title: Temporal trends and current practice patterns for intraoperative ventilation at U.S. academic medical centers: a retrospective study.
abstract: BACKGROUND
  Lung protective ventilation strategies utilizing lower tidal volumes per predicted body weight (PBW) and positive end-expiratory pressure (PEEP) have been suggested to be beneficial in a variety of surgical populations. Recent clinical studies have used control groups ventilated with high tidal volumes without PEEP based on the assumption that this reflects current clinical practice. We hypothesized that ventilation strategies have changed over time, that most anesthetics in U.S. academic medical centers are currently performed with lower tidal volumes, and that most receive PEEP.
  
  
  METHODS
  Intraoperative data were pooled for adults undergoing general anesthesia with tracheal intubation. Median tidal volumes per kilogram of PBW were categorized as > 10, 8-10 and < 8 mL per kg of PBW. The percentages of cases in 2013 that were performed with median tidal volumes < 8 mL per kg of PBW and PEEP were determined. As a secondary analysis, a proportional odds model using institution, year, height, weight and gender determined the relative associations of these factors using categorical and interquartile odds ratios.
  
  
  RESULTS
  295,540 cases were analyzed from 5 institutions over a period of 10 years. In 2013, 59.3% of cases used median tidal volumes < 8 mL per kg of PBW, 83.3% used PEEP, and 51.0% used both. Of those cases with PEEP, 60.9% used a median pressure of ≥ 5 cmH2O. Predictors of lower categories of tidal volumes included height (odds ratio (OR) 10.83, 95% confidence interval [10.50, 11.16]), institution (lowest OR 0.98 [0.96, 1.00], highest OR 9.63 [9.41, 9.86]), year (lowest OR 1.32 [1.21, 1.44], highest OR 6.31 [5.84, 6.82]), male gender (OR 1.10 [1.07, 1.12]), and weight (OR 0.30 [0.29, 0.31]).
  
  
  CONCLUSIONS
  Most general anesthetics with tracheal intubation at the institutions surveyed are currently performed with a median tidal volume < 8 mL per kg of PBW, most are managed with PEEP of ≥ 5 cmH2O and approximately half utilize both. Given the diversity of the institutions included, this is likely reflective of practice in U.S. academic medical centers. The utilization of higher tidal volumes without PEEP in control groups for clinical research studies should be reconsidered.
authors: Departments of Anesthesiology and Biomedical Informatics, Vanderbilt University, The Vanderbilt Clinic, 1301 Medical Center Drive, Suite 4648, Nashville, TN USA.
authors: Jonathan P
authors: JP
authors: Wanderer
authors: Departments of Anesthesiology, Biomedical Informatics, Health Policy and Surgery, Vanderbilt University, Nashville, TN USA.
authors: Jesse M
authors: JM
authors: Ehrenfeld
authors: Department of Anesthesiology, Sidney Kimmel College of Medicine at Thomas Jefferson University, Philadelphia, PA USA.
authors: Richard H
authors: RH
authors: Epstein
authors: Department of Anesthesiology, Mayo Clinic, Rochester, MN USA.
authors: Daryl J
authors: DJ
authors: Kor
authors: Department of Anesthesiology, Duke University School of Medicine, Durham, NC USA.
authors: Raquel R
authors: RR
authors: Bartz
authors: Department of Anesthesiology, University of Colorado School of Medicine, Colorado, CO USA.
authors: Ana
authors: A
authors: Fernandez-Bustamante
authors: Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA USA.
authors: Marcos F
authors: MF
authors: Vidal Melo
authors: Department of Anesthesiology, Emory University Hospital, Atlanta, GA USA.
authors: James M
authors: JM
authors: Blum
mesh_terms: D000046:Academic Medical Centers; D005260:Female; D006801:Humans; D007430:Intraoperative Care / Q000639:trends*; D007442:Intubation, Intratracheal; D008171:Lung Diseases / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration / Q000639:trends*; D011183:Postoperative Complications / Q000517:prevention & control*; D010818:Practice Patterns, Physicians' / Q000639:trends*; D012189:Retrospective Studies; D013990:Tidal Volume / Q000502:physiology; D014481:United States
keywords: Intraoperative ventilation; Lung protective ventilation; Practice patterns