Christopher Palmer

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

Study objective: We evaluated the efficacy of an emergency department (ED)–based lung‐protective mechanical ventilation protocol for the prevention of pulmonary complications. Methods: This was a quasi‐experimental, before‐after study that consisted of a preintervention period, a run‐in period of approximately 6 months, and a prospective intervention period. The intervention was a multifaceted ED‐based mechanical ventilator protocol targeting lung‐protective tidal volume, appropriate setting of positive end‐expiratory pressure, rapid oxygen weaning, and head‐of‐bed elevation. A propensity score–matched analysis was used to evaluate the primary outcome, which was the composite incidence of acute respiratory distress syndrome and ventilator‐associated conditions. Results: A total of 1,192 patients in the preintervention group and 513 patients in the intervention group were included. Lung‐protective ventilation increased by 48.4% in the intervention group. In the propensity score–matched analysis (n=490 in each group), the primary outcome occurred in 71 patients (14.5%) in the preintervention group compared with 36 patients (7.4%) in the intervention group (adjusted odds ratio 0.47; 95% confidence interval [CI] 0.31 to 0.71). There was an increase in ventilator‐free days (mean difference 3.7; 95% CI 2.3 to 5.1), ICU‐free days (mean difference 2.4; 95% CI 1.0 to 3.7), and hospital‐free days (mean difference 2.4; 95% CI 1.2 to 3.6) associated with the intervention. The mortality rate was 34.1% in the preintervention group and 19.6% in the intervention group (adjusted odds ratio 0.47; 95% CI 0.35 to 0.63). Conclusion: Implementing a mechanical ventilator protocol in the ED is feasible and is associated with significant improvements in the delivery of safe mechanical ventilation and clinical outcome.

A Quasi-experimental, Before-after Trial Examining the Impact of an Emergency Department Mechanical Ventilator Protocol on Clinical Outcomes and Lung-protective Ventilation in Acute Respiratory Distress Syndrome

Objectives: To evaluate the impact of an emergency department mechanical ventilation protocol on clinical outcomes and adherence to lung-protective ventilation in patients with acute respiratory distress syndrome. Design: Quasi-experimental, before-after trial. Setting: Emergency department and ICUs of an academic center. Patients: Mechanically ventilated emergency department patients experiencing acute respiratory distress syndrome while in the emergency department or after admission to the ICU. Interventions: An emergency department ventilator protocol which targeted variables in need of quality improvement, as identified by prior work: 1) lung-protective tidal volume, 2) appropriate setting of positive end-expiratory pressure, 3) oxygen weaning, and 4) head-of-bed elevation. Measurements and Main Results: A total of 229 patients (186 preintervention group, 43 intervention group) were studied. In the emergency department, the intervention was associated with significant changes (p < 0.01 for all) in tidal volume, positive end-expiratory pressure, respiratory rate, oxygen administration, and head-of-bed elevation. There was a reduction in emergency department tidal volume from 8.1 mL/kg predicted body weight (7.0–9.1) to 6.4 mL/kg predicted body weight (6.1–6.7) and an increase in lung-protective ventilation from 11.1% to 61.5%, p value of less than 0.01. The intervention was associated with a reduction in mortality from 54.8% to 39.5% (odds ratio, 0.38; 95% CI, 0.17–0.83; p = 0.02) and a 3.9 day increase in ventilator-free days, p value equals to 0.01. Conclusions: This before-after study of mechanically ventilated patients with acute respiratory distress syndrome demonstrates that implementing a mechanical ventilator protocol in the emergency department is feasible and associated with improved clinical outcomes.

