The effects of dexmedetomidine on pulmonary artery pressure in experiment

The primary purpose of this study is to assess the effects of dexmedetomidine (DEX) infusion on pulmonary artery pressures (PAP), heart rate (HR), and mean arterial pressure (MAP) in pigs. The secondary purpose is to evaluate whether DEX infusion via the pulmonary artery has any beneficial effect over the peripheral IV route.

Sixteen healthy male pigs (25-35 kg) scheduled for laparoscopy training were used in this study. The animals were randomly allocated into two groups: Group I (n = 9): A loading dose of 1 μg/kg DEX was administered over 10 minutes followed by an infusion of 0.5 μg/kg/hr for one hour via the pulmonary artery catheter. Group II (n = 7): A loading dose of 1 μg/kg DEX was administered over 10 minutes followed by an infusion of 0.5 μg/kg/hr for one hour via the peripheral venous catheter. Mean PAP, HR, MAP, SpO2, and ETCO2 were recorded at 5, 10, 15, 30, 45, and 60 minutes after the initiation of the DEX infusion.

Heart rate and MAP were similar in both groups at all time points. Also, neither the HR nor the MAP deviated from the basal values in Groups I and II at any time point. The mean PAP values were similar in Groups I and II, and in Group I, the mean PAP values were similar to Group I's basal value at all time points. However, in Group II, the mean PAP values at 5, 45, and 60 minutes were significantly lower than Group II's basal value (p = 0.023, p = 0.041, p = 0.015, respectively).

DEX infusion did not elevate the mean PAP and the results from the administration of DEX through the peripheral vein and pulmonary artery were similar (Tab. 3, Ref. 13).