Journal of anesthesia
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Journal of anesthesia · Dec 1994
Effect of alkalimized mepivacaine for epidural anesthesia on the skin temperature and skin blood flow: A mathematical analysis by simulation model.
The changes in skin blood flow after barbiturate injection are predictable based upon changes in skin temperature, assuming that these changes are followed by ramp function of the first-order system composed of blood vessel-tissue-skin. We applied this simulation model to epidural anesthesia, and investigated the analogy between theoretical and measured values using 2% alkalinized and nonalkalinized mepivacaine. During epidural anesthesia, a Laser Doppler flowmeter and a skin temperature probe were used to simultaneously measure skin blood flow and skin temperature. ⋯ In the alkalinized group, however, the skin blood flow change was in accord with the theoretical values calculated from the skin temperature. These results indicate that the precise prediction of measured values by the simulation model is dependent on the speed of the sympathetic blockade. Conversely, the response to sympathetic nerve and blood vessels in different conditions can be assessed using this simulation model.
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Journal of anesthesia · Dec 1994
Alteration of vascular capacitance and blood flow distribution during halothane anesthesia.
We examined the effect of halothane on systemic vascular capacitance as well as on systemic vascular resistance using cardiopulmonary bypass in dogs. Venous outflows from two different vascular beds, the splanchnic and extrasplanchnic beds, were also measured. Under constant perfusion flow and constant central venous pressure, a change in reservoir blood volume inversely represented a change in systemic blood volume and then in systemic vascular capacitance, and a change in mean arterial pressure directly reflected a change in systemic vascular resistance. ⋯ Halothane did not cause significant blood flow redistribution between the splanchnic and extrasplanchnic vascular beds. These results suggest that halothane causes an increase in systemic vascular capacitance as well as a decrease in systemic vascular resistance. This increase in vascular capacitance may contribute in part to a decrease in cardiac output during halothane anesthesia.