Topical Cooling for Myocardial Protection: The Results of a Prospective Randomized Study of the "Shallow Technique"

Effects of topical hypothermia on postoperative inflammatory markers in patients undergoing coronary artery bypass surgery

Background

We aimed to examine the effects of topical hypothermia on inflammatory markers in patients undergoing coronary artery bypass surgery.

Methods

Fifty patients undergoing isolated coronary artery bypass surgery were included the study. They were randomised to two groups. Mild hypothermic cardiopulmonary bypass (28–32°C) was performed on both groups using standardised anaesthesiology and surgical techniques. Furthermore, topical cooling with 4°C saline was performed on patients in group I. We recorded peri-operative and intra-operative results of blood samples, pre-operative and postoperative outcomes of electrocardiography and echocardiography, diaphragm levels on X-ray, and the necessity of positive inotropic medication and intra-aortic balloon pump (IABP).

Results

Time-dependent changes in blood samples were compared between the two groups. The changes on complement 3 (C3) and TNF-α levels were more significant in group I than group II (p < 0.05 and p < 0.001, respectively). Spontaneous restoration rate of sinus rhythm was higher in group II than group I (80 vs 32%, p < 0.01). Atrial fibrillation was seen in six patients in group I and one patient in group II (p < 0.05). IABP was performed on four patients (16%) in group I (p < 0.05). Diaphragmatic paralysis was seen in seven patients in group I but not in group II (p < 0.01). Partial pericardiotomy rates were compared within the groups but there was no statistically significant difference (p > 0.05). One patient in group I died on the 18th postoperative day, but operative mortality rate was not statistically significant between the two groups (p > 0.05).

Conclusions

Topical hypothermia had a negative impact on inflammatory markers and postoperative morbidities.

Hypothermie in der Herzchirurgie

Since the beginning of the era of cardiac surgery hypothermia remains a mainstay in perioperative management. This role is increasingly being questioned because of many disadvantages and the lack of evidence of advantages. Using modern techniques of perfusion and myocardial protection as well as improved surgical techniques the results with normothermia seem to be comparable. The importance of hypothermia in present day cardiac surgery is discussed with respect to myocardial and cerebral protection.