The Risk of Acute Kidney Injury from Fluid Restriction and Hydroxyethyl Starch in Thoracic Surgery.

BACKGROUND: Fluid is restricted in thoracic surgery to reduce acute lung injury, and hydroxyethyl starches (HES) are often administered to reduce fluid amount. This strategy may contribute to the development of acute kidney injury (AKI). We evaluated the incidence, risk factors, and prognosis of AKI in thoracic surgery. We especially focused on whether fluid restriction/HES administration increased AKI.

METHODS: This is a retrospective study of patients undergoing thoracic surgery in a tertiary care academic center. Postoperative AKI was diagnosed within 72 hours after surgery based on the Acute Kidney Injury Network criteria. Demographic, intraoperative, and postoperative data were compared between non-AKI and AKI groups. Logistic regression was used to model the association between risk factors and AKI.

RESULTS: Final analysis included 1442 patients. Of these, 74 patients developed AKI (5.1%). Crystalloid restriction (≤3 mL·kg·h) was unrelated to AKI, regardless of preoperative renal functions (odds ratio [OR], 0.5; 95% confidence interval [CI] 0.2-1.4). AKI occurred more often when HES were administered to the patients with decreased renal function (OR, 7.6; 95% CI, 1.5-58.1) or having >2 risk factors with normal renal function (OR, 7.2; 95% CI, 3.6-14.1). Multivariate analysis revealed several risk factors: angiotensin-converting enzyme inhibitor/angiotensin receptor blockers, open thoracotomy, pneumonectomy/esophagectomy, diabetes mellitus, cerebrovascular disease, low albumin level, and decreased renal function.

CONCLUSIONS: Fluid restriction neither increased nor was a risk factor for AKI. HES should be administered with caution in high-risk patients undergoing thoracic surgery.