뇌동맥류 수술시 Halothane 저혈압 마취에 대한 임상적 고찰

For lesions like intracranial aneurysms which are located near highly vascularized regions, adequate dissection becomes almost impossible unless local blood flow can be reduced. Deliberate hypotension, purposefully lowering the arterial pressure to a level at which bleedirig is no longer a problem, facilitates surgery, allows performance of a better dissection, and shortens the length of the procedure. Currently, the most useful method for induced hypotensive anesthesia is the use of chemical drugs, such as trimethaphan, nitroprusside and halothane. Induced hypotension with halothane has been reported to be a relatively safe and useful method by Murtagh (1960) and Schettini, et al (1967). Halothane has the effect of depression of myocardial contractility, central autonomic inhibition, ganglionic blocking action and suppression of the peripheral actions of norepinephrine and direct vasodilation on the vessel wall. The advantage of halothane is the reduction of mean arterial pressure slowly (1-3 mm Hg/min) and it has a transient effect on EKG, little effect on brain cortical function and appropriate oxygen supply to brain tissue. The halothane induced hypotension in 100 cases of intracranial aneurysm surgery, which were performed at Severance Hospital of the Yonsei University College of Medicine from .1972 to 1977, was investigated clinically. The results of our study were as follows: 1) The locations of intracranial aneurysm in order were the anterior cerebral artery (37 cases), internal carotid artery (35 cases), middle cerebral artery (23 cases) and posterior cerebral artey (2 cases). Three cases of multiple cerebral aneurysm were found in our study. 2) In the hypotensive phase, the mean systolic and diastolic pressures were 73. 45 mmHg± 0. 86, 54. 95 mmHg± 0. 86 and the mean duration was 34. 74 min± l. 60. 3) The blood pressure control by halothane was comparatively easy and there was no cliaical evidence of direct injury to the brain, heart, kidney and liver due to halothane induced hypotension. 4) The mortality rate in the 100 cases of the intracranial aneurysm was 16 percent. From the above observation it may be concluded that the technique of deliberate hypotension induced by halothane anesthesia is a useful method in tne surgery of intracranial aneurysm.