EFFECTS OF PH AND TEMPERATURE ON LUNG PRESERVATION - A STUDY WITH AN ISOLATED RAT LUNG REPERFUSION MODEL

After the rat lung was flushed with 40 mmol/L phosphate-buffered salin e solution containing 160 mEq/L of sodium and the heart-lung block was immersed in the same solution for 6 hours, the lung was reperfused wi th diluted autologous blood and ventilated for 30 minutes. Pulmonary a rtery pressure, airway pressure, difference in oxygen tension between inflow and outflow perfusate, and wet to dry weight ratio of the tissu e were determined. Lungs treated at pH 7.75 showed a significantly low er pulmonary artery pressure and wet to dry weight ratio than those tr eated at pH 7.26 or 7.96. Organs preserved at 10 degrees C showed a si gnificantly lower pulmonary artery pressure than those preserved at 5 degrees or 15 degrees C. When the effect of smaller temperature variat ions was examined, the 12 degrees C group showed a significantly lower pulmonary artery pressure than the 10 degrees C group. Thus, the isol ated rat lung reperfusion model appears to provide an efficient screen ing system to examine the preservation solution or other conditions fo r lung preservation. Under the present experimental conditions, the op timal pH and temperature for rat lung preservation seem to be 7.75 and 12 degrees C, respectively.