Hawnwan Moy, MD
Assistant Professor of Emergency Medicine
Washington University School of Medicine, United States
Disclosure information not submitted.
David Olvera, BA,FP-C, NRP, CMTE
Director of Clinical Research
Air Methods Corporation, United States
Disclosure information not submitted.
B Daniel Nayman, MBA, NRP, FP-C
Clinical Patient Care Consultant
ZOLL Data Systems, United States
Disclosure information not submitted.
Robert Stephens, MD
Resident Physician
Barnes Jewish Hospital
Saint Louis, MO
Disclosure information not submitted.
Ryan Pappal, n/a
Medical Student
Washington University School of Medicine, United States
Disclosure information not submitted.
Nicholas Mohr, MD, MS, FCCM
Professor
University of Iowa Hospital and Clinics
Iowa City, IA
Disclosure information not submitted.
Marin Kollef, MD
Professor
Washington Univ. School of Medicine, United States
Disclosure information not submitted.
Christopher Palmer, MD, FCCM
Washington University in Saint Louis School of Medicine
Saint Louis, MO
Disclosure information not submitted.
Enyo Ablordeppey, MD, MPH, FACEP
Washington University School of Medicine
Saint Louis, MO, United States
Disclosure information not submitted.
Brian Fuller, MD, MSCI,FCCM
Associate Professor of Anesthesiology and Emergency Medicine
Washington University/Barnes-Jewish Hospital
Saint Louis, MO
Disclosure information not submitted.
Title: Mechanical ventilation practices among air medical transport patients: a cohort study
Introduction:
Despite the high volume of mechanically ventilated patients in the air medical transport domain, there is limited data on mechanical ventilation practices in this cohort. Small studies have demonstrated low tidal volume ventilation (LTVV) is rare in the prehospital environment. Additionally, prehospital tidal volume has been shown to be a critical determinant of ever receiving LTVV in the intensive care unit (ICU). This study’s objectives were to describe prehospital mechanical ventilation practices in air medical transport patients.
Methods:
This was a retrospective cohort study (January 2015 - December 2020) of consecutive, adult mechanically ventilated air medical transport patients (n=72,148) treated in the pre-hospital environment. All patients were transported by Air Methods, an air medical transport provider with > 300 bases in 48 states. Descriptive statistics were used to assess characteristics of the cohort. For patients with no documented height, linear interpolation was used to replace missing predicted body weight (PBW) values.
Results:
Volume control-assist control (VC-AC) was the most common mode (50.7%), followed by VC-synchronized intermittent mandatory ventilation (SIMV; 29.9%). From 95,004 ventilator settings, median tidal volume was 475 mL (425-500). Height was recorded in only 4,225 (5.9%) patients. Median tidal volume was 6.6 (6.1-7.3) mL/kg PBW in patients with measured height and 7.1 (6.4-7.5) mL/kg PBW when missing values were replaced. Plateau pressure was recorded in 43,611 (60.4%) patients with a median of 18 cmH2O (15-22). Median positive end-expiratory pressure (PEEP) was 5 cmH2O (5-6) and fraction of inspired oxygen (FiO2) was 83% (50-100).
Conclusions:
In this largest study of mechanically ventilated air medical transport patients to date, we identified important areas for quality improvement which could impact patient-centered outcomes. These include: 1) measuring height (or ulna length given prehospital space constraints) and indexing tidal volume to PBW; 2) checking and limiting plateau pressure; and 3) limitation of hyperoxia with appropriate PEEP-FiO2 combinations. Given the known impact that lung-protective ventilation has on outcome, systemic implementation of lung protection in the prehospital environment could be a high fidelity intervention to improve outcome.