Effect of ventilatory frequency on fluid filtration rate in isolated perfused rabbit lungs
Martínez Ruiz, R.; Zabner, J.; Angeli, S.; Sánchez de León, R.
Acta Cientifica Venezolana 39(2): 151-154
1988
ISSN/ISBN: 0001-5504 PMID: 3075104 Document Number: 311956
We studied the effect of varying ventilatory frequency (VF) using intermittent positive pressure ventilation (IPPV) on fluid filtration rate (FFR) in 16 isolated rabbit lung preparations perfused at constant blood flow and airway pressure (AWP). Mean pulmonary artery pressure (MPAP), AWP, pulmonary vascular resistance (PVR), pH, PaO2, PaCO2 and colloid osmotic pressure (COP) were measured. Ventilation was performed by a piston pump ventilator. VF was changed every 10 min. by the following schedule: 25-40-55-70-55-40-25 breaths per min. A group of 6 rabbits was ventilated under normal hemodynamic conditions and another group of 10 rabbit was ventilated after the production of hydrostatic pulmonary edema. Blood gas exchange was satisfactory in both groups of rabbits. There was no statistically significant correlation between VF and FFR in the two experimental situations (p > 0.05). In conclusion, VF variation using IPPV (keeping AWP constant) did not alter liquid transfer between the microvasculature and lung interstitial space under normal hemodynamic conditions nor in hydrostatic lung edema in isolated perfused rabbits lung.