COMPARATIVE STUDIES OF DIRECT AND INDIRECT ARTERIAL BLOOD PRESSURE MEASUREMENTS, BY THE OSCILLOMETRIC METHOD, IN ANESTHETIZED TIGERS

Abstract

Direct and indirect arterial blood pressure measurements, by the oscillometric method, were carried out on twelve anesthetized healthy tigers during claw amputation. There were seven males and five females aged (mean ± SD) 4 ± 1 months and weighing (mean ± SD) 18 ± 11 kg. Anesthesia was induced using intramuscular ketamine, in conjunction with xylazine and atropine sulphate, and maintained by halothane inhalation. Heart rates, direct and indirect systolic, diastolic and mean arterial blood pressures were measured at 5 min intervals using 3 oscillometric monitors. The measurem ent of direct arterial blood pressure was made at the dorsal metatarsal artery of the left hock, while indirect blood pressure was measured at the dorsal metatarsal artery of the right hock and at the
artery under the tail base. Mean ± SD of the heart rates was 109 ± 16 beats per minute, direct systolic, diastolic and mean arterial blood pressures were (mean ± SD) 111 ± 31, 62 ± 29 and 81 ± 30 mm.Hg, respectively. Indirect systolic, diastolic and mean arterial blood pressures measured at the two sites were significantly different (p < 0.05) from the arterial blood pressures that were measured directly. Despite the differences, they were all correlated. Correlation coefficient (r) between the direct and indirect systolic blood pressures (SBP), measured at the right hock, was 0.80 which was higher than
r between direct and indirect SBP measured at the tail base (r = 0.77). The same correlation (r=0.70) was found between the direct and indirect mean arterial blood pressures (MBP) measured at the right hock and at the tail base. The results of this study showed that the indirect arterial blood pressures measured at the right hock were closer to the direct arterial blood pressures and significantly higher than the indirect blood pressures measured at the tail base. A high correlation(r=0.87) was observed between the direct and indirect mean arterial blood pressures measured at the hocks of tigers that had direct mean arterial blood pressure below 60 mmHg. This implies that the oscillometric measurement of indirect arterial blood pressure can be used in
hypotensive tigers.