Use of airway pressure release ventilation is associated with a reduced incidence of ventilator-associated pneumonia in patients with pulmonary contusion.
BACKGROUND
Past studies suggest that airway pressure release ventilation (APRV) is associated with reduced sedative requirements and increased recruitment of atelectatic lung, two factors that might reduce the risk for ventilator-associated pneumonia (VAP). We investigated whether APRV might be associated with a decreased risk for VAP in patients with pulmonary contusion.


METHODS
Retrospective cohort study.


RESULTS
Of 286, 64 (22%) patients requiring mechanical ventilation for >48 hours met criteria for pulmonary contusion and were the basis for this study. Subjects with pulmonary contusion had a significantly higher rate of VAP than other trauma patients, [VAP rate contusion patients: 18.3/1,000, non-contusion patients: 7.7/1,000, incidence rate ratio 2.37 (95% confidence interval [CI], 1.11-4.97), p=0.025]. Univariate analysis showed that APRV (hazard ratio, 0.15 [0.03-0.72; p=0.018]) was associated with a decreased incidence of VAP. Cox proportional hazards regression, using propensity scores for APRV to control for confounding, supported a protective effect of APRV from VAP (hazard ratio, 0.10 [95% CI, 0.02-0.58]; p=0.01). Pao2/FiO2 ratios were higher during APRV compared with conventional ventilation (p<0.001). Subjects attained the goal Sedation Agitation Score for an increased percentage of time during APRV (median [interquartile range (IQR)] 72.7% [33-100] of the time) compared with conventional ventilation (47.2% [0-100], p=0.044), however, dose of sedatives was not different between these subjects. APRV was not associated with hospital mortality (odds ratio 0.57 [95% CI, 0.06-5.5]; p=0.63) or ventilator-free days (No APRV 15.4 vs. APRV 13.7 days, p=0.49).


CONCLUSIONS
Use of APRV in patients with pulmonary contusion is associated with a reduced risk for VAP.
Division of Pulmonary and Critical Care Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, USA. Allan.Walkey@bmc.org
Allan J
AJ
Walkey
Sunil
S
Nair
Stella
S
Papadopoulos
Suresh
S
Agarwal
Christine C
CC
Reardon
D000328:Adult; D045422:Continuous Positive Airway Pressure; D003288:Contusions / Q000628:therapy*; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D015994:Incidence; D055370:Lung Injury / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D053717:Pneumonia, Ventilator-Associated / Q000453:epidemiology / Q000517:prevention & control*; D016012:Poisson Distribution; D016016:Proportional Hazards Models; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D018709:Statistics, Nonparametric; D015599:Trauma Severity Indices