Cerebrospinal fluid biochemistry reflects effects of therapeutic hypothermia after cardiac arrest in a porcine model.
BACKGROUND
Mild induced hypothermia (MIH) is recommended to treat neurologic injury after cardiac arrest (CA). However, clinical trials to assess MIH benefit after CA have been largely inconclusive. We investigated the subsequent changes in cerebrospinal fluid (CSF) biochemistry after MIH (33°C-34°C for 12 hours) and evaluated the importance of ongoing fever control.


METHODS
Thirty-two male Wuzhishan inbred mini pigs (n = 16/group) underwent ventricular fibrillation followed by cardiopulmonary resuscitation and were randomized into 2 groups: hypothermic and control. Upon resumption of spontaneous circulation (ROSC) from CA, the hypothermic group was treated with MIH by endovascular cooling. The control group received no temperature intervention. Core temperatures were continually monitored. At various points throughout the procedure, CSF samples were obtained to measure glutamate, lactate, and pyruvate levels.


RESULTS
The core temperature of the hypothermic group was found to have increased postrewarming and reached levels comparable with those of the control group at ROSC 72 hours. In both groups, glutamate increased significantly after ROSC, but the glutamate levels in the hypothermic group were lower than those in the control group, except at ROSC 1 hour. The lactate-pyruvate ratio increased in the control group at ROSC 1 hour and was significantly lower in the hypothermic group (P < .05).


CONCLUSIONS
Mild induced hypothermia mitigated and delayed the CA-induced increase of CSF glutamate. Therefore, our results suggest that clinically inducing hypothermia as soon as possible after CA, or prolonging the time of MIH in combination with controlling ongoing fever, may enhance hypothermic protective effects.
Beijing Chaoyang Hospital affiliated with Capital Medical University, Beijing 100020, China.
Rong
R
Hua
Chunsheng
C
Li
Ping
P
Gong
Ziren
Z
Tang
Xue
X
Mei
Hong
H
Zhao
D000818:Animals; D001831:Body Temperature; D004195:Disease Models, Animal; D005947:Glucose / Q000134:cerebrospinal fluid; D018698:Glutamic Acid / Q000134:cerebrospinal fluid; D005990:Glycerol / Q000134:cerebrospinal fluid; D006323:Heart Arrest / Q000134:cerebrospinal fluid* / Q000628:therapy; D007036:Hypothermia, Induced; D019344:Lactic Acid / Q000134:cerebrospinal fluid; D008297:Male; D019289:Pyruvic Acid / Q000134:cerebrospinal fluid; D013552:Swine; D013556:Swine, Miniature; D016896:Treatment Outcome
D019344:Lactic Acid; D018698:Glutamic Acid; D019289:Pyruvic Acid; D005947:Glucose; D005990:Glycerol