Predicting the Need for Medical Intensive Care Monitoring in Drug-Overdosed Patients

Abstract

Drug overdose (OD) is one of the most common single diagnoses admitted to medical intensive care units (MICUs). The diagnosis results in relatively little morbidity or mortality, suggesting a need to improve the methods utilized in deciding on MICU admission. Our objective in this study was to develop a quantitative system whereby the emergency room (ER) physician, with reasonable safety and ease, would be able to discriminate between the need for an ICU and a nonmonitored bed. We reviewed the charts of 216 consecutive MICU admissions for intentional OD involving 199 patients between the years 1995 and 1998. Clinical histories, vital signs, laboratory data inclusive of toxicologic analysis, and both APACHE II and Glasgow coma scores (GCS) were assessed from the ER and on transfer to the MICU 4–6 hours later. These scores, as well as individual components of the APACHE II score, were evaluated for significance. Of 216 admissions reviewed, 75 (35%) had MICU-requiring morbidity: intubation 61%, pneumonia 20%, arrhythmia or EKG changes 20%, and hypotension 3%. Mortality was 2.7%. The remaining admissions were for ICU monitoring due to lethargy, irritability, laboratory abnormalities, or simply based on the diagnosis of drug overdose. Urine examinations for drugs were positive in only 53%, with the most common agent identified being benzodiazepines (39%). Age, Apache II score, and GCS were significantly different between those patients who developed MICU-requiring morbidity and those who did not, as well as when comparing the morbidity with the mortality group. Receiver operator control (ROC) curves reveal that both the APACHE and GCS are excellent and equal predictors of morbidity, with a GCS of ≤ 12 having 88% sensitivity and 92% specificity in predicting MICU-requiring morbidity. We conclude that ER evaluation of GCS can be used to accurately assess and predict the need for MICU monitoring in drug overdose. OD patients with a persistent GCS of greater than 12 or who do not demonstrate any hemodynamic, infectious, or electrocardiographic complications in the ER do not require MICU admission.