Epidural block in local kidney cancer as a way to preserve the adrenal function influencing urine formation processes.

Abstract

592 Background: Our purpose was to study the dynamics of cortisol (C) and aldosterone (A) in the blood plasma in patients receiving surgery with the epidural block (EB) for local kidney cancer. Methods: 58 patients aged 56.5±8.7 years underwent partial nephrectomy with warm ischemia for 15-20 minutes (EB – 35 patients, standard anesthesia (SA) - 23 patients). EB involved catheterization of the epidural space at Th10-L1 with the following infusion of a mixture of ropivacaine 2 mg/ml and epinephrine 2 μg/ml at 6-10 ml/hr using a syringe doser, intraoperatively and within the first three postoperative days. The levels of C and A were studied by radioimmunoassay in the blood plasma of patients before the surgery (b/s), 40 min after the start of the surgery (40' s/s) and on days 1 and 3 after the surgery (a/s). Results were compared to the levels in the blood plasma of 32 healthy donors (N). Results: C and A exceeded N in all patients b/s (p < 0.01). C increased by an order of magnitude 40' s/s only in SA (p < 0.001), while A increased in all patients, compared to the levels b/s. C decreased by 1.5 times in EB on day 1 a/s; C in SA was similar to the levels b/s; A decreased to similar levels in all patients but was still higher than N by 1.4 times on average (p < 0.01). The C levels remained stable in all patients on day 3; A levels became normal in EB only, while in SA they were 2.1 times lower which caused the loss of salts and fluid. Conclusions: SA affected the regulation of the adrenal function by the central nervous system and urine formation processes in the kidney. In SA, abnormal C and A levels preserve for a longer period of time enhancing the water and salt imbalance in the body. Significant decrease of C and the normalization of A in EB indicate the preservation of the adrenal function influencing urine formation processes in the kidney. In local kidney cancer, it is advisable to use epidural block instead of standard anesthesia as the latter blocks regulatory functions of the central nervous system.