Academic Emergency Medicine Physicians' Knowledge of Mechanical Ventilation

Enhancing pulmonary function and arterial blood gas readings through immediate chest physiotherapy among extubated patients in ICU

OBJECTIVE

To examine the effect of immediate chest physiotherapy (ICPT) on pulmonary function and arterial blood gases among extubated patients.

METHOD

This prospective study enrolled patients aged 20-60 years who had been intubated for 48 h. They were randomly assigned to either a control or study group. The study group received ICPT by trained critical care nurses and physiotherapists, which included early mobilization, breathing exercises and airway clearance. The control group received standard nursing chest care (positioning, oral and endotracheal suctioning) without ICPT. Researchers evaluated participants using pulmonary function tests, arterial blood gas tests and mechanical ventilation parameters.

RESULTS

The study enrolled 70 patients. There were no significant differences in the sociodemographic characteristics and medical data before intubation between the two groups except for preparatory education. After extubation, the vital capacity was significantly higher in the study group compared with the control group. There were also significant differences between the two groups in other lung function tests and arterial blood gas tests. After extubation, the total lung capacity, functional residual capacity and residual volume were significantly higher in the study group compared with the control group.

CONCLUSION

The use of ICPT improved both pulmonary function and arterial blood gases.

Myths and Misconceptions of Airway Pressure Release Ventilation: Getting Past the Noise and on to the Signal

In the pursuit of science, competitive ideas and debate are necessary means to attain knowledge and expose our ignorance. To quote Murray Gell-Mann (1969 Nobel Prize laureate in Physics): “Scientific orthodoxy kills truth”. In mechanical ventilation, the goal is to provide the best approach to support patients with respiratory failure until the underlying disease resolves, while minimizing iatrogenic damage. This compromise characterizes the philosophy behind the concept of “lung protective” ventilation. Unfortunately, inadequacies of the current conceptual model–that focuses exclusively on a nominal value of low tidal volume and promotes shrinking of the “baby lung” - is reflected in the high mortality rate of patients with moderate and severe acute respiratory distress syndrome. These data call for exploration and investigation of competitive models evaluated thoroughly through a scientific process. Airway Pressure Release Ventilation (APRV) is one of the most studied yet controversial modes of mechanical ventilation that shows promise in experimental and clinical data. Over the last 3 decades APRV has evolved from a rescue strategy to a preemptive lung injury prevention approach with potential to stabilize the lung and restore alveolar homogeneity. However, several obstacles have so far impeded the evaluation of APRV’s clinical efficacy in large, randomized trials. For instance, there is no universally accepted standardized method of setting APRV and thus, it is not established whether its effects on clinical outcomes are due to the ventilator mode per se or the method applied. In addition, one distinctive issue that hinders proper scientific evaluation of APRV is the ubiquitous presence of myths and misconceptions repeatedly presented in the literature. In this review we discuss some of these misleading notions and present data to advance scientific discourse around the uses and misuses of APRV in the current literature.

Simulation-based Assessment to Measure Proficiency in Mechanical Ventilation among Residents

Background

Mechanical ventilation (MV) skills are essential for clinicians caring for critically ill patients, yet few training programs use structured curricula and appropriate assessments. Objective structured clinical exams (OSCEs) have been used to assess clinical competency in many areas, but there are no OSCE models focused on MV.

Objective

To develop and validate a simulation-based assessment (SBA) with an OSCE structure to assess baseline MV competence among residents and identify knowledge gaps.

Methods

We developed an SBA using a lung simulator and a mechanical ventilator, and an OSCE structure, with six clinical scenarios in MV. We included internal medicine residents at the beginning of their rotation in the respiratory intensive care unit (ICU) of a university-affiliated hospital. A subset of residents was also evaluated with a validated multiple-choice exam (MCE) at the beginning and at the end of the ICU rotation. Scores on both assessments were normalized to range from 0 to 10. We used Cronbach’s α coefficient to assess reliability and Spearman correlation to estimate the correlation between the SBA and the MCE.

Results

We included 80 residents, of whom 42 also completed the MCE examinations. The final version of the SBA had 32 items, and the Cronbach’s α coefficient was 0.72 (95% confidence interval [CI], 0.64–0.81). The average SBA score was 6.2 ± 1.3, and performance was variable across items, with 80% correctly adjusting initial ventilatory settings and only 12% correctly identifying asynchrony. The MCE had 24 questions, and the average score was 7.6 ± 2.4 at the beginning of the rotation and 8.2 ± 2.3 at the end of the rotation (increase of 0.6 points; 95% CI, 0.30–0.90; P < 0.001). There was moderate correlation between the SBA and the MCE (rho = 0.41; P = 0.002).

