Lung lavage and surfactant replacement for hydrochloric acid aspiration in rabbits

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.

Pulmonary Surfactant: Physical Chemistry, Physiology, and Replacement

“…However, benefits to lung function and/or mechanics from exogenous surfactant therapy have now been demonstrated in a number of animal models of ARDS-related acute lung injury (eg, (18,21,107,162,163,168,169,177,184,299,343)). (Table 14).…”

“…The existence of lung surfactant inactivation, with or without an associated surfactant-deficiency, has been demonstrated in multiple ARDSrelated animal models. Examples and representative references include acute lung injury from: hyperoxia (121,177,184), fatty acid infusion (100,102), injection of N-nitroso-N-methylurethane (NNNMU) (107,172), acid aspiration(162,343), bilateral vagotomy(21,166), anti-lung serum infusion(169), in vivo lung lavage(18,163,168,170), and flu-induced pneumonia (299).…”

Effect of surfactant replacement onPneumocystis carinii pneumonia in rats

“…It has been repeatedly demonstrated by several authors that intratracheal instillation of exogenous surfactam restores lung function in animals with respiratory failure due to surfactant depletion or intratracheal HC1 administration [5,6]. Also large numbers of neonates with respiratory distress syndrome (RDS) due to lack of surfactant have been successfully treated with exogenous surfactant [7][8][9][10].…”

Surfactant Therapy for Acute Lung Injury and Acute Respiratory Distress Syndrome

“…The ability of exogenous surfactant therapy to improve acute respiratory pathology in animal models of ALI/ARDS in vivo is similarly well-documented (Table 3). Examples of animal models found to display acute improvements in arterial oxygenation and/or lung mechanics following surfactant therapy are: acid aspiration 80–82 , meconium aspiration 83–86 , anti-lung serum 87 , bacterial or endotoxin injury 88–93 , pulmonary contusion 78 , bilateral vagotomy 94 , hyperoxia 95–99 , in vivo lavage 100–105 , N-nitroso-N-methylurethane (NNNMU) injury 106–108 , and viral pneumonia 109, 110 . Animals studies of acute injury are typically not designed to assess efficacy based on long-term outcomes.…”