Renal function during sevoflurane or total intravenous propofol anaesthesia: a single-centre parallel randomised controlled study.

BACKGROUND: The choice of anaesthetic may influence regulation of renal perfusion and function. We investigated renal function in patients anaesthetised with propofol or sevoflurane before surgery and postoperatively. METHODS: Patients with ASA physical status 1-2 planned for spinal surgery were randomised to propofol or sevoflurane anaesthesia. Blood and urine were collected before anaesthesia, during anaesthesia (before surgery), during postoperative care, and the day after surgery. RESULTS: Twenty-seven patients completed the study protocol (average age, 51 yr; average BMI, 28 kg m-2) and 11 were women. Urine output and sodium excretion were lower during sevoflurane anaesthesia (n=14) than during propofol anaesthesia (n=13) (0.3 vs 1.1 ml kg-1 h-1 [P=0.01] and 2.6 vs 6.0 mmol h-1 [P=0.04], respectively). Urinary potassium excretion was lower during anaesthesia than after, without intergroup difference (2.3 vs 5.7 mmol h-1, P<0.001). Sevoflurane anaesthesia increased plasma renin compared with baseline (138 vs 23 mIU L-1, P<0.001) and propofol anaesthesia (138 vs 27 mIU L-1, P=0.008). Plasma arginine-vasopressin did not change significantly during anaesthesia, but was elevated postoperatively compared with baseline irrespective of anaesthetic (21 vs 12 ng L-1, P=0.02). Sevoflurane caused higher postoperative plasma creatinine than propofol (83 vs 66 mmol L-1, P=0.01). Kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin did not change significantly in either group. CONCLUSIONS: Sevoflurane anaesthesia reduced urine output and sodium excretion and increased plasma renin compared with propofol anaesthesia. The impact of this on acute kidney injury and fluid resuscitation during surgery warrants further investigation. CLINICAL TRIAL REGISTRATION: EudraCT: 2017-001646-10; Clinicaltrials.gov: NCT0333680.

Role of Renal Sympathetic Nerve Activity in Volatile Anesthesia's Effect on Renal Excretory Function.

Regulation of fluid balance is pivotal during surgery and anesthesia and affects patient morbidity, mortality, and hospital length of stay. Retention of sodium and water is known to occur during surgery but the mechanisms are poorly defined. In this study, we explore how the volatile anesthetic sevoflurane influences renal function by affecting renal sympathetic nerve activity (RSNA). Our results demonstrate that sevoflurane induces renal sodium and water retention during pediatric anesthesia in association with elevated plasma concentration of renin but not arginine-vasopressin. The mechanisms are further explored in conscious and anesthetized ewes where we show that RSNA is increased by sevoflurane compared with when conscious. This is accompanied by renal sodium and water retention and decreased renal blood flow (RBF). Finally, we demonstrate that renal denervation normalizes renal excretory function and improves RBF during sevoflurane anesthesia in sheep. Taken together, this study describes a novel role of the renal sympathetic nerves in regulating renal function and blood flow during sevoflurane anesthesia.

Renal effects of treatment with a TLR4 inhibitor in conscious septic sheep.

INTRODUCTION: Acute kidney injury (AKI) is a common and feared complication of sepsis. The pathogenesis of sepsis-induced AKI is largely unknown, and therapeutic interventions are mainly supportive. In the present study, we tested the hypothesis that pharmacological inhibition of Toll-like receptor 4 (TLR4) would improve renal function and reduce renal damage in experimental sepsis, even after AKI had already developed. METHODS: Sheep were surgically instrumented and subjected to a 36-hour intravenous infusion of live Escherichia coli. After 12 hours, they were randomized to treatment with a selective TLR4 inhibitor (TAK-242) or vehicle. RESULTS: The E. coli caused normotensive sepsis characterized by fever, increased cardiac index, hyperlactemia, oliguria, and decreased creatinine clearance. TAK-242 significantly improved creatinine clearance and urine output. The increase in N-acetyl-beta-D-glucosaminidas, a marker of tubular damage, was attenuated. Furthermore, TAK-242 reduced the renal neutrophil accumulation and glomerular endothelial swelling caused by sepsis. These effects were independent of changes in renal artery blood flow and renal microvascular perfusion in both cortex and medulla. TAK-242 had no effect per se on the measured parameters. CONCLUSIONS: These results show that treatment with a TLR4 inhibitor is able to reverse a manifest impairment in renal function caused by sepsis. In addition, the results provide evidence that the mechanism underlying the effect of TAK-242 on renal function does not involve improved macro-circulation or micro-circulation, enhanced renal oxygen delivery, or attenuation of tubular necrosis. TLR4-mediated inflammation resulting in glomerular endothelial swelling may be an important part of the pathogenesis underlying Gram-negative septic acute kidney injury.