Conclusion

We developed and validated an objective structured assessment on MV using a pulmonary simulator and a mechanical ventilator addressing the main competencies in MV. The performance of residents in the SBA at the beginning of an ICU rotation was lower than the performance in MCE, highlighting the need for greater emphasis on practical skills in MV during residency.

Emergency Department Management of Severe Hypoxemic Respiratory Failure in Adults With COVID-19

Background

While emergency physicians are familiar with the management of hypoxemic respiratory failure, management of mechanical ventilation and advanced therapies for oxygenation in the emergency department have become essential during the coronavirus disease 2019 (COVID-19) pandemic.

Objective

We review the current evidence on hypoxemia in COVID-19 and place it in the context of known evidence-based management of hypoxemic respiratory failure in the emergency department.

Discussion

COVID-19 causes mortality primarily through the development of acute respiratory distress syndrome (ARDS), with hypoxemia arising from shunt, a mismatch of ventilation and perfusion. Management of patients developing ARDS should focus on mitigating derecruitment and avoiding volutrauma or barotrauma.

Conclusions

High flow nasal cannula and noninvasive positive pressure ventilation have a more limited role in COVID-19 because of the risk of aerosolization and minimal benefit in severe cases, but can be considered. Stable patients who can tolerate repositioning should be placed in a prone position while awake. Once intubated, patients should be managed with ventilation strategies appropriate for ARDS, including targeting lung-protective volumes and low pressures. Increasing positive end-expiratory pressure can be beneficial. Inhaled pulmonary vasodilators do not decrease mortality but may be given to improve refractory hypoxemia. Prone positioning of intubated patients is associated with a mortality reduction in ARDS and can be considered for patients with persistent hypoxemia. Neuromuscular blockade should also be administered in patients who remain dyssynchronous with the ventilator despite adequate sedation. Finally, patients with refractory severe hypoxemic respiratory failure in COVID-19 should be considered for venovenous extracorporeal membrane oxygenation.

Comparison of three methods for teaching mechanical ventilation in an emergency setting to sixth-year medical students: a randomized trial

SUMMARY OBJECTIVE: To determine if there are significant differences between the tutorial, simulation, or clinical-case-based discussion teaching methods regarding the transmission of medical knowledge on mechanical ventilation. METHODS: A randomized, multicenter, open-label controlled trial was carried out using 3 teaching methods on mechanical ventilation: clinical-case-based discussion, simulation, and online tutorial. Voluntary students of the sixth year of medical school from 11 medical colleges answered a validated questionnaire on knowledge about mechanical ventilation for medical students before, immediately after, and 6 months after in-person training consisting of 20 multiple-choice questions, and 5 questions about the participants' demographic profile. RESULTS: Immediately after the test there was no difference between the scores in the simulation and clinical case groups,[15,06 vs 14,63] whereas, after some time, there was a significant difference in retention between the case-based and simulation groups, with the score in the simulation group 1.46 [1.31; 1.64] times higher than the score of the case group (p-value < 0.001). In the multivariate analysis, an individual who had received more than 4 hours of information showed an increase of 20.0% [09.0%; 33.0%] in the score (p-value = 0.001). CONCLUSIONS: Our results indicate that, in comparison with other forms of training, simulation in mechanical ventilation provides long-lasting knowledge in the medium term. Further studies are needed to improve the designing and evaluation of training that provides minimal mechanical ventilation skills.

Invasive Mechanical Ventilation

Invasive mechanical ventilation is a potentially lifesaving intervention for acutely ill patients. The goal of this review is to provide a concise, clinically focused overview of basic invasive mechanical ventilation for the many clinicians who care for mechanically ventilated patients. Attention is given to how common ventilator modes differ in delivering a mechanical breath, evaluation of respiratory system mechanics, how to approach acute changes in airway pressure, and the diagnosis of auto-positive end-expiratory pressure. Waveform interpretation is emphasized throughout the review.

Mechanical Ventilation Training During Graduate Medical Education: Perspectives and Review of the Literature

BACKGROUND

Management of mechanical ventilation (MV) is an important and complex aspect of caring for critically ill patients. Management strategies and technical operation of the ventilator are key skills for physicians in training, as lack of expertise can lead to substantial patient harm.

OBJECTIVE

We performed a narrative review of the literature describing MV education in graduate medical education (GME) and identified best practices for training and assessment methods.

METHODS

We searched MEDLINE, PubMed, and Google Scholar for English-language, peer-reviewed articles describing MV education and assessment. We included articles from 2000 through July 2018 pertaining to MV education or training in GME.

