STUDY OF RESPIRATORY-FAILURE IN ORGANOPHOSPHATE AND CARBAMATE POISONING

Objective: To study the clinical profile and cholinesterase levels of subjects of organophosphate and carbamate poisoning and to identify th ose subjects who would require ventilatory support. Design: Prospectiv e, observational study. Setting: Intensive care unit of a tertiary car e urban hospital. Subjects: Fifty-two patients admitted with a diagnos is of organophosphate or carbamate poisoning. Outcome Measures: Subjec t survival and ventilator requirement. Intervention: Treatment with at ropine and pralidoxime and mechanical ventilation for patients with re spiratory failure. Clinical features were monitored at every stage, an d blood for plasma and red blood cell cholinesterase levels was collec ted on admission. Results: According to the ingested poison, subjects were divided into four groups: organophosphates (13 subjects), mixed o rganophosphate and carbamate (18), carbamates (13), and a fourth misce llaneous group (8). Dyspnea and vomiting were the most common symptom and miosis and cyanosis were the most frequently observed signs. Plasm a and red cell cholinesterase levels were lowest in the mixed poison g roup and highest in the carbamate group. Twenty-seven subjects develop ed Type I respiratory failure and 7 had Type II respiratory failure. M echanical ventilation was required in 31 subjects. Overall 33 subjects survived. A scoring system, on a point scale of 16, was developed usi ng miosis, unconsciousness, fasciculations, and plasma cholinesterase levels to predict ventilator requirement. Conclusion: This study helps to identify at an early stage those patients with organophosphate or carbamate poisoning who would ultimately require ventilatory support. We found miosis, unconsciousness, fasciculations, and a low plasma cho linesterase level to be of greatest predictive value.