The Use of Rapid Ventricular Pacing to Facilitate Stent Graft Deployment in the Distal Aortic Arch / 대한흉부외과학회지

Systemic hypotension has been traditionally used to facilitate deployment of thoracic stent grafts. Decreasing blood pressure with vasodilating agents further increases cardiac output and, consequently, the cardiac output-mediated windsock effect during deployment. Use of rapid ventricular pacing reduces the windsock effect during stent graft deployment and allows the graft to appose to the aortic wall under zero cardiac output, thus minimizing aortic wall shear stress. In this case we report the use of transvenous rapid ventricular pacing, a safe and reproducible technique to allow precise deployment of a Valiant Captivia stent graft in the distal thoracic arch for a saccular thoracic aneurysm.

Spectral Analysis of Heart Rate and Blood Pressure Variability during Hemorrhage in Thiopental-anesthetized Rats / 대한마취과학회지

BACKGROUND: This study was aimed to elucidate the effect of thiopental anesthesia on circulatory response to hemorrhage in rats by power spectral analysis of heart rate and blood pressure variability. METHODS: Sixteen male Sprague-Dawley rats weighing 350~475 g were divided into thiopental (50 mg/kg, ip)-anesthetized (T, n=10) and conscious (C, n=6) groups. Hemorrhage was induced with a withdrawal pump from the femoral artery at 3 ml/kg/min for 5 min. Arterial pressure was measured with a pressure transducer connected to the contralateral femoral artery for 5 min before, during and after hemorrhage. The blood pressure signal digitized at 500 Hz through a data acquisition system was analyzed with fast Fourier transform algorithm to yield power spectra of sytolic (SP) and diastolic (DP) blood pressure and instantaneous heart rate (HR). Powers of very low frequency (VLF, 0.02~0.26 Hz), low frequency (LF, 0.26~0.75 Hz) and high frequency (HF, 0.75~5.00 Hz) band were expressed as percent of total power. RESULTS: Before Hemorrhage blood pressure was lower in T (113 6/83 6 mmHg) than in C (157 4/101 2) rats, but was not changed by hemorrhage in both groups. Before Hemorrhage HR was lower in T (331 22 beats/min) than in C (378 27) rats. HR was significantly increased to 412 26 beats/min in C, but was not changed in T during hemorrhage. Total powers of Before Hemorrhage blood pressure and HR variability were lower in T than in C. During hemorrhage, total power of blood pressure variability tended to increase in both groups, and that of DP was significantly increased during hemorrhage in T. Total power of HR was significantly increased in C, but was not changed in T. T rats showed lower LF and higher HF power of blood pressure, and lower VLF and LF and higher HF power of HR than C rats. During hemorrhage, both groups showed no significant change in spectral distribution of HR power, except for a significant increase in LF of HR after hemorrhage in C. Spectral distribution of blood pressure power was not changed by hemorrhage in C. In T rats, VLF of DP was significantly increased and HF of DP was decreased during hemorrhage. CONCLUSIONS: It suggests that autonomic activity, especially cardiac sympathetic activity is increased in response to hemorrhage in C. Thiopental anesthesia depresses overall autonomic activity, especially sympathetic activity, and vasomotor tone. Hemorrhage under thiopental anesthesia induces depression of baroreceptor reflex activity, while increased levels of vasoconstrictor hormones help to maintain the blood pressure.

Hemodynamic Changes During Spinal Anesthesia by the Bioimpedance Method / 대한마취과학회지

The cardiac output and hemodynamic indices were measured by the bioimpedance method using NCCOM3 in 38 selected spinal anesthetic cases with 0.5% bupivacain. The authors observed MAP, HR, PFI, EDI, CI and SI changes before-and during spinal anesthesia. The results were as follows: The mean values for MAP before, 10 minutes and 30 minutes after spinal anesthesia were observed to be 96.18+/-14.25 and 9.45+/-14.89 mmHg. These values during spinal anesthesia were significantly decreased compared with the value before spinal anesthesia(P<0.01). The mean values for HR before, and 30 minutes after spinal anesthesia were observed to be 71.34+/-17.25 and 72.39+/-19,01 beat/min. The value during spinal anesthesia was significantly decreased compared with the value before spinal anesthesia(P<0.01). The mean value for PFI before and during spinal anesthesia were observed to be 306.55+/-75.63 and 285.47+/-73.60 1/sec/m2 . The value duing spinal anesthesia was insignificantly decreased compared with the value before spinal anesthesia.(P<0.05). The changes of mean values of EF, EDI and SI were insignificant statistically. The mean values for CI before and 30 minutes after spinal anesthesia were observed to be 3.49+/-1.02 and 3.11+/-0.86(1/min/m2) The value during spinal anesthesia was significantly decreased compared with the value before spinal Anesthesia(P<0.01)