Cardiovascular and renal effects of constant rate infusions of remifentanildexmedetomidine and their combination in dogs anesthetized withsevoflurane

摘要

We evaluated changes in cardiovascular and renal functions as well as argininevasopressin (AVP) secretion, with remifentanil and dexmedetomidine administration alone orin combination in sevoflurane-anesthetized dogs. Six healthy adult Beagle dogs receivedone of the following four treatments in a randomized crossover study: saline (C),remifentanil alone at successively increasing doses (R; 0.15, 0.60, and 2.40 µg/kg/min),dexmedetomidine alone (D; 0.5 µg/kg intravenously for initial 10 min followed by aconstant rate infusion at 0.5 µg/kg/hr), and a combination of remifentanil anddexmedetomidine at the above-mentioned doses (RD). Sevoflurane doses were adjusted to 1.5times of minimum alveolar concentration (MAC) equivalent according to MAC-sparing effectswith remifentanil and dexmedetomidine as previously reported. Cardiovascular measurements,renal function data, and plasma AVP concentrations were determined before and every 60 minuntil 180 min after drug administration as per each treatment. In the R, D and RD, heartrate significantly decreased and mean arterial pressure significantly increased frombaseline or with C. Cardiac index significantly decreased and systemic vascular resistanceindex increased with D and RD. Oxygen extraction ratio, renal blood flow, and glomerularfiltration rate were not affected. The plasma AVP concentrations significantly decreasedin D and RD, but increased in R. Only in D, the natriuresis was elicited. The combinationof remifentanil and dexmedetomidine in sevoflurane-anesthetized dogs was acceptable interms of the hemodynamics, oxygenation, and renal function. Remifentanil may interferewith dexmedetomidine-induced diuresis and inhibition of AVP secretion.