Evaluation of a variable ratio cardioplegia system.

Area of Science:

• Cardiovascular Surgery
• Biomedical Engineering
• Physiology

Background:

• Myocardial preservation during cardiac surgery is critical.
• Accurate delivery of cardioplegia solutions is essential for effective myocardial protection.
• Existing systems may face challenges in precisely controlling cardioplegia composition.

Purpose of the Study:

• To evaluate the Gish Biomedical MyoManager system's ability to control blood and crystalloid solution ratios.
• To assess the device's precision in delivering specific hematocrit and potassium ion concentrations ([K+]) in cardioplegia.
• To determine the impact of varying flow rates and blood-to-crystalloid ratios on cardioplegia delivery accuracy.

Main Methods:

• An in vitro circuit was established to simulate cardioplegia delivery.
• Blood perfusate with a known [K+] was mixed with a crystalloid solution containing a high [K+].
• Data on hematocrit, [K+], and volumes were collected at multiple blood-to-crystalloid ratios (1:1 to 25:1) and flow rates (100-250 ml/min).

Main Results:

• No statistically significant differences in hematocrit were observed across tested flows and ratios.
• Crystalloid delivery volume differences were higher at 100 ml/min compared to 200 and 250 ml/min.
• Potassium ion concentration ([K+]) showed no statistical significance between flows across ratios, except at a 1:1 ratio and 100 ml/min, which was significantly different.
• Total cardioplegia delivery volume showed a significant difference between 100 ml/min and 200 ml/min.

Conclusions:

• The MyoManager system demonstrates effective control of potassium ion concentration ([K+]) and hematocrit in cardioplegia solutions.
• Precise control is reliably achieved at cardioplegia delivery flow rates greater than 100 ml/min.
• The device shows potential for improving myocardial preservation strategies through accurate cardioplegia delivery.