Authors: Schweizer T, Nossen et al
Anesthesia & Analgesia 141(2): 267-272, August 2025. doi:10.1213/ANE.0000000000007106
This experimental study examined whether intraoperative hyperglycemia during cardiopulmonary bypass is partly due to insulin loss from adhesion to circuit surfaces or degradation from hemolysis. Researchers compared conventional extracorporeal circulation (cECC) systems with roller pumps against mini-ECC (MiECC) systems with centrifugal pumps.
Twelve systems primed with red blood cells and plasma were studied, with insulin added to achieve a target concentration of 400 mU/L. Over four hours, insulin concentration decreased markedly in both systems, but more significantly in cECC (−92%) compared to MiECC (−63%). Importantly, when only plasma (no red cells) was used, insulin levels did not decline, pointing to hemolysis as the key factor. Hemolysis was higher in cECC, and a strong inverse correlation was found between hemolysis and insulin concentration (r = −0.99).
The findings suggest that insulin degradation by hemolysis products, rather than surface adhesion, drives intraoperative insulin loss, with conventional ECC systems producing the greatest effect.
Practical takeaway: During cardiac surgery with cardiopulmonary bypass, insulin requirements may be significantly higher due to hemolysis-induced degradation, especially with conventional roller pump circuits; anesthesiologists should anticipate and proactively manage this to avoid uncontrolled hyperglycemia.
KEY POINTS
- Question: Are the changes in insulin concentrations in an extracorporeal circulation circuit (ECC) related to surface adhesion or insulin degradation?
- Findings: Insulin concentration decreased significantly only in ECC systems containing red blood cells, which was correlated to the degree of hemolysis in the system.
- Meaning: Our results favor insulin degradation by hemolysis rather than insulin adhesion to the ECC surfaces as an explanation for insulin loss during cardiopulmonary bypass.