title: Favorable Neurocognitive Outcome with Low Tidal Volume Ventilation after Cardiac Arrest.
abstract: Neurocognitive outcome after out-of-hospital cardiac arrest (OHCA) is often poor, even when initial resuscitation succeeds. Lower tidal volumes (Vts) attenuate extrapulmonary organ injury in other disease states and are neuroprotective in preclinical models of critical illness.
  
  
  
  To evaluate the association between Vt and neurocognitive outcome after OHCA.
  
  
  
  We performed a propensity-adjusted analysis of a two-center retrospective cohort of patients experiencing OHCA who received mechanical ventilation for at least the first 48 hours of hospitalization. Vt was calculated as the time-weighted average over the first 48 hours, in milliliters per kilogram of predicted body weight (PBW). The primary endpoint was favorable neurocognitive outcome (cerebral performance category of 1 or 2) at discharge.
  
  
  
  Of 256 included patients, 38% received time-weighted average Vt greater than 8 ml/kg PBW during the first 48 hours. Lower Vt was independently associated with favorable neurocognitive outcome in propensity-adjusted analysis (odds ratio, 1.61; 95% confidence interval [CI], 1.13-2.28 per 1-ml/kg PBW decrease in Vt; P = 0.008). This finding was robust to several sensitivity analyses. Lower Vt also was associated with more ventilator-free days (β = 1.78; 95% CI, 0.39-3.16 per 1-ml/kg PBW decrease; P = 0.012) and shock-free days (β = 1.31; 95% CI, 0.10-2.51; P = 0.034). Vt was not associated with hypercapnia (P = 1.00). Although the propensity score incorporated several biologically relevant covariates, only height, weight, and admitting hospital were independent predictors of Vt less than or equal to 8 ml/kg PBW.
  
  
  
  Lower Vt after OHCA is independently associated with favorable neurocognitive outcome, more ventilator-free days, and more shock-free days. These findings suggest a role for low-Vt ventilation after cardiac arrest.
authors.affiliation: 1 Division of Pulmonary and Critical Care Medicine and.
authors.forename: Jeremy R
authors.identifier: 0000-0003-0797-2374
authors.initials: JR
authors.lastname: Beitler
authors.affiliation: 2 Department of Medicine, University of California, San Diego, San Diego, California; and.
authors.forename: Tiffany Bita
authors.initials: TB
authors.lastname: Ghafouri
authors.affiliation: 3 Department of Anesthesia and Critical Care Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts.
authors.forename: Sayuri P
authors.initials: SP
authors.lastname: Jinadasa
authors.affiliation: 3 Department of Anesthesia and Critical Care Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts.
authors.forename: Ariel
authors.initials: A
authors.lastname: Mueller
authors.affiliation: 2 Department of Medicine, University of California, San Diego, San Diego, California; and.
authors.forename: Leeyen
authors.initials: L
authors.lastname: Hsu
authors.affiliation: 2 Department of Medicine, University of California, San Diego, San Diego, California; and.
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Anderson
authors.affiliation: 2 Department of Medicine, University of California, San Diego, San Diego, California; and.
authors.forename: Jisha
authors.initials: J
authors.lastname: Joshua
authors.affiliation: 2 Department of Medicine, University of California, San Diego, San Diego, California; and.
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Tyagi
authors.affiliation: 1 Division of Pulmonary and Critical Care Medicine and.
authors.forename: Atul
authors.initials: A
authors.lastname: Malhotra
authors.affiliation: 1 Division of Pulmonary and Critical Care Medicine and.
authors.forename: Rebecca E
authors.initials: RE
authors.lastname: Sell
authors.affiliation: 3 Department of Anesthesia and Critical Care Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts.
authors.forename: Daniel
authors.initials: D
authors.lastname: Talmor
mesh_terms: D000368:Aged; D001930:Brain Injuries / Q000209:etiology*; D005260:Female; D006801:Humans; D055370:Lung Injury / Q000209:etiology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D058687:Out-of-Hospital Cardiac Arrest / Q000150:complications / Q000628:therapy*; D012121:Respiration, Artificial / Q000379:methods*; D012189:Retrospective Studies; D013990:Tidal Volume; D016896:Treatment Outcome
keywords: acute lung injury; cardiac arrest; cerebral ischemia; out-of-hospital cardiac arrest; ventilator-induced lung injury