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Bleeding complications associated with cardiopulmonary bypass
1Department of Molecular and Experimental Medicine, Research Institute of Scripps Clinic, La Jolla, CA.
Insights
Bleeding after cardiopulmonary bypass (CPB) is complex, often linked to temporary platelet dysfunction. Prophylactic aprotinin shows promise in reducing CPB-related bleeding and may offer insights into platelet dysfunction mechanisms.
Area of Science:
- Cardiovascular Surgery
- Hematology
- Anesthesiology
Background:
- Bleeding after cardiopulmonary bypass (CPB) presents significant management challenges due to complex hemostatic alterations.
- Transient platelet dysfunction is a common, clinically relevant issue during CPB, though excessive bleeding occurs in a minority of patients.
- Predicting hemorrhagic complications remains difficult, with prolonged CPB times being a risk factor.
Purpose of the Study:
- To review the complexities of bleeding management following CPB.
- To discuss current and emerging strategies for minimizing blood loss and transfusion requirements.
- To evaluate the role of pharmacologic agents in improving hemostasis during and after CPB.
Main Methods:
- Literature review of studies investigating bleeding after CPB.
- Analysis of factors contributing to CPB-associated hemostatic changes.
- Evaluation of autotransfusion techniques and pharmacologic interventions.
Main Results:
- Platelet dysfunction is a universal finding during CPB, but only affects bleeding in some patients.
- Aprotinin, a protease inhibitor, demonstrates potential for reducing bleeding when administered prophylactically.
- Desmopressin is indicated for treating post-CPB bleeding, not for prevention.
Conclusions:
- CPB-induced bleeding is multifactorial, involving hemostatic changes and procedural variables.
- Pharmacologic agents like aprotinin offer promising therapeutic avenues for managing CPB-related bleeding.
- Minimizing homologous blood product use is a key driver in advancing bleeding management strategies post-CPB.
Abstract:
Bleeding after CPB has been difficult to characterize and its treatment equally difficult to standardize. The complexity of this problem is related to the hemostatic process, the technical variations in the operative procedures, and the many uncontrolled variables associated with CPB, including the effects of anesthetic or pharmacologic agents, the nature of the priming solution, hemodilution, hypothermia, the type of oxygenator, and the use of transfused blood products. Although there are multiple and generally predictable complex changes in the hemostatic mechanism during CPB, the temporary loss of platelet function is the most common and clinically relevant. This transient platelet dysfunction occurs in all patients undergoing CPB; however, it only causes excessive bleeding in a small percentage of patients. Unfortunately, it has not yet been possible to predict which patients will develop hemorrhagic complications, although prolonged pump times are a contributing risk factor. Over the past decade there has been extensive investigation into the management of bleeding associated with CPB, provoked primarily by the increased awareness of transfusion-transmitted viral diseases and the inappropriately excessive use of homologous blood products. Several approaches to autotransfusion of shed blood and autologus blood donation have been developed to minimize perioperative homologous blood transfusion. Pharmacologic agents such as desmopressin, aprotinin, and topical fibrin glues have also been introduced to improve hemostasis during CPB. The protease inhibitor aprotinin is particularly promising in the reduction of bleeding associated with CPB when given prophylactically. Aprotinin may provide new insights into the mechanism of CPB-induced platelet dysfunction. Desmopressin is indicated only for the treatment of bleeding after CPB. The management of bleeding associated with CPB will undoubtedly