The Annals of Thoracic Surgery, Vol 28, 317-322, Copyright © 1979 by The Society of Thoracic Surgeons
The importance of monitoring intramyocardial temperature during hypothermic myocardial protection
RC Chiu, PE Blundell, HJ Scott and S Cain
In 50 patients undergoing cardiac operation, hypothermic cardioplegic
solution was infused into the root of the aorta immediately after aortic
cross-clamping. Cardiac standstill was achieved within 1 to 3 minutes.
However, monitoring of intramyocardial temperature with a needle thermistor
revealed that such core cooling is unpredictable (the intramyocardial
temperature achieved ranged from 7 degrees to 33 degrees C), unstable (this
temperature can rise at more than 0.5 degrees C per minute), and uneven (a
difference of up to 17 degrees C was observed between the intramyocardial
temperature of the anterior and posterior left ventricular sites). The area
supplied by the stenotic coronary artery was least protected. Monitoring of
intramyocardial temperature enables one to know when supplementary cooling
is indicated. We conclude that widespread differences in this temperature
during cardiac operation make monitoring advisable for optimal myocardial
protection.
