Inhibitory mechanisms of insulin secretion associated with hypothermic open-heart surgery

Neuroprotection during cardiac surgery

Cerebral injury following cardiac surgery continues to be a significant source of morbidity and mortality after cardiac surgery. A spectrum of injuries ranging from subtle neurocognitive dysfunction to fatal strokes are caused by a complex series of multifactorial mechanisms. Protecting the brain from these injuries has focused on intervening on each of the various etiologic factors. Although numerous studies have focused on a pharmacologic solution, more success has been found with nonpharmacologic strategies, including optimal temperature management and reducing emboli generation.

[Glucose metabolism in children undergoing extracorporeal circulation: its correlation with weight and the degree of hypothermia]

INTRODUCTION

A prospective study has been carried out in 33 children with congenital heart disease, aged 5 days to 16 years, operated on with the aid of cardiopulmonary bypass (CPB), in order to evaluate intra and postoperative glycemia in relation to children's weight and intra-CPB perfusion temperature.

MATERIAL AND METHODS

Plasmatic levels of glucose, lactate, insulin, C-peptide, growth hormone (GH) and cortisol were measured at five different times, from pre-CPB up to 18 hours post-CPB. Thirteen children weighing less than 10 kilograms (group I) were compared to 20 children weighing more than 10 kilograms (group II), and 15 children operated on with perfusion temperature below 27 degrees C (group A) were compared to 18 with perfusion temperature above 27 degrees C.

RESULTS

All the cases showed intraoperative hyperglycemia. In relation to weight, evolution of glycemia was similar in both groups but anaerobic glycolysis was significantly higher in group I. In relation to temperature, glycemia, lactic acidemia intra- and post-CPB and serum C-peptide post-CPB were significantly higher in group A. Intraoperative insulin was decreased and GH serum levels were also higher in group I and A, but fell drastically post-CPB in all groups.

CONCLUSIONS

Perioperative control of glycemia is important in children operated on with the aid of CPB. Control of lactic acidemia is also expedient. Carbohydrates metabolism and its hormonal regulation are more disturbed in infants and in children operated on with low perfusion temperature.