What is the recommended Hydroxyethyl Starch (HES) to blood loss ratio?

Hydroxyethyl Starch (HES) to Blood Loss Ratio

There is no specific recommended HES to blood loss ratio, as current guidelines advise against routine use of HES for volume replacement in surgical patients due to safety concerns including increased risk of acute kidney injury.1, 2

Current Recommendations on HES Use

• HES should not be used for volume replacement therapy in surgical patients until new evidence emerges due to safety concerns 1
• Initial fluid resuscitation should be with crystalloids rather than colloids like HES 1
• If colloids are administered, dosing should be within prescribed limits, and if HES is employed, a modern HES solution should be used 1
• Resuscitation with at least 1 L crystalloid per unit of red blood cells is associated with reduced overall mortality when high ratios of FFP:RBC cannot be administered 1

Safety Concerns with HES

• HES solutions are associated with:
  • Acute kidney injury and impaired coagulation 1, 2
  • Increased need for renal replacement therapy 2
  • Hemorrhagic complications due to decreased factor VIII/von Willebrand factor and platelet function defects 3
  • Pruritus, which can be severe and protracted 4
  • Potential anaphylactoid reactions 4

Maximum Safe Dosage Considerations

• The maximum safe dosage of HES is approximately 30 mL/kg, as clinical microbleeding has been observed when patients received HES more than 30 mL/kg 5
• The daily dose limit is typically 50 mL/kg for modern HES solutions 6
• For HES 130/0.4 (modern HES solution), the median cumulative dose used in studies was 2465 mL (range 328 to 6229 mL), corresponding to about 35 mL/kg in a 70-kg patient 6

Fluid Replacement Ratios

• There is a common belief that 3-4 times more crystalloid than colloid volume is needed to achieve similar hemodynamic effects 6
• However, actual studies show a considerably lower ratio in surgical studies (mean 1.8) 6
• The extent of fluid load reduction that can be achieved by HES 130/0.4 is often overestimated 6

Alternative Approaches

• For intraoperative fluid administration, aim for 1-2 L positive balance by the end of surgery to protect kidney function 1
• Crystalloids are the preferred priming solution in European centers for cardiopulmonary bypass 1
• In trauma patients, if high ratios of FFP:RBC cannot be administered, resuscitation with at least 1 L crystalloid per unit RBC is associated with reduced overall mortality 1

Pitfalls and Caveats

• Most studies on HES are not designed to evaluate clinically important safety outcomes due to small sample sizes, inadequate control fluids, and short observation periods 6
• Different HES solutions exist worldwide with varying pharmacological properties based on molecular weight and degree of hydroxyethyl substitution 3
• Slowly degradable high MW HES 450/0.7 and medium MW HES 200/0.62 have longer-lasting volume effects but more potential for complications 3
• Rapidly degradable medium MW HES 200/0.5 or low MW HES 70/0.5 have faster elimination and potentially fewer adverse effects on coagulation 3