HISTAMINE LIBERATION RELATED TO CARDIOPULMONARY BYPASS IN CHILDREN - POSSIBLE RELATION TO TRANSIENT POSTOPERATIVE ARRHYTHMIAS

Tumor necrosis factor-alpha production and products of mast cell, baso phil, and eosinophil degranulation (prostaglandin D-2, histamine, and eosinophil cationic protein) were prospectively studied in 26 children undergoing cardiac operations, The relationship between inflammatory response to cardiopulmonary bypass and transient postoperative arrhyth mias was analyzed, Cardiopulmonary bypass was conducted with circulato ry arrest and deep hypothermia in 10 patients and with continuous low- flow and moderate hypothermia in 16 patients, Transient postoperative arrhythmias diagnosed on standard or atrial electrocardiograms (or bot h) were seen in eight of the 26 examined children: accelerated junctio nal rhythm (n = 3),junctional ectopic tachycardia (n = 3), second-degr ee atrioventricular block (n = 1), and third-degree atrioventricular b lock (n = 1), Children with transient postoperative arrhythmias were y ounger than those without (p < 0.05), Compared with baseline values, t here was in all patients a significant release of histamine and eosino phil cationic protein (p < 0.05) related to cardiopulmonary bypass, re aching peak values 4 hours after the operation, In contrast, tumor nec rosis factor-alpha production and prostaglandin D-2 release were not s ignificant, This suggests that activated basophils but not mast cells are the major sources of histamine liberated during and after cardiopu lmonary bypass, Histamine release but not eosinophil cationic protein release correlated with circulatory arrest and deep hypothermia (p < 0 .05), suggesting the participation of physicochemical alterations of c irculating basophils leading to histamine liberation, Four hours after the operation, patients with transient postoperative arrhythmias had significantly higher blood concentrations of histamine (p < 0.02) and eosinophil cationic protein (p < 0.05) than did those without transien t postoperative arrhythmias, On the first postoperative day, four of t he eight patients with transient postoperative arrhythmias had persist ing elevated histamine levels, whereas in patients without transient p ostoperative arrhythmias histamine reached baseline values, The multiv ariate analysis retained histamine release and eosinophil cationic pro tein variations related to cardiopulmonary bypass for the emerging mod el to predict transient postoperative arrhythmias. The results of this study show significant histamine release related to cardiopulmonary b ypass. Furthermore, they document a possible relationship between circ ulating histamine and transient postoperative arrhythmias. The latter may therefore be suspected among the consequences of the inflammatory response to cardiopulmonary bypass.