To characterize the frequency of aspiration
pneumonitis in an unselected population of overdose patients and, further, to identify factors that predispose to aspiration
pneumonitis and the outcomes of patients with aspiration
pneumonitis compared with those without.
DESIGN: Retrospective cohort study.
SETTING: Toxicology unit of a tertiary referral hospital.
PATIENTS: A total of 71 of 4,562
poisoning admissions to the Hunter Area Toxicology Service between January 1997 and October 2002 had definite aspiration
pneumonitis (1.6%; 95% confidence interval, 1.2-2.0). Older age, Glasgow
Coma Score of <15, spontaneous
emesis,
seizures, delayed presentation to hospital, and ingestion of
tricyclic antidepressants were associated with an increased risk of aspiration
pneumonitis.
Paracetamol poisoning and female sex were associated with a decreased risk of aspiration
pneumonitis with univariate analysis. Ingestion of alcohol,
benzodiazepines,
antipsychotics, and administration of
activated charcoal were not associated with aspiration
pneumonitis. A logistic regression model for predicting aspiration
pneumonitis contained seven predictors: age, sex, Glasgow
Coma Score of <15 (odds ratio, 3.14; 95% confidence interval, 1.87-5.27),
emesis (odds ratio, 4.17; 95% confidence interval, 2.44-7.13), seizure,
tricyclic antidepressant ingestion, and time from ingestion to presentation (delay of >24 hrs [odds ratio, 4.42; 95% confidence interval, 2.42-8.10]). The mortality for patients with aspiration
pneumonitis was 8.5% compared with 0.4% for those without (odds ratio, 23; 95% confidence interval, 9-60; p <.0001), and they had a significantly higher intensive care unit admission rate. The median
length of stay of patients with aspiration
pneumonitis was 126 hrs (interquartile range, 62-210 hrs) compared with 14.7 hrs (interquartile range, 7-23 hrs) in patients without (p <.0001).
CONCLUSIONS: Our study has shown a number of risk factors in overdose patients that are associated with aspiration
pneumonitis that may allow the early identification of these patients for appropriate observation and management. Patients with aspiration
pneumonitis have a significantly increased mortality and
length of stay in the hospital.