PERIOPERATIVE EFFECTS OF ALPHA-STAT VERSUS PH-STAT STRATEGIES FOR DEEP HYPOTHERMIC CARDIOPULMONARY BYPASS IN INFANTS

Objectives: In a randomized, single-center trial, we compared perioper ative outcomes in infants undergoing cardiac operations after use of t he alphastat versus pH-stat strategy during deep hypothermic cardiopul monary bypass. Methods: Admission criteria included reparative cardiac surgery, age less than 9 months, birth weight 2.25 kg or more, and ab sence of associated congenital or acquired extracardiac disorders. Res ults: Among the 182 infants in the study, diagnoses included D-transpo sition of the great arteries (n = 92), tetralogy of Fallot (n = 50), t etralogy of Fallot with pulmonary atresia (n = 6), ventricular septal defect (n = 20), truncus arteriosus (n = 8), complete atrioventricular canal (n = 4), and total anomalous pulmonary venous return (n = 2). N inety patients were assigned to alpha-stat and 92 to pH-stat strategy. Early death occurred in four infants (2%), all in the alpha-stat grou p (p = 0.058). Postoperative electroencephalographic seizures occurred in five of 57 patients (9%) assigned to alpha-stat and one of 59 pati ents (2%) assigned to pH-stat strategy (p = 0.11). Clinical seizures o ccurred in four infants in the alpha-stat group (4%) and two infants i n the pH-stat group (2%) (p = 0.44). First electroencephalographic act ivity returned sooner among infants randomized to pH-stat strategy (p = 0.03). Within the homogeneous D-transposition subgroup, those assign ed to pH-stat tended to have a higher cardiac index despite a lower re quirement for inotropic agents; less frequent postoperative acidosis ( p = 0.02) and hypotension (p = 0.05); and shorter duration of mechanic al ventilation (p = 0.01) and intensive care unit stay (p = 0.01). Con clusions: Use of the pH-stat strategy in infants undergoing deep hypot hermic cardiopulmonary bypass was associated with lower postoperative morbidity, shorter recovery time to first electroencephalographic acti vity, and, in patients with D-transposition, shorter duration of intub ation and intensive care unit stay. These data challenge the notion th at alpha-stat management is a superior strategy for organ protection d uring reparative operations in infants using deep hypothermic cardiopu lmonary bypass.