Pre-treatment with the angiotensin receptor 1 blocker losartan protects renal blood flow and oxygen delivery after propofol-induced hypotension in pigs

• Hypotensive events are strongly correlated to the occurrence of perioperative acute kidney injury, but the underlying mechanisms for this are not completely elucidated. We hypothesised that anaesthesia-induced hypotension causes renal vasoconstriction and decreased oxygen delivery via angiotensin II-mediated renal vasoconstriction. Pigs were anaesthetised, surgically prepared and randomised to vehicle/losartan treatment (0.15 mg*kg(-1)). A deliberate reduction in arterial blood pressure was caused by infusion of propofol (30 mg*kg(-1)) for 10 min. Renal function and haemodynamics were recorded 60 min before and after hypotension. Propofol induced hypotension in all animals (p<0.001). Renal blood flow (RBF) and renal oxygen delivery (RDO2) decreased significantly regardless of treatment but more so in vehicle-treated compared to losartan-treated (p=0.001, p=0.02, respectively). During recovery RBF and RDO2 improved to a greater extent in the losartan-treated compared to vehicle-treated (+28 ml*min(-1), 95%CI 8-50 ml*min(-1), p=0.01 and+3.1 ml*min(-1), 95%CI 0.3-5.8 ml*min(-1), p=0.03, respectively). Sixty minutes after hypotension RBF and RDO2 remained depressed in vehicle-treated, as renal vascular resistance was still increased (p<0.001). In losartan-treated animals RBF and RDO2 had normalised. Pre-treatment with losartan improved recovery of renal blood flow and renal oxygen delivery after propofol-induced hypotension, suggesting pronounced angiotensin II-mediated renal vasoconstriction during blood pressure reductions caused by anaesthesia.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Anestesi och intensivvård (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Anesthesiology and Intensive Care (hsv//eng)

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