Level of consciousness as a predictor of complications following tricyclic overdose

In order to determine whether patients at low risk for complications following tricyclic antidepressant (TCA) overdose can be identified, we analyzed the records of all admissions for TCA overdose from 1975 to 1985. Of the 92 patients reviewed, 37 had serious complications including hypoventilation, loss of protective airway reflexes, seizures, hypotension, hemodynamically significant arrhythmias, or death. Patients with complications had increased heart rate, depressed level of consciousness, depressed Glasgow Coma Scale, and prolonged QRS interval, as compared to patients without complications. All 37 patients with serious complications required intubation in the emergency department. A Glasgow Coma Scale of less than 8 was the most sensitive predictor of serious complications (sensitivity = .86; specificity = .89). This was significantly better than the QRS interval (QRS greater than or equal to 100 msec; sensitivity = 59; specificity = .76). We conclude that level of consciousness is a better predictor of risk of complications and need for ICU admission than the QRS interval. Patients who are responsive to verbal stimuli on leaving the ED are at very low risk of developing complications.