[Comparison of blood pressures measured directly at the radial and dorsalis pedis arteries during epidural anesthesia].

Differences of blood pressures measured directly at the radial and dorsalis pedis arteries were compared in relation to the sites of the epidural puncture. Epidural catheters were inserted at C7-Th9 in the upper (U) group (n = 7), and at L1-4 in lower (L) group (n = 7). In the awake, unanesthetized state, the systolic, mean and diastolic radial-to-dorsal pressure differences (DR-D) were -21.9 +/- 11.0 mmHg (mean +/- SD), 0.9 +/- 1.1 mmHg and 2.1 +/- 2.1 mmHg respectively. Following epidural infusion of mepivacaine, the DR-D values shifted to the negative direction in the U group, and to the positive direction in the L group. Epidural anesthesia had little effect on the DR-D changes during general anesthesia; however, it affected significantly the mean pressure DR-D as well as the systolic pressure DR-D during the periods of preinduction and postemergence. The maximum change in systolic pressure DR-D values was from -19.4 to -36.3 mmHg in a patient of the U group and from -15.6 to 45.4 mmHg in a patient of the L group. The maximum change in mean pressure DR-D values was from 0.0 to -7.4 mmHg in the U group and from 2.1 to 18.3 mmHg in the L group. The DR-D values had significant negative correlations with the deep temperature (palm to sole) differences; the correlation coefficients were: systolic, r = -0.50; mean, r = -0.50; and diastolic, r = -0.41. These results demonstrated that epidural anesthesia changed the physiological central-to-peripheral pressure gradients, probably by influencing the regional peripheral vascular resistance.