Resource-use analysis of a medical toxicology consultation service

To evaluate the impact of a medical toxicology consulting service (MTCS) on resource use and efficiency of care in patients hospitalized with a diagnosis of tricyclic antidepressant (TCA) poisoning.

We conducted a retrospective, case-controlled medical-records review at two urban tertiary care teaching hospitals. The study population comprised patients who presented to the emergency department with a diagnosis of TCA poisoning, in two phases. The first phase was longitudinal; we evaluated cases over 4 years before and after inception of an MTCS at one institution. In the second phase we compared consecutive cases of TCA poisoning treated at two urban teaching hospitals located within a mile of each other with similar patient populations, one with and one without MTCS backup. Inclusion criteria consisted of complete medical records, ingestion of first- and second-generation TCAs, and age greater than 16 years. Patients were excluded if history, physical examination, or laboratory analysis suggested that multiple substances had been ingested. Extensive demographic data were collected in each case. Clinical information obtained from each patient included admission vital signs, pupil size, QRS and corrected QT duration, and the presence of markers of severe TCA toxicity such as hypotension, seizures, pulmonary edema, respiratory insufficiency necessitating intubation, and the occurrence of antimuscarinic signs and symptoms. Information regarding treatment was also collected from each case, including laboratory tests, decontamination procedures, administration of sodium bicarbonate, and use of other medications and therapies.

We identified a total of 88 patients in both phases of the study. Comparison groups were similar with respect to age, sex, presenting vital signs, presenting QRS and corrected QT duration, and incidence of recorded antimuscarinic signs, hypotension, seizures, and respiratory insufficiency requiring intubation. Total length of stay in a monitored hospital bed was also similar between groups. One fatality was recorded, but all other patients were discharged home or to a psychiatric facility. Patients seen by the MTCS consumed fewer health care resources in the form of less decontamination and fewer laboratory tests.

The MTCS may provide a resource-efficient means of treating patients with TCA poisoning. A larger, multicenter study of a variety of poisoned patients should be undertaken to further investigate this issue.