Variability in sedation assessment among intubated patients in the emergency department (2021)

Analgesia and sedation for patients who are mechanically ventilated may improve endotracheal tube tolerance, alleviate pain, reduce agitation, and facilitate other aspects of care including imaging, procedures, and travel to different parts of the hospital. Notwithstanding these benefits, lighter levels of sedation are associated with improved patient outcomes in intensive care unit (ICU) settings, including decreased duration of mechanical ventilation and length of stay.1-4 Consequently, clinical practice guidelines recommend routine sedation assessments for medication titration among mechanically ventilated patients in the ICU.5 There is little evidence to guide early sedation practices in the emergency department (ED), where mechanical ventilation is regularly initiated. Observational data suggest early deep sedation Richmond Agitation Sedation Scale Richmond Agitation Sedation Scale (RASS –3 to –5) after intubation is common and associated with increased delirium, coma, length of stay, and mortality.6-9 There may be opportunities to improve patient outcomes by targeting interventions in the early postintubation period, but there is limited understanding of current ED practices regarding sedation assessment. This study evaluated variation in sedation assessment among mechanically ventilated patients in EDs within the Prevention and Early Treatment of Acute Lung Injury (PETAL) hospital network and investigated factors associated with documentation of ED sedation assessment. The study was a secondary analysis of the Low Tidal Volume Universal Support: Feasibility of Recruitment for Interventional Trial (LOTUS-FRUIT).10 LOTUS-FRUIT was an observational cohort study of consecutive patients presenting with acute respiratory failure at PETAL hospitals in July 2016. The objective was to assess feasibility of a larger trial to determine whether default low tidal volume ventilation (6 mL/kg) improved outcomes compared to usual care. All data were deidentified and the present study was exempt from institutional review board review. Adult patients who were intubated in the ED or prehospital setting were included in this study. Patients were excluded if electively intubated or from sites with less than five ED or prehospital intubations in July 2016. The parent study (LOTUS-FRUIT) suggested clinical practices related to mechanical ventilation varied by hospital site, patient severity of illness, and the presence of acute respiratory distress syndrome (ARDS).10 Building on these findings, 11 exposure variables were hypothesized to be potentially associated with assessment of sedation in ED settings: hospital site, age, continuous infusion of benzodiazepines, propofol, and/or opioids, receipt of any sedative/analgesic medication beyond induction for intubation, time from intubation to ICU admission, reason for intubation, location of intubation (ED or prehospital), presence of ARDS in the ED, PaO2:FiO2 (P:F) ratio in the ED, type of admitting ICU (e.g., medical or surgical), and Sequential Organ Failure Assessment (SOFA) scores. ARDS was defined as a P:F ratio ≤ 300 and chest radiograph within 24 hours showing bilateral infiltrates unexplained by mass, collapse, or effusion.10 SOFA scores were examined without the Glasgow Coma Scale given expected collinearity with sedation assessments. The primary outcome was a documented sedation assessment in the ED using a standardized sedation scale (Richmond Agitation–Sedation Scale [RASS], Riker, or Ramsay). Patient characteristics were examined using descriptive statistics. The proportion of patients with a documented ED sedation assessment was compared across sites with 95% binomial confidence intervals (CIs). Hypothesized associations between patient characteristics, treatment factors, hospital site, and the outcome of ED sedation assessment were tested using a generalized linear mixed-effects model, including hospital site as a random effect and all other exposure variables as fixed effects. The intraclass correlation coefficient (ICC) and covariance parameters of hospital site were used to evaluate variability in documentation of ED sedation assessments across hospitals. The covariance matrix of the parameter estimates was calculated using empirical (sandwich) estimators. All statistical tests were performed at the ⍺ = 0.05 level (two-sided) using SAS version 9.4 and Stata version 15. Of the 2,200 patients included in LOTUS-FRUIT, this study excluded 1,409 patients who were not intubated in the ED or prehospital setting, 10 patients who were electively intubated, and 11 patients from sites with fewer than five ED or prehospital intubations. The final sample included 770 patients from 45 sites. The most common reason for intubation was altered mental status (n = 374, 49%), followed by respiratory failure (n = 355, 45%; Data Supplement S1, available as supporting information in the online version of this paper, which is available at http://onlinelibrary.wiley.com/doi/10.1111/acem.14259/full). A majority of patients (n = 546, 71%) were intubated in the ED, while 29% (n = 224) were intubated prehospital. Patients were most commonly admitted to medical ICUs (n = 366, 48%), followed by surgical (n = 160, 21%), mixed (n = 137, 18%), neurological (n = 65, 8%), and cardiac (n = 42, 6%). The median time from intubation to ICU admission was 3.2 hours (IQR = 1.4–4.2 hours). Most patients (n = 569, 74%) received sedation/analgesia in the ED, including 63% (n = 487) who received continuous infusions of sedative/analgesic medication. Twenty-six percent (n = 198) of patients met criteria for ARDS in the ED (mean ± SD P:F ratio = 244 ± 161 mm Hg). The overall proportion of intubated patients with a documented sedation assessment in the ED was 30% (95% CI = 26% to 33%) but ranged from 0% to 100% by hospital (Figure 1A). Among the 74% (n = 569) of