When the kidney is at risk: anaesthetic technique as one piece of a larger puzzle

We read with great interest the article by Yoon and colleagues examining the influence of anaesthetic technique on the development of acute kidney injury (AKI) following nephrectomy (1). The question they address is both timely and clinically important. Despite advances in perioperative care, AKI remains a common complication after nephrectomy and is strongly associated with prolonged hospital stay, progression to chronic kidney disease (2) and increased mortality (3). Identifying potentially modifiable intra-operative factors, including the choice of anaesthetic, is therefore of major relevance to anaesthetists and perioperative physicians (4,5).

The authors should be commended for conducting a rigorously designed randomised controlled trial in a surgical population at intrinsically high renal risk. By comparing propofol-based total intravenous anaesthesia with desflurane-based inhalational anaesthesia in 317 patients, and by using Kidney Disease: Improving Global Outcomes (KDIGO) criteria to define postoperative AKI (6), the investigators have provided one of the most methodologically robust evaluations of this topic to date. The finding that the incidence of AKI did not differ significantly between the two anaesthetic techniques is clinically reassuring and challenges the notion, derived largely from experimental and observational studies, that one modality may be intrinsically more renoprotective than the other (7).

Perhaps the most striking result of the study is the finding observed in the partial nephrectomy subgroup, where patients allocated to propofol had a higher incidence of postoperative AKI compared with those receiving desflurane (19% vs. 8%; absolute risk difference 10.8%, 95% confidence interval: 1.5–19.8%; P=0.02). While this observation is intriguing and may suggest a potential differential effect of anaesthetic technique in a setting where renal perfusion is particularly critical, it should be interpreted with caution. Subgroup analyses are inherently prone to multiplicity, and the risk of type I error increases when multiple comparisons are performed. It is also unclear whether this subgroup analysis was pre-specified and whether a formal test for interaction was statistically significant—both key elements in assessing the credibility of subgroup effects. Importantly, the trial was not powered to detect differences within surgical subgroups. Therefore, rather than indicating a definitive harmful effect of propofol in partial nephrectomy, this finding should be viewed as hypothesis-generating. It nonetheless raises an interesting mechanistic question: in patients in whom renal parenchyma is preserved, subtle differences in haemodynamic or microcirculatory effects between anaesthetic techniques could become more clinically relevant (8). This hypothesis warrants further investigation in adequately powered, prospectively designed studies focusing on high-risk surgical subgroups, with careful control of intra-operative blood pressure, fluid balance and renal perfusion, and incorporation of both functional (urine output, creatinine) and injury-based renal biomarkers.

To address this question properly, future studies must also refine how perioperative kidney injury is measured (9). Although AKI was defined using established KDIGO criteria in line with current clinical standards, reliance on creatinine-based endpoints may incompletely capture early or subclinical renal injury in the perioperative setting, potentially obscuring clinically relevant differences between anaesthetic strategies. In this context, incorporating urine output as a dynamic marker of renal perfusion, alongside emerging injury biomarkers and longer-term renal outcomes, may provide a more sensitive and mechanistic assessment of renal vulnerability, although the feasibility and standardisation of such measures in routine clinical practice remain evolving. Such an approach is likely to be essential if we are to determine whether the subgroup finding reported here represents a true biological effect or a chance observation.

In conclusion, Yoon and colleagues provide important and practice-relevant evidence that, within the study setting/protocol and perioperative management, for most patients undergoing nephrectomy, the choice between propofol and desflurane does not meaningfully alter the overall risk of postoperative AKI. For surgeons, these findings reinforce that renal outcomes are unlikely to be determined by anaesthetic technique alone, but rather by the cumulative impact of surgical factors (10). The study therefore redirects attention toward multi-disciplinary strategies for renal protection, in which meticulous surgical technique, careful volume and blood pressure management, and close monitoring of urine output and renal function are central. In this high-risk surgical population, preserving remaining nephrons requires coordinated input across surgical, anaesthetic, and perioperative care to optimise renal perfusion, minimise injury, and support long-term kidney function.

Acknowledgments

None.

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, Translational Andrology and Urology. The article has undergone external peer review.

Peer Review File: Available at https://tau.amegroups.com/article/view/10.21037/tau-2026-1-0125/prf

Funding: None.

Conflicts of Interest: Both authors have completed the ICMJE uniform disclosure form (available at https://tau.amegroups.com/article/view/10.21037/tau-2026-1-0125/coif). The authors have no conflicts of interest to declare.

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