The role of inhalation injury in burn trauma. A Canadian experience

From 1977 to 1987, 1705 thermally injured patients were admitted to the Firefighters' Burn Center at the University of Alberta Hospitals. Thirteen hundred forty-four were male (78.8%) and 361 were female (21.2%), with a mean total burn surface area (TBSA) of 15.1 (SEM +/- 0.4%) and a range of 1% to 99% TBSA. Sixteen hundred thirty-five patients survived to be discharged from hospital, with an overall survival rate of 95.9%. One hundred twenty-four burn patients (7.3%) suffered concomitant inhalation injury diagnosed by bronchoscopy. Patients with inhalation injury suffered from larger TBSA (39.7% +/- 2.8% versus 12.2% +/- 0.3%; p less than 0.01) than those without inhalation injury. Inhalation injury increased the number of deaths from burn injury (34.7% versus 1.7%; p less than 0.01) independent of age and TBSA. Inhalation injury was associated with a threefold prolongation of hospital stay (23.7 +/- 0.7 versus 74.4 +/- 6.2 days; p less than 0.01) and was independent of age and TBSA. Multifactorial probit analysis was performed for both inhalation- and noninhalation-injured burned patients to allow TBSA and age adjusted rates of mortality for the burn population presented. The maximum detrimental effects of inhalation injury in burn patient outcome occurred when it coexisted with moderate (15% to 29% TBSA) to large (30% to 69% TBSA) thermal injuries. These data demonstrate that inhalation injury is an important comorbid factor in burn injury that increases the number of deaths substantially. Most importantly such injuries also independently prolong the duration of hospitalization in a highly unpredictable fashion as compared to patients with cutaneous burns only. As such our data illustrate the extreme importance of inhalation injury as a comorbid factor following thermal injury and reveal the present limitations for accurate quantification of the magnitude of respiratory tract injury accompanying thermal trauma.