Respiratory failure in acute organophosphorus pesticide self-poisoning.
BACKGROUND
Acute organophosphorus (OP) pesticide poisoning is a major clinical problem in the developing world. Textbooks ascribe most deaths to respiratory failure occurring in one of two distinct clinical syndromes: acute cholinergic respiratory failure or the intermediate syndrome. Delayed failure appears to be due to respiratory muscle weakness, but its pathophysiology is unclear.


OBJECTIVE
To describe the clinical patterns of OP-induced respiratory failure, and to determine whether the two syndromes are clinically distinct.


METHODS
Prospective study of 376 patients with confirmed OP poisoning.


METHODS
Patients were observed throughout their admission to three Sri Lankan hospitals. Exposure was confirmed by butyrylcholinesterase and blood OP assays.


RESULTS
Ninety of 376 patients (24%) required intubation: 52 (58%) within 2 h of admission while unconscious with cholinergic features. Twenty-nine (32%) were well on admission but then required intubation after 24 h while conscious and without cholinergic features. These two syndromes were not clinically distinct and had much overlap. In particular, some patients who required intubation on arrival subsequently recovered consciousness but could not be extubated, requiring ventilation for up to 6 days.


CONCLUSIONS
Respiratory failure did not occur as two discrete clinical syndromes within distinct time frames. Instead, the pattern of failure was variable and overlapped in some patients. There seemed to be two underlying mechanisms (an early acute mixed central and peripheral respiratory failure, and a late peripheral respiratory failure) rather than two distinct clinical syndromes.
Eddleston
M
M
Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK. eddlestonm@eureka.lk
Mohamed
F
F
Davies
J O J
JO
Eyer
P
P
Worek
F
F
Sheriff
M H R
MH
Buckley
N A
NA
D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000931:Antidotes / Q000627:therapeutic use; D002606:Charcoal / Q000627:therapeutic use; D003906:Developing Countries; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007442:Intubation, Intratracheal; D008297:Male; D062025:Organophosphate Poisoning; D010575:Pesticides / Q000506:poisoning*; D011446:Prospective Studies; D012131:Respiratory Insufficiency / Q000139:chemically induced* / Q000175:diagnosis / Q000628:therapy; D013406:Suicide, Attempted; D013997:Time Factors
D000931:Antidotes; D010575:Pesticides; D002606:Charcoal