title: Provider Bias Impacts Tidal Volume Selection and Ventilator Days in Trauma Patients.
abstract: BACKGROUND
  The ARDSnet (Acute Respiratory Distress Syndrome Clinical Network) study demonstrated that low tidal volume (Vt) reduces mortality from ARDS. It is unknown whether low Vt is beneficial in at-risk trauma patients. We hypothesized that Vt selection would be low in accordance with ARDSnet criteria and that subsequent outcomes would be improved.
  
  
  METHODS
  A 1-year retrospective observational study was conducted on all trauma patients aged 15 years and older and on mechanical ventilation for 48 hours or longer, excluding those with cardiopulmonary disease. Using maximum Vt, we identified low and high Vt groups (≤8 mL/predicted body weight (PBW) and >8 mL/PBW). Data collected included demographic characteristics, lengths of stay, ventilator and ICU days, ARDS, and other complications.
  
  
  RESULTS
  A total of 364 patients were identified and organized into low Vt (n = 181) and high Vt (n = 183) groups. There was no difference between groups in age, Injury Severity Score, Glasgow Coma Scale, or mechanism of injury. The rate of ARDS was the same in each group. Patients with a high Vt had lower PBW (63.1 ± 8.8 vs 71.7 ± 6.9; p < 0.001), higher BMI(29.7 ± 6.9 kg/m(2) vs 26.6 ± 6.5 kg/m(2); p < 0.001), and were more likely to be female. Height was inversely correlated with Vt (r(2) = -0.579; p < 0.001). The high Vt group experienced longer ICU stays (9.9 ± 8.8 days vs 8.1 ± 7.9 days; p = 0.045) and more ventilator days (8.55 ± 10.5 days vs 6.14 ± 7.4 days; p = 0.015).
  
  
  CONCLUSIONS
  Trauma patients receiving high Vt were shorter, had higher BMI, and were more likely to be female. The consequences included longer ICU stays and more ventilator days. Formal calculation of PBW and subsequent Vt is advocated.
authors.affiliation: Department of Surgery, Section of Trauma, Virginia Tech Carilion School of Medicine, Roanoke, VA. Electronic address: brcollier@carilionclinic.org.
authors.forename: Bryan
authors.initials: B
authors.lastname: Collier
authors.affiliation: Department of Family Practice, Carolinas Medical Center, Charlotte, NC.
authors.forename: Chris
authors.initials: C
authors.lastname: Vieau
authors.affiliation: Department of Surgery, Section of Trauma, Virginia Tech Carilion School of Medicine, Roanoke, VA.
authors.forename: Ellen
authors.initials: E
authors.lastname: Lockhart
authors.affiliation: Department of Surgery, Section of Trauma, Virginia Tech Carilion School of Medicine, Roanoke, VA.
authors.forename: Eric
authors.initials: E
authors.lastname: Bradburn
authors.affiliation: Department of Surgery, Section of Trauma, Virginia Tech Carilion School of Medicine, Roanoke, VA.
authors.forename: Mark
authors.initials: M
authors.lastname: Hamill
authors.affiliation: Department of Surgery, Section of Trauma, Virginia Tech Carilion School of Medicine, Roanoke, VA.
authors.forename: Katie
authors.initials: K
authors.lastname: Love
authors.affiliation: Department of Surgery, Section of Trauma, Virginia Tech Carilion School of Medicine, Roanoke, VA.
authors.forename: Chris
authors.initials: C
authors.lastname: Reed
authors.affiliation: Department of Surgery, Section of Trauma, Virginia Tech Carilion School of Medicine, Roanoke, VA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Baker
mesh_terms: D000328:Adult; D000368:Aged; D015982:Bias; D015992:Body Mass Index; D003422:Critical Care; D005260:Female; D006801:Humans; D015601:Injury Severity Score; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D012121:Respiration, Artificial; D012128:Respiratory Distress Syndrome / Q000175:diagnosis* / Q000209:etiology / Q000628:therapy*; D012189:Retrospective Studies; D013990:Tidal Volume; D016896:Treatment Outcome; D014947:Wounds and Injuries / Q000150:complications* / Q000628:therapy*