattern revealed a reduction in central apnea during neurally adjusted ventilatory assist use.

Comparing Percutaneous to Open Access for Extracorporeal Membrane Oxygenation in Pediatric Respiratory Failure.

OBJECTIVES: Evaluate trends in method of access (percutaneous cannulation vs open cannulation) for pediatric extracorporeal membrane oxygenation and determine the effects of cannulation method on morbidity and mortality. DESIGN: Retrospective cohort study. SETTING AND SUBJECTS: The Extracorporeal Life Support Organization's registry was queried for pediatric patients on extracorporeal membrane oxygenation for respiratory failure from 2007 to 2015. INVERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of 3,501 patients identified, 77.2% underwent open cannulation, with the frequency of open cannulation decreasing over the study period from approximately 80% to 70% (p < 0.001). Percutaneous cannulation patients were more commonly male (24.2% vs 21.5%; p = 0.01), older (average 7.6 vs 4.5 yr; p < 0.001), and heavier (average 33.0 vs 20.2 kg; p < 0.001). Subset analysis of patients on venovenous extracorporeal membrane oxygenation revealed higher rates of mechanical complications due to blood clots (28.9% vs 22.6%; p = 0.003) or cannula problems (18.9% vs 12.7%; p < 0.001), cannula site bleeding (25.3% vs 20.2%; p = 0.01) and increased rates of cannula site repair in the open cannulation cohort. Limb related complications were not significantly different on subset analysis for venovenous extracorporeal membrane oxygenation patients stratified by access site. Logistic regression analysis revealed that method of access was not associated with a difference in mortality. CONCLUSIONS: The proportion of pediatric patients undergoing percutaneous extracorporeal membrane oxygenation cannulation is increasing. Mechanical and physiologic complications occur with both methods of cannulation, but percutaneous cannulation appears safe in this cohort. Further analysis is needed to evaluate long-term outcomes with this technique.

Ventilator use by emergency medical services during 911 calls in the United States.

BACKGROUND: Emergency and transport ventilators use in the prehospital field is not well described. This study examines trends of ventilator use by EMS agencies during 911 calls in the United States and identifies factors associated with this use. METHODS: This retrospective study used four consecutive releases of the US National Emergency Medical Services Information System (NEMSIS) public research dataset (2011-2014) to describe scene EMS activations (911 calls) with and without reported ventilator use. RESULTS: Ventilator use was reported in 260,663 out of 28,221,321 EMS 911 scene activations (0.9%). Patients with ventilator use were older (mean age 67±18years), nearly half were males (49.2%), mostly in urban areas (80.2%) and cared for by advanced life support (ALS) EMS services (89.5%). CPAP mode of ventilation was most common (71.6%). "Breathing problem" was the most common dispatch complaint for EMS activations with ventilator use (63.9%). Common provider impression categories included "respiratory distress" (72.5%), "cardiac rhythm disturbance" (4.6%), "altered level of consciousness" (4.3%) and "cardiac arrest"(4.0%). Ventilator use was consistently higher at the Specialty Care Transport (SCT) and Air Medical Transport (AMT) service levels and increased over the study period for both suburban and rural EMS activations. Significant factors for ventilator use included demographic characteristics, EMS agency type, specific complaints, provider's primary impressions and condition codes. CONCLUSIONS: Providers at different EMS levels use ventilators during 911 scene calls in the US. Training of prehospital providers on ventilation technology is needed. The benefit and effectiveness of this intervention remain to be assessed.

Associations between intraoperative ventilator settings during one-lung ventilation and postoperative pulmonary complications: a prospective observational study.

