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Pulsatile flow during routine cardiopulmonary bypass
Insights
Pulsatile flow during cardiopulmonary bypass (CPB) stabilizes blood pressure and vascular resistance. This pulsatile flow also improves renal and hepatic function in patients undergoing heart surgery.
Area of Science:
- Cardiovascular Surgery
- Physiology
Background:
- Cardiopulmonary bypass (CPB) is a critical procedure in open heart surgery.
- The hemodynamic effects of pulsatile versus non-pulsatile flow during CPB are not fully understood.
- Maintaining stable physiological parameters during CPB is crucial for patient outcomes.
Purpose of the Study:
- To investigate the impact of pulsatile flow during CPB on hemodynamic stability.
- To evaluate the effects of pulsatile flow on renal and hepatic function during CPB.
- To compare physiological responses between pulsatile and non-pulsatile CPB in cardiac surgery patients.
Main Methods:
- Two groups of 11 patients undergoing valvular and congenital heart surgery were studied.
- One group received pulsatile flow CPB, while the other received non-pulsatile flow CPB.
- Hemodynamic parameters (BP, SVRI), oxygen consumption, carbon dioxide production, urine flow, and liver enzymes (sGOT) were monitored.
Main Results:
- Non-pulsatile CPB led to a significant increase in systemic vascular resistance index (SVRI) after 40 minutes compared to pulsatile CPB.
- Oxygen consumption and carbon dioxide production appeared lower in the non-pulsatile group, though not statistically significant.
- Pulsatile CPB demonstrated significantly increased urine flow and reduced postoperative liver enzyme changes, indicating better renal and hepatic function.
Conclusions:
- Pulsatile flow during CPB helps maintain hemodynamic stability, particularly by preventing increases in systemic vascular resistance.
- Pulsatile CPB is associated with improved renal and hepatic function compared to non-pulsatile CPB.
- The findings suggest pulsatile flow may be advantageous for patient recovery after cardiac surgery.
Abstract:
The effect of pulsatile flow during cardiopulmonary bypass (CPB) was studied on two groups of 11 patients each (aged between 18 and 48 years) undergoing open valvular and congenital heart surgery. In the nonpulsatile group, mean blood pressure (BP) and systemic vascular resistance index (SVRI) increased steadily during CPB; while in the pulsatile group, both BP and SVRI remained stationary. The difference of SVRI between the two groups was not significant within 30 minutes after initiation of CPB (3136 +/- 882 to 2536 +/- 530 dynes X sec X cm-5 X m2). Contrarily, it was significantly higher in the nonpulsatile group after 40 minutes of CPB (3748 +/- 562 to 2612 +/- 609 dynes X sec X cm-5 X m2, p less than 0.02) and thereafter. Oxygen consumption index (59.6 +/- 12.9 to 77.8 +/- 32.6 ml X min-1 X m-2) and carbon dioxide production index (41.1 +/- 16.0 to 59.3 +/- 28.1 ml X min-1 X m-2) measured 20 minutes after institution of CPB seemed lower in the nonpulsatile group than in the pulsatile group, but the differences were not statistically significant. Increased urine flow during CPB (1.8 +/- 1.1 to 6.3 +/- 3.8 ml X min-1 X m-2, p less than 0.001) with less variability indicated better reserve of renal function in the pulsatile group; and less percent change of postoperative sGOT from preoperative level (529.8 +/- 129.8 to 310.0 +/- 175.2%, p less than 0.005) also showed better hepatic function in the pulsatile group.(ABSTRACT TRUNCATED AT 250 WORDS)