Complications of Crystalloid and Lidocaine Cardioplegia in Cardiac Surgery
The use of crystalloid cardioplegia with lidocaine in cardiac surgery can lead to several complications including hemodilution, increased bleeding risk, myocardial injury, and potential systemic lidocaine toxicity, with blood-based cardioplegia solutions being preferred in high-risk patients to reduce these complications.
Hemodilution-Related Complications
- Crystalloid cardioplegia causes significant hemodilution compared to blood cardioplegia, resulting in decreased hematocrit and reduced oxygen-carrying capacity 1
- Increased intraoperative hemodilution leads to greater blood loss and higher packed red blood cell transfusion requirements 2
- Hemodilution from crystalloid cardioplegia can contribute to acute kidney injury, especially in patients with pre-existing renal dysfunction 2
- Reduced plasma protein concentrations from hemodilution affect drug pharmacokinetics and pharmacodynamics, potentially altering the effects of anesthetics and other medications 1
Myocardial Protection Issues
- Higher postoperative cardiac enzyme (CK-MB) levels have been observed with lidocaine-containing cardioplegia compared to standard whole blood cardioplegia, suggesting potential increased myocardial injury 3
- Inadequate myocardial protection can occur with crystalloid cardioplegia, particularly in complex cases with extended cross-clamp times 2
- Right ventricular protection may be incomplete when using retrograde cardioplegia delivery, as experimental results show inadequate flow to the right ventricular microvasculature 2
- Interruption of cardioplegia delivery during normothermic techniques can induce anaerobic metabolism and warm ischemic injury 2
Lidocaine-Specific Complications
- Lidocaine in cardioplegia can potentially cause cardiac conduction abnormalities, although studies show no significant increase in high-grade atrioventricular block 4
- Systemic absorption of lidocaine may lead to central nervous system toxicity including seizures, although this is rare with standard cardioplegia doses 5
- Lidocaine may alter gene expression related to inflammation and apoptosis, which could have both protective and potentially harmful effects 6
Electrolyte and Metabolic Disturbances
- High potassium concentrations (8-20 mEq/L) in cardioplegia solutions can lead to transient hyperkalemia upon reperfusion 2
- Crystalloid cardioplegia solutions with high chloride content can contribute to hyperchloremic metabolic acidosis 7
- Glucose-containing cardioplegia solutions may exacerbate perioperative hyperglycemia, which is associated with adverse outcomes including atrial fibrillation and longer ICU stays 2
Delivery-Related Complications
- Antegrade cardioplegia delivery at excessive pressures (>100 mmHg) can cause endothelial damage 2
- Retrograde cardioplegia administered at pressures above 50 mmHg can cause coronary venous system injury 2
- Inadequate distribution of cardioplegia in patients with severe coronary disease or aortic valvular insufficiency can lead to uneven myocardial protection 2
Special Considerations for High-Risk Patients
- Crystalloid cardioplegia should be avoided in patients with anemia, low body surface area, or chronic kidney disease due to increased risk of hemodilution-related complications 2
- Blood cardioplegia is preferred for complex procedures with extended cross-clamp times to reduce the risk of inadequate myocardial protection 2
- For patients with diabetes, blood glucose levels should be monitored closely as hyperglycemia during cardiopulmonary bypass is common and may require management 2
Recommendations to Minimize Complications
- Consider using blood cardioplegia instead of crystalloid cardioplegia in high-risk patients to reduce hemodilution-related complications 2, 1
- When using retrograde cardioplegia, maintain coronary sinus pressure between 30-50 mmHg to prevent venous injury 2
- For complex cases with extended cross-clamp times, consider combined antegrade and retrograde cardioplegia to ensure adequate distribution 2
- Monitor cardiac enzymes postoperatively to assess for myocardial injury, particularly when using lidocaine-containing cardioplegia 3, 6