BACKGROUND: The interest in perioperative lung protective ventilation has been increasing. However, optimal management during one-lung ventilation (OLV) remains undetermined, which not only includes tidal volume (VT) and positive end-expiratory pressure (PEEP) but also inspired oxygen fraction (FIO2). We aimed to investigate current practice of intraoperative ventilation during OLV, and analyze whether the intraoperative ventilator settings are associated with postoperative pulmonary complications (PPCs) after thoracic surgery. METHODS: We performed a prospective observational two-center study in Japan. Patients scheduled for thoracic surgery with OLV from April to October 2014 were eligible. We recorded ventilator settings (FIO2, VT, driving pressure (ΔP), and PEEP) and calculated the time-weighted average (TWA) of ventilator settings for the first 2 h of OLV. PPCs occurring within 7 days of thoracotomy were investigated. Associations between ventilator settings and the incidence of PPCs were examined by multivariate logistic regression. RESULTS: We analyzed perioperative information, including preoperative characteristics, ventilator settings, and details of surgery and anesthesia in 197 patients. Pressure control ventilation was utilized in most cases (92%). As an initial setting for OLV, an FIO2 of 1.0 was selected for more than 60% of all patients. Throughout OLV, the median TWA FIO2 of 0.8 (0.65-0.94), VT of 6.1 (5.3-7.0) ml/kg, ΔP of 17 (15-20) cm H2O, and PEEP of 4 (4-5) cm H2O was applied. Incidence rate of PPCs was 25.9%, and FIO2 was independently associated with the occurrence of PPCs in multivariate logistic regression. The adjusted odds ratio per FIO2 increase of 0.1 was 1.30 (95% confidence interval: 1.04-1.65, P = 0.0195). CONCLUSIONS: High FIO2 was applied to the majority of patients during OLV, whereas low VT and slight degree of PEEP were commonly used in our survey. Our findings suggested that a higher FIO2 during OLV could be associated with increased incidence of PPCs.

Variability of Care in Infants with Severe Bronchiolitis: Less-Invasive Respiratory Management Leads to Similar Outcomes.

OBJECTIVE: To compare the management of children with severe bronchiolitis requiring intensive care (based on duration of ventilatory support and duration of pediatric intensive care unit [PICU] stay) in 2 countries with differing pediatric transport and PICU organizations. STUDY DESIGN: This was a prospective observational care study in 2 PICUs of tertiary care university hospitals, 1 in France and 1 in Canada. All children with bronchiolitis who required admission to the PICU between November 1, 2013, and March 31, 2014, were included. RESULTS: A total of 194 children were included. Baseline characteristics and illness severity were similar at the 2 sites. There was a significant difference between centers in the use of invasive ventilation (3% in France vs 26% in Canada; P < .0001). The number of investigations performed from admission to emergency department presentation and during the PICU stay was significantly higher in Canada for both chest radiographs and blood tests (P < .001). The use of antibiotics was significantly higher in Canada both before (60% vs 28%; P < .001) and during (72% vs 33%; P < .0001) the PICU stay. The duration of ventilatory support, median length of stay, and rate of PICU readmission were similar in the 2 centers. CONCLUSION: Important differences in the management of children with severe bronchiolitis were observed during both prehospital transport and PICU treatment. Less invasive management resulted in similar outcomes with in fewer complications.

Cost-effectiveness analysis of N95 respirators and medical masks to protect healthcare workers in China from respiratory infections.

BACKGROUND: There are substantial differences between the costs of medical masks and N95 respirators. Cost-effectiveness analysis is required to assist decision-makers evaluating alternative healthcare worker (HCW) mask/respirator strategies. This study aims to compare the cost-effectiveness of N95 respirators and medical masks for protecting HCWs in Beijing, China. METHODS: We developed a cost-effectiveness analysis model utilising efficacy and resource use data from two cluster randomised clinical trials assessing various mask/respirator strategies conducted in HCWs in Level 2 and 3 Beijing hospitals for the 2008-09 and 2009-10 influenza seasons. The main outcome measure was the incremental cost-effectiveness ratio (ICER) per clinical respiratory illness (CRI) case prevented. We used a societal perspective which included intervention costs, the healthcare costs of CRI in HCWs and absenteeism costs. RESULTS: The incremental cost to prevent a CRI case with continuous use of N95 respirators when compared to medical masks ranged from US $490-$1230 (approx. 3000-7600 RMB). One-way sensitivity analysis indicated that the CRI attack rate and intervention effectiveness had the greatest impact on cost-effectiveness. CONCLUSIONS: The determination of cost-effectiveness for mask/respirator strategies will depend on the willingness to pay to prevent a CRI case in a HCW, which will vary between countries. In the case of a highly pathogenic pandemic, respirator use in HCWs would likely be a cost-effective intervention.

Volume-Targeted Ventilation in the Neonate: Benchmarking Ventilators on an Active Lung Model.

