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Reduction of microemboli count in the priming fluid of cardiopulmonary bypass circuits
Frank Merkle1, Wolfgang Boettcher, Fritz Schulz
1Academy for Perfusion, Department of Surgery, Deutsches Herzzentrum, Berlin, Germany. merkle@dhzb.de
Abstract:
Microemboli may impair cognitive function in patients undergoing heart surgery. Prebypass filtration has been shown to reduce particle load in the cardiopulmonary bypass (CPB) priming fluid. This study was performed to detect the embolic load of CPB priming fluid, to determine the efficacy of a 0.2 microm prebypass filter (PBF) in reducing emboli in the range of 0.1-5 microm and to provide guidelines for the handling of the device. A total of 12 CPB circuits were tested in two groups, using a laser light scattering particle counter, sensitive to microemboli in the range of 0.1-5 microm. In control group A, priming fluid before administration to the CPB circuit was analyzed. Group B circuits contained microporous membrane oxygenators (N = 5); group C consisted of CPB circuits with excluded membrane oxygenators (N = 7). When group A was compared to groups B and C, significantly more microemboli were found in the categories 0.2 microm, 0.5 microm, 0.8 microm for both groups B and C (p < .05). Group C circuits had higher microemboli counts in the categories 1.5 microm and 3 microm (p < .05) when compared to group B. Microemboli bigger than 0.2 microm could be eliminated after 2 min of prebypass filtration with a CPB flow of 5 L/min. The number of microemboli smaller than 0.2 microm was reduced substantially. Small microemboli with a size of 0.1 microm originate mainly from the priming solution. Microemboli in the range of 0.2 microm, 0.5 microm, and 0.8 microm originate mainly from the CBP circuit. In circuits with bypassed membrane oxygenators, a higher microemboli count in the range of 1.5 microm and 3 microm may be explained by a possible filtering capacity of membrane oxygenators. The 0.2 microm PBF is an effective tool to reduce the particle load in the CPB priming fluid.
Insights
A 0.2 micrometer prebypass filter effectively reduces microemboli in cardiopulmonary bypass (CPB) circuits. This filtration is crucial for minimizing particle load and potentially improving patient outcomes during heart surgery.
Area of Science:
- Cardiovascular Surgery
- Biomedical Engineering
- Medical Device Technology
Background:
- Microemboli are a concern in heart surgery, potentially impacting cognitive function.
- Cardiopulmonary bypass (CPB) circuits can introduce microemboli into patient circulation.
- Prebypass filtration aims to reduce the embolic load in CPB priming fluid.
Purpose of the Study:
- To quantify the embolic load in CPB priming fluid.
- To evaluate the efficacy of a 0.2 micrometer prebypass filter (PBF) in reducing microemboli (0.1-5 microm).
- To provide guidelines for PBF device handling.
Main Methods:
- 12 CPB circuits were tested, divided into control (no filter), membrane oxygenator, and bypassed oxygenator groups.
- A laser light scattering particle counter measured microemboli in the range of 0.1-5 microm.
- Priming fluid and CPB circuit fluid were analyzed before and after filtration.
Main Results:
- Prebypass filtration significantly reduced microemboli of 0.2, 0.5, and 0.8 micrometers.
- Circuits with bypassed oxygenators showed higher counts of 1.5 and 3 micrometer emboli compared to those with oxygenators.
- Microemboli >0.2 micrometers were eliminated after 2 minutes of filtration at 5 L/min CPB flow.
- 0.1 micrometer emboli primarily originated from priming solution; larger emboli originated from the CPB circuit.
Conclusions:
- The 0.2 micrometer PBF is effective in reducing particle load in CPB priming fluid.
- Membrane oxygenators may possess a filtering capacity, reducing larger microemboli.
- Prebypass filtration is a valuable tool for enhancing CPB safety by reducing microembolic load.
