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A-160
2001
Influence of Endoscopic Thoracic Sympathectomy on Baroreflex Control of Heart Rate in Patients with Palmar Hyperhidrosis
Yurie T. Kawamata, M.D.; Eiji Homma, M.D.; Tomoyuki Kawamata, M.D.; Kiichi Omote, M.D.; Akiyoshi Namiki, M.D.
Anesthesiology, Sapporo Medical University, Sapporo, Hokkaido, Japan
Introduction

Recently, endoscopic thoracic (T2-3) sympathectomy (ETS) has been widespread as a highly effective treatment for palmar hyperhidrosis. Since the T2-3 sympathetic ganglia are involved in the direct sympathetic innervation of the heart, it is possible that T2-3 sympathectomy would alter baroreflex control of heart rate. Purpose of our study is to examine the influence of ETS on baroreflex response.

Methods

After approval by our Institution Committee and obtaining the informed consent from each patient, we studied 16 patients (ASA physical status I) with palmar hyperhidrosis, who were scheduled to receive the ETS under general anesthesia. All patients were free of cardiac disease and did not take any drugs known to influence the cardiovascular and neuroendocrine systems. After intubation, anesthesia was maintained at sevoflurane 1.0-1.5% and 100% oxygen during study. Patients were randomized to receive either pressor (n=8, 25.5±11 yr old) or depressor (n=8, 25.8±9.2 yr old) test. Each test was performed before and after the ETS. In the ETS procedure, the sympathetic trunk was identified at the second and third dorsal rib heads using the thoracic endoscopy and was transected. The pressor or depressor test was performed using intravenous infusions of phenylephrine or nitroglycerin, respectively, in order to change systolic blood pressure (SBP) by 20-30 mmHg. Measurement of R-R intervals was obtained from electrocardiography and SBP was measured through a radial arterial catheter. R-R intervals were plotted against the preceding arterial pulse, and the data from the pressor and depressor tests were analyzed using least square linear regression analysis. Baroreflex sensitivity was expressed as the slope of regression. For comparisons between pre- and post-ETS, a paired t test was used. All values were expressed as mean±SD. A P value<0.05 was considered to be statistical significant.

Results

Before and after the ETS, there were no significant differences in resting SBP (105.0±8.7 and 105.3±13.7 mmHg, respectively) and heart rate (88.9±14.4 and 86.0±15.1 beats/min, respectively). In the pressor test, the ETS produced a significant suppression of baroreflex response in all petient studied; baroreflex sensitivity before and after the ETS were 7.6±2.8 and 3.4±2.5 msec/mmHg, respectively (P<0.05). In the depressor test, the ETS also suppressed baroreflex response. In two of eight patients, baroreflex response was completely suppressed after the ETS. Baroreflex sensitivity before and after the ETS were 3.8±0.4 and 1.2±1.4 msec/mmHg, respectively (P<0.05). All patients showed the increase in skin temperatures of bilateral palmars and arms, and the ceasing sweat after the ETS, indicating successful T2-3 sympathectomy.

Conclusion

Our results indicated that T2-3 sympathectomy suppressed baroreflex control of heart rate in both pressor and depressor tests in the patients with palmar hyperhidrosis. We should note that baroreflex response for maintaining cardiovascular stability is suppressed in the patients who received the ETS.

Anesthesiology 2001; 95:A160