Effects of exogenous surfactant on gas exchange and compliance in rabbits after meconium aspiration

• Published in: Pediatric pulmonology Vol. 33; no. 2; pp. 117 - 123
• Main Authors: Robinson, Tonya W., Roberts, Andrew M.
• Format: Journal Article
• Language: English
• Published: New York John Wiley & Sons, Inc 01.02.2002; Wiley-Liss
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; animal model; Animals; Animals, Newborn; Biological and medical sciences; Biological Products; Disease Models, Animal; Emergency and intensive care: neonates and children. Prematurity. Sudden death; Humans; Infant, Newborn; Intensive care medicine; Lung Compliance - drug effects; Male; meconium aspiration; Meconium Aspiration Syndrome - drug therapy; Meconium Aspiration Syndrome - physiopathology; Medical sciences; Oxygen - blood; pulmonary aspiration syndromes; pulmonary compliance; Pulmonary Gas Exchange - drug effects; Pulmonary Surfactants - pharmacology; Pulmonary Surfactants - therapeutic use; Rabbits; surfactant; Time Factors; Intravenous administration; Continuous; Rabbit; Respiratory intensive care; Ox; Lung function; Respiratory failure; Pulmonary surfactant; Ungulata; Lung disease; Exogenous; Respiratory disease; Treatment efficiency; Animal origin; Exploration; Lagomorpha; Trauma; Vertebrata; Experimental disease; Mammalia; Bolus injection; Treatment; Aspiration pneumonia; Animal; Meconium; Artiodactyla; Comparative study
• ISSN: 8755-6863; 1099-0496
• DOI: 10.1002/ppul.10056

Success in using adjunctive surfactant therapy for meconium aspiration has been inconsistent. We tested the hypothesis that the ability of exogenous surfactant to improve gas exchange and pulmonary compliance after meconium aspiration is related to the method of surfactant administration. In anesthetized rabbits (2.4 ± 0.16 kg body weight), an endotracheal tube (ETT) was placed in the lower trachea, and the lungs were ventilated mechanically. After a control period, filtered meconium (3–5 mL/kg) was instilled through the ETT. Group 1 (n = 5) was not given surfactant. Thirty minutes after meconium instillation, group 2 (n = 5) was given a bolus of bovine surfactant (Beractant, 4 mL/kg) through the ETT, and group 3 (n = 5) was given an infusion of Beractant (4 mL/kg for 1 hr) through the side‐port of the ETT. Thirty minutes after meconium instillation, tracheal pressure increased by 8 ± 1 cm H2O (mean ± SEM), dynamic compliance decreased by 0.36 ± 0.07 mL/cm H2O/kg, arterial PO2 (PaO2) decreased by 49 ± 6.0 mmHg, arterial PCO2 (PaCO2) increased by 12 ± 2.4 mmHg, and arterial pH (pHa) decreased by 0.09 ± 0.02. After 3 hr of exposure to meconium, tracheal pressure was significantly (P < 0.001) lower in group 3 compared to groups 1 or 2. PaO2 remained below baseline in all groups. Group 3 had a significantly (P = 0.001) higher dynamic compliance than groups 1 or 2. Likewise, static compliance was higher for group 3 compared to groups 1 or 2, with the greatest difference at low lung volume. Mean arterial blood pressure, pulse rate, PaCO2, and pHa were not significantly different between groups. These results suggest that continuous infusion of exogenous surfactant is more effective than bolus administration in improving pulmonary function after meconium aspiration. Pediatr Pulmonol. 2002; 33:117–123. © 2002 Wiley‐Liss, Inc.