The impact of inhalation injury in patients with small and moderate burns

Abstract

Background: Inhalation injury is an independent risk factor of mortality in burn patients. The burn index (BI), which includes burn depth and size, also plays a role in predicting mortality. We aimed to establish a relationship between survival rate, inhalation injury, and BI.

Methods: From 1997 to 2010, 21,791 burn patients from 44 hospitals were retrospectively reviewed. Kaplan-Meier and log-rank assessments were used for survival curve analysis. Chi-square, Fishers-exact test and odds ratio evaluations were used to assess the relationship between mortality rate, inhalation injury, BI. Two population proportion Z test was used to analyze the causes of death and morbidity. The significance level was set at 0.01.

Results: The overall mortality rate was 2.1%. Inhalation injuries were found in 7.9% of the patients. The mortality rate of inhalation and non-inhalation injury group was 17.9% and 0.7%, respectively. The survival rate of the inhalation injury group was significantly lower than that of the non-inhalation injury group at BI 0-50. The patients with both inhalation injury and BI less than 50 had significant higher rate to die of pneumonia, respiratory failure, sepsis and wound infection. There was no significant difference when BI was larger than 50.

Conclusions: Inhalation injuries significantly reduced the survival rate, especially when the BI was less than 50. The possibility of pulmonary dysfunction and complications arising from inhalation injury should be considered even in patients who have small cutaneous burns associated with inhalation injuries.

Keywords: Burn index; Inhalation injury; Survival rate.