Changes in tryptase levels during cardiac surgery in patients at low risk for allergic reactions

Tryptase test can be used as a clinical marker of mast cell activation. The present study is was aimed to identify variations in serum tryptase levels and their possible relationships with allergic reactions to protamine in low-risk patients undergoing cardiac bypass surgery. Thirty patients according to American Society of Anesthesiologists physical status III who underwent cardiac bypass surgery were enrolled. This prospective, non-randomised, clinical study was conducted in an operating room. Venous blood samples for tryptase measurements were obtained from cardiac bypass surgery patients upon admission to the operating room and immediately before and 30 min after the initiation of protamine administration. Signs of allergic reactions were recorded and management steps based on rapid effect response-based clinical assessments for diagnosis and treatment decisions during protamine administrations were described. Serum tryptase levels and clinical signs of allergic reactions, primarily mean arterial pressure (MAP), were recorded. Serum tryptase levels increased significantly and progressively during the bypass procedure (study power, 80%; sample size, 28; power of analysis, 99.8% with α=0.05); however, tryptase levels did not reach a sufficiently high level to confirm an allergic reaction. The MAP and heart rate decreased in 50% of the patients. Although tryptase increased significantly when compared with baseline levels, protamine-associated increases were not significant and failed to provide an unequivocal indication of an allergic response to protamine.