Blood Warming and Hemolysis: A Systematic Review With Meta-Analysis

Area of Science:

• Medical Devices
• Transfusion Medicine
• Biomedical Engineering

Background:

• Fluid warmers are recommended for blood transfusions to prevent hypothermia.
• Current guidelines lack clear maximum heating temperatures for fluid warmers concerning hemolysis risk.
• Manufacturer devices can reach 43°C, necessitating a review of safety limits.

Purpose of the Study:

• To systematically review literature and perform a meta-analysis on blood hemolysis caused by fluid warmers.
• To determine safe temperature limits for contact heating fluid warmers during blood transfusions.
• To address the gap in regulatory recommendations regarding maximum heating temperatures.

Main Methods:

• Systematic literature review and meta-analysis of 24 observational studies.
• Included studies used contact heating fluid warmers, excluding radiofrequency or microwave methods.
• Analyzed factors influencing hemolysis: blood age, anticoagulant, heating duration, circuit components, and infusion pumps.

Main Results:

• Multiple factors influence hemolysis, including blood age, heating duration, and infusion pump type.
• At temperatures ≤43°C and up to 45-46°C, blood heating via contact warming is safe.
• Hemolysis levels were clinically negligible within the tested temperature ranges.

Conclusions:

• Contact heating fluid warmers are safe for blood transfusions up to 45-46°C.
• Blood warming within these limits effectively prevents hypothermia without significant hemolysis.
• Findings support updated guidelines for safe blood warming practices.