Intrathecal Endothelin-1 Reduced the MAC of Isoflurane in the Rat / 대한마취과학회지

BACKGROUND: Recent evidences suggest that anesthetic action within the spinal cord is important in suppressing somatic responses to painful stimuli. Intrathecal endothelin-1 (ET-1) is known to have antinociceptive effect. The purpose of this experiment was to determine whether intrathecal ET-1 may influence the minimum alveolar concentration (MAC) of isoflurane in rats and access the role of the spinal cord as the sites of anesthetic action in blocking somatic responsiveness. METHODS: In Sprague-Dawley rats fitted with an indwelling intrathecal catheter, we determined the MAC of isoflurane using a tail-clamp technique as a painful stimulus, combined with end-tidal anesthetic sampling. In experiment 1, the control MAC was determined and changes of control MAC were observed after intrathecal ET-1 (4x10-2 nmol, 4x10-3 nmol) administration. In experiment 2, we observed the effects of L or N type Ca++ channel blocker such as verapamil (50 g) or W-conotoxin (0.5 g) on the MAC after measurement of the control MAC. In experiment 3, after measurement of the control MAC, ET-1 (10-2 nmol) was administered intrathecally and the MAC was determined again. Next, intrathecal verapamil (50 g) or W-conotoxin (0.5 g) was injected. After that, the MAC was determined again. RESULTS: In experiment 1, ET-1 decreased the MAC of isoflurane and its effect was sustained over 2 hours. In experiment 2, the MAC, determined following administration of verapamil or W-conotoxin, was not different from that of the control. In experiment 3, the MAC was decreased after ET-1 administration and then increased following injection of verapamil or W-conotoxin. CONCLUSIONS: These results suggested that ET-1, in relation to calcium, might play an important role in determining the MAC of isoflurane in the spinal cord.

Change of Blood Pressure after Aortic Declamping during Open Heart Surgery / 대한마취과학회지

BACKGROUND: A decrease in mean arterial pressure (MAP) often accompanies aortic declamping during open heart surgery (OHS). But, there are no many reports to evaluate the extent of the decrease in MAP following the aortic declamping during OHS. METHOD: Twenty nine patients undergoing OHS, 17 patients for repair of cushion defect and 12 patients for valve replacement were evaluated. Anesthesia was provided by fentanyl (30 g/kg bolus followd by 0.3 ug/kg/min infusion) and intermittent inhalation of N2O-Isoflurane. An indwelling radial artery catheter was used to measure MAP. Systemic vascular resistance (SVR) was calculated using the formula. Measurements were made just before aortic declamping (control), and 1,3,5,7 and 10 minutes after declamping. RESULTS: MAP and SVR were decreased significantly until 7 minutes after aortic declamping compared to those of control value, and have a significant difference in decrease pattern of MAP following time interval after declamping between the patients for repair of cushion defect and the patient for valve replacement. The extent of decrease in MAP and/or SVR showed no significant relationship with difference the duration of bypass, patients body temperature and age. CONCLUSION: The results of this study indicated that there is a significant decrease in MAP and SVR after aortic declamping and it persists for about 7 minutes, without significant relation with bypass time, body temperaure and age.

Anesthetic Management for Thoraco-Xiphopagus Conjoined Twins: A case report / 대한마취과학회지

The incidence of conjoined twins is so rare that few anesthesiologists have an opportunity of managing them. Especially in Korea, there are only a few reports describing the anesthetic management for surgical separation of newborn conjoined twins. We experienced the successful anesthetic management for surgical separation of thoraco-xiphopagus conjoined twins without any particular problems. After applying the noninvasive monitors (ECG, pulse oximeter), one of the twins (twinA) with congenital heart disease was administered with intravenous ketamine for induction of anesthesia and intubated without neuromuscular blocker. Anesthesia was maintained with N2O-O2 and hand ventilation using Mapleson D breathing circuit. After maintaining airway of the twinA, the twinB was intubated and maintained with the same manner. Eighteen days after the separation procedure, the twinA with congenital heart disease died and the other one, twinB has been alive with normal growth and development.