The renal artery pulsatility index enables real-time monitoring of acute kidney injury after digestive surgery.

BACKGROUND

Postoperative acute kidney injury after digestive surgery can be a critical problem that causes morbidity or mortality. Although serum creatinine reflects the renal function, it takes time to measure, and only severe renal failure induces an increase in creatinine. We tried to calculate the renal artery pulsatility index as a parameter to enable the real-time monitoring of acute kidney injury, which can be measured by routine bedside ultrasonography. This study aimed to evaluate the accuracy of the renal artery pulsatility index for the early detection of acute kidney injury after digestive surgery.

METHODS

One hundred consecutive patients who underwent digestive surgery in a single institution from March to July 2018 were included. The renal artery pulsatility index was measured at 4 time points (preoperative day, postoperative day 1, postoperative day 4, and postoperative day 7). Perioperative acute kidney injury I was defined as a >0.3 mg/dL increase in serum creatinine and a serum creatinine level of >1.0 mg/dL at any postoperative time point. The association of the renal artery pulsatility index with perioperative acute kidney injury was analyzed.

RESULTS

The preoperative renal artery pulsatility index (average 1.4) was significantly high in aged patients and those with diabetes mellitus, hypertension, or chronic kidney disease. Furthermore, a high preoperative renal artery pulsatility index (cut-off: 1.6) was a predictor of perioperative acute kidney injury (n = 13). Moreover, the postoperative renal artery pulsatility index significantly increased in acute kidney injury cases.

CONCLUSION

The renal artery pulsatility index was strongly correlated with acute kidney injury in the perioperative period. It appears to be an effective and less invasive procedure for the real-time monitoring that enables the early detection of acute kidney injury after digestive surgery.