Neurocognitive function in patients undergoing coronary artery bypass graft surgery with cardiopulmonary bypass: the effect of two different rewarming strategies.
OBJECTIVE
Hypothermia followed by rewarming during cardiopulmonary bypass can lead to cerebral hyperthermia, which has been implicated as 1 of the causes for postoperative deterioration in neurocognitive function in patients undergoing coronary revascularization. Hence, the authors studied the effects of 2 different rewarming strategies on postoperative neurocognitive function in adult patients undergoing coronary artery bypass graft surgery with the aid of cardiopulmonary bypass.


METHODS
This was a randomized clinical trial.


METHODS
A cardiothoracic center of a tertiary level referral, teaching hospital.


METHODS
A total of 80 adult patients aged 45 to 70 years undergoing elective primary isolated coronary artery bypass graft surgery with cardiopulmonary bypass under moderate hypothermia at 30 degrees C were included in this study.


METHODS
The patients were randomly allocated into 2 groups of 40 each. In group A, patients were rewarmed to a nasopharyngeal temperature of 37 degrees C; whereas, in group B, patients were rewarmed to a nasopharyngeal temperature of 33 degrees C before weaning off bypass. The anesthetic and bypass management were standardized for both groups.


METHODS
All patients were assessed for neurocognitive function preoperatively and on the fifth postoperative day using the Post Graduate Institute Memory Scale. The amount of blood loss and need for blood and blood product transfusion postoperatively, the need for pacing, increased inotrope or vasodilator use, and time to extubation were also noted. Serum S100beta levels were measured after anesthetic induction and at 24 hours postoperatively. The jugular venous oxygen saturation and oxygen tension were noted at 30 degrees C and at the end of full rewarming (ie, at 37 degrees C or 33 degrees C, respectively, in the 2 groups).


RESULTS
There was a significant deterioration in neurocognitive function postoperatively as compared with preoperative function in patients of group A (37 degrees C). This was associated with higher S100beta levels 24 hours postoperatively in group A (37 degrees C) compared with group B (33 degrees C) patients. Also, there was a significant decrease in jugular venous oxygen saturation in group A (37 degrees C) as compared with group B (33 degrees C) at the end of rewarming. The time to extubation was longer in group B (33 degrees C). No significant differences were noted in the amount of postoperative blood loss, blood and blood product use, inotrope or vasodilator use, and the need for pacing.


CONCLUSIONS
Weaning from CPB at 33 degrees C may be a simple and useful strategy to lower the postoperative impairment of neurocognitive function and may be used as a tool to decrease morbidity after coronary revascularization.
Sahu
Bikash
B
Department of Cardiac Anesthesiology, All India Institute of Medical Sciences, New Delhi, India. drbikash_sahu@rediffmail.com
Chauhan
Sandeep
S
Kiran
Usha
U
Bisoi
Akshay
A
Lakshmy
Ramakrishnan
R
Selvaraj
Thiruvenkadam
T
Nehra
Ashima
A
D000368:Aged; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D003071:Cognition / Q000502:physiology*; D003072:Cognition Disorders / Q000097:blood / Q000209:etiology / Q000517:prevention & control; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009414:Nerve Growth Factors / Q000097:blood; D009483:Neuropsychological Tests; D011183:Postoperative Complications / Q000097:blood / Q000209:etiology / Q000517:prevention & control; D011300:Preoperative Care / Q000379:methods; D017694:Rewarming / Q000009:adverse effects* / Q000379:methods; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000097:blood
D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins