Lung-Protective Ventilation Initiated in the Emergency Department (LOV-ED): A Quasi-Experimental, Before-After Trial

Partial pressure of carbon dioxide/pH interaction and its association with mortality among patients mechanically ventilated in the emergency department

OBJECTIVES

There is currently conflicting data as to the effects of hypercapnia on clinical outcomes among mechanically ventilated patients in the emergency department (ED). These conflicting results may be explained by the degree of acidosis. We sought to test the hypothesis that hypercapnia is associated with increased in-hospital mortality and decreased ventilator-free days at lower pH, but associated with decreased in-hospital mortality and increased ventilator-free days at higher pH, among patients requiring mechanical ventilation in the emergency department (ED).

METHODS

Secondary analysis of patient level data from prior clinical trials and cohort studies that enrolled adult patients who required mechanical ventilation in the ED. Patients who had a documented blood gas while on mechanical ventilation in the ED were included in these analyses. The primary outcome was in-hospital mortality, and secondary outcome was ventilator-free days. Mixed-effects logistic, linear, and survival-time regression models were used to test if pH modified the association between partial pressure of carbon dioxide (pCO2) and outcome measures.

RESULTS

Of the 2348 subjects included, the median [interquartile range (IQR)] pCO2 was 43 (35-54) and pH was 7.31 (7.22-7.39). Overall, in-hospital mortality was 27%. We found pH modified the association between pCO2 and outcomes, with higher pCO2 associated with increased probability of in-hospital mortality when pH is below 7.00, and decreased probability of in-hospital mortality when pH is above 7.10. These results remained consistent across multiple sensitivity and subgroup analyses. A similar relationship was found with ventilator-free days.

CONCLUSIONS

Higher pCO2 is associated with decreased mortality and greater ventilator-free days when pH is >7.10; however, it is associated with increased mortality and fewer ventilator-free days when the pH is below 7.00. Targeting pCO2 based on pH in the ED may be a potential intervention target for future clinical trials to improve clinical outcomes.

Investigating distributions of inhaled aerosols in the lungs of post-COVID-19 clusters through a unified imaging and modeling approach

BACKGROUND

Recent studies, based on clinical data, have identified sex and age as significant factors associated with an increased risk of long COVID. These two factors align with the two post-COVID-19 clusters identified by a deep learning algorithm in computed tomography (CT) lung scans: Cluster 1 (C1), comprising predominantly females with small airway diseases, and Cluster 2 (C2), characterized by older individuals with fibrotic-like patterns. This study aims to assess the distributions of inhaled aerosols in these clusters.

METHODS

140 COVID survivors examined around 112 days post-diagnosis, along with 105 uninfected, non-smoking healthy controls, were studied. Their demographic data and CT scans at full inspiration and expiration were analyzed using a combined imaging and modeling approach. A subject-specific CT-based computational model analysis was utilized to predict airway resistance and particle deposition among C1 and C2 subjects. The cluster-specific structure and function relationships were explored.

RESULTS

In C1 subjects, distinctive features included airway narrowing, a reduced homothety ratio of daughter over parent branch diameter, and increased airway resistance. Airway resistance was concentrated in the distal region, with a higher fraction of particle deposition in the proximal airways. On the other hand, C2 subjects exhibited airway dilation, an increased homothety ratio, reduced airway resistance, and a shift of resistance concentration towards the proximal region, allowing for deeper particle penetration into the lungs.

CONCLUSIONS

This study revealed unique mechanistic phenotypes of airway resistance and particle deposition in the two post-COVID-19 clusters. The implications of these findings for inhaled drug delivery effectiveness and susceptibility to air pollutants were explored.

Physical and respiratory therapy in the critically ill patient with obesity: a narrative review

Obesity has become increasingly prevalent in the intensive care unit, presenting a significant challenge for healthcare systems and professionals, including rehabilitation teams. Caring for critically ill patients with obesity involves addressing complex issues. Despite the well-established and safe practice of early mobilization during critical illness, in rehabilitation matters, the diverse clinical disturbances and scenarios within the obese patient population necessitate a comprehensive understanding. This includes recognizing the importance of metabolic support, both non-invasive and invasive ventilatory support, and their weaning processes as essential prerequisites. Physiotherapists, working collaboratively with a multidisciplinary team, play a crucial role in ensuring proper assessment and functional rehabilitation in the critical care setting. This review aims to provide critical insights into the key management and rehabilitation principles for obese patients in the intensive care unit.

Awareness with paralysis and symptoms of post-traumatic stress disorder among mechanically ventilated emergency department survivors (ED-AWARENESS-2 Trial): study protocol for a pragmatic, multicenter, stepped wedge cluster randomized trial

BACKGROUND

Awareness with paralysis (AWP) is memory recall during neuromuscular blockade (NMB) and can cause significant psychological harm. Decades of effort and rigorous trials have been conducted to prevent AWP in the operating room, where prevalence is 0.1-0.2%. By contrast, AWP in mechanically ventilated emergency department (ED) patients is common, with estimated prevalence of 3.3-7.4% among survivors given NMB. Longer-acting NMB use is a critical risk for AWP, and we have shown an association between ED rocuronium use and increased AWP prevalence. As NMB are given to more than 90% of ED patients during tracheal intubation, this trial provides a platform to test an intervention aimed at reducing AWP. The overall objective is to test the hypothesis that limiting ED rocuronium exposure will significantly reduce the proportion of patients experiencing AWP.

METHODS

This is a pragmatic, stepped wedge cluster randomized trial conducted in five academic EDs, and will enroll 3090 patients. Per the design, all sites begin in a control phase, under observational conditions. At 6-month intervals, sites sequentially enter a 2-month transition phase, during which we will implement the multifaceted intervention, which will rely on use of nudges and defaults to change clinician decisions regarding ED NMB use. During the intervention phase, succinylcholine will be the default NMB over rocuronium. The primary outcome is AWP, assessed with the modified Brice questionnaire, adjudicated by three independent, blinded experts. The secondary outcome is the proportion of patients developing clinically significant symptoms of post-traumatic stress disorder at 30 and 180 days after hospital discharge. We will also assess for symptoms of depression and anxiety, and health-related quality of life. A generalized linear model, adjusted for time and cluster interactions, will be used to compare AWP in control versus intervention phases, analyzed by intention-to-treat.

DISCUSSION

The ED-AWARENESS-2 Trial will be the first ED-based trial aimed at preventing AWP, a critical threat to patient safety. Results could shape clinical use of NMB in the ED and prevent more than 10,000 annual cases of AWP related to ED care.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT05534243 . Registered 06, September 2022.

Arterial to end-tidal carbon dioxide gap and its characterization in mechanically ventilated adults in the emergency department

PURPOSE

To evaluate early measurement of the arterial to end-tidal carbon dioxide (PaCO2-PetCO2) gap, a surrogate for physiologic dead space, and its association with clinical outcomes in intubated adults in the emergency department (ED).

MATERIALS AND METHODS

Observational cohort study of invasively mechanically ventilated adults in an academic medical center (years 2009 to 2016). The association of the PaCO2-PetCO2 gap was evaluated with respect to clinical outcomes; the primary outcome was in-hospital mortality.

RESULTS

519 patients were included. 325 (63%) patients had an elevated (>5 mmHg) PaCO2-PetCO2. Patients with an elevated PaCO2-PetCO2 were significantly older, had higher APACHE II scores, more frequently had chronic obstructive pulmonary disease (COPD), had lower arterial oxygen to fraction of inspired oxygen (P:F) ratios, and were more likely to be intubated for exacerbation of COPD or sepsis. There was no difference in mortality for patients with an elevated PaCO2-PetCO2 (25% vs 26%) in unadjusted analysis (p = 0.829) or adjusted analysis (aOR = 0.81 [95% CI: 0.53-1.26]), as compared to a non-elevated PaCO2-PetCO2.

CONCLUSIONS

An elevated PaCO2-PetCO2 gap is common in the post-intubation period in the ED, but not significantly associated with clinical outcomes.

Timing of Transport of Patients with COVID-19

RATIONALE

The objective of this study was to evaluate the risk of mortality or ECMO cannulation for patients with confirmed or suspected COVID-19 transferred from sending hospitals to receiving tertiary care centers as a function of the duration of time at the sending hospital.

OBJECTIVE

To determine outcomes of critically ill patients with COVID-19 who were transferred to tertiary or quarternary care medical centers.

MATERIALS AND METHODS

Retrospective cohort study of critical care transports of patients to one of seven consortium tertiary care centers from March 1, 2020, through September 4, 2020. Age 14 years and older with confirmed or suspected COVID-19 transported from a sending hospital to a receiving tertiary care center by the critical care transport organization.

RESULTS

Patients transported with confirmed or suspected COVID-19 to tertiary care centers had a mortality rate of 38.0%. Neither the number of days admitted, nor the number of days intubated at the sending hospital correlated with mortality (correlation coefficient 0.051 and -0.007, respectively). Similarly, neither the number of days admitted, nor number of days intubated at the sending hospital correlated with ECMO cannulation (correlation coefficient 0.008 and -0.036, respectively).

CONCLUSION

It may be reasonable to transfer a critically ill COVID-19 patient to a tertiary care center even if they have been admitted at the sending hospital for several days.

Blueprint for the development of resuscitation and emergency critical care fellowships

The volume of critically ill patients presenting to the emergency department (ED) is increasing rapidly. Continued growth will likely further stress an already strained U.S. health care system. Numerous studies have demonstrated an association with worsened outcomes for critically ill patients boarding in the ED. To address the increasing volume and complexity of critically ill patients presenting to EDs nationwide, resuscitation and emergency critical care (RECC) fellowships were developed. RECC programs teach a general approach to the management of the undifferentiated critically ill patient, advanced management of critically ill patients by disease presentation, and ongoing supportive care of the critically ill patient boarding in the ED. The result is critical care training beyond that of a typical emergency medicine (EM) residency with a focus on the unique features and challenges of caring for critically ill patients in the ED not normally found in critical care fellowships. Graduates from RECC fellowships are well suited to practicing in any ED practice model and may be especially well prepared for EDs that distinguish acuity between zones (e.g., resuscitative care units, ED-based intensive care units). In addition to further developing clinical acumen, RECC fellowships provide graduates with a niche in EM education, research, and administration. In this article, we describe the philosophical principles and practical components necessary for the creation of future RECC fellowships.

Decreased Utilization of Low Tidal Volume Ventilation Outside of the Intensive Care Unit as Compared to Inside

Background: Investigations into the use of low tidal volume ventilation (LTVV) have been performed for patients in emergency departments (EDs) or intensive care units (ICUs). Practice differences between the ICU and non-ICU care areas have not been described. We hypothesized that the initial implementation of LTVV would be better inside ICUs than outside. Methods: This is a retrospective observational study of patients initiated on invasive mechanical ventilation (IMV) between January 1, 2016, and July 17, 2019. Initial recorded tidal volumes after intubation were used to compare the use of LTVV between care areas. Low tidal volume was considered 6.5 cc/kg of ideal body weight (IBW) or less. The primary outcome was the initiation of low tidal volume. Sensitivity analyses used a tidal volume of 8 cc/kg of IBW or less, and direct comparisons were performed between the ICU, ED, and wards. Results: There were 6392 initiations of IMV: 2217 (34.7%) in the ICU and 4175 (65.3%) outside. LTVV was more likely to be initiated in the ICU than outside (46.5% vs 34.2%; adjusted odds ratio [aOR] 0.62, 95% confidence interval [CI] 0.56-0.71, P < .01). The ICU also had more implementation when PaO2/FiO2 ratio was less than 300, (48.0% vs 34.6%; aOR 0.59, 95% CI 0.48-0.71, P < .01). When comparing individual locations, wards had lower odds of LTVV than the ICU (aOR 0.82, 95% CI 0.70-0.96, P  =  .02), the ED had lower odds than the ICU (aOR 0.55, 95% CI 0.48-0.63, P < .01), and the ED had lower odds than the wards (aOR 0.66, 95% CI 0.56-0.77, P < .01). Interpretation: Initial low tidal volumes were more likely to be initiated in the ICU than outside. This finding remained when examining only patients with a PaO2/FiO2 ratio less than 300. Care areas outside of the ICU do not employ LTVV as often as ICUs and are, therefore, a possible target for process improvement.

Mechanical ventilation in patients with acute respiratory distress syndrome: current status and future perspectives

INTRODUCTION

Although there has been extensive research on mechanical ventilation for acute respiratory distress syndrome (ARDS), treatment remains mainly supportive. Recent studies and new ventilatory modes have been proposed to manage patients with ARDS; however, the clinical impact of these strategies remains uncertain and not clearly supported by guidelines. The aim of this narrative review is to provide an overview and update on ventilatory management for patients with ARDS.

AREAS COVERED

This article reviews the literature regarding mechanical ventilation in ARDS. A comprehensive overview of the principal settings for the ventilator parameters involved is provided as well as a report on the differences between controlled and assisted ventilation. Additionally, new modes of assisted ventilation are presented and discussed. The evidence concerning rescue strategies, including recruitment maneuvers and extracorporeal membrane oxygenation support, is analyzed. PubMed, EBSCO, and the Cochrane Library were searched up until June 2023, for relevant literature.

EXPERT OPINION

Available evidence for mechanical ventilation in cases of ARDS suggests the use of a personalized mechanical ventilation strategy. Although promising, new modes of assisted mechanical ventilation are still under investigation and guidelines do not recommend rescue strategies as the standard of care. Further research on this topic is required.

A NOVEL EQUATION SUCCESSFULLY CALCULATES TIDAL VOLUMES FOR LUNG PROTECTIVE VENTILATION

BACKGROUND

Early application of low-tidal-volume ventilation (LTVV) has been associated with improved outcomes in the emergency department (ED) and intensive care unit (ICU), but is not consistently applied. The perceived complexity of calculating an ideal body weight (IBW)-based tidal volume (Vt) may contribute to this disparity. We hypothesized that a simplified equation could successfully predict LTVV.

OBJECTIVE

To create a memorable, single-step, sex-independent equation to estimate LTVV based on height.

METHODS

We conducted a retrospective observational cohort study of patients who received mechanical ventilation (MV) at 2 EDs from January 2016 to June 2019. Data were abstracted by automatic query. Patients < 18 years old, < 60 inches in height, and with implausible or incomplete data were excluded. LTVV was defined as ≤ 8 mL/kg IBW. We created a formula predicting a 6-8-mL/kg IBW Vt. We applied this formula to a population of ICU patients in the same health care system who received MV from January 2017 to December 2019 using the same exclusion criteria. The outcome was whether the equation predicted a 6-8-mL/kg IBW Vt.

RESULTS

A total of 982 ED patients were included; 753 (76.7%) had an initial Vt < 8 mL/kg IBW. The equation Vt = 20*(Ht-60) + 300 was derived. A total of 3720 ICU patients were included. The Vt equation successfully predicted a Vt of 6-8 mL/kg IBW in 3720 (100%) of ICU patients.

CONCLUSIONS

A novel equation successfully predicted a 6-8-mL/kg IBW Vt in a cohort of patients with height ≥ 60 inches.

Challenges in ARDS Definition, Management, and Identification of Effective Personalized Therapies

Over the last decade, the management of acute respiratory distress syndrome (ARDS) has made considerable progress both regarding supportive and pharmacologic therapies. Lung protective mechanical ventilation is the cornerstone of ARDS management. Current recommendations on mechanical ventilation in ARDS include the use of low tidal volume (V_T) 4-6 mL/kg of predicted body weight, plateau pressure (P_PLAT) < 30 cmH₂O, and driving pressure (∆P) < 14 cmH₂O. Moreover, positive end-expiratory pressure should be individualized. Recently, variables such as mechanical power and transpulmonary pressure seem promising for limiting ventilator-induced lung injury and optimizing ventilator settings. Rescue therapies such as recruitment maneuvers, vasodilators, prone positioning, extracorporeal membrane oxygenation, and extracorporeal carbon dioxide removal have been considered for patients with severe ARDS. Regarding pharmacotherapies, despite more than 50 years of research, no effective treatment has yet been found. However, the identification of ARDS sub-phenotypes has revealed that some pharmacologic therapies that have failed to provide benefits when considering all patients with ARDS can show beneficial effects when these patients were stratified into specific sub-populations; for example, those with hyperinflammation/hypoinflammation. The aim of this narrative review is to provide an overview on current advances in the management of ARDS from mechanical ventilation to pharmacological treatments, including personalized therapy.

The Practice Change and Clinical Impact of Lung-Protective Ventilation Initiated in the Emergency Department: A Secondary Analysis of Individual Patient-Level Data From Prior Clinical Trials and Cohort Studies

OBJECTIVES

Mechanically ventilated emergency department (ED) patients experience high morbidity and mortality. In a prior trial at our center, ED-based lung-protective ventilation was associated with improved care delivery and outcomes. Whether this strategy has persisted in the years after the trial remains unclear. The objective was to assess practice change and clinical outcomes associated with ED lung-protective ventilation.

DESIGN

Secondary analysis of individual patient-level data from prior clinical trials and cohort studies.

SETTING

ED and ICUs of a single academic center.

PATIENTS

Mechanically ventilated adults.

INTERVENTIONS

A lung-protective ventilator protocol used as the default approach in the ED.

MEASUREMENTS AND MAIN RESULTS

The primary ventilator-related outcome was tidal volume, and the primary clinical outcome was hospital mortality. Secondary outcomes included ventilator-, hospital-, and ICU-free days. Multivariable logistic regression, propensity score (PS)-adjustment, and multiple a priori subgroup analyses were used to evaluate outcome as a function of the intervention. A total of 1,796 patients in the preintervention period and 1,403 patients in the intervention period were included. In the intervention period, tidal volume was reduced from 8.2 mL/kg predicted body weight (PBW) (7.3-9.1) to 6.5 mL/kg PBW (6.1-7.1), and low tidal volume ventilation increased from 46.8% to 96.2% ( p < 0.01). The intervention period was associated with lower mortality (35.9% vs 19.1%), remaining significant after multivariable logistic regression analysis (adjusted odds ratio [aOR], 0.43; 95% CI, 0.35-0.53; p < 0.01). Similar results were seen after PS adjustment and in subgroups. The intervention group had more ventilator- (18.8 [10.1] vs 14.1 [11.9]; p < 0.01), hospital- (12.2 [9.6] vs 9.4 [9.5]; p < 0.01), and ICU-free days (16.6 [10.1] vs 13.1 [11.1]; p < 0.01).

CONCLUSIONS

ED lung-protective ventilation has persisted in the years since implementation and was associated with improved outcomes. These data suggest the use of ED-based lung-protective ventilation as a means to improve outcome.

A computed tomography imaging-based subject-specific whole-lung deposition model

The respiratory tract is an important route for beneficial drug aerosol or harmful particulate matter to enter the body. To assess the therapeutic response or disease risk, whole-lung deposition models have been developed, but were limited by compartment, symmetry or stochastic approaches. In this work, we proposed an imaging-based subject-specific whole-lung deposition model. The geometries of airways and lobes were segmented from computed tomography (CT) lung images at total lung capacity (TLC), and the regional air-volume changes were calculated by registering CT images at TLC and functional residual capacity (FRC). The geometries were used to create the structure of entire subject-specific conducting airways and acinar units. The air-volume changes were used to estimate the function of subject-specific ventilation distributions among acinar units and regulate flow rates in respiratory airway models. With the airway dimensions rescaled to a desired lung volume and the airflow field simulated by a computational fluid dynamics model, particle deposition fractions were calculated using deposition probability formulae adjusted with an enhancement factor to account for the effects of secondary flow and airway geometry in proximal airways. The proposed model was validated in silico against existing whole-lung deposition models, three-dimensional (3D) computational fluid and particle dynamics (CFPD) for an acinar unit, and 3D CFPD deep lung model comprising conducting and respiratory regions. The model was further validated in vivo against the lobar particle distribution and the coefficient of variation of particle distribution obtained from CT and single-photon emission computed tomography (SPECT) images, showing good agreement. Subject-specific airway structure increased the deposition fraction of 10.0-μm particles and 0.01-μm particles by approximately 10%. An enhancement factor increased the overall deposition fractions, especially for particle sizes between 0.1 and 1.0 μm.

Awareness With Paralysis Among Critically Ill Emergency Department Patients: A Prospective Cohort Study

OBJECTIVES

In mechanically ventilated patients, awareness with paralysis (AWP) can have devastating consequences, including post-traumatic stress disorder (PTSD), depression, and thoughts of suicide. Single-center data from the emergency department (ED) demonstrate an event rate for AWP factors higher than that reported from the operating room. However, there remains a lack of data on AWP among critically ill, mechanically ventilated patients. The objective was to assess the proportion of ED patients experiencing AWP and investigate modifiable variables associated with its occurrence.

DESIGN

An a priori planned secondary analysis of a multicenter, prospective, before-and-after clinical trial.

SETTING

The ED of three academic medical centers.

PATIENTS

Mechanically ventilated adult patients that received neuromuscular blockers.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

All data related to sedation and analgesia were collected. AWP was the primary outcome, assessed with the modified Brice questionnaire, and was independently adjudicated by three expert reviewers. Perceived threat, in the causal pathway for PTSD, was the secondary outcome. A total of 388 patients were studied. The proportion of patients experiencing AWP was 3.4% ( n = 13), the majority of whom received rocuronium ( n = 12/13; 92.3%). Among patients who received rocuronium, 5.5% ( n = 12/230) experienced AWP, compared with 0.6% ( n = 1/158) among patients who did not receive rocuronium in the ED (odds ratio, 8.64; 95% CI, 1.11-67.15). Patients experiencing AWP had a higher mean ( sd ) threat perception scale score, compared with patients without AWP (15.6 [5.8] vs 7.7 [6.0]; p < 0.01).

CONCLUSIONS

AWP was present in a concerning proportion of mechanically ventilated ED patients, was associated with rocuronium exposure in the ED, and led to increased levels of perceived threat, placing patients at greater risk for PTSD. Studies that aim to further quantify AWP in this vulnerable population and eliminate its occurrence are urgently needed.

Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) occurs in up to 10% of patients with respiratory failure admitted through the emergency department. Use of noninvasive respiratory support has proliferated in recent years; clinicians must understand the relative merits and risks of these technologies and know how to recognize signs of failure. The cornerstone of ARDS care of the mechanically ventilated patient is low-tidal volume ventilation based on ideal body weight. Adjunctive therapies, such as prone positioning and neuromuscular blockade, may have a role in the emergency department management of ARDS depending on patient and department characteristics.

A dual-center cohort study on the association between early deep sedation and clinical outcomes in mechanically ventilated patients during the COVID-19 pandemic: The COVID-SED study

BACKGROUND

Mechanically ventilated patients have experienced greater periods of prolonged deep sedation during the coronavirus disease (COVID-19) pandemic. Multiple studies from the pre-COVID era demonstrate that early deep sedation is associated with worse outcome. Despite this, there is a lack of data on sedation depth and its impact on outcome for mechanically ventilated patients during the COVID-19 pandemic. We sought to characterize the emergency department (ED) and intensive care unit (ICU) sedation practices during the COVID-19 pandemic, and to determine if early deep sedation was associated with worse clinical outcomes.

STUDY DESIGN AND METHODS

Dual-center, retrospective cohort study conducted over 6 months (March-August, 2020), involving consecutive, mechanically ventilated adults. All sedation-related data during the first 48 h were collected. Deep sedation was defined as Richmond Agitation-Sedation Scale of - 3 to - 5 or Riker Sedation-Agitation Scale of 1-3. To examine impact of early sedation depth on hospital mortality (primary outcome), we used a multivariable logistic regression model. Secondary outcomes included ventilator-, ICU-, and hospital-free days.

RESULTS

391 patients were studied, and 283 (72.4%) experienced early deep sedation. Deeply sedated patients received higher cumulative doses of fentanyl, propofol, midazolam, and ketamine when compared to light sedation. Deep sedation patients experienced fewer ventilator-, ICU-, and hospital-free days, and greater mortality (30.4% versus 11.1%) when compared to light sedation (p < 0.01 for all). After adjusting for confounders, early deep sedation remained significantly associated with higher mortality (adjusted OR 3.44; 95% CI 1.65-7.17; p < 0.01). These results were stable in the subgroup of patients with COVID-19.

CONCLUSIONS

The management of sedation for mechanically ventilated patients in the ICU has changed during the COVID pandemic. Early deep sedation is common and independently associated with worse clinical outcomes. A protocol-driven approach to sedation, targeting light sedation as early as possible, should continue to remain the default approach.

Mechanical Ventilation Practices and Low Tidal Volume Ventilation in Air Medical Transport Patients: The AIR-VENT Study

BACKGROUND

The management of mechanical ventilation critically impacts outcome for patients with acute respiratory failure. Ventilator settings in the early post-intubation period may be especially influential on outcome. Low tidal volume ventilation in the prehospital setting has been shown to impact the provision of low tidal volume after admission and influence outcome. However, there is an overall paucity of data on mechanical ventilation for air medical transport patients. The objectives of this study were to characterize air medical transport ventilation practices and assess variables associated with nonprotective ventilation.

METHODS

This was a multi-center, nationwide (approximately 130 bases) retrospective cohort study conducted on consecutive, adult mechanically ventilated air medical transport patients treated in the prehospital environment. Descriptive statistics were used to assess the cohort; the chi-square test compared categorical variables, and continuous variables were compared using independent samples t test or Mann-Whitney U test. To assess for predictors of nonprotective ventilation, a multivariable logistic regression model was constructed to adjust for potentially confounding variables. Low tidal volume ventilation was defined as a tidal volume of ≤ 8 mL/kg predicted body weight (PBW).

RESULTS

A total of 68,365 subjects were studied. Height was documented in only 4,186 (6.1%) subjects. Significantly higher tidal volume/PBW (8.6 [8.3-9.2] mL vs 6.5 [6.1-7.0] mL) and plateau pressure (20.0 [16.5-25.0] cm H2O vs 18.0 [15.0-22.0] cm H2O) were seen in the nonpro-tective ventilation group (P < .001 for both). According to sex, females received higher tidal volume/PBW compared to males (7.4 [6.6-8.0] mL vs 6.4 [6.0-6.8] mL, P < .001) and composed 75% of those subjects with nonprotective ventilation compared to 25% male, P < .001. After multivariable logistic regression, female sex was an independent predictor of nonprotective ventilation (adjusted odds ratio 6.79 [95% CI 5.47-8.43], P < .001).

CONCLUSIONS

The overwhelming majority of air medical transport subjects had tidal volume set empirically, which may be exposing patients to nonprotective ventilator settings. Given a lack of PBW assessments, the frequency of low tidal volume use remains unknown. Performance improvement initiatives aimed at indexing tidal volume to PBW are easy targets to improve the delivery of mechanical ventilation in the prehospital arena, especially for females.

Low tidal volume ventilation is associated with mortality in COVID-19 patients-Insights from the PRoVENT-COVID study

Purpose

Low tidal volume ventilation (LTVV) is associated with mortality in patients with acute respiratory distress syndrome. We investigated the association of LTVV with mortality in COVID-19 patients.

Methods

Secondary analysis of a national observational study in COVID-19 patients in the first wave of the pandemic. We compared COVID-19 patients that received LTVV, defined as controlled ventilation with a median tidal volume ≤ 6 mL/kg predicted body weight over the first 4 calendar days of ventilation, with patients that did not receive LTVV. The primary endpoint was 28-day mortality. In addition, we identified factors associated with use of LTVV.

Results

Of 903 patients, 294 (32.5%) received LTVV. Disease severity scores and ARDS classification was not different between the two patient groups. The primary endpoint, 28-day mortality, was met in 68 out of 294 patients (23.1%) that received LTVV versus in 193 out of 609 patients (31.7%) that did not receive LTVV (P < 0.001). LTVV was independently associated with 28-day mortality (HR, 0.68 (0.45 to 0.95); P = 0.025). Age, height, the initial tidal volume and continuous muscle paralysis was independently associated with use of LTVV.

Conclusions

In this cohort of invasively ventilated COVID-19 patients, approximately a third of patients received LTVV. Use of LTVV was independently associated with reduced 28-day mortality. The initial tidal volume and continuous muscle paralysis were potentially modifiable factors associated with use of LTVV. These findings are important as they could help clinicians to recognize patients who are at risk of not receiving LTVV.

["B problems" in non-traumatic resuscitation room management]

In the primary survey of resuscitation room management in critically ill nontrauma patients, the ABCDE (airway, breathing, circulation, disability, exposure) approach is used for immediate recognition and treatment of life-threatening conditions. "B problems" are associated with respiratory failure and require immediate treatment. The pathogenesis is diverse, especially in the nontrauma resuscitation room. Clinical examination, emergency sonography and knowledge of oxygenation techniques and ventilation are important components of diagnosis and therapy. Standardized procedures and regular training in the emergency room are of fundamental importance.

Quality Improvement Intervention associated with Improved Lung Protective Ventilation Settings in an Emergency Department

INTRODUCTION

Patients requiring endotracheal intubation and mechanical ventilation in the emergency department (ED) are critically ill, and their ventilator management is crucial for their subsequent clinical outcomes. Lung-protective ventilation (LPV) setting strategies are key considerations for this care. The objectives of this 2019-2020 community-based quality improvement project were to: a) identify patients at greater risk of not receiving LPV, and b) evaluate the effectiveness of a series of brief quality improvement educational sessions to improve LPV setting protocol adherence rates.

METHODS

A 15-month retrospective chart review of ventilator settings and subject characteristics (N = 200) was conducted before and after a series of 10-15-minute educational sessions were delivered to improve LPV adherence. This information was presented at a series of four educational sessions for 25 attending physicians (n = two sessions) and 27 residents at conferences (n = two sessions). Two additional materials (e.g., LPV reference charts, tape measures to gauge patients’ heights) were also posted in three ED resuscitation rooms and on cabinets containing emergency airway equipment. The pre and post-intervention occurrence rates of LPV setting orders were inferentially compared before and after educational sessions.

RESULTS

Patients ventilated using LPV increased from 70% to 82% after the educational sessions (p = 0.04). All patients who were 67 inches or greater in height were ventilated appropriately before and after sessions. For patients under 65 inches in height, post-session LPV adherence increased from 13% to 53% (p = 0.01).

CONCLUSIONS

Based on these results, a brief ED provider educational intervention can significantly improve the utilization of LPV guideline-based settings. Patients under 65 inches in height may also be especially at risk of receiving non-LPV ventilator setting orders.

Initiation of a Lung Protective Ventilation Strategy in the Emergency Department: Does an Emergency Department-Based ICU Make a Difference?

BACKGROUND:

Lung protective ventilation (LPV) is a key component in the management of acute respiratory distress syndrome and other acute respiratory pathology. Initiation of LPV in the emergency department (ED) is associated with improved patient-centered and system outcomes, but adherence to LPV among ED patients is low. The impact of an ED-based ICU (ED-ICU) on LPV adherence is not known.

METHODS:

This single-center, retrospective, cohort study analyzed rates of adherence to a multifaceted LPV strategy pre- and post-implementation of an ED-ICU. LPV strategy components included low tidal volume ventilation, avoidance of severe hyperoxia and high plateau pressures, and positive end-expiratory pressure settings in alignment with best-evidence recommendations. The primary outcome was adherence to the LPV strategy at time of ED departure.

RESULTS AND CONCLUSIONS:

A total of 561 ED visits were included in the analysis, of which 60.0% received some portion of their emergency care in the ED-ICU. Adherence to the LPV strategy was statistically significantly higher in the ED-ICU cohort compared with the pre-ED-ICU cohort (65.8% vs 41.4%; p < 0.001) and non-ED-ICU cohort (65.8% vs 43.1%; p < 0.001). Among the ED-ICU cohort, 92.8% of patients received low tidal volume ventilation. Care in the ED-ICU was also associated with shorter ICU and hospital length of stay. These findings suggest improved patient and resource utilization outcomes for mechanically ventilated ED patients receiving care in an ED-ICU.

Low Tidal Volume Ventilation for Emergency Department Patients: A Systematic Review and Meta-Analysis on Practice Patterns and Clinical Impact

OBJECTIVES

Data suggest that low tidal volume ventilation (LTVV) initiated in the emergency department (ED) has a positive impact on outcome. This systematic review and meta-analysis quantify the impact of ED-based LTVV on outcomes and ventilator settings in the ED and ICU.

DATA SOURCES

We systematically reviewed MEDLINE, EMBASE, Scopus, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, references, conferences, and ClinicalTrials.gov.

STUDY SELECTION

Randomized and nonrandomized studies of mechanically ventilated ED adults were eligible.

DATA EXTRACTION

Two reviewers independently screened abstracts. The primary outcome was mortality. Secondary outcomes included ventilation duration, lengths of stay, and occurrence rate of acute respiratory distress syndrome (ARDS). We assessed impact of ED LTVV interventions on ED and ICU tidal volumes.

DATA SYNTHESIS

The search identified 1,023 studies. Eleven studies (n = 12,912) provided outcome data and were meta-analyzed; 10 additional studies (n = 1,863) provided descriptive ED tidal volume data. Overall quality of evidence was low. Random effect meta-analytic models revealed that ED LTVV was associated with lower mortality (26.5%) versus non-LTVV (31.1%) (odds ratio, 0.80 [0.72-0.88]). ED LTVV was associated with shorter ICU (mean difference, -1.0; 95% CI, -1.7 to -0.3) and hospital (mean difference, -1.2; 95% CI, -2.3 to -0.1) lengths of stay, more ventilator-free days (mean difference, 1.4; 95% CI, 0.4-2.4), and lower occurrence rate (4.5% vs 8.3%) of ARDS (odds ratio, 0.57 [0.44-0.75]). ED LTVV interventions were associated with reductions in ED (-1.5-mL/kg predicted body weight [PBW] [-1.9 to -1.0]; p < 0.001) and ICU (-1.0-mL/kg PBW [-1.8 to -0.2]; p = 0.01) tidal volume.

CONCLUSIONS

The use of LTVV in the ED is associated with improved clinical outcomes and increased use of lung protection, recognizing low quality of evidence in this domain. Interventions aimed at implementing and sustaining LTVV in the ED should be explored.

Improving delivery of low tidal volume ventilation in 10 ICUs

Low tidal volume ventilation (LTVV) is standard of care for mechanically ventilated patients with acute respiratory distress syndrome and has been shown to improve outcomes in the general mechanically ventilated population. Despite these improved outcomes, in clinical practice the LTVV standard of care is often not met. We aimed to increase compliance with LTVV in mechanically ventilated patients in 10 intensive care units at 3 hospitals within the University of Pittsburgh School of Medicine Department of Critical Care Medicine. Four Plan-Do-Study-Act (PDSA) cycles were implemented to improve compliance with LTVV. Initial compliance rates of 40.6%–60.1% improved to 91%–96% by the end of the fourth PDSA cycle. The most impactful step in the intervention was providing education and giving responsibility of selecting the tidal volume to the respiratory therapist. The overall intervention resulted in improved compliance with LTVV that has been sustained for multiple years after our active PDSA cycles.

Influence of Critical Care Transport Ventilator Management on Intensive Care Unit Care

OBJECTIVE

High tidal volume ventilation is associated with ventilator-induced lung injury. Early introduction of lung protective ventilation improves patient outcomes. This study describes ventilator management during critical care transport and the association between transport ventilator settings and ventilator settings in the intensive care unit (ICU).

METHODS

This was a retrospective review of mechanically ventilated adult patients transported to an academic medical center via a critical care transport program between January 2018 and April 2019. Ventilator settings during transport were compared with the initial and 6- and 12-hour postadmission ventilator settings.

RESULTS

Three hundred eighty patients were identified; 114 (30%) received tidal volumes > 8 mL/kg predicted body weight at the time of transfer. The transport handoff tidal volume strongly correlated with the ICU tidal volume (Pearson r = 0.7). Patients receiving high tidal volumes during transport were more likely to receive high tidal volumes initially upon transfer (relative risk [RR] = 4.6; 95% confidence interval [CI], 3.3-6.5) and at 6 and 12 hours after admission (RR = 2.6; 95% CI, 1.8-3.8 and RR = 2.7; 95% CI, 1.7-4.3, respectively).

CONCLUSION

Exposure to high tidal volumes during transport is associated with high tidal volume ventilation in the ICU, even up to 12 hours after admission. This study identifies opportunities for improving patient care through the application of lung protective ventilation strategies during transport.

Utility of solar-powered oxygen delivery in a resource-constrained setting

BACKGROUND

Pneumonia is a leading cause of childhood mortality globally. Children with severe pneumonia associated with hypoxaemia require oxygen (O₂) therapy, which is scarce across resource-constrained countries. Solar-powered oxygen (SPO2) is a novel technology developed for delivering therapeutic O₂ in resource-constrained environments.

RESEARCH QUESTION

Is the introduction of SPO2 associated with a reduction in mortality, relative to the existing practice?

STUDY DESIGN

This was a pragmatic, quasi-experimental study comparing mortality amongst children < 5 years of age with hypoxaemic respiratory illness before and after the installation of SPO2 in two resource-constrained hospitals.

METHODS

Participants were children < 5 years old admitted with acute hypoxaemic respiratory illness. The intervention was SPO2, installed at two resource-constrained hospitals. The primary outcome was 30-day mortality. Secondary outcomes included in-hospital mortality (time to death), length of hospital stay among survivors, duration of O₂ therapy (time to wean O₂), and O₂ delivery system failure(s).

RESULTS

Mortality amongst children admitted with acute hypoxaemic respiratory illness decreased from 30/50 (60%) pre-SPO2 to 15/50 (30%) post-SPO2 (relative risk reduction 50%, 95%CI 19 - 69, p = 0.0049). The post-SPO2 period was consistently associated with decreased mortality in statistical models adjusting for potential confounding factors. Likewise, survival curves pre- and post- SPO2 differed significantly (hazard ratio 0.39, 95% CI 0.20 - 0.74, p = 0.0043). A reduction in the frequency of O₂ delivery interruptions due to fuel shortages and multiple patients needing the concentrator at once was observed, explaining the mortality reduction.

INTERPRETATION

Solar-powered oxygen installation was associated with decreased mortality in resource-constrained settings.

Management of COVID-19 Patients in the Emergency Department

COVID-19 is an emerging disease of global public health concern. As the pandemic overwhelmed emergency departments (EDs), a restructuring of emergency care delivery became necessary in many hospitals. Furthermore, with more than 2000 papers being published each week, keeping up with ever-changing information has proven to be difficult for emergency physicians. The aim of the present review is to provide emergency physician with a summary of the current literature regarding the management of COVID-19 patients in the emergency department.

