Introduction: We previously reported ventilator associated pneumonia (VAP) in emergently intubated trauma patients was associated with blunt injury, higher injury severity, and intubations >24 hours, but among these, only higher injury severity was independently predictive of VAP diagnosis. A subset of prehospital (PH) intubations subject to ongoing quality improvement data collection were re-examined to identify possible intubation factors associated with subsequent VAP.

Methods: Using an existing dataset of all consecutive adult trauma patients intubated prior to inpatient admission at a Level I trauma center between July 2007-July 2008 (excluding PH surgical airways, deaths and discharges within 48 hours), PH intubations with quality improvement data were identified. Intubation details were recorded including vital signs, medications, experience of intubating personnel, bag-valve mask (BVM) ventilation, and presence of material in the airway. The diagnosis of VAP was made by quantitative bronchoalveolar lavage (BAL) cultures (104 CFU), or by clinical assessment when BAL was impossible. Baseline data, injury characteristics and circumstances of intubation of patients with and without VAP were compared by univariate analysis.

Results: Detailed data were available for 114 PH intubated patients; 17 (15%) developed VAP on average 6 ± 0.7 days after admission. There was no difference in age, sex or comorbid diseases except diabetes which was more common in VAP (3 [17.7%] vs. 3 [3.1%], p=0.01). There was a trend toward more blunt injury in VAP patients (14 [82.4%] vs. 59 [60.8%], p=0.09) and higher injury severity as measured by both ISS (32.2 ± 2.9 vs. 22.6 ± 1.5, p=0.01) and chest AIS (2.7 ± 0.4 vs. 1.4 ± 0.2, p=0.01). No patients with stab wounds (25 [25.8%]) or pedestrians struck by vehicles (12 [12.4%]) developed VAP. GCS<8 was the most common indication for intubation in both groups (8 [47.1% vs. 42 [43.8%], p=0.71). Preintubation vital signs and level of consciousness did not differ, and medications and BVM ventilation were administered prior to intubation at a similar rate (table 1). Senior medics performed more of the intubations with subsequent VAP, but this was not significant (15 [88%] vs. 71 [73.2%], p=0.38). No patient with >1 recorded attempt prior to successful intubation developed VAP. Of those noted to have aspirated, 2 of 4 patients with emesis developed VAP, compared to only 1 of 13 with blood in the airway (p=0.05).

Table 1.	VAP (n = 17)	No VAP (n = 97)	P value
Systolic BP (mmHg)	113.8 ± 13.5	121.9 ± 3.7	0.43
Pulse (beats/minute)	95.9 ± 7.6	99.9 ± 2.5	0.55
Resp (per minute)	19.1 ± 2.1	18.5 ± 0.7	0.79
GCS	9.1 ± 1.2	10.2 ± 0.5	0.40
BVM	7 (41.2%)	42 (43.8%)	0.84
NMB	17 (100%)	95 (98.9%)	0.67
Sedation	14 (82.4%)	77 (80.2%)	0.27

(VAP=ventilator associated pneumonia, BP= blood pressure, GCS=Glasgow Coma Score, BVM=bag valve mask ventilation, NMB=neuromuscular blockade)

Conclusion: Patient injury factors, rather than PH intubation circumstances, appear to be associated with development of VAP. Future prospective examinations of emergent intubation factors in trauma patients should focus on risk, timing and character of aspiration.