EFFECTS OF DEEP HYPOTHERMIA AND CIRCULATORY ARREST ON SYSTEMIC METABOLIC STATE OF INFANTS UNDERGOING CORRECTIVE OPEN-HEART SURGERY - COMPARISON OF 2 METHODS

Forty-one of 187 infants undergoing corrective surgery for their congenital cardiac lesions using profound hypothermic circulatory arrest were randomly selected for metabolic studies. Deep hypothermia of 21 to 22°C core temperature was reached by two different techniques: Perfusion cooling by extracorporeal circulation (ECC-C). Surface cooling with ice bags combine with perfusion cooling (SC + ECC-C). After circulatory arrest (34.2 min. ECC-C v.s. 46.7 min. SC + ECC-C) bypass rewarming was used in both groups. The metabolic reaction to these interventions are described. No significant differences in acid base status in oxygen consumption, lactate concentration, serum electrolytes (K+, Na+, Ca++, Cl-) and serum enzyme activity (CPK, alpha-HBDH, LDH, SGOT, SGPT) could be demonstrated between the two groups of patients during the entire course of cooling, circulatory arrest an rewarming. The glucose concentration was significantly lower in the ECC-C group during the entire period of operation. Total cooling time was significantly shorter in the group without surface cooling. (ECC-C: 12 min, v.s. SC + ECC-C: 64 min). Since no favourable effects of the SC + ECC-C method on systemic metabolism could be demonstrated an operative results were similar we now prefer the time-saving ECC-C technique.