Effect of perfluorochemical liquid ventilation on cardiac output and bloodpressure variability in neonatal piglets with respiratory insufficiency

Respiration and mechanical ventilation induce cyclic variation in cardiac o utput and blood pressure. We examined these phasic hemodynamic influences o f mechanical ventilation during gas ventilation and partial and tidal liqui d ventilation in 7 anesthetized and paralyzed young piglets (body weight, 3 .0-4.9 kg) made respiratory-insufficient by repeated saline lung lavage. No nlinear regression analysis of cardiovascular parameters vs. time was done to quantify respiratory-induced fluctuations in hemodynamic variables. The amplitude of oscillations was expressed as a percentage of the mean hemodyn amic variable during the study period. and was called the relative oscillat ion amplitude. The relative oscillation amplitude of left ventricular stroke volume, left ventricular output, systemic arterial pressure, and systemic perfusion pres sure was significantly larger (at least twofold) during tidal liquid ventil ation compared to partial liquid ventilation. No such differences were obse rved between gas and partial liquid ventilation at comparable gas ventilato r settings. We conclude that in this animal model, within-breath modulation of left ven tricular output, systemic blood pressure, and perfusion pressure was signif icantly increased during tidal liquid ventilation as compared to partial li quid ventilation. (C) 2000 Wiley-Liss, Inc.