A Target for Increased Mortality Risk in Critically Ill Patients: The Concept of Perpetuity

Background: Emergency medicine is acuity-based and focuses on time-sensitive treatments for life-threatening diseases. Prolonged time in the emergency department, however, is associated with higher mortality in critically ill patients. Thus, we explored management after an acuity-based intervention, which we call perpetuity, as a potential mechanism for increased risk. To explore this concept, we evaluated the impact of each hour above a lung-protective tidal volume on risk of mortality. Methods: This cohort analysis includes all critically ill, non-trauma, adult patients admitted to two academic EDs between 1 November 2013 and 30 April 2017. Cox models with time-varying covariates were developed with time in perpetuity as a time-varying covariate, defined as hours above 8 mL/kg ideal body weight, adjusted for covariates. The primary outcome was the time to in-hospital death. Results: Our analysis included 2025 patients, 321 (16%) of whom had at least 1 h of perpetuity time. A partial likelihood-ratio test comparing models with and without hours in perpetuity was statistically significant (χ²(3) = 13.83, p = 0.0031). There was an interaction between age and perpetuity (Relative risk (RR) 0.9995; 95% Confidence interval (CI₉₅): 0.9991–0.9998). For example, for each hour above 8 mL/kg ideal body weight, a 20-year-old with 90% oxygen saturation has a relative risk of death of 1.02, but a 40-year-old with 90% oxygen saturation has a relative risk of 1.01. Conclusions: Perpetuity, illustrated through the lens of mechanical ventilation, may represent a target for improving outcomes in critically ill patients, starting in the emergency department. Research is needed to evaluate the types of patients and interventions in which perpetuity plays a role.

Heart-Protective Mechanical Ventilation in Postoperative Cardiosurgical Patients

BACKGROUND

This study compared the hemodynamic effects and gas exchange under several different ventilator settings-with regard to tidal volume, respiratory rate, and end-expiratory pressure-in patients after coronary artery bypass grafting (CABG).

METHODS

Prospective interventional cohort study with a controlled group in a single cardiosurgical ICU involving 119 patients following on-pump CABG surgery. During the 1st postoperative hour, the intervention group patients were ventilated with Vt 10 ml × kg-1, RR 14/min, PEEP 5 cmH2O ("conventional ventilation"). During the 2nd hour, RR was reduced to 8/min ("reduced RR ventilation"). At 3 hrs, Vt was decreased to 6 ml × kg-1, RR returned to 14/min, and PEEP increased to 10 cmH2O ("low Vt-high PEEP ventilation").

RESULTS

Patients in the "low Vt-high PEEP" ventilation period showed significantly lower alveolar ventilation and thoraco-pulmonary compliance than during "reduced RR" ventilation. Mean airway pressure and Vds/Vt peaked during low Vt-high PEEP ventilation; however, driving pressure was lower. Vt decrease and PEEP increase did not lead to oxygenation improvement and worsened CO2 elimination. Hemodynamically, the study revealed significant cardiac output decrease during low Vt-high PEEP ventilation. In 23.2% of patients, catecholamine therapy was initiated.

CONCLUSIONS

In postoperative cardiosurgical patients, MV with Vt 6 ml × kg-1 and PEEP 10 cm H2O is characterized by worsened oxygenation and elimination of CO2 and a less favorable hemodynamic profile than ventilation with Vt 10 ml × kg-1 and PEEP 5 cmH2O. New and Noteworthy. (i) Patients after CABG may be especially sensitive to low tidal volume and increased PEEP as it negatively affects hemodynamic profile by means of the right heart preload decrease and afterload increase. (ii) Mechanical ventilation settings aiming to minimize mean airway pressure reduce the negative effects of positive inspiratory pressure and are favorable for hemodynamics.

The ED-AWARENESS Study: A Prospective, Observational Cohort Study of Awareness With Paralysis in Mechanically Ventilated Patients Admitted From the Emergency Department

STUDY OBJECTIVE

Awareness with paralysis is a devastating complication for patients receiving mechanical ventilation and risks long-term psychological morbidity. Data from the emergency department (ED) demonstrate a high rate of longer-acting neuromuscular blocking agent use, delayed analgosedation, and a lack of sedation depth monitoring. These practices are discordant with recommendations for preventing awareness with paralysis. Despite this, awareness with paralysis has not been rigorously studied in the ED population. Our objective is to assess the prevalence of awareness with paralysis in ED patients receiving mechanical ventilation.

METHODS

This was a single-center, prospective, observational cohort study on 383 mechanically ventilated ED patients. After extubation, we assessed patients for awareness with paralysis by using the modified Brice questionnaire. Three expert reviewers independently adjudicated awareness with paralysis. We report the prevalence of awareness with paralysis (primary outcome); the secondary outcome was perceived threat, a mediator for development of posttraumatic stress disorder.

RESULTS

The prevalence of awareness with paralysis was 2.6% (10/383). Exposure to rocuronium at any point in the ED was significantly different between patients who experienced awareness with paralysis (70%) versus the rest of the cohort (31.4%) (unadjusted odds ratio 5.1; 95% confidence interval 1.30 to 20.1). Patients experiencing awareness with paralysis had higher mean values on the threat perception scale, denoting a higher degree of perceived threat, compared with patients who did not experience awareness with paralysis (13.4 [SD 7.7] versus 8.5 [SD 6.2]; mean difference 4.9; 95% confidence interval 0.94 to 8.8).

CONCLUSION

Awareness with paralysis occurs in a significant minority of ED patients who receive mechanical ventilation. Potential associations of awareness with paralysis with ED care and increased perceived threat warrant further evaluation.

Impact of Providing a Tape Measure on the Provision of Lung-protective Ventilation

INTRODUCTION

Emergency department (ED) patients are frequently ventilated with excessively large tidal volumes for predicted body weight based on height, which has been linked to poorer patient outcomes. We hypothesized that supplying tape measures to respiratory therapists (RT) would improve measurement of actual patient height and adherence to a lung-protective ventilation strategy in an ED-intensive care unit (ICU) environment.

METHODS

On January 14, 2019, as part of a ventilator-associated pneumonia prevention bundle in our ED-based ICU, we began providing RTs with tape measures and created a best practice advisory reminding them to record patient height. We then retrospectively collected data on patient height and tidal volumes before and after the intervention.

RESULTS

We evaluated 51,404 tidal volume measurements in 1,826 patients over the 4 year study period; of these patients, 1,579 (86.5%) were pre-intervention and 247 (13.5%) were post-intervention. The intervention was associated with a odds of the patient's height being measured were 10 times higher post-intervention (25.1% vs 3.2%, P <0.05). After the bundle was initiated, we observed a significantly higher percentage of patients ventilated with mean tidal volumes less than 8 cubic centimeters per kilogram (93.9% vs 84.5% P < 0.05).

CONCLUSION

Patients in an ED-ICU environment were ventilated with a lung-protective strategy more frequently after an intervention reminding RTs to measure actual patient height and providing a tape measure to do so. A significantly higher percentage of patients had height measured rather than estimated after the intervention, allowing for more accurate determination of ideal body weight and calculation of lung-protective ventilation volumes. Measuring all mechanically ventilated patients' height with a tape measure is an example of a simple, low-cost, scalable intervention in line with guidelines developed to improve the quality of care delivered to critically ill ED patients.

Lung-Protective Ventilation Over 6 Years at a Large Academic Medical Center: An Evaluation of Trends, Adherence, and Perceptions of Benefit

The main objective of this study was to evaluate trends in set tidal volumes across all adult ICUs at a large academic medical center over 6 years, with a focus on adherence to lung-protective ventilation (≤ 8-cc/kg ideal body weight). A secondary objective was to survey providers on their perceptions of lung-protective ventilation and barriers to its implementation.