Analgosedation Practices and the Impact of Sedation Depth on Clinical Outcomes Among Patients Requiring Mechanical Ventilation in the ED: A Cohort Study

BACKGROUND: Analgesia and sedation are cornerstone therapies for mechanically ventilated patients. Despite data showing that early deep sedation in the ICU influences outcome, this has not been investigated in the ED. Therefore, ED‐based sedation practices, and their influence on outcome, remain incompletely defined. This studys objectives were to describe ED sedation practices in mechanically ventilated patients and to test the hypothesis that ED sedation depth is associated with worse outcomes. METHODS: This was a cohort study of a prospectively compiled ED registry of adult mechanically ventilated patients at a single academic medical center. Hospital mortality was the primary outcome and hospital‐, ICU‐, and ventilator‐free days were secondary outcomes. A backward stepwise multivariable logistic regression model evaluated the primary outcome as a function of ED sedation depth. Sedation depth was assessed with the Richmond Agitation‐Sedation Scale (RASS). RESULTS: Four hundred fourteen patients were studied. In the ED, 354 patients (85.5%) received fentanyl, 254 (61.3%) received midazolam, and 194 (46.9%) received propofol. Deep sedation was observed in 244 patients (64.0%). After adjusting for confounders, a deeper ED RASS was associated with mortality (adjusted OR, 0.77; 95% CI, 0.63–0.94). CONCLUSIONS: Early deep sedation is common in mechanically ventilated ED patients and is associated with worse mortality. These data suggest that ED‐based sedation is a modifiable variable that could be targeted to improve outcome.

448: INCREASED RISK OF HOSPITAL MORTALITY ASSOCIATED WITH ICU READMISSION IN INITIALLY LOW-RISK PATIENTS

www.ccmjournal.org Critical Care Medicine • Volume 46 • Number 1 (Supplement) Learning Objectives: ICU readmission has been associated with increased mortality, and attempts have been made to prospectively identify risk factors to reduce ICU readmission and improve outcomes. Methods: We measured hospital mortality (HM) and APACHE IVa-predicted hospital mortality (pHM) in 13,587 consecutive patients admitted to 5 ICUs in a large academic medical center over 18 months that included 1,017 (7%) patients readmitted to the ICU during this period. During the first ICU stay, patients were assigned to ‘low’ (pHM< 10%), ‘medium’ (pHM=10–50%) and ‘high’ (pHM> 50%) risk groups, and HM and hospital mortality index (‘HMI’ = HM/pHM) for nonreadmitted vs. readmitted patients were compared for each risk (pMH) group. Results: HM and HMI were 10.6% and 0.8 overall, and 10.0% vs 18.5%, and 0.8 vs 1.3 in non-readmitted vs readmitted patients, respectively. 8,734 (64%), 4,082 (30%) and 771 (6%) patients were assigned to the low, medium and high risk (pHM) groups during initial admission, respectively, with 586 (7%), 382 (9%), and 49 (6%) readmissions in each of these groups. HM was 2.7%, 17.9% and 62.5%, and HMI was 0.6, 0.8, and 0.9 in the low, medium, and high risk groups, respectively. HM for non-readmitted vs readmitted patients in the low, medium and high risk groups were 1.9% vs 13.1% (6.9 fold), 17.1% vs 25.4% (1.5 fold), and 64.8% vs 28.6% (0.4 fold), respectively. HMI for non-readmitted vs. readmitted patients were 0.5 vs 2.8 (5.6 fold), 0.8 vs 1.2 (1.5 fold) and 0.9 vs 0.4 (0.4 fold) for the low, medium and high risk groups, respectively. Conclusions: It is notable that the majority of ICU readmissions come from the initially low risk (pHM< 10%) group, and this study indicates that readmission is associated with a marked increase in risk of HM in that group. The parallel increase in HMI in the low risk group indicates that the increased HM risk is not evident a priori using APACHE. However, APACHE identifies and allows focus on this low risk population, and thus provides an opportunity to better understand the readmission phenomenon, and to develop multidimensional profiles to prospectively predict ICU readmission in this group.

Production Scale Growth of AlGaN/GaN Field Effect Transistors

This paper addresses issues with the manufacturability of AlGaN/GaN FET structures. A robust Metalorganic Chemical Vapor Deposition growth process has been developed that will now allow reliability measurements to be obtained on the resulting devices. During a small scale production run mobilities in excess of 1600 cm 2 /V.s, sheet charge (N s ) between 0.8x10 13 and 1.2x10 13 cm -2 , and R s