Moderate Intraoperative Use of Hydroxyethyl Starch Solutions Is Safe

To the Editor I read, with great interest, the report by Farag et al1 of no association of vasopressor infusion during prone spine surgery with renal injury. Although retrospective data, it is reassuring for clinicians that management of hypotension with a vasopressor infusion for almost 3 hours in this clinical cohort was not associated with deterioration in glomerular filtration rate (GFR). This is relevant given the known association of intraoperative hypotension with cardiac and renal outcomes. Of note in the report is moderate use of Hextend (Pfizer, New York, NY), a low molecular weight 6% hydroxyethyl starch (HES) in a balanced electrolyte solution. As seen in Table 1, 60%–62% of patients (mean volume 786–800 mL) received Hextend in the no vasopressor and vasopressor groups, respectively. This was part of balanced fluid management with estimated blood loss 556–666 mL and administration of 3.3–3.4-L crystalloid, 732–738 mL albumin, and 142–186 mL red blood cells. This moderate intraoperative use (approximately 10 mL/kg over a finite period ≤3 hours) contrasts with many prior critical care studies and adds further support to safe intraoperative use when used appropriately.2 Concern for HES-associated renal injury developed from reports of excessive use in critically ill intensive care unit patients which do not match routine intraoperative, elective conditions. In many of those reports in critically ill patients, HES was administered for extended periods and at significantly large amounts, approaching 33–50 mL/kg. The dilemma of HES use in the United States continues3 given the paucity of level 1 evidence for intraoperative use. Although HES use was not the primary goal of this study, safe use of moderate-dose HES in a large surgical cohort (1080) affirms the role of balanced clinical use of HES with no renal injury (in fact, there was a small increase in estimated GFR). The authors reported no confounding effect of colloid amount on sensitivity analysis of outcome (Table 3) but did not specifically address HES use as part of clinical care in the cohort. In addition to supporting active vasopressor management of hypotension in spine surgery without evidence of renal injury, this study also highlights appropriate use of moderate-dose HES without evidence of renal dysfunction. Evan G. Pivalizza, MBChB, FFASADepartment of AnesthesiologyUTHealth McGovern Medical SchoolHouston, Texas[email protected]