Alveolar fluid clearance in healthy pigs and influence of positive end-expiratory pressure

• Published in: Critical care (London, England) England), 2010-01, Vol.14 (2), p.R36-R36, Article R36
• Main Authors: García-Delgado, Manuel, Touma-Fernández, Angel, Chamorro-Marín, Virginia, Ruiz-Aguilar, Antonio, Aguilar-Alonso, Eduardo, Fernández-Mondéjar, Enrique
• Format: Article
• Language: English
• Subjects: Animals; Extravascular Lung Water - metabolism; Hemodynamics; Measurement; Models, Animal; Physiological aspects; Positive-Pressure Respiration - methods; Pressure; Properties; Pulmonary alveoli; Pulmonary Edema - therapy; Respiratory intensive care; Swine; Treatment Outcome
• ISSN: 1364-8535; 1466-609X; 1364-8535
• DOI: 10.1186/cc8914

The objectives were to characterize alveolar fluid clearance (AFC) in pigs with normal lungs and to analyze the effect of immediate application of positive end-expiratory pressure (PEEP). Animals (n = 25) were mechanically ventilated and divided into four groups: small edema (SE) group, producing pulmonary edema (PE) by intratracheal instillation of 4 ml/kg of saline solution; small edema with PEEP (SE + PEEP) group, same as previous but applying PEEP of 10 cmH2O; large edema (LE) group, producing PE by instillation of 10 ml/kg of saline solution; and large edema with PEEP (LE + PEEP) group, same as LE group but applying PEEP of 10 cmH2O. AFC was estimated from differences in extravascular lung water values obtained by transpulmonary thermodilution method. At one hour, AFC was 19.4% in SE group and 18.0% in LE group. In the SE + PEEP group, the AFC rate was higher at one hour than at subsequent time points and higher than in the SE group (45.4% vs. 19.4% at one hour, P < 0.05). The AFC rate was also significantly higher in the LE + PEEP than in the LE group at three hours and four hours. In this pig model, the AFC rate is around 20% at one hour and around 50% at four hours, regardless of the amount of edema, and is increased by the application of PEEP.