Microbial contamination in burn patients undergoing urgent intubation as part of their early airway management

Inhalation injuries occur in approximately one third of all major burns and account for a significant number of deaths in burn patients each year. Previous studies have examined ventilator-associated pneumonia in patients with inhalation injury, but no study to date has evaluated the incidence of bacterial contamination of the airways on admission in patients with inhalation injuries. Because pulmonary complications have been found to cause or directly contribute to mortality in as high as 77% of patients, with combined inhalation injury and thermal injury, early detection of community-acquired pneumonia may significantly alter treatment outcomes. The authors conducted a retrospective review of all burn patients with early intubation and inhalation injury admitted between January 1, 2004 and December 31, 2006 who underwent bronchoscopy with bronchoalveolar lavage (BAL) within 24 hours of admission. Seventy-four consecutive patients fulfilled the inclusion criteria. Age, sex, percentage of total body surface area (%TBSA), presence of alcohol, site of intubation, grade of injury, and BAL results were examined. Analysis revealed a patient population that was 67.6% male, with a 42.0 +/- 17.1-year-old mean age, 27.0 +/- 24.7 %TBSA average burn, 1.6 +/- 1.2 inhalation grade, 17.8 +/- 24.4 ventilator days requirement, 27.3 +/- 31.4 days of length of stay, and 21.6% mortality. BAL results were grouped into four categories: 1) No growth, 2) Normal flora, 3) <100,000 colony-forming units (cfu), and 4) >100,000 cfu. By this criteria, 13 patients (17.6%) had no growth, 22 (29.7%) had normal flora, 27 (36.5%) had <100,000 cfu, and 12 (16.2%) had >100,000 cfu on the initial BAL. Therefore, 53% grew pathogenic organisms and 16% had >100,000 cfu on BAL with initial bronchoscopy. The predominant organisms were gram-positive cocci, with Streptococcus viridans found in 15 patients (20%), Staphylococcus aureus in eight (11%), and Streptococcus pneumonia in four (6%). Analysis of the patients with the highest bacterial loads revealed that they were 75% female and had a trend toward an increased ventilator requirement and longer length of stay. Patients with combined thermal and inhalation injury requiring urgent intubation have a high incidence of bacterial bronchial contamination. Inhalation injury creates a damaged tracheobronchial mucosa and early intubation provides a portal for bacterial contamination. Further studies with a larger patient population and randomization to treatment and nontreatment of the BAL culture results may show statistically significant differences in ventilator days, length of stay, and mortality.