OBJECTIVE: Mechanically ventilated neonates have been observed to receive substantially different ventilation after switching ventilator models, despite identical ventilator settings. This study aims at establishing the range of output variability among 10 neonatal ventilators under various breathing conditions. DESIGN: Relative benchmarking test of 10 neonatal ventilators on an active neonatal lung model. SETTING: Neonatal ICU. SUBJECTS: Ten current neonatal ventilators. INTERVENTIONS: Ventilators were set identically to flow-triggered, synchronized, volume-targeted, pressure-controlled, continuous mandatory ventilation and connected to a neonatal lung model. The latter was configured to simulate three patients (500, 1,500, and 3,500 g) in three breathing modes each (passive breathing, constant active breathing, and variable active breathing). MEASUREMENTS AND MAIN RESULTS: Averaged across all weight conditions, the included ventilators delivered between 86% and 110% of the target tidal volume in the passive mode, between 88% and 126% during constant active breathing, and between 86% and 120% under variable active breathing. The largest relative deviation occurred during the 500 g constant active condition, where the highest output machine produced 147% of the tidal volume of the lowest output machine. CONCLUSIONS: All machines deviate significantly in volume output and ventilation regulation. These differences depend on ventilation type, respiratory force, and patient behavior, preventing the creation of a simple conversion table between ventilator models. Universal neonatal tidal volume targets for mechanical ventilation cannot be transferred from one ventilator to another without considering necessary adjustments.

Are we fully utilizing the functionalities of modern operating room ventilators?

PURPOSE OF REVIEW: The modern operating room ventilators have become very sophisticated and many of their features are comparable with those of an ICU ventilator. To fully utilize the functionality of modern operating room ventilators, it is important for clinicians to understand in depth the working principle of these ventilators and their functionalities. RECENT FINDINGS: Piston ventilators have the advantages of delivering accurate tidal volume and certain flow compensation functions. Turbine ventilators have great ability of flow compensation. Ventilation modes are mainly volume-based or pressure-based. Pressure-based ventilation modes provide better leak compensation than volume-based. The integration of advanced flow generation systems and ventilation modes of the modern operating room ventilators enables clinicians to provide both invasive and noninvasive ventilation in perioperative settings. Ventilator waveforms can be used for intraoperative neuromonitoring during cervical spine surgery. SUMMARY: The increase in number of new features of modern operating room ventilators clearly creates the opportunity for clinicians to optimize ventilatory care. However, improving the quality of ventilator care relies on a complete understanding and correct use of these new features. VIDEO ABSTRACT: http://links.lww.com/COAN/A47.

The usability of ventilators: a comparative evaluation of use safety and user experience.

BACKGROUND: The design complexity of critical care ventilators (CCVs) can lead to use errors and patient harm. In this study, we present the results of a comparison of four CCVs from market leaders, using a rigorous methodology for the evaluation of use safety and user experience of medical devices. METHODS: We carried out a comparative usability study of four CCVs: Hamilton G5, Puritan Bennett 980, Maquet SERVO-U, and Dräger Evita V500. Forty-eight critical care respiratory therapists participated in this fully counterbalanced, repeated measures study. Participants completed seven clinical scenarios composed of 16 tasks on each ventilator. Use safety was measured by percentage of tasks with use errors or close calls (UE/CCs). User experience was measured by system usability and workload metrics, using the Post-Study System Usability Questionnaire (PSSUQ) and the National Aeronautics and Space Administration Task Load Index (NASA-TLX). RESULTS: Nine of 18 post hoc contrasts between pairs of ventilators were significant after Bonferroni correction, with effect sizes between 0.4 and 1.09 (Cohen's d). There were significantly fewer UE/CCs with SERVO-U when compared to G5 (p = 0.044) and V500 (p = 0.020). Participants reported higher system usability for G5 when compared to PB980 (p = 0.035) and higher system usability for SERVO-U when compared to G5 (p < 0.001), PB980 (p < 0.001), and V500 (p < 0.001). Participants reported lower workload for G5 when compared to PB980 (p < 0.001) and lower workload for SERVO-U when compared to PB980 (p < 0.001) and V500 (p < 0.001). G5 scored better on two of nine possible comparisons; SERVO-U scored better on seven of nine possible comparisons. Aspects influencing participants' performance and perception include the low sensitivity of G5's touchscreen and the positive effect from the quality of SERVO-U's user interface design. CONCLUSIONS: This study provides empirical evidence of how four ventilators from market leaders compare and highlights the importance of medical technology design. Within the boundaries of this study, we can infer that SERVO-U demonstrated the highest levels of use safety and user experience, followed by G5. Based on qualitative data, differences in outcomes could be explained by interaction design, quality of hardware components used in manufacturing, and influence of consumer product technology on users' expectations.

