Induced hypothermia does not preserve kidney function during partial nephrectomy
08 May 2021
Surgeons were alleged to have permanently disabled a kidney cancer patient by removing his healthy kidney instead of the affected organ.While surgeons usually induce renal hypothermia during partial nephrectomy, recent evidence from a randomized controlled trial (RCT) suggests that such approach does not preserve kidney function in patients with normal or mildly impaired renal function.
The investigators conducted this parallel RCT of hypothermia compared with no hypothermia (control group) during partial nephrectomy at six academic hospitals. Eligible patients had a planned open partial nephrectomy for the treatment of a renal tumour.
During surgery, after clamping the renal hilum, patients were randomly assigned 1:1 to either the intervention or control group using permuted blocks of variable lengths (2 and 4), stratified by institution, using a computer-based programme. Surgeons and study coordinators were blinded to treatment allocation until the renal hilum was clamped.
Finally, the investigators determined the overall glomerular filtration rates (GFR) before and 1 year after surgery; they assessed measured (m)GFR using the plasma clearance of 99mTc-DTPA. The trial was designed with 90-percent power to detect a minimally clinically significant difference in mGFR of 10 ml/min/1.73 m2 at a 5-percent significance level.
A total of 184 patients were included, with both arms having similar baseline mean mGFR (87.1 vs 81.0 ml/min/1.73 m2). Of these, 169 (79 hypothermia, 82 control) were alive with primary outcome data at 1 year after surgery.
The change in mGFR at 1 year was –6.6 ml/min/1.73 m2 in the hypothermia group and –7.8 ml/min/1.73 m2 in the control group (mean difference, 1.2 ml/min/1.73 m2, 95 percent confidence interval [CI], –3.3 to 5.6). Operated-kidney change in mGFR was similar between the two groups (–5.8 vs –6.3 ml/min/1.73 m2; mean difference, 0.5 ml/min/1.73 m2, 95 percent CI, –2.9 to 3.8).
When patients were stratified by preplanned subgroups, no clinically significant between-group difference was noted in mGFR. Moreover, renal hypothermia showed no impact on surgical complications and patient-reported quality of life.