Randomized comparison between mild and moderate hypothermic cardiopulmonary bypass for neonatal arterial switch operation.
OBJECTIVE
To compare neonates receiving arterial switch operation (ASO) either with mild or moderate hypothermic cardiopulmonary bypass.


METHODS
Forty neonates undergoing ASO were randomized to receive either mild (Mi > 32 °C, n = 20) or moderate (Mo > 26 °C, n = 20) hypothermic cardiopulmonary bypass (CPB) between April 2007 and June 2010. All patients were diagnosed with simple transposition of the great arteries. Mean age (Mi: 8.32 ± 4.5 days, Mo: 7.54 ± 5.0 days, P = 0.21) and body weight were similar in both groups (Mi: 3.64 ± 0.91 kg, Mo: 3.73 ± 0.84 kg, P = 0.14). Follow-up was 3.1 ± 2.5 years for all patients.


RESULTS
Lowest perioperative rectal temperature was 33.5 ± 1.4 °C (Mi) versus 28.2 ± 2.1 °C (Mo) (P < 0.001). All patients safely weaned from CPB required lower doses of dopamine (Mi: 5.1 ± 2.4 µg/kg min, Mo: 6.5 ± 2.1 µ/kg min, P = 0.04), dobutamine (Mi: 7.2 ± 2.5 µg/kg min, Mo: 8.6 ± 2.4 µ/kg min, P = 0.04) and adrenalin (Mi: 0.02 ± 0.02 µg/kg min, Mo: 0.05 ± 0.03 µ/kg min, P = 0.03) in mild hypothermia group. Intraoperative blood transfusion (Mi: 190 ± 58 ml, Mo: 230 ± 24 ml, P = 0.03) and postoperative lactate levels (Mi: 2.7 ± 0.9 mmol/l, Mo: 3.1 ± 2.2 mmol/l, P = 0.02) were lower under mild hypothermia. Secondary chest closure was performed in 30% (Mi) versus 35% (Mo) (P = 0.65). Duration of inotropic support (Mi: 7 (4-11) days, Mo: 11 (7-15) days, P = 0.03), time to extubation (Mi: 108 (88-128) h, Mo: 128 (102-210) h, P = 0.04), lengths of intensive care unit (ICU) stay (Mi: 9 (5-14) days, Mo: 12 (10-18) days, P = 0.04) and hospital stay (Mi: 19 (10-29) days, Mo: 23 (15-37) days, P = 0.04) were significantly shorter under mild hypothermia. Two-year freedom from reoperation was 100% for both the groups.


CONCLUSIONS
The ASO under mild hypothermia seemed to be beneficial for pulmonary recovery, need for inotropic support and length of ICU and hospital stay. No worse early- or intermediate-term effects of mild hypothermia were found.
Department of Pediatric Cardiac Surgery,  Dr. Siyami Ersek Thoracic and Cardiovascular Training and Research Hospital, Istanbul,  Turkey.
Numan
N
Ali Aydemir
Bugra
B
Harmandar
Ali Riza
AR
Karaci
Abdullah
A
Erdem
Nurgul
N
Yurtseven
Ahmet
A
Sasmazel
Ibrahim
I
Yekeler
D000768:Anesthesia, General / Q000379:methods; D001831:Body Temperature; D001835:Body Weight; D002315:Cardiopulmonary Bypass / Q000379:methods*; D002316:Cardiotonic Agents / Q000008:administration & dosage; D004334:Drug Administration Schedule; D005500:Follow-Up Studies; D006801:Humans; D007036:Hypothermia, Induced / Q000379:methods*; D007231:Infant, Newborn; D007902:Length of Stay / Q000706:statistics & numerical data; D011182:Postoperative Care / Q000379:methods; D014188:Transposition of Great Vessels / Q000601:surgery*
D002316:Cardiotonic Agents