Evaluation of respiratory dysfunction in a pig model of severe acute dichlorvos poisoning.
BACKGROUND
Respiratory failure is the main cause of death in acute organophosphorus pesticide poisoning. In this study, a pulse-induced contour cardiac output monitor was used to evaluate the respiratory status in a pig model of acute dichlorvos poisoning.


METHODS
Twenty female pigs were randomly allocated to dichlorvos (n = 7), atropine (n = 7), and control (n = 6) groups. In the dichlorvos group, pigs were administered 80% emulsifiable dichlorvos (100 mg/kg) via a gastric tube. In the atropine group, pigs were similarly administered dichlorvos, and 0.5 hours later, atropine was injected to attain and maintain atropinization. The control group was administered saline solution. Arterial blood gas was measured at 0, 0.5, 1, 2, 4, and 6 hours post-injection. The extravascular lung water index and pulmonary vascular permeability index were recorded by the pulse-induced contour cardiac output monitor. At termination of the study, the animals were euthanized, the lung wet-to-dry weight ratio was determined, and histopathology was observed.


RESULTS
In the dichlorvos group, the extravascular lung water index and pulmonary vascular permeability index were substantially increased from 0.5 hours and were particularly high within 1 hour. In the atropine group, these indices increased initially, but decreased from the 1-hour mark. The control group exhibited no obvious changes. In both the dichlorvos and atropine groups, the extravascular lung water index was negatively correlated with partial pressure of oxygen/fraction of inspiration oxygen (PO2/FiO2) and positively correlated with the pulmonary vascular permeability index. Compared with the control group, the lung wet-to-dry weight ratio markedly increased and the histopathological findings obviously changed in the dichlorvos group, but only mildly increased and changed, respectively, in the atropine group.


CONCLUSIONS
The extravascular lung water index is an appropriate and valuable parameter for assessment of respiratory function in acute dichlorvos poisoning.
Department of Emergency Medicine, Beijng Chaoyang Hospital, Capital Medical University, Beijing 100020, China.
Xin-Hua
XH
He
Jun-Yuan
JY
Wu
Chun-Sheng
CS
Li
Zhi-Yu
ZY
Su
Xian-Fei
XF
Ji
Yi
Y
Han
Sheng-Qi
SQ
Wang
Jian
J
Zhang
D000110:Acetylcholinesterase / Q000097:blood; D000208:Acute Disease; D000818:Animals; D004006:Dichlorvos / Q000633:toxicity*; D015633:Extravascular Lung Water / Q000187:drug effects; D005260:Female; D007306:Insecticides / Q000506:poisoning*; D008168:Lung / Q000473:pathology; D012131:Respiratory Insufficiency / Q000139:chemically induced* / Q000473:pathology; D013552:Swine
D007306:Insecticides; D004006:Dichlorvos; D000110:Acetylcholinesterase