Efeitos da infusão contínua de dopamina sobre a atividade renal de cães sob anestesia balanceada.

Abstract

Most of anesthetics cause changes in the glomerular filtration rate (GFR). Dopamine, an endogenous catecholamine, in continuous administration of low doses, increases the GFR. There are multiple etiologic factors that trigger chronic renal failure in dogs. And, anesthesia accomplishment can be one of this factors. In order to avoid the occurrence and/or progression of renal disease and improve the life quality of patients who needs be submitted to anestesia, is necessary to develop protocols that maintain the stability of the glomerular function. The main goal of this study was to evaluate the effects of continuous infusion of dopamine in 0.9% NaCl solution on renal activity of dogs during anesthesia, concomitantly, we evaluated the quality and undesired effects in each protocols. Thirty canines, healthy, between two and eight years of age were randomly grouped into two blocks divided into three groups composed of five animais. For the block 1 (MPF) was established midazolam and propofol as induction protocol, and maintenance of anestesia with isoflurane and fentanyl. In block 2 (DPF) midazolam was replaced by diazepam. The group 1 (Gl), on the both blocks, is the control group, in which the dopamine infusion was not used; groups 2 and 3 (G2 and G3) were treated with an infusion rate of 2mcg/kg/min 3mcg/kg/min of dopamine, respectively. Before and during the procedure serum creatinine and phosphorus were measured; protein/creatinine urinary (PU/CU) and GFR was estimated by creatinine clearance (Ccr). The systolic (SBP), diastolic (DBP) and mean (MBP), heart rate (HR) and respiratory rate (RR) also were measured. The GFR increased in ali groups treated with dopamine on the both protocols (p <0.05). Serum creatinine was reduced in ali groups. The PU/CU and phosphorus showed no statistically significant changes. The G2/MPF SBP was increased in the first 10 minutes after induction and dopamine infusion. The MBP and DBP did not differ between protocols, groups and anesthetic time (p <0.05). The HR and RR reduced according to the group/protocol and anesthesia time (p <0.05). The general anesthesia in dogs associated with continuous dopamine infusion at doses of 2mcg/kg/min and 3mcg/kg/min is efficient and advantageous for the preservation of glomerular filtration rate leading to lower anesthetic risk and without causing significant changes in the physiological parameters analyzed.