High incidence of adult respiratory distress syndrome associated with amphetamine use in the burn population: a retrospective cohort study

Background:A high incidence of adult respiratory distress syndrome (ARDS) is observed in patients with a history of amphetamine use with limited studies addressing this exact topic. The authors sought to understand and compare the clinical features of patients experiencing amphetamine-associated lung injury with features of similar patients naive to amphetamines, in a population of burn patients. Patients in this population tend to be young with few comorbidities offering a unique opportunity to study the relationship between amphetamine use and ARDS. Materials and methods:A total of 188 patients age 18 and older with total body surface area (TBSA) between 20 and 60% were sampled over 5 years. To capture the moderate to severe burn population, a lower limit of 20% was chosen while 60% was used as the upper limit to exclude patients likely to die from the burns alone. Patients eligible to be include in the study had to meet the TBSA criteria. Demographic data was ascertained. Patients were placed into two cohorts: the amphetamine positive group (AmPOS), the amphetamine negative group (AmNEG). Key endpoints included hospital mortality, length of ICU stay, development of ARDS, and cardiac output parameters. Nonparametric data was evaluated with the Mann-Whitney test and categorical variables were compared using chi(2). Results:Data from 49 patients with ARDS were collected retrospectively out of the 188 patients in this TBSA range. The incidence of amphetamine abuse in these burn patients is 14.9%. The average age of AmPOS and AmNEG patients was 36 and 34 and the average TBSA of burns in the AmPOS and AmNEG group was 51.8 and 45.2%. The mean onset of ARDS was 2.2 days for the AmPOS versus 3.3 days for the AmNEG (P=0.19). At admission, patients with amphetamine use exhibited less inhalational injury and a lower Acute Physiology and Chronic Health Evaluation II (APACHE II) score. In AmPOS, 64% developed ARDS compared to 19% in AmNEG (P<0.001). Mortality, time on a ventilator, ICU days, packed Red Blood Cell, Fresh Frozen Plasm, platelets transfused, and initial cardiac parameters all were not statistically significant. On the initial date of ARDS diagnosis, there was no statistically significant difference with PaO2/FiO(2) and compliance (P=0.67), but positive end expiratory pressure requirements was higher in AmPOS (P=0.018). Conclusions:Amphetamine Use was associated with increased risk of developing ARDS in the burn population. This is despite having a better APACHE II and lower incidence of inhalational injury in the AmPOS group, supporting amphetamine as an independent risk factor for ARDS.