DESIGN

Retrospective observational analysis (primary objective) and cross-sectional survey study (secondary objective), both at a single center.

PARTICIPANTS

Mechanically ventilated adult patients with a set tidal volume (primary objective) and providers rotating through the Medical and Neurosciences ICUs (secondary objective).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

From 2013 to 2018, the average initial set tidal volume (cc/kg ideal body weight) decreased from 8.99 ± 2.19 to 7.45±1.34 (p < 0.001). The cardiothoracic ICU had the largest change in tidal volume from 11.09 ± 1.96 in 2013 to 7.97 ± 1.03 in 2018 (p < 0.001). Although the majority of tidal volumes across all ICUs were between 6.58 and 8.01 (interquartile range) in 2018, 27% of patients were still being ventilated at volumes greater than 8-cc/kg ideal body weight. Most surveyed respondents felt there was benefit to lung-protective ventilation, though many did not routinely calculate the set tidal volume in cc/kg ideal body weight, and most did not feel it was easily calculable with the current electronic medical record system.

CONCLUSIONS

Despite a trend toward lower tidal volumes over the years, in 2018, over a quarter of mechanically ventilated adult patients were being ventilated with tidal volumes greater than 8 cc/kg. Survey data indicate that despite respondents acknowledging the benefits of lung-protective ventilation, there are barriers to its optimal implementation. Future modifications of the electronic medical record, including a calculator to set tidal volume in cc/kg and the use of default set tidal volumes, may help facilitate the delivery of and adherence to lung-protective ventilation.

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.

A study protocol for a multicentre, prospective, before-and-after trial evaluating the feasibility of implementing targeted SEDation after initiation of mechanical ventilation in the emergency department (The ED-SED Pilot Trial)

INTRODUCTION

Sedation is a cornerstone therapy in the management of patients receiving mechanical ventilation and is highly influential on outcome. Early sedation depth appears especially influential, as early deep sedation is associated with worse outcome when compared with light sedation. Our research group has shown that patients receiving mechanical ventilation in the emergency department (ED) are exposed to deep sedation commonly, and ED sedation depth is impactful on intensive care unit (ICU) care and clinical outcomes. While extensive investigation has occurred for patients in the ICU, comparatively little data exist from the ED. Given the influence that ED sedation seems to carry, as well as a lack of ED-based sedation trials, there is significant rationale to investigate ED-based sedation as a means to improve outcome.

METHODS AND ANALYSIS

This is a multicentre (n=3) prospective, before-and-after pilot trial examining the feasibility of implementing targeted sedation in the immediate postintubation period in the ED. A cohort of 344 patients receiving mechanical ventilation in ED will be included. Feasibility outcomes include: (1) participant recruitment; (2) proportion of Richmond Agitation-Sedation Scale (RASS) scores in the deep sedation range; (3) reliability (agreement) of RASS measurements performed by bedside ED nurses; and (4) adverse events. The proportion of deep sedation measurements before and after the intervention will be compared using the χ² test. Logistic regression will be used to compare before-and-after differences, adjusting for potential confounders. The inter-rater correlation coefficient will be used to assess paired observations between a study team member and bedside ED nurses, and to describe reliability of RASS measurements.

ETHICS AND DISSEMINATION

The Human Research Protection Office at Washington University in St. Louis School of Medicine has approved the study. The publication of peer-reviewed manuscripts and the presentation of abstracts at scientific meetings will be used to disseminate the work.

REGISTRATION

ClinicalTrials.gov identifier NCT04410783; Pre-results.

Lung-Protective Ventilation and Associated Outcomes and Costs Among Patients Receiving Invasive Mechanical Ventilation in the ED

BACKGROUND

Invasive mechanical ventilation is often initiated in the ED, and mechanically ventilated patients may be kept in the ED for hours before ICU transfer. Although lung-protective ventilation is beneficial, particularly in ARDS, it remains uncertain how often lung-protective tidal volumes are used in the ED, and whether lung-protective ventilation in this setting impacts patient outcomes.

RESEARCH QUESTION

What is the association between the use of lung-protective ventilation in the ED and outcomes among invasively ventilated patients?

STUDY DESIGN AND METHODS

A retrospective analysis (2011-2017) of a prospective registry from eight EDs enrolling consecutive adult patients (≥ 18 years) who received invasive mechanical ventilation in the ED was performed. Lung-protective ventilation was defined by use of tidal volumes ≤ 8 mL/kg predicted body weight. The primary outcome was hospital mortality. Secondary outcomes included development of ARDS, hospital length of stay, and total hospital costs.

RESULTS

The study included 4,174 patients, of whom 2,437 (58.4%) received lung-protective ventilation in the ED. Use of lung-protective ventilation was associated with decreased odds of hospital death (adjusted OR [aOR], 0.91; 95% CI, 0.84-0.96) and development of ARDS (aOR, 0.87; 95% CI, 0.81-0.92). Patients who received lung-protective ventilation in the ED had shorter median duration of mechanical ventilation (4 vs 5 days; P < 0.01), shorter median hospital length of stay (11 vs 14 days; P < .001), and reduced total hospital costs (Can$44,348 vs Can$52,484 [US$34,153 vs US$40,418]; P = .03) compared with patients who received higher tidal volumes.

INTERPRETATION

Use of lung-protective ventilation in the ED was associated with important patient- and system-centered outcomes, including lower hospital mortality, decreased incidence of ARDS, lower hospital length of stay, and decreased total costs. Protocol development promoting the regular use of lung-protective ventilation in the ED may be of value.

Initial emergency department mechanical ventilation strategies for COVID-19 hypoxemic respiratory failure and ARDS

INTRODUCTION

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an emerging viral pathogen that causes the novel coronavirus disease of 2019 (COVID-19) and may result in hypoxemic respiratory failure necessitating invasive mechanical ventilation in the most severe cases.

OBJECTIVE

This narrative review provides evidence-based recommendations for the treatment of COVID-19 related respiratory failure requiring invasive mechanical ventilation.

DISCUSSION

In severe cases, COVID-19 leads to hypoxemic respiratory failure that may meet criteria for acute respiratory distress syndrome (ARDS). The mainstay of treatment for ARDS includes a lung protective ventilation strategy with low tidal volumes (4-8 mL/kg predicted body weight), adequate positive end-expiratory pressure (PEEP), and maintaining a plateau pressure of < 30 cm H₂O. While further COVID-19 specific studies are needed, current management should focus on supportive care, preventing further lung injury from mechanical ventilation, and treating the underlying cause.

CONCLUSIONS

This review provides evidence-based recommendations for the treatment of COVID-19 related respiratory failure requiring invasive mechanical ventilation.

Standardized Management for Hypoxemic Respiratory Failure and ARDS: Systematic Review and Meta-analysis

BACKGROUND

Treatment of hypoxemic respiratory failure (HRF) and ARDS is complex. Standardized management of HRF and ARDS may improve adherence to evidence-informed practice and improve outcomes.

RESEARCH QUESTION

What is the effect of standardized treatment compared with usual care on survival of patients with HRF and ARDS?

STUDY DESIGN AND METHODS

MEDLINE, EMBASE, Cochrane, CINAHL, Scopus, and Web-of-Science were searched (inception to 2018). Included studies were randomized clinical trials or quasi-experimental studies that examined the effect of standardized treatment (care-protocol, care-pathway, or bundle) compared with usual treatment among mechanically ventilated adult patients admitted to an ICU with HRF or ARDS. Study characteristics, pathway components, and patient outcomes were abstracted independently by two reviewers.