Hyperbaric programs in the United States: Locations and capabilities of treating decompression sickness, arterial gas embolisms, and acute carbon monoxide poisoning: survey results.

Hyperbaric oxygen therapy is the primary treatment for arterial gas embolism, decompression sickness and acute carbon monoxide poisoning. Though there has been a proliferation of hyperbaric centers throughout the United States, a scarcity of centers equipped to treat emergency indications makes transport of patients necessary. To locate and characterize hyperbaric chambers capable of treating emergency cases, a survey of centers throughout the entire United States was conducted. Using Google, Yahoo, HyperbaricLink and the UHMS directory, a database for United States chambers was created. Four researchers called clinicians from the database to administer the survey. All centers were contacted for response until four calls went unreturned or a center declined to be included. The survey assessed chamber readiness to respond to high-acuity patients, including staff availability, use of medical equipment such as ventilators and intravenous infusion devices, and responding yes to treating hyperbaric emergencies within a 12-month period. Only 43 (11.9%, N = 361) centers had equipment, intravenous infusion pumps and ventilators, and staff necessary to treat high-acuity patients. Considering that a primary purpose of hyperbaric oxygen therapy is the treatment of arterial gas embolism and decompression sickness, more hyperbaric centers nationwide should be able to accommodate these emergency cases quickly and safely.

Audit of UK ventilator care bundles and discussion of subglottic secretion drainage.

AIMS: The UK Department of Health (2012) recommends a ventilator care bundle in the form of a high impact intervention to reduce the incidence of ventilator-associated pneumonia. The aims of this project were to audit compliance with individual components of this care bundle in the UK. DESIGN: The first survey directly addressed compliance with each component of the recommended ventilator care bundle. The second survey was targeted towards the use of subglottic secretion drainage (SSD) and the logistics of implementing it. METHODS: The first survey was distributed electronically to the Nurse Leads of the Critical Care National Network Nurses Forum and then circulated more widely through local networks. This Forum covers England, Wales and Northern Ireland. The second survey was circulated electronically to the Intensive Care Society Linkmen and was UK-wide. RESULTS: The first survey received 112 responses following circulation via 40 Leads. Ninety-nine percent of responses were from nurses, the rest were from doctors. The second survey had 77 responses, 88% from doctors and was circulated via 155 Linkmen. The surveys showed that over 95% of respondents worked in intensive care units that use a ventilator care bundle. Compliance with each component of the bundle was greater than 85% in all units, except for SSD, which was performed in 47-53% of the units. CONCLUSIONS: In this survey, most units comply with most of the nationally recommended ventilator care bundle components with the exception of SSD. Because of a lack of availability of suitable endotracheal tubes, a significant number of patients are being re-intubated to facilitate this therapy. RELEVANCE TO CLINICAL PRACTICE: Compliance with most components of the nationally recommended ventilator care bundle is good. SSD has not been as widely implemented as the other components and patients are undergoing re-intubation to facilitate it.

Review of economic evaluations of mask and respirator use for protection against respiratory infection transmission.

BACKGROUND: There has been increasing debate surrounding mask and respirator interventions to control respiratory infection transmission in both healthcare and community settings. As decision makers are considering the recommendations they should evaluate how to provide the most efficient protection strategies with minimum costs. The aim of this review is to identify and evaluate the existing economic evaluation literature in this area and to offer advice on how future evaluations on this topic should be conducted. METHODS: We searched the Scopus database for all literature on economic evaluation of mask or respirator use to control respiratory infection transmission. Reference lists from the identified studies were also manually searched. Seven studies met our inclusion criteria from the initial 806 studies identified by the search strategy and our manual search. RESULTS: Five studies considered interventions for seasonal and/or pandemic influenza, with one also considering SARS (Severe Acute Respiratory Syndrome). The other two studies focussed on tuberculosis transmission control interventions. The settings and methodologies of the studies varied greatly. No low-middle income settings were identified. Only one of the reviewed studies cited clinical evidence to inform their mask/respirator intervention effectiveness parameters. Mask and respirator interventions were generally reported by the study authors to be cost saving or cost-effective when compared to no intervention or other control measures, however the evaluations had important limitations. CONCLUSIONS: Given the large cost differential between masks and respirators, there is a need for more comprehensive economic evaluations to compare the relative costs and benefits of these interventions in situations and settings where alternative options are potentially applicable. There are at present insufficient well conducted cost-effectiveness studies to inform decision-makers on the value for money of alternative mask/respirator options.