Risk of early postoperative acute kidney injury with stroke volume variation-guided tetrastarch versus Ringer's lactate.

BACKGROUND: Whether intraoperative use of hydroxyethyl starch (HES) solutions is associated with postoperative acute kidney injury (AKI) continues to be researched. Urinary neutrophil gelatinase-associated lipocalin (NGAL) is validated for early detection of AKI. Previous studies are limited and use empirically predefined volumes of HES solutions with serum creatinine as marker for AKI.

MATERIALS AND METHODS: Adults scheduled for orthopedic surgery under general anesthesia with >200-300 mL blood loss expected were included; 40 were randomized to receive 6% HES 130/0.4 (tetrastarch) (group HES) or Ringer's lactate (group RL) boluses when stroke volume variation (SVV) >10% in supine or lateral position, or >14% in prone position. Incidence of early postoperative AKI using urinary NGAL (>100 ng/mL) was the primary outcome, and using derangement of serum creatinine was the secondary measure.

RESULTS: In 38 patients, intervention was completed, and incidence of AKI (postoperative urinary NGAL >100 ng/mL) among them was 0% in both groups. Patients with urinary NGAL >50 ng/mL were insignificantly higher for group RL versus group HES (6/19 vs. 4/19) ( P = 0.461), as were those with incidence of AKI as per creatinine values (5/19 vs. 4/19) ( P = 1.000). Group RL had significantly higher requirement of fluid (1211 ± 758 mL vs. 689 ± 394 mL) ( P = 0.013) and lower cardiac index ( P < 0.05) versus group HES.

CONCLUSION: SVV-guided tetrastarch and Ringer's lactate do not result in postoperative AKI diagnosed by urinary NGAL >100 ng/mL; however, an insignificant trend for better renal functions as well as significantly more efficacious volume expansion and hemodynamic stability were seen with tetrastarch instead.