Author/Editor		Geršak, B; Gabrijelčič, T; Trobec, R; Slivnik, B
Title		Temperature distribution in human heart during hypothermic cardioplegic arrest
Type		članek
Source		Cor Eur
Vol. and No.		Letnik 6
Publication year		1997
Volume		str. 172-6
Language		eng
Abstract		Purpose: A 3D-thermal analysis of the human heart and temperature distribution during induced hypothermic cardioplegic arrest in cardiac surgery was performed. Methods: The heat equation which represents a physical behaviour is transformed to a set of differential equations which are solved numerically by the finite difference method. The heart modelling method is based on a series of axial-slice images obtained by a human heart CT-scan. The parallel computer simulation was used. Results: The situation at the start of aortic cross-clamping was chosen: esophageal temperature 28 degree C, rectal temperature 30 degrees C and cardiac septal temperature (STemp) 11 degrees C after fhe infusion of cold cardioplegic solution of 4 degrees C. The additional and continuous topical cardiac cooling with freezing water at a constant 0.2 degree C in the pericardial cavity showed unequal temperature distribution during the first 30 min. of simulated cardiac arrest, the STemp being at much higher levels than the left ventricular free wall temperature (LVTemp), however both were well below the starting 11 degrees C. The STemp was between 10 and 10.5 degrees C, the LVTemp between 1.5 and 2 (gradient 8.5sdegrees C). A t 60 minutes when the simulation stopped, the temperature gradient between the STemp and LVTemp had not changed. The STemp was between 8.5 and 9 degrees C, the LVTemp was between 0 and 0.5 degree C. The situation without topical cardiac cooling showed the expected rise of STemp and L VTemp. A t 30 minutes the gradient was 6-6.5 degrees C (STemp was 13 degrees C, L VTemp was between 19-19.5 degrees C) and at 60 min. 5.5 degrees C (STemp was 17 17.5sdegrees C, LVTemp was 22.5-23degrees C). Conclusion: The STemp during hypothermic cardio-plegic cardiac arrest is relatively stable, the LVTemp, however, is influenced by local conditions. The constant rise pf particularly the LVTemp with greater anaerobic metabolism could be expected without the use of topical cardiac cooling.
Descriptors		HYPOTHERMIA, INDUCED CARDIOPLEGIC SOLUTIONS COMPUTER SIMULATION TEMPERATURE HEART ARREST, INDUCED MODELS, THEORETICAL