Impact of En Route Critical Care Provider Experience on Lung Protective Ventilation Compliance During Air Transport of Combat Wounded.

Introduction: The primary objective of this study was to evaluate the association between the U.S. Air Force Critical Care Air Transport (CCAT) provider operational experience with compliance for lung protective ventilation (LPV) volumes recommended by Acute Respiratory Distress Syndrome Clinical Network guidelines.

Materials And Methods: We performed a retrospective cohort study of CCAT providers transporting combat casualties requiring mechanical ventilation from the Middle East to Germany from 2007 to 2012. We reviewed CCAT medical records from 2007 to 2012 for the total number of patient transports by CCAT physicians and respiratory care practitioners (RCPs). Center for Sustainment of Trauma and Readiness Skills Cincinnati process improvement questionnaire data described provider demographics and clinical backgrounds. We linked these data to patient demographics and in-flight ventilation management from a prior CCAT cohort study. Patient inclusion criteria included transport by CCAT from the Middle East to Germany for traumatic injury requiring mechanical ventilation between 2007 and 2012. We excluded patients with no documented height or tidal volume. LPV compliance was defined as tidal volumes ≤8 mL/kg of predicted body weight during en route critical care transport. We performed a logistic regression analysis. This study was reviewed and approved by the 59th Medical Wing institutional review board (IRB).

Results: We analyzed 491 patient transports conducted by 71 (RCPs and 84 physicians. Patients had a median age of 25 years (IQR 22-30), 98% were male, median injury severity score was 24 (IQR 17-34), and median preflight PaO2/FiO2 was 285 (IQR 220-365). Median experience was 26 missions (IQR 13-40) for RCPs and 23 missions (IQR 12-38) for physicians. All in-flight tidal volumes were LPV compliant in 58.3% of missions. Unadjusted analysis showed higher LPV compliance for RCPs with in-garrison critical care experience. Multivariate models did not find an association between missions flown and LPV compliance but did demonstrate a positive association with physician specialty of medical intensivist (OR 3.0, 95% CI 1.6-5.7) and a negative association with flights in 2008 (OR 0.4, 95% CI 0.2-0.7) for LPV compliance.

Conclusion: No association was found between number of missions flown by CCAT providers and lung protective tidal volume compliance. Linkage of multiple data sources enabled investigation of clinical and operational currency associations with a care quality metric compliance in the combat en route care environment. Future studies should evaluate the impact of ongoing CCAT training and quality improvement interventions on LPV compliance.