On 2017 Oct 22, Christian J. Wiedermann commented:

Comment on “The dose of hydroxyethyl starch 6% 130/0.4 for fluid therapy and the incidence of acute kidney injury after cardiac surgery: A retrospective matched study”

In a retrospective cohort study (Momeni M, 2017), it was analyzed whether the incidence of acute kidney injury (AKI) in cardiac surgery differed depending on weight-adjusted cumulative doses of 6% hydroxyethyl starch (HES) 130/0.4 for pump priming and/or perioperative fluid therapy. In the absence of any safety study, authors concluded that in cardiac surgery the cumulative dose of modern HES should be kept less than 30 mL/kg.

From a total of 1564 evaluable patients fulfilling the study`s inclusion criteria, 63 subjects were excluded from analyses because cardiac surgery had been performed without administration of HES. Without a control group (patients not receiving HES excluded), the study was performed on 983 subjects who received a low dose of HES and 518 who were in a high dose HES group. Among these HES-receiving patients, a dose-dependent increase of AKI was observed, thus, confirming in cardiac surgery patients previous observations of dose-dependent nephrotoxicity of HES (Mutter TC, 2013).

A safe volume of any HES solution has yet to be determined (Mutter TC, 2013, Wiedermann CJ, 2009). Because AKI in response to 6% HES 130/0.4 may be seen at low doses, the authors' conclusions (Momeni M, 2017) that modern HES should be kept at cumulative doses less than 30 mL/kg ignores the fact that in patients not receiving any HES at all, AKI frequency may be even lower than in their low dose group. Thus, the only conclusion should have been that in cardiac surgery, HES-induced nephrotoxicity is dose dependent. The recommendation of using HES doses less than 30 mL/kg carries the risk of increasing AKI. Unless a safe volume is determined, 6% HES 130/0.4 should be avoided in cardiac surgery.

On 2017 Oct 22, Christian J. Wiedermann commented:

Comment on “The dose of hydroxyethyl starch 6% 130/0.4 for fluid therapy and the incidence of acute kidney injury after cardiac surgery: A retrospective matched study”

In a retrospective cohort study (Momeni M, 2017), it was analyzed whether the incidence of acute kidney injury (AKI) in cardiac surgery differed depending on weight-adjusted cumulative doses of 6% hydroxyethyl starch (HES) 130/0.4 for pump priming and/or perioperative fluid therapy. In the absence of any safety study, authors concluded that in cardiac surgery the cumulative dose of modern HES should be kept less than 30 mL/kg.

From a total of 1564 evaluable patients fulfilling the study`s inclusion criteria, 63 subjects were excluded from analyses because cardiac surgery had been performed without administration of HES. Without a control group (patients not receiving HES excluded), the study was performed on 983 subjects who received a low dose of HES and 518 who were in a high dose HES group. Among these HES-receiving patients, a dose-dependent increase of AKI was observed, thus, confirming in cardiac surgery patients previous observations of dose-dependent nephrotoxicity of HES (Mutter TC, 2013).

A safe volume of any HES solution has yet to be determined (Mutter TC, 2013, Wiedermann CJ, 2009). Because AKI in response to 6% HES 130/0.4 may be seen at low doses, the authors' conclusions (Momeni M, 2017) that modern HES should be kept at cumulative doses less than 30 mL/kg ignores the fact that in patients not receiving any HES at all, AKI frequency may be even lower than in their low dose group. Thus, the only conclusion should have been that in cardiac surgery, HES-induced nephrotoxicity is dose dependent. The recommendation of using HES doses less than 30 mL/kg carries the risk of increasing AKI. Unless a safe volume is determined, 6% HES 130/0.4 should be avoided in cardiac surgery.