Related Experiment Video
Updated: Aug 14, 2026
Increasing Pulmonary Artery Pulsatile Flow Improves Hypoxic Pulmonary Hypertension in Piglets
Published on: May 11, 2015
The relation between pump flow rate and pulsatility on cerebral hemodynamics during pediatric cardiopulmonary bypass
G Chow1, I G Roberts, A D Edwards
1Department of Neurosciences, Institute of Child Health (UCL)/Great Ormond Street Hospital for Children, London, United Kingdom.
Insights
Cerebral blood flow in children undergoing cardiopulmonary bypass is directly related to pump flow rate. Pulsatile flow does not improve cerebral blood flow or hemoglobin concentration during this procedure.
Area of Science:
- Pediatric Cardiology
- Neurology
- Biomedical Engineering
Background:
- Neurologic impairment occurs in up to 25% of infants after cardiopulmonary bypass.
- The impact of pump flow (pulsatile vs. nonpulsatile) on cerebral blood flow remains debated.
Purpose of the Study:
- To investigate the relationship between pump flow rate and cerebral hemodynamics.
- To compare cerebral blood flow during pulsatile and nonpulsatile cardiopulmonary bypass in pediatric patients.
Main Methods:
- A randomized crossover study involving 40 pediatric patients.
- Near-infrared spectroscopy used to measure cerebral blood flow and volume.
- Evaluated three pump flow rates (0.6, 1.2, 2.4 L x m(-2) x min(-1)) with both pulsatile and nonpulsatile flow.
Main Results:
- Cerebral blood flow decreased by 36% for every 1 L x m(-2) x min(-1) reduction in pump flow rate.
- Mean arterial pressure changes correlated with cerebral blood flow.
- No significant difference in cerebral blood flow or hemoglobin concentration was observed between pulsatile and nonpulsatile flow.
Conclusions:
- Cerebral blood flow is significantly influenced by pump flow rate during pediatric cardiopulmonary bypass.
- Pulsatile flow, using a Stöckert pump, did not demonstrate a benefit in enhancing cerebral blood flow or hemoglobin concentration in this cohort.
Objectives:
Neurologic impairment, at least partly ischemic in origin, has been reported in up to 25% of infants undergoing cardiopulmonary bypass, with or without circulatory arrest. Controversy continues about the effect of pump flow, pulsatile or nonpulsatile, on the brain and in particular on cerebral blood flow. This study examines the relationship between pump flow rate and cerebral hemodynamics during pulsatile and nonpulsatile cardiopulmonary bypass.
Method:
Near-infrared spectroscopy was used to determine cerebral blood flow and cerebral blood volume (measured as concentration change) in a randomized crossover study. Pulsatile and nonpulsatile flow were used for six 5-minute intervals at each of three different pump flow rates (0.6, 1.2, and 2.4 L x m2 x min(-1)) in 40 patients, median age 2 months (range 2 weeks to 20 years 5 months). The relations between pulsatile flow, pump flow rate, cerebral blood flow, hemoglobin concentration change (cerebral blood volume), mean arterial pressure, arterial carbon dioxide tension, and hematocrit value were prospectively examined by means of multivariate analysis.
Results:
Cerebral blood flow decreased 36% per L x m(-2) x min(-1) decrease in pump flow rate and was associated with changes in mean arterial pressure but did not differ according to pulsatility. Change in hemoglobin concentration was unrelated to changes in pulsatility of pump flow.
Conclusion:
Cerebral blood flow is related to pump flow rate. Pulsatile flow delivered with a Stöckert pump does not increase cerebral blood flow or alter hemoglobin concentration during cardiopulmonary bypass in children.
