OBJECTIVE: To independently validate the negative predictive value of the Tanta University risk model for intensive care requirements in poison center telephone consultations with other physicians.
METHODS: This study included 400 consecutive patients with acute poisoning. Clinical and laboratory parameters were recorded during the initial consultation with the poison center. Patients who were already ventilated or on vasopressors at the time of consultation were excluded. The Tanta University risk model score was calculated from the data according to the following equation: Tanta University risk model score = 1.966*Glasgow Coma Scale + 0.329*oxygen saturation (percent) + 0.212*diastolic blood pressure (mmHg) - 0.27*respiratory rate (breaths/minute) + 0.33*standard bicarbonate (mmol/L). Twenty-four hours later, the patients' courses were followed up by telephone. The Tanta University risk model was then compared to a composite endpoint indicating the requirement for admission to an intensive care unit (vasopressors, need for intubation, or death).
RESULTS: Four hundred patients with acute poisoning were included. Thirty-seven patients had a complicated clinical course as defined by the composite endpoint. Receiver operating characteristic analysis revealed the area under the curve to be 0.87 (95 percent confidence interval 0.83-0.90). An unfavorable Tanta University risk model score was defined as less than 73.46, using a cut-off derived from a previous study of an unrelated series of patients with acute poisoning admitted to our service. Thirty-one of 37 patients with complicated courses had an unfavorable Tanta University risk model score compared to six patients with complicated courses among 306 patients with a favorable Tanta University risk model score (P < 0.0002, Fisher's exact test). Sixty-three patients had an unfavorable Tanta University risk model score but an uneventful course. The negative predictive value of the Tanta University risk model was 0.98 (95 percent confidence interval 0.96-0.99), sensitivity was 0.84, and specificity 0.83.
CONCLUSIONS: In the present study of poison center telephone consultations, the Tanta University risk model was significantly related to the outcomes in patients with acute poisoning. Patients with a favorable Tanta University risk model score (greater than or equal to 73.46) were unlikely to need intensive care unit level of care.