Survival pattern in patients with acute organophosphate poisoning receiving intensive care.

BACKGROUND: Approximately 35% of patients acutely poisoned with organophosphates (OP) in developing countries like Sri Lanka require intensive care and mechanical ventilation. However, death rates remain high.

OBJECTIVE: To study the outcomes and predictors of mortality in patients with acute OP poisoning requiring intensive therapy at a regional center in Sri Lanka over a period of 40 months.

METHODS: Retrospective analysis of all intensive care records of patients with acute OP poisoning admitted to the Intensive Care Unit (ICU) between March 1998 and July 2001.

RESULTS: During the study period, 126 subjects were admitted to the ICU with acute OP poisoning. Records of 10 patients were lost and those of 37 were incomplete and hence were excluded. All the remaining 71 patients (59 male) had required endotracheal intubation and mechanical ventilation for a period of four (median) days (range 1-27) in addition to gastric lavage and standard therapy with atropine and oximes and adequate hydration. Of these 71 patients, 36 (28 male) had died. Life table analysis demonstrated a steep decline in the cumulative survival to 67% during the first three days. Systolic blood pressure of < 100 mmHg and FiO2 of >40% to maintain a SpO2 of >92% within the first 24 h were recognized as poor prognostic indicators among mechanically ventilated patients.

CONCLUSION: Mortality following OP poisoning remains high despite adequate respiratory support, intensive care, and specific therapy with atropine and oximes. One-third of the subjects needing mechanical ventilation and reaching intensive care units die within the first 72 h of poisoning. Systolic blood pressure of less than 100 mmHg and the necessity of a FiO2>40% to maintain adequate oxygenation are predictors of poor outcome in patients mechanically ventilated in the ICU.