[The Contribution of Vascular Capacity and Blood Volume to Maintain Stable Blood Circulation during General Anesthesia].
To maintain proper cardiac preload is one of the most effective procedures for the systemic circulation remaining stable. In particular, the balance between vascular capacity and total blood volume must be maintained within appropriate range by the administration of fluids, blood and/or vasoactive drugs with mean circulatory filling pressure (Pmcf), central venous pressure (CVP) or stroke volume variation (SVV). End-diastolic left ventricular volume (Ved) is theoretically the best index of cardiac preload; however, without transesophageal echocardbalanceiogram we cannot directly monitor Ved during anesthesia. The infused fluid volume remaining in intravascular space, the vascular capacity controlled by autonomic nervous system and/or vasoactive agents, and the unstressed blood volume properly mobilized to excess blood volume are the crucial factors to maintain cardiac output The knowledge of vascular physiology contribute the decision making to manipulate such factors to control blood circulation during general anesthesia. For example, CVP is usually maintained in the narrow range and seems to be stable; however, it must be changed just after the circulatory disturbances, such as acute bleeding, blood transfusion, and fluid infusion, and followed by gradual returning to initial value, because of the solid mechanism to preserve cardiac output
Kenji
K
Shigemi
D000768:Anesthesia, General; D001810:Blood Volume / Q000502:physiology*; D002302:Cardiac Output / Q000502:physiology; D002496:Central Venous Pressure / Q000502:physiology; D006801:Humans; D008991:Monitoring, Physiologic; D013318:Stroke Volume / Q000502:physiology