RESULTS

Fifteen articles met inclusion criteria. Studies related to MV training in anesthesiology, emergency medicine, general surgery, and internal medicine residency programs, as well as subspecialty training in critical care medicine, pediatric critical care medicine, and pulmonary and critical care medicine. Nearly half of trainees assessed were dissatisfied with their MV education. Six studies evaluated educational interventions, all employing simulation as an educational strategy, although there was considerable heterogeneity in content. Most outcomes were assessed with multiple-choice knowledge testing; only 2 studies evaluated the care of actual patients after an educational intervention.

CONCLUSIONS

There is a paucity of information describing MV education in GME. The available literature demonstrates that trainees are generally dissatisfied with MV training. Best practices include establishing MV-specific learning objectives and incorporating simulation. Next research steps include developing competency standards and validity evidence for assessment tools that can be utilized across MV educational curricula.

The effect of emergency department crowding on lung-protective ventilation utilization for critically ill patients

OBJECTIVE

To measure effects of ED crowding on lung-protective ventilation (LPV) utilization in critically ill ED patients.

METHODS

This is a retrospective cohort study of adult mechanically ventilated ED patients admitted to the medical intensive care unit (MICU), over a 3.5-year period at a single academic tertiary care hospital. Clinical data, including reason for intubation, severity of illness (MPM₀-III), acute respiratory distress syndrome (ARDS) risk score (EDLIPS), and ventilator settings were extracted via electronic query of electronic health record and standardized chart abstraction. Crowding metrics were obtained at 5-min intervals and averaged over the ED stay, stratified by acuity and disposition. Multivariate logistic regression was used to predict likelihood of LPV prior to ED departure.

RESULTS

Mechanical ventilation was used in 446 patients for a median ED duration of 3.7 h (interquartile ratio, IQR, 2.3, 5.6). Mean MPM₀-III score was 32.5 ± 22.7, with high risk for ARDS (EDLIPS ≥5) seen in 373 (82%) patients. Initial and final ED ventilator settings differed in 134 (30.0%) patients, of which only 47 (35.1%) involved tidal volume changes. Higher percentages of active ED patients (workup in-progress) and those requiring eventual admission were associated with lower odds of LPV utilization by ED departure (OR 0.97, 95%CI 0.94-1.00; OR 0.97, 95%CI 0.94-1.00, respectively). In periods of high volume, ventilator adjustments to settings other than the tidal volume were associated with higher odds of LPV utilization. Reason for intubation, MPM₀-III, and EDLIPS were not associated with LPV utilization, with no interactions detected in times of crowding.

CONCLUSIONS

ED patients remain on suboptimal tidal volume settings with infrequent ventilator adjustments during the ED stay. Hospitals should focus on both systemic factors and bedside physician and/or respiratory therapist interventions to increase LPV utilization in times of ED boarding and crowding for all patients.

Mechanical ventilation patterns and trends over 20 years in an Israeli hospital system: policy ramifications

Background

Mechanical ventilation is a life supporting modality increasingly utilized when caring for severely ill patients. Its increasing use has extended the survival of the critically ill leading to increasing healthcare expenditures. We examined changes in the hospital-wide use of mechanical ventilation over 20 years (1997–2016) in two Israeli hospitals to determine whether there were specific patterns (e.g. seasonality, weekday vs. weekend) and trends (e.g. increases or decreases) among various hospital departments and units.

Methods

Retrospective analysis of prospectively collected data on all mechanically ventilated patients over 20-years in a two-hospital Israeli medical system was performed. Data were collected for each hospital unit caring for ventilated patients. Time-series analysis examined short and long-term trends, seasonality and intra-week variation.

Results

Over two decades overall ventilator-days increased from 11,164 (31 patients/day) in 1997 to 24,317 (67 patients/day) in 2016 mainly due to more patients ventilated on internal medicine wards (1997: 4 patients/day; 2016: 24 patients/day). The increases in other hospital areas did not approach the magnitude of the internal medicine wards increases. Ventilation on wards reflected the insufficient number of ICU beds in Israel. A detailed snapshot over 4 months of patients ventilated on internal medicine wards (n = 745) showed that they tended to be elderly (median age 75 years) and that 24% were ventilated for more than a week. Hospital-wide ventilation patterns were the weighted sum of the various individual patient units with the most noticeable pattern being peak winter prevalence on the internal medical wards and in the emergency department. This seasonality is not surprising, given the greater incidence of respiratory ailments in winter.

Conclusions

Increased mechanical ventilation plus seasonality have budgetary, operational and staffing consequences for individual hospitals and the entire healthcare system. The Israeli healthcare leadership needs to plan and support expanding, equipping and staffing acute and chronic care units that are staffed by providers trained to care for such complex patients.

