Am. J. Respir. Crit. Care Med.,
Volume 164, Number 1, July 2001, 36-42
Preserved Spontaneous Breathing Improves Cardiac
Output during Partial Liquid Ventilation
AXEL R.
FRANZ,
CHRISTINA
MACK,
JULIA
REICHART,
FRANK
POHLANDT,
and
HELMUT D.
HUMMLER
Department of Pediatrics, Division of Neonatology and Pediatric Critical Care, University of Ulm, Ulm, Germany
The aim of this study was to examine whether preserved spontaneous breathing (SB) supported by proportional-assist ventilation (PAV) would improve cardiac output (CO) during partial liquid ventilation (PLV) in rabbits with and without lung disease if compared with time-cycled, volume-controlled ventilation (CV) combined with muscle paralysis (MP). PLV was initiated in 17 healthy rabbits and 17 surfactant-depleted rabbits using 12 to 15 ml/kg of
perfluorodecaline. Both ventilatory modes, SB+PAV and CV+MP, were applied in random sequence using a crossover design. CO
was measured by thermodilution. CO was significantly higher during SB+PAV than during CV+MP: 136 ± 21 ml/kgmin (mean ± SD) versus 120 ± 30 ml/kgmin (p = 0.004) in healthy rabbits, and
147 ± 19 ml/kgmin versus 111 ± 13 ml/kgmin (p < 0.0001) in
surfactant-depleted rabbits, resulting in an improved oxygen delivery. This difference was mainly caused by a larger stroke volume
during SB+PAV, whereas there was little change in heart rate. In
surfactant-depleted rabbits, SB+PAV resulted in improved arterial
blood pressure and arterial and mixed venous pH and in a higher
PaO2 at the same level of PEEP and mean airway pressure. We conclude that during PLV, CO is higher during SB+PAV than during
CV+MP, resulting in an improved oxygen delivery. In surfactant-depleted rabbits, improved CO, oxygen delivery, and arterial
blood pressure resulted in higher pH, possibly reflecting improved
tissue perfusion and oxygenation.
Keywords: Fluorocarbons; ventilation, mechanical; respiration, artificial; hemodynamics; cardiac output; paralysis
