Effects of local injection of prilocaine-felypressin on the myocardial oxygen balance in dogs.

The authors investigated the effects of felypressin (Fely), a non-adrenergic vasoconstrictor, used together with prilocaine on myocardial oxygen balance. Six open-chest dogs were studied under urethane and alpha-chloralose anesthesia. Systolic arterial pressure, diastolic arterial pressure, mean pulmonary arterial pressure and pulmonary capillary wedge pressure, heart rate, coronary blood flow (CBF), internal and external myocardial oxygen tension (int- or ext-PmO2), and cardiac output were observed. Three doses of Citanest-Octapressin, which contains 3% prilocaine and 0.03 IU ml(-1) Fely (Pri-Fely) - 0.09, 0.18, and 0.3 ml kg(-1)- were injected into the tongue. Observations were performed up to 60 min after the injection. The CBF and int-PmO2 was reduced following the injection of each of the three doses of Pri-Fely. There were negative correlations between the Pri-Fely dose per body weight and the maximum reductions in CBF (r = -0.52, P < 0.05), in int-PmO2 (r = -0.78, P < 0.05), and in ext-PmO2 (r = -0.55, P < 0.05), respectively [corrected]. These results suggest that an administration of Fely at doses more than 2.7-5.4 mIU kg(-1) (3-6 cartridges of Pri-Fely) may induce an imbalance between the oxygen supply and demand in myocardial tissues of patients with cardiovascular diseases.