Can surgery with heart-lung machine cause low oxygen in baby brains?
Babies with congenital heart disease often need surgery that uses a heart-lung machine (cardiopulmonary bypass, or CPB). This machine takes over the work of the heart and lungs during the operation. However, research shows that CPB can sometimes lead to low oxygen levels in the baby's brain after surgery, a condition called cerebral desaturation. A 2024 study found that about 1 in 6 infants experience these events soon after surgery 1. The risk depends on factors like the baby's size, the type of heart defect, and how long the CPB machine was used 1.
What the research says
A 2024 retrospective study of 397 infants who had congenital heart surgery with CPB found that early postoperative cerebral desaturation events (CDEs) occurred in 16.88% of the overall group 1. The study identified several risk factors that make CDEs more likely: smaller body surface area, a higher RACHS-1 category (a measure of surgical complexity), longer CPB duration, lower hematocrit (red blood cell level) during CPB, and the temperature strategy used during CPB 1. These factors were combined into a prediction tool called a nomogram to help doctors identify high-risk infants 1. Another study using brain MRI in 41 neonates with CHD found that after cardiac surgery, the brain shows altered patterns of growth and coordination compared to healthy newborns 6. This suggests that surgery and CPB can affect brain development, which may be linked to low oxygen events 6. A separate study on brain age (a measure of brain maturity) in neonates with CHD found that after surgery, the brain age gap (difference between predicted and actual age) increased, indicating delayed brain development 8. While this study did not directly measure oxygen levels, it shows that surgery can impact the brain, and low oxygen is a likely contributor 8.
What to ask your doctor
- What is my baby's risk of low oxygen in the brain after surgery?
- How will you monitor my baby's brain oxygen levels during and after the procedure?
- What steps can be taken to reduce the chance of low oxygen events?
- Are there any signs I should watch for at home after discharge?
- How might this affect my baby's long-term brain development?
This question is drawn from common patient questions about this topic and answered using cited medical research. We do not provide individualized advice.