American College of Surgeons trauma centre designation and mechanical ventilation outcomes.

Objective: The association between hospital volume and outcomes following mechanical ventilation has been previously examined in diverse patient populations. The American College of Surgeons (ACS) Committee on Trauma has outlined criteria for trauma centre level designations with specific requirements for both specialty capabilities and hospital volume. Our objective is to determine the relationship between ACS centre designation and outcomes for trauma patients undergoing mechanical ventilation.

Methods: We conducted a retrospective cohort study using the National Trauma Databank (NTDB), identifying 13,933 adult (age>or=18) trauma patients receiving mechanical ventilation for greater than 48 h from 2000 to 2004 who were admitted to either an ACS Level I or Level II trauma centre. The primary endpoints examined were mortality, pneumonia and Acute Respiratory Distress Syndrome (ARDS). Univariate analysis defined differences between those patients admitted to ACS Level I and Level II facilities. Logistic regression analysis was used to identify if ACS level designation was an independent risk factor for the goal outcomes.

Results: Patients admitted to a Level I facility and mechanically ventilated for greater than 48 h were more commonly greater than age 55 (71.3% vs. 67.9%, p<0.01), hypotensive (SBP<90) (16.1% vs. 12.8%, p<0.01), and likely to have sustained injury due to penetrating mechanism (11.1% vs. 5.1%, p<0.01). On univariate analysis, mortality and the incidence of pneumonia did not differ between the two groups. Level I admission was, however, less commonly associated with the development of ARDS (5.8% vs. 7.7%, p<0.01) and patients admitted to Level I facilities were significantly more likely to be discharged to home than Level II counterparts (29.7% vs. 22.9%, p<0.01). Logistic regression revealed that, while ACS Level designation was not a predictive factor for mortality or the development of pneumonia, admission to an ACS Level II facility was an independent predictor for the development of ARDS [p<0.01, odds ratio, 95% CI: 1.35 (1.18-1.59)].

Conclusion: For trauma patients requiring mechanical ventilation for >48 h, ACS trauma centre designation had no effect on overall mortality or the incidence of pneumonia. Compared to Level I counterparts, however, patients admitted to an ACS Level II facility were significantly more likely to develop ARDS following trauma. This finding needs further investigation in a large, prospective analysis.