Acute Kidney Injury After Pediatric Cardiac Surgery: A Secondary Analysis of the Safe Pediatric Euglycemia After Cardiac Surgery Trial

Abstract

Objectives: To understand the effect of tight glycemic control on cardiac surgery-associated acute kidney injury.

Design: Secondary analysis of data from the Safe Pediatric Euglycemia after Cardiac Surgery trial of tight glycemic control versus standard care.

Setting: Pediatric cardiac ICUs at University of Michigan, C.S. Mott Children's Hospital, and Boston Children's Hospital.

Patients: Children 0-36 months old undergoing congenital cardiac surgery.

Interventions: None.

Measurements and main results: Cardiac surgery-associated acute kidney injury was assigned using the Acute Kidney Injury Network criteria with the modification that a greater than 0.1 mg/dL increase in serum creatinine was required to assign cardiac surgery-associated acute kidney injury. We explored associations between cardiac surgery-associated acute kidney injury and tight glycemic control and clinical outcomes. Of 799 patients studied, cardiac surgery-associated acute kidney injury occurred in 289 patients (36%), most of whom had stage II or III disease (72%). Cardiac surgery-associated acute kidney injury rates were similar between treatment groups (36% vs 36%; p = 0.99). Multivariable modeling showed that patients with cardiac surgery-associated acute kidney injury were younger (p = 0.002), underwent more complex surgery (p = 0.005), and had longer cardiopulmonary bypass times (p = 0.002). Cardiac surgery-associated acute kidney injury was associated with longer mechanical ventilation and ICU and hospital stays and increased mortality. Patients at University of Michigan had higher rates of cardiac surgery-associated acute kidney injury compared with Boston Children's Hospital patients (66% vs 15%; p < 0.001), but University of Michigan patients with cardiac surgery-associated acute kidney injury had shorter time to extubation and ICU and hospital stays compared with Boston Children's Hospital patients.

Conclusions: Tight glycemic control did not reduce the cardiac surgery-associated acute kidney injury rate in this trial cohort. We observed significant differences in cardiac surgery-associated acute kidney injury rates between the two study sites, and there was a differential effect of cardiac surgery-associated acute kidney injury on clinical outcomes by site. These findings warrant further investigation to identify causal variation in perioperative practices that affect cardiac surgery-associated acute kidney injury epidemiology.

Figure 1. Cardiac intensive care unit length of stay by duration of cardiac surgery-associated acute kidney injury

CS-AKI, cardiac surgery-associated acute kidney injury; ICU, intensive care unit.

Figure 2. Confidence intervals for Figure 1 by duration of cardiac surgery-associated acute kidney injury

CS-AKI, cardiac surgery-associated acute kidney injury; ICU, intensive care unit.