Surfactant replacement reverse respiratory failure induced by intratracheal endotoxin in rats.
OBJECTIVE
To evaluate the effect of surfactant replacement on respiratory failure induced by intratracheal injection of endotoxin in rats.


METHODS
Prospective, randomized study.


METHODS
Laboratory at a large university.


METHODS
Male Wistar rats, weighing 353 +/- 50 (SD) g.


METHODS
Escherichia coli endotoxin (53 +/- 19 mg/kg) was injected into the trachea of 32 rats anesthetized with pentobarbital and mechanically ventilated with an FIO2 of 1.0. After PaO2 decreased to < 200 torr (< 26.7 kPa), the rats were assigned to three groups: a) a surfactant group (n = 16), given a modified natural surfactant suspension (100 mg/kg in 2.0 mL/kg of saline) by instillation into the airway; b) a saline control group (n = 8), given 2.0 mL/kg of saline; and c) an air control group (n = 8), given 2.0 mL/kg of air. An additional nine rats were ventilated in the same way but were not given endotoxin.


RESULTS
Among the rats receiving endotoxin, the PaO2 of the saline and air control groups remained < 200 torr (< 26.7 kPa), while PaO2 of the surfactant group increased to 390 +/- 116 torr (52.0 +/- 15.5 kPa; p < .05 vs. the preassignment value) 15 mins after the assignment. These high levels were maintained throughout the experiment. Surfactant replacement also led to significant improvements in the PaCO2, the dynamic lung-thorax compliance, the pressure-volume recordings of the lung, and the chest roentgenograms. Histologic examination showed that the alveoli of the surfactant group were better aerated than the alveoli of the control groups. Findings in the rats not given endotoxin were almost normal, indicating that the influences of mechanical ventilation were negligible.


CONCLUSIONS
Surfactant replacement reversed respiratory failure induced by intratracheal injection of endotoxin in rats.
Tashiro
K
K
Department of Anesthesiology and Intensive Care Medicine, School of Medicine, Kanazawa University, Japan.
Li
W Z
WZ
Yamada
K
K
Matsumoto
Y
Y
Kobayashi
T
T
D000818:Animals; D001794:Blood Pressure; D002245:Carbon Dioxide / Q000097:blood; D004731:Endotoxins / Q000008:administration & dosage*; D004926:Escherichia coli; D008170:Lung Compliance; D008297:Male; D010100:Oxygen / Q000097:blood; D011446:Prospective Studies; D011663:Pulmonary Surfactants / Q000627:therapeutic use*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D012131:Respiratory Insufficiency / Q000097:blood / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D014132:Trachea
D004731:Endotoxins; D011663:Pulmonary Surfactants; D002245:Carbon Dioxide; C044101:endotoxin, Escherichia coli; D010100:Oxygen