By using adult rabbits in which the lung surfactant had been reduced by repeated whole-lung lavage, we examined the effects of surfactant supplement and positive end-expiratory pressure (PEEP). The rabbits were anesthetized with pentobarbital sodium and mechanically ventilated with pure O2. Surfactant that was extracted from pigs' lungs was supplemented to the rabbits through the trachea. The PEEP was set at 4 cmH2O. The seven rabbits that were ventilated without the supplement and without the PEEP all died of hypoxia, hypercapnia, and reduction of lung compliance within 2 h. The 18 rabbits that were ventilated with either the supplement or the PEEP showed some elevations of arterial O2 tension, but 9 of them died within 4 h. After application of both the surfactant supplement and the PEEP, six out of the eight rabbits survived for more than 11 h with nearly normal values of blood gases and compliance. We concluded that the combination of the transtracheal surfactant supplement and ventilation with PEEP has favorable therapeutic effects on surfactant deficiency.

No abstract

No abstract

Hydrochloric acid (0.1 N, 5.0 ml.kg-1 in total) was administered intratracheally to 28 adult rabbits anesthetized with pentobarbital and mechanically ventilated with pure oxygen. When the PaO2 decreased to 14.1 +/- 2.8 kPa (mean +/- s.d.), the PaCO2 increased to 8.9 +/- 2.5 kPa, and the minute ventilation (VE) decreased to 51 +/- 8% of the baseline value, animals were divided into 4 groups. The deteriorated values did not improve in the non-treated (control) animals, whereas the animals treated with lung lavage and surfactant replacement showed a significant increase in PaO2 to 35.1 +/- 12.2 kPa, and maintained lower PaCO2 and larger VE than the controls. These parameters showed no significant improvement with surfactant replacement alone, and deteriorated further with lung lavage alone. The minimum surface tension (gamma min) of the edema fluid that accumulated in the airways after acid administration was 22.5 +/- 1.7 mN.m-1, and was not lowered by adding surfactant preparation (10 mg.ml-1) whose original gamma min was less than 2 mN.m-1. We concluded that surfactant inhibition by edema fluid was a cause of respiratory failure, and that lung lavage followed by surfactant replacement might be of therapeutic value for acid aspiration.

A 56-year-old woman is presented with a large coronary-artery-to-bronchial-artery anastomosis associated with aortitis syndrome. Her angina, which was the result of a coronary artery steal, was relieved by surgical division of the anastomotic vessel. Pulmonary artery obstruction, as a pulmonary lesion of aortitis syndrome, might increase the collateral flow from the coronary artery through the bronchial artery to the pulmonary circulation.