EFFECTS OF HYPOTHERMIA ON EVOKED-POTENTIALS, MAGNETIC-RESONANCE-IMAGING, AND BLOOD-FLOW IN FOCAL ISCHEMIA IN RABBITS

被引:65
作者
LO, EH [1 ]
STEINBERG, GK [1 ]
机构
[1] STANFORD UNIV,MED CTR,SCH MED,DEPT NEUROSURG,STANFORD,CA 94305
关键词
CEREBRAL BLOOD FLOW; CEREBRAL ISCHEMIA; HYPOTHERMIA; MAGNETIC RESONANCE IMAGING; RABBITS;
D O I
10.1161/01.STR.23.6.889
中图分类号
R74 [神经病学与精神病学];
学科分类号
摘要
Background and Purpose: Mild hypothermia has been shown to ameliorate neuronal damage due to cerebral ischemia. In our study, the influence of mild-to-moderate hypothermia was examined in a rabbit model of focal cerebral ischemia. Methods: After 4 hours of permanent ischemia induced by occlusion of the anterior and middle cerebral and internal carotid arteries, somatosensory evoked potentials and regional cerebral blood How were measured. Ex vivo magnetic resonance imaging scans were also obtained to determine the degree of ischemic brain injury. Three temperature (temporalis muscle) groups were studied: 37-degrees-C, 33-degrees-C, and 30-degrees-C (n=5 per group). An additional two animals were used to confirm that temporalis muscle temperatures were well correlated with brain temperature. Rectal temperatures were kept constant (37.5-degrees-C) in all groups. Results: After 4 hours of focal ischemia, evoked potentials in the normothermic animals remained depressed (2.2+/-2.1% [mean+/-SEM] preocclusion values). Recovery of potentials was significantly enhanced in both hypothermic groups (p<0.05): 18.2+/-6.5% (33-degrees-C) and 43.6+/-12.2% (30-degrees-C). Quantitative magnetic resonance measurements showed that T1 and T2 relaxation times were increased in the core ischemic regions within the cortex (20.4+/-4.0% and 25.3+/-5.9%, respectively). These elevations in T1 and T2 were reduced by hypothermia. However, blood flow was not improved by lowered temperature; in fact, How in the 30-degrees-C group was significantly decreased compared with the other groups (p<0.01). There was no statistically significant correlation between specific cerebral blood flow values and T1 or T2 elevations. Conclusions: These results demonstrate that hypothermia can improve evoked potentials and magnetic resonance parameters in permanent focal ischemia. However, moderate hypothermia (30-degrees-C) appears to also significantly decrease blood flow in the ischemic brain.
引用
收藏
页码:889 / 893
页数:5
相关论文
共 26 条
[1]   QUANTITATIVE PROTON MAGNETIC-RESONANCE-IMAGING IN FOCAL CEREBRAL-ISCHEMIA IN RAT-BRAIN [J].
BENVENISTE, H ;
COFER, GP ;
PIANTADOSI, CA ;
DAVIS, JN ;
JOHNSON, GA .
STROKE, 1991, 22 (02) :259-268
[2]   CEREBRAL PROTECTIVE EFFECT OF LOW-GRADE HYPOTHERMIA [J].
BERNTMAN, L ;
WELSH, FA ;
HARP, JR .
ANESTHESIOLOGY, 1981, 55 (05) :495-498
[3]  
BOTTOMLEY PA, 1984, MED PHYS, V11, P425, DOI 10.1118/1.595535
[4]  
BOYD RS, 1967, SURG FORUM, V12, P408
[5]   HYPOTHERMIA REDUCES CEREBRAL METABOLIC-RATE AND CEREBRAL BLOOD-FLOW IN NEWBORN PIGS [J].
BUSIJA, DW ;
LEFFLER, CW .
AMERICAN JOURNAL OF PHYSIOLOGY, 1987, 253 (04) :H869-H873
[6]   EFFECT OF MILD HYPOTHERMIA ON ISCHEMIA-INDUCED RELEASE OF NEUROTRANSMITTERS AND FREE FATTY-ACIDS IN RAT-BRAIN [J].
BUSTO, R ;
GLOBUS, MY ;
DIETRICH, WD ;
MARTINEZ, E ;
VALDES, I ;
GINSBERG, MD .
STROKE, 1989, 20 (07) :904-910
[7]   SMALL DIFFERENCES IN INTRAISCHEMIC BRAIN TEMPERATURE CRITICALLY DETERMINE THE EXTENT OF ISCHEMIC NEURONAL INJURY [J].
BUSTO, R ;
DIETRICH, WD ;
GLOBUS, MYT ;
VALDES, I ;
SCHEINBERG, P ;
GINSBERG, MD .
JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM, 1987, 7 (06) :729-738
[8]   LATENCY OF THE CORTICAL COMPONENT OF THE SOMATOSENSORY EVOKED-POTENTIAL IN RELATION TO CEREBRAL BLOOD-FLOW MEASURED IN THE WHITE MATTER OF THE CAT BRAIN DURING FOCAL ISCHEMIA [J].
COYER, PE ;
SIMEONE, FA ;
MICHELE, JJ .
NEUROSURGERY, 1987, 21 (04) :497-502
[9]  
DELAPAZ RL, 1991, AM J NEURORADIOL, V12, P89
[10]  
DELAPAZ RL, 1991, SOC MAGN RESON IMAGI, V10, P332