The Effects of Deep Hypothermia and Circulatory Arrest on Systemic Metabolic State of Infants Undergoing Corrective Open Heart Surgery: A Comparison of Two Methods

Summary

Fortyone 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:

1. Perfusion cooling by extracorporeal circulation (ECC-C)

2. Surface cooling with ice bags combined 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 and 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 and operative results were similar we now prefer the time-saving ECC-C technique.

Key-Words:

Deep hypothermia - Circulatory arrest - Congenital heart defects - Corrective surgery - Metabolism