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[Systemic oxygen demand and supply balance during warm heart surgery without blood transfusion]
Insights
Systemic oxygen balance was maintained during warm heart surgery without blood transfusion. However, longer extracorporeal circulation (ECC) times may reduce oxygen supply, suggesting a higher flow index might be beneficial.
Area of Science:
- Cardiovascular Surgery
- Physiology
- Anesthesiology
Context:
- Warm heart surgery without blood transfusion presents unique challenges to maintaining systemic oxygen balance.
- Extracorporeal circulation (ECC) is a critical component of cardiac surgery, impacting oxygen delivery and consumption.
- Understanding oxygen demand and supply dynamics is crucial for patient outcomes in complex cardiac procedures.
Purpose:
- To investigate the balance between systemic oxygen demand and supply during warm heart surgery utilizing extracorporeal circulation (ECC) without blood transfusion.
- To compare the effects of different extracorporeal circulation flow indices (2.4 vs. 2.6 l.min-1.m-2) on oxygenation parameters.
- To evaluate the impact of ECC duration on oxygen supply and demand during coronary artery bypass surgery.
Summary:
- This study analyzed 203 patients undergoing coronary artery bypass surgery, assessing oxygen delivery (DO2), oxygen consumption (VO2), and oxygen extraction ratio (OER) during ECC.
- Initiation of ECC led to decreased hemoglobin and mixed venous oxygen saturation (SvO2), with DO2 lower than pre-ECC levels, while VO2 and OER increased.
- A higher OER was observed with a flow index of 2.4 l.min-1.m-2 compared to 2.6 l.min-1.m-2, indicating increased oxygen extraction. Oxygen profiles improved post-ECC.
Impact:
- Findings suggest that oxygen demand and supply can be maintained during normothermic ECC without transfusion, but prolonged ECC may compromise oxygen supply.
- A higher extracorporeal circulation flow index may be necessary during normothermic ECC to ensure adequate oxygen delivery.
- This research provides insights into optimizing perfusion strategies during bloodless warm heart surgery to improve patient safety and outcomes.
Abstract:
We investigated systemic oxygen demand and supply balance during warm heart surgery without blood transfusion on 203 patients. The patients aged 63-years on average, for coronary artery bypass surgery, were assigned to extracorporeal circulation (ECC) with flow index of either 2.4 l.min-1.m-2 or 2.6. Hemoglobin concentration (Hb), mixed venous oxygen saturation (SvO2), cardiac index (CI), oxygen delivery (DO2), oxygen consumption (VO2) and oxygen extraction ratio (OER) were determined. The mean operation time was 314 min, and the mean ECC time was 94 min. In both groups, the initiation of ECC decreased Hb to 6.5 g.dl-1, and SVO2 decreased gradually during ECC. In addition, DO2 was lower than the pre-ECC level, which may indicate the shortage of oxygen supply, while VO2 and OER increased during ECC. OER increased by 0.38 in the group with flow index of 2.4, which is higher than 0.35 of the group with 2.6. The discontinuation of ECC improved oxygen profile, mainly due to the increase of Hb and CI. These findings indicate that oxygen demand and supply balance was maintained during normothermic ECC without transfusion, although longer duration o ECC may cause the shortage of oxygen supply. A higher flow may be required during normothermic ECC.