RESULTS

From 15,932 unique citations, 14 studies were included in the systematic review (three randomized clinical trials and 11 quasi-experimental studies). Twelve studies (including 5,767 patients) were included in the meta-analysis. Standardized management of HRF was associated with a 23% relative reduction in mortality (relative risk, 0.77; 95% CI, 0.65-0.91; I², 70%; P = .002). In studies targeting patients with ARDS (n = 8), a 21% pooled mortality reduction was observed (relative risk, 0.79; 95% CI, 0.71-0.88; I², 3.1%). Standardized management was associated with increased 28-day ventilator-free days (weighted mean difference, 3.48 days; 95% CI, 2.43-4.54 days; P < .001). Standardized management was also associated with a reduction in tidal volume (weighted mean difference, -1.80 mL/kg predicted body weight; 95% CI, -2.80 to -0.80 mL/kg predicted body weight; P < .001). Meta-regression demonstrated that the reduction in mortality was associated with provision of lower tidal volume (P = .045).

INTERPRETATION

When compared with usual treatment, standardized treatment of patients with HRF and ARDS is associated with increased ventilator-free days, lower tidal volume ventilation, and lower mortality. ICUs should consider the use of standardized treatment to improve the processes and outcomes of care for patients with HRF and ARDS.

CLINICAL TRIAL REGISTRATION

PROSPERO; No.: CRD42019099921; URL: www.crd.york.ac.uk/prospero/.

High-Risk Airway Management in the Emergency Department. Part I: Diseases and Approaches

BACKGROUND

Successful airway management is critical to the practice of emergency medicine. Emergency physicians must be ready to optimize and prepare for airway management in critically ill patients with a wide range of physiologic challenges. Challenges in airway management commonly encountered in the emergency department are discussed using a pearl and pitfall discussion in this first part of a 2-part series.

OBJECTIVE

This narrative review presents an evidence-based approach to airway and patient management during endotracheal intubation in challenging cases that are commonly encountered in the emergency department.

DISCUSSION

Adverse events during emergent airway management are common, with postintubation cardiac arrest reported in as many as 1 in 25 intubations. Many of these adverse events can be avoided with the proper identification and understanding of the underlying physiology, preparation, and postintubation management. Patients with high-risk features including severe metabolic acidosis; shock and hypotension; obstructive lung disease; pulmonary hypertension, right ventricle failure, and pulmonary embolism; and severe hypoxemia must be managed with airway expertise.

CONCLUSIONS

This narrative review discusses the pearls and pitfalls of commonly encountered physiologic high-risk intubations with a focus on the emergency clinician.

Males Receive Low-Tidal Volume Component of Lung Protective Ventilation More Frequently than Females in the Emergency Department

Introduction

Mechanical ventilation is a commonly performed procedure in the emergency department (ED). Approximately 240,000 patients per year receive mechanical ventilation in the ED representing 0.23% of ED visits. An ED-based trial published in 2017 showed that a bundle of interventions in mechanically ventilated patients, including low tidal volume ventilation, reduced the development of acute respiratory distress syndrome by nearly 50%. Prior literature has shown that as many as 40% of ED patients do not receive lung protective ventilation. Our goal was to determine whether differences exist between the percent of males vs females who are ventilated at ≥ 8 milliliters per kilogram (mL/kg) of predicted body weight.

Methods

We conducted this study at Temple University Hospital, a tertiary care center located in Philadelphia, Pennsylvania. This was a planned subgroup analysis of study looking at interventions to improve adherence to recommended tidal volume settings. We used a convenience sample of mechanically ventilated patients in our ED between September 1, 2017, and September 30, 2018. All adult patient > 18 years old were eligible for inclusion in the study. Our primary outcome measure was the number of patients who had initial tidal volumes set at > 8 mL/kg of predicted body weight. Our secondary outcome was the number of patients who had tidal volumes set at ≥ 8 mL/kg at 60 minutes after initiation of mechanical ventilation.

Results

A total of 130 patients were included in the final analysis. We found that significantly more females were initially ventilated with tidal volumes ≥ 8 mL/kg compared to men: 56% of females vs 9% of males (p=<0.001). Data was available for 107 patients (82%) who were in the ED at 60 minutes after initiation of mechanical ventilation. Again, a significantly larger percentage of females were ventilated with tidal volumes ≥ 8 mL/kg at 60 minutes: 56% of females vs 10% of males (p<0.001).

Conclusion

The vast majority of tidal volumes ≥ 8 mL/kg during mechanical ventilation occurs in females. We suggest that objective measurements, such as a tape measure and tidal volume card, be used when setting tidal volumes for all patients, especially females.

Protocol for a prospective, observational cohort study of awareness in mechanically ventilated patients admitted from the emergency department: the ED-AWARENESS study

INTRODUCTION

Awareness with paralysis is a complication with potentially devastating psychological consequences for mechanically ventilated patients. While rigorous investigation into awareness has occurred for operating room patients, little attention has been paid outside of this domain. Mechanically ventilated patients in the emergency department (ED) have been historically managed in a way that predisposes them to awareness events: high incidence of neuromuscular blockade use, underdosing of analgesia and sedation, delayed administration of analgesia and sedation after intubation, and a lack of monitoring of sedation targets and depth. These practice patterns are discordant to recommendations for reducing the incidence of awareness, suggesting there is significant rationale to examine awareness in the ED population.

METHODS AND ANALYSIS

This is a single centre, prospective cohort study examining the incidence of awareness in mechanically ventilated ED patients. A cohort of 383 mechanically ventilated ED patients will be included. The primary outcome is awareness with paralysis. Qualitative reports of all awareness events will be provided. Recognising the potential problem with conventional multivariable analysis arising from a small number of events (expected less than 10-phenomenon of separation), Firth penalised method, exact logistic regression model or penalised maximum likelihood estimation shrinkage (Ridge, LASSO) will be used to assess for predictors of awareness.

ETHICS AND DISSEMINATION

Approval of the study by the Human Research Protection Office has been obtained. This work will be disseminated by publication of peer-reviewed manuscripts, presentation in abstract form at scientific meetings and data sharing with other investigators through academically established means.

Adoption of low tidal volume ventilation in the emergency department: A quality improvement intervention

BACKGROUND

Ventilator tidal volumes of >8 mL/kg of predicted body weight (PBW) may increase the risk of lung injury. We sought to evaluate the impact of a quality improvement intervention among intubated Emergency Department (ED) patients to protocolize the prescription of low tidal volume ventilation.

METHODS

In this before-and-after study, the average tidal volume delivered to ED patients receiving volume assist-control ventilation was compared before (2007-2014) and after (2015-2016) implementation of a ventilator initiation protocol (the quality improvement intervention). The intervention emphasized 1) measurement of the patient's height to calculate PBW and therefore tailor the tidal volume to estimated lung size (<8 mL/kg PBW), and 2) focused education and reference materials for ED physicians and respiratory therapists.

RESULTS

Among ventilated ED patients meeting inclusion criteria in the before (N = 2185) and after (N = 774) cohorts, the mean (±SD) tidal volume decreased from 9.0 ± 1.4 mL/kg to 7.2 ± 0.9 mL/kg PBW following the intervention (absolute difference 1.8 mL/kg, 95% confidence interval 1.7 to 1.9 mL/kg, p < 0.001). The proportion of patients receiving low tidal volume ventilation increased after the intervention (72%), as compared to before (23%). Low tidal volume ventilation continued to be utilized at 24 h after ICU admission in patients who remained intubated in the cohort following the intervention (mean tidal volume 7.3 mL/kg PBW).

CONCLUSIONS

Pairing a ventilator initiation protocol with focused education and resources for emergency physicians and respiratory therapists was associated with a significant reduction in tidal volume delivered to ED patients.

Invasive mechanical ventilation in the emergency department

Emergency department (ED) lenght of stay of the patients requiring admission to the intensive care units has increased gradually in recent years. Mechanical ventilation is an integral part of critical care and mechanically ventilated patients have to be managed and monitored by emergency physicians for longer than expected in EDs. This early period of care has significant impact on the outcomes of these patients. Therefore, emergency physicians should have comprehensive knowledge of mechanical ventilation. This review will summarize the current literature of the basic concepts, appropriate clinical applications, monitoring parameters, components and mechanisms of mechanical ventilation in the ED.