patients who received sedation/analgesia in the ED, 35% (95% CI = 31% to 39%) had a documented sedation assessment. Descriptive statistics comparing patients with and without a documented sedation assessment in the ED suggested those who were older (56.3 years vs. 52.9 years), had longer time from intubation to ICU admission (4.0 hours vs. 3.2 hours), and were receiving continuous infusion of benzodiazepines (18% vs. 11%), propofol (55% vs. 41%), and/or opioids (41% vs. 25%) were more likely to be assessed (Data Supplement S1). Using multivariable linear mixed-effects regression, time from intubation to ICU admission (RR = 1.08, 95% CI = 1.02 to 1.14) and continuous infusion of benzodiazepines (RR = 1.72, 95% CI = 1.21 to 2.22), propofol (RR = 1.38, 95% CI = 1.07 to 1.72), and/or opioids (RR = 1.38, 95% CI = 1.03 to 1.76) remained significantly associated with documentation of a sedation assessment in the ED. Hospital site contributed 39% of estimated variability in the adjusted model (ICC = 0.39), with a statistically significant covariance parameter (<0.01; Figure 1B). In this study of patients who were intubated in the ED or prehospital setting, documented sedation assessments in the ED were uncommon and varied considerably across hospitals. This clinical variation may reflect differences in quality of care that require further investigation. Lack of sedation assessments may preclude systematic quality improvement interventions targeting light sedation in the early postintubation period. Data describing sedation assessments in the ED are rare. Randomized trials comparing sedation strategies have generally enrolled patients 48 to 96 hours after initiation of mechanical ventilation, when patients have transferred to an ICU. Fuller et al.8 performed a multicenter observational cohort study of mechanically ventilated patients in the ED, but used the first ICU RASS assessment as a proxy in patients lacking documented sedation assessments in the ED. As such, this study represents the first multicenter investigation explicitly describing the proportion of patients receiving sedation assessments in the ED. Time from intubation to ICU admission and continuous infusion of sedative/analgesic medications were associated with sedation assessments in the ED. The effect of hospital site was also significant, accounting for 39% of variability in the multivariable model. Unmeasured factors associated with hospital site such as sedation/analgesia protocols, staffing ratios, electronic health record differences, hybrid ED-ICUs, and local clinical champions, may influence these observed differences across hospitals. Unpacking the relationships between site-specific factors and ED sedation assessment will be essential to future work to improve early management of sedation/analgesia. This study has several limitations. Documentation of level of sedation was used as a proxy for sedation assessment. It is possible that frontline providers perform informal or formal sedation assessments without documenting their findings. Additionally, while hospital site was strongly associated with documentation of sedation assessments in the ED, the more granular factors contributing to this association are unknown. Information on neuromuscular blocking agents was not available and paralysis may have precluded sedation assessments in some patients; however, most patients remained intubated in the ED for over 3 hours, limiting the effects of induction paralytics for much of their ED stay. Eleven hypothesis-driven exposure variables were tested for association with sedation assessment in the ED; other factors, such as race/ethnicity or specific comorbidities, could be influential but were not included in the analyses. The feasibility of measuring depth of sedation in the ED is under investigation but has not been established.11 While data suggest that early deep sedation is detrimental,6, 8 interventions to lighten sedation may be more appropriate in the ICU, where staffing ratios can better accommodate the needs of patients with lighter levels of sedation. This argument should include the caveat, however, that ED length of stay is frequently prolonged for mechanically ventilated patients. Just as interventions to prevent and treat delirium rely on widespread detection of delirium using validated assessment tools, interventions focused on depth of sedation require routine assessment of sedation in whatever locations mechanical ventilation occurs. Further research is needed to understand the utility of specific sedation strategies and barriers to sedation assessments in the ED. In this multicenter study, depth of sedation was infrequently documented in the ED. Time from intubation to ICU admission, continuous infusion of sedative/analgesic medications, and hospital site were associated with sedation assessment in the ED. Further work is needed to determine barriers to sedation assessment and the clinical impact of routine sedation monitoring on early management of sedation and analgesia in ED settings. All data were deidentified and deemed exempt from Human Subjects Division Institutional Review Board review. The authors have no potential conflicts to disclose. Tessa L. Steel—project management, study design, results interpretation, drafting and editing of the manuscript. Sharukh Lokhandwala—study design, data acquisition, statistical analyses, results interpretation, drafting and editing of the manuscript. Ellen S. Caldwell—data cleaning and statistical analyses. Nicholas J. Johnson—study design, results interpretation, drafting and editing of the manuscript. CDM—study design, results interpretation, drafting and editing of the manuscript. Michelle N. Gong—study design, results interpretation, drafting and editing of the manuscript. Catherine L. Hough—study design, data acquisition, results interpretation, drafting and editing of the manuscript. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.