title: Surfactant improves gas mixing and alveolar ventilation in preterm lambs.
abstract: Prophylactic treatment with ovine surfactant was evaluated in preterm lambs at risk for development of hyaline membrane disease. Eight mechanically ventilated newborn lambs were treated before delivery and 10 served as controls (gestational age 129-131 d). Lung mechanics, functional residual capacity, alveolar ventilation, efficiency of ventilation, and distribution of ventilation were tested using pressure, flow, and nitrogen elimination (nitrogen washout during 100% oxygen breathing) measurements in the endotracheal tube. The surfactant-treated animals showed significantly improved gas mixing efficiency in the lung with improved alveolar ventilation. Single exponential washout pattern dominated in both groups. Adequate functional residual capacity was established earlier after birth in the treated lambs than in the control animals. Lung mechanics in the treated group showed significant improvement in dynamic lung compliance. Surfactant treatment also improved gas exchange and reduced respirator pressure requirement. We speculate that the main functional effect of surfactant treatment in preterm lambs at risk to develop hyaline membrane disease is to maintain the patency of the peripheral airways in the lung, which improves diffusive gas mixing, alveolar ventilation, and gas exchange. The techniques used in this study should also be useful to evaluate lung function in preterm human infants after specific adaptation of the equipment size.
authors.affiliation: Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
authors.forename: K
authors.initials: K
authors.lastname: Sandberg
authors.forename: K E
authors.initials: KE
authors.lastname: Edberg
authors.forename: W
authors.initials: W
authors.lastname: Benton
authors.forename: A
authors.initials: A
authors.lastname: Silberberg
authors.forename: M
authors.initials: M
authors.lastname: Sladek
authors.forename: H W
authors.initials: HW
authors.lastname: Sundell
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D005865:Gestational Age; D006801:Humans; D006819:Hyaline Membrane Disease / Q000188:drug therapy*; D007231:Infant, Newborn; D011663:Pulmonary Surfactants / Q000627:therapeutic use*; D012119:Respiration / Q000187:drug effects*; D012129:Respiratory Function Tests; D012756:Sheep
chemical_list: D011663:Pulmonary Surfactants