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

Respiration and mechanical ventilation induce cyclic variation in cardiac output and blood pressure. We examined these phasic hemodynamic influences of mechanical ventilation during gas ventilation and partial and tidal liquid ventilation in 7 anesthetized and paralyzed young piglets (body weight, 3.0–4.9 kg) made respiratory‐insufficient by repeated saline lung lavage. Nonlinear 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 hemodynamic variable during the study period, and was called the relative oscillation amplitude. The relative oscillation amplitude of left ventricular stroke volume, left ventricular output, systemic arterial pressure, and systemic perfusion pressure was significantly larger (at least twofold) during tidal liquid ventilation compared to partial liquid ventilation. No such differences were observed between gas and partial liquid ventilation at comparable gas ventilator settings. We conclude that in this animal model, within‐breath modulation of left ventricular output, systemic blood pressure, and perfusion pressure was significantly increased during tidal liquid ventilation as compared to partial liquid ventilation. Pediatr Pulmonol. 2000;30:114–124. © 2000 Wiley‐Liss, Inc.