OBJECTIVETo explore the epidemiological characteristics of inhalation injury and to summarize the clinical application experience of diagnostic standard of burn of larynx.

METHODSMedical records of 443 patients with inhalation injury admitted to our burn unit from January 1999 to June 2013 were analyzed, including gender, age, severity of inhalation injury, complications and diseases before injury; total area and that of full-thickness burn injury, admission time after burn, and burn condition of larynx of patients with different degrees of inhalation injury; treatment and outcome including rate, time, and complication of tracheotomy, mortality, and cause of death. Data were processed with nonparametric Kruskal-Wallis test and chi-square test. The relationship between severity of inhalation injury and total burn area, degree of burn of larynx, tracheotomy rate, and mortality was assessed by Spearman correlation analysis.

RESULTS(1) Among the patients, there were 353 (79.7% ) male and 90 (20.3% ) female, with the ratio of male to female 4:1. There were 64 (14.4%) patients younger than or equal to 20 years, 203 (45.8%) patients older than 20 years and younger than or equal to 40 years, 144 (32.5%) patients older than 40 years and younger than or equal to 60 years, and 32 (7.2%) patients older than 60 years. The numbers of patients with mild, moderate, and severe inhalation injury were respectively 297, 108, and 38. Seven patients suffered from complications, and 21 patients had diseases before injury. There were statistically significant differences among the patients with different degree of inhalation injury in regard to total burn area and full-thickness burn area (with H values respectively 73.752 and 142.830, P values below 0.01), while no statistically significant difference was observed in admission time after burn ( H = 1.528, P > 0.05). Correlation analysis showed that severity of inhalation injury was positively correlated with total burn area (r = 0.399, P < 0.001). Among the patients with mild inhalation injury, incidences of patients with mild, moderate, and severe burn of larynx were respectively 68.0% (202/297), 32.0% (95/297), and 0, and those among the patients with moderate inhalation injury were respectively 0,53.7% (58/108), and 46.3% (50/108). There were statistically significant differences in degree of burn of larynx of patients with different degree of inhalation injury (χ2 = 336.703, P < 0.001). Correlation analysis showed that severity of burn of larynx was positively correlated with severity of inhalation injury (r = 0.700, P < 0.001). (2) The rate of tracheotomy was 37.02% (164/443). The rates of tracheotomy in patients with mild, moderate, and severe inhalation injury were respectively 10.44% (31/297), 87.96% (95/108), and 100.00% (38/38), χ2 = 271.654, P < 0.001. Correlation analysis showed that the rate of tracheotomy was positively correlated with severity of inhalation injury (r = 0.784, P < 0.001). Tracheotomy was done mainly within 6 h post burn (63.4%, 104/164). The incidence rate of complication of tracheotomy was 5.5% (9/164). (3) Thirty-one patients died, with a mortality rate of 7.00%. The mortality rates of patients with mild, moderate, and severe inhalation injury were respectively 1.01% (3/297), 12.96% (14/108), and 36.84% (14/38), H = 74.273, P < 0.001. It was found that the mortality was positively correlated with severity of inhalation injury (r = 0.371, P < 0.001). The causes of death of the patients were respectively sepsis (14, 45.2%), respiratory failure (7, 22.6%), airway obstruction (2, 6.5%), airway hemorrhage (2, 6.5%), cerebral hemorrhage (2, 6.5%), cardiac accident (2, 6.5%), and diabetes insipidus (1, 3.2%), and 1 (3.2%) patient quit treatment and discharged from hospital for economic reason.

CONCLUSIONSAmong the patients with inhalation injury, male is dominated in number, and the young adults formed the highest constituent ratio. The severity of inhalation injury was correlated with total burn area, severity of burn of larynx, tracheotomy rate, and mortality. With the guidance of diagnostic criteria of burn of larynx and indication of tracheotomy, the risk of laryngeal obstruction can be eliminated. The early preventive tracheotomy can decrease the difficulty and risk of the operation.