Postoperative kidney oxygen saturation as a novel marker for acute kidney injury after adult cardiac surgery

Abstract

Objective: Acute kidney injury is a severe complication and one of the stronger risk factors for death in patients undergoing cardiac surgery. The relationship between postoperative brain oxygen saturation and kidney oxygen saturation with acute kidney injury in adults undergoing cardiac surgery has not been determined. We designed a single-center prospective study to determine if the continuous monitoring of postoperative brain oxygen saturation and kidney oxygen saturation could predict postoperative acute kidney injury.Methods: We conducted a prospective open cohort study from January to September 2017. The primary outcome was postoperative acute kidney injury using the Kidney Disease: Improving Global Outcomes criteria. Brain oxygen saturation and kidney oxygen saturation, the metrics of which were area measurements (%-min), were recorded during the surgery and the first 48 hours after the cardiac procedure. Receiver operating characteristic curve analysis was used to evaluate the predictive power of kidney oxygen saturation for acute kidney injury.Results: A total of 121 consecutive patients were enrolled. Thirty-five patients (28.9%) developed acute kidney injury. Brain oxygen saturation showed no statistical difference in both groups; however, kidney oxygen saturation was related to acute kidney injury (P ¼ .001). Receiver operating characteristic curve analysis showed that kidney oxygen saturation could predict the risk of acute kidney injury. Kidney oxygen saturation less than 65% (area under the curve-receiver operating characteristic, 0.679 AE 0.054, 95% confidence interval, 0.573-0.785, P ¼ .002) and 20% decrease from baseline (area under the curve-receiver operating characteristic, 0.639 AE 0.059, 95% confidence interval, 0.523-0.755, P ¼ .019) showed the better performance, respectively.Conclusions: Postoperative kidney oxygen saturation is related to the development of cardiac surgery-associated acute kidney injury. Continuous kidney saturation monitoring might be a promising, noninvasive tool for predicting acute kidney injury during the postoperative period for adult patients after cardiac surgery.

Reply: Cardiac surgery–associated acute kidney injury—A protective armor rather than a lethal ammunition

“…Arguably, brain oxygen saturation monitoring has some drawbacks, which does not necessarily translate into a safer environment to other vulnerable organs, such as the kidneys. In fact, this was demonstrated in our study, 2 in which the kidney oxygen saturation but not the brain oxygen saturation was closely related to the development of CSA-AKI during the postoperative stage. 2.…”

Investigating the Effect of Near Infra-red Spectroscopy (NIRS) on Early Diagnosis of Cardiac Surgery Associated Acute Kidney Injury

“…A fast and plausible approach in CSA-AKI could save many of cardiac surgery patients. Recently, measuring kidney tissue oxygen saturation via NIRS as a novel and non-invasive method has been suggested (6,(15)(16)(17)(18).…”

“…Monitoring of kidney oxygen saturation based on Near-infrared spectroscopy (NIRS) is a new approach in the diagnosis of CSA-AKI before the rise of creatinine (6). Near-infrared spectroscopy (NIRS) is a noninvasive approach for the detection of CSA-AKI, which can continue to measures the difference between oxygenated and deoxygenated hemoglobin in a local tissue zone, and so procurement the regional oxygen saturation(rSo2) (7).…”

Near-Infrared Spectroscopy Monitoring in Cardiac and Noncardiac Surgery: Pairwise and Network Meta-Analyses

“…This has left an unexplored gap in the postoperative period, where NIRS dynamics is also vital and may help to further understand clinical consequences [61]. Ortega-Loubon et al demonstrated that postoperative kidney oxygen saturation (kSo 2 ), but neither intraoperative kSo 2 nor bSo 2, was correlated with the occurrence of postoperative AKI [14,70]. Therefore, it may be necessary to more closely monitor susceptible organs that are more likely to suffer acute injury during and after major procedures.…”

“…Thus, patients need to be closely monitored [13]. Near-infrared spectroscopy (NIRS) is a promising technique that continuously maintains oxygen saturation within a regional tissue area [14]. Despite the cerebral benefits of brainoxygen-saturation (bSo 2 ) monitoring [15], whether NIRS should be a standard of care remains hotly debated [16,17].…”