Circulatory responses to epidural blockade of treated and untreated hypertensive patients.

The circulatory effects of epidural blockade were studied in 82 hypertensive patients. To compare the circulatory responses to epidural blockade between treated and untreated hypertensive patients, patients were divided into 60 treated and 22 untreated hypertensive patients groups, and to confirm the magnitude of hemodynamic changes according to the segment of epidural approach, each group was then subdivided into 3 groups as cervical, thoracic and lumbar. The blood pressure and the pulse rate were measured before and after establishment of epidural blockade. The baseline blood pressure of untreated group was significantly higher than that of treated one (P < 0.05), but there was no difference between two groups in the initial pulse rate. At 20 min after meperidine administration to epidural space, blood pressure drop was more pronounced in untreated thoracic subgroup than in treated one (P < 0.05), but there was no significant difference in blood pressure drop between treated and untreated groups of cervical and lumbar blockade. Regarding the pulse rate change, there was no significant difference between treated and untreated cases of all the subgroups. The rate of fluid load required to maintain the adequate blood pressure in the first 20 min of epidural blockade was more in treated than in untreated cases of cervical subgroup. During surgery the administration of vasopressor agents was more frequently required to maintain blood pressure in treated and untreated thoracic subgroups, while the administration of vasodilator agents was more frequent in treated and untreated cases of cervical and thoracic subgroups. The incidence of rebound hypertension was relatively high in untreated cervical and thoracic subgroups as compared to treated ones.