Electronic supplementary material

The online version of this article (10.1186/s13584-019-0291-y) contains supplementary material, which is available to authorized users.

Critical Appraisal of Emergency Medicine Educational Research: The Best Publications of 2016

OBJECTIVES

The objectives were to critically appraise the emergency medicine (EM) medical education literature published in 2016 and review the highest-quality quantitative and qualitative studies.

METHODS

A search of the English language literature in 2016 querying MEDLINE, Scopus, Education Resources Information Center (ERIC), and PsychInfo identified 510 papers related to medical education in EM. Two reviewers independently screened all of the publications using previously established exclusion criteria. The 25 top-scoring quantitative studies based on methodology and all six qualitative studies were scored by all reviewers using selected scoring criteria that have been adapted from previous installments. The top-scoring articles were highlighted and trends in medical education research were described.

RESULTS

Seventy-five manuscripts met inclusion criteria and were scored. Eleven quantitative and one qualitative papers were the highest scoring and are summarized in this article.

CONCLUSION

This annual critical appraisal series highlights the best EM education research articles published in 2016.

Interventions affecting blood pressure variability and outcomes after intubating patients with spontaneous intracranial hemorrhage

INTRODUCTION

Spontaneous intracranial hemorrhage (sICH) that increases intracranial pressure (ICP) is a life-threatening emergency often requiring intubation in Emergency Departments (ED). A previous study of intubated ED patients found that providing ≥5 interventions after initiating mechanical ventilation (pMVI) reduced mortality rate. We hypothesized that pMVIs would lower blood pressure variability (BPV) in patients with sICH and thus improve survival rates and neurologic outcomes.

METHOD

We performed a retrospective study of adults, who were transferred to a quaternary medical center between 01/01/2011 and 09/30/2015 for sICH, received an extraventricular drain during hospitalization. They were identified by International Classification of Diseases, version 9 (430.XX, 431.XX), and procedure code 02.21. Outcomes were BPV indices, death, and being discharged home.

RESULTS

We analyzed records from 147 intubated patients transferred from 40 EDs. Forty-one percent of patients received ≥5 pMVIs and was associated with lower median successive variation in systolic blood pressure (BP_SV) (31,[IQR 18-45) compared with those receiving 4 or less pMVIs (38[IQR 16-70]], p = 0.040). Three pMVIs, appropriate tidal volume, sedative infusion, and capnography were significantly associated with lower BPV. In addition to clinical factors, BP_SV (OR 26; 95% CI 1.2, >100) and chest radiography (OR 0.3; 95% CI 0.09, 0.9) were associated with mortality rate. Use of quantitative capnography (OR 8.3; 95%CI, 4.7, 8.8) was associated with increased likelihood of being discharged home.

CONCLUSIONS

In addition to disease severity, individual pMVIs were significantly associated with BPV and patient outcomes. Emergency physicians should perform pMVIs more frequently to prevent BPV and improve patients' outcomes.

Duration of Mechanical Ventilation in the Emergency Department

INTRODUCTION

Due to hospital crowding, mechanically ventilated patients are increasingly spending hours boarding in emergency departments (ED) before intensive care unit (ICU) admission. This study aims to evaluate the association between time ventilated in the ED and in-hospital mortality, duration of mechanical ventilation, ICU and hospital length of stay (LOS).

METHODS

This was a multi-center, prospective, observational study of patients ventilated in the ED, conducted at three academic Level I Trauma Centers from July 2011 to March 2013. All consecutive adult patients on invasive mechanical ventilation were eligible for enrollment. We performed a Cox regression to assess for a mortality effect for mechanically ventilated patients with each hour of increasing LOS in the ED and multivariable regression analyses to assess for independently significant contributors to in-hospital mortality. Our primary outcome was in-hospital mortality, with secondary outcomes of ventilator days, ICU LOS and hospital LOS. We further commented on use of lung protective ventilation and frequency of ventilator changes made in this cohort.

RESULTS

We enrolled 535 patients, of whom 525 met all inclusion criteria. Altered mental status without respiratory pathology was the most common reason for intubation, followed by trauma and respiratory failure. Using iterated Cox regression, a mortality effect occurred at ED time of mechanical ventilation > 7 hours, and the longer ED stay was also associated with a longer total duration of intubation. However, adjusted multivariable regression analysis demonstrated only older age and admission to the neurosciences ICU as independently associated with increased mortality. Of interest, only 23.8% of patients ventilated in the ED for over seven hours had changes made to their ventilator.

CONCLUSION

In a prospective observational study of patients mechanically ventilated in the ED, there was a significant mortality benefit to expedited transfer of patients into an appropriate ICU setting.