[Dose-related response of adenosine in hypoxic pulmonary hypertension in canines]

The vasodilator test is of critical importance in determining the reversibility of pulmonary hypertension and hence the indication of surgical treatments for cases of marginal pulmonary hypertension associated with left to right shunt. This study aimed at the dose-related vasodilation effect of adenosine (AD) on hypoxic pulmonary hypertension. The hemodynamic indexes were examined in 8 canines with acute hypoxic pulmonary hypertension after administration of intravenous adenosine. The results showed that AD decreased both systemic and pulmonary pressures in a dose-dependent way, with very close linear correlation; so did the systemic and pulmonary resistance (r = -0.970 and -0.994, respectively; P < 0.001). The PASP reductions were significantly greater than SASP reductions at AD doses of 100 to 200 micrograms/(kg.min) (from -11.0% +/- 4.2% to -27.7% +/- 14.8% vs from -2.6% +/- 7.4% to -14.9% +/- 7.0%, respectively), while PVR reductions were significantly greater than SVR reductions (-18.8% +/- 8.05% vs -10.2% +/- 6.86% and -29.8% +/- 14.46% vs -21.1% +/- 9.53%, respectively, P < 0.05). AD increased cardiac output and cardiac index to the significant degree only when the dosage increased to 300 micrograms/(kg.min) or above. These results suggest that AD seems to be the choice of drug in vasodilator test of left to right shunt pulmonary hypertension, and the proper dosage ranges from 100 to 200 micrograms/(kg.min).