Background: Several studies report hemolysis when packed red blood cells (PRBCs) are transfused through small-inner-diameter (ID) catheters using presence of biomarkers but do not address cause and amount of hemolysis. This study aims to determine the cause and index of hemolysis percent (IH%) when PRBCs are infused through small-ID catheters.

Methods: The IH% was calculated using Giersiepen’s empirical power law, which describes a relationship between hemolysis and magnitude of shear stress and exposure time. Six- and 27-day-old PRBCs were infused through five catheters with IDs of 0.20 mm to 0.70 mm at infusion rates of 3 mL and 10 mL/hour. Shear stress and exposure time were calculated. Data were analyzed as a function of catheter ID, infusion rates, and blood age.

Results: The study demonstrated that shear stress was supraphysiologic during laminar flow in catheters with IDs of 0.20 mm and 0.28 mm. These catheters’ IH% were ∼117 times higher at 3 mL/hour and ∼75 times higher at 10 mL/hour than catheters with larger IDs of 0.48 mm, 0.51 mm, and 0.70 mm. For blood age, in catheters with IDs of 0.20 mm and 0.28 mm, IH% was ∼155 times higher at 6 days and ∼76 times higher at 27 days than in catheters with IDs of 0.48 mm, 0.51 mm, and 0.70 mm.

Conclusions: This study demonstrated that when RBCs are subjected to supraphysiologic shear stress in catheters with IDs of ≤0.28 mm, index of hemolysis is greater than in catheters with IDs ≥0.48 mm.

Chang GY, Cox CA, Kane EA, Tye GP, Fawcett P, Shaffer TH. Comparison of stress-induced hemolysis in neonatal intravenous catheters: Theoretical and experimental analysis of shear stress, exposure time, and index of hemolysis. J Neonatal Perinatal Med. 2025 Mar 21:19345798251326071. doi: 10.1177/19345798251326071. Epub ahead of print. PMID: 40116425.