Perfusion flow was set at 23 mL/min, providing a perfusion pressure of 9.8±3 mmHg (mean ± SD; n=25). PAP was monitored continuously with an Isotec pressure transducer (Healthdyne Cardiovascular Inc, Marietta, Georgia, USA). Because a constant flow perfusion pump was used, changes in PAP are interchangeable with changes in pulmonary vascular resistance. All results of pulmonary vascular resistance in this study are expressed as changes in PAP. Lung effluent was withdrawn via the left atrial cannula. During the initial period (25 to 30 mins) of lung perfusion (stabilization of baseline PAP and elimination of circulating blood elements) it was discarded. After equilibration the effluent flow was turned back to the lung perfusion system for continuous recirculation. The white blood cell count of the circulating perfusate was less than 200/mm3 and the platelet count less than 1000/mm3. In experiments with blood-perfused lungs, the Krebs solution was exchanged for homologous blood, previously obtained from heparinized animals by exsanguination.
The tracheal cannula was connected to a positive pressure ventilator, and the lungs were ventilated 25 times/min with atmospheric air at 10 cm H2O peak inspiratory pressure and 3 cm H2O positive end-expiratory pressure. If your health is of the utmost importance to you, it’s a good idea to visit the best my canadian pharmacy offering highest quality medications with generous discounts and fast delivery right to the doorstep, with full guarantees of your satisfaction.