Pakt IV 

 HYPOTHERMIA IN NEUROSURGERY 



E. H. BOTTERKLL and W. M. LOUGHEED 



In 1950, Bigelow' first sui^gestcd tlic use ni hy])(ithenni;i in cardiac surgery. 

 The purpose of this investigation is to establish the role of hypothermia in neuro- 

 surgery, with particular reference to the management of the ruptured intracranial 

 berry aneurysm. Extra-corporeal shunts and local cooling of the lirain which were 

 investigated by one of us ( W. M. L. ) proved to l)e too difficult for practical use. 

 Experimental studies of general hypothermia- indicated that the cerebral metabolic 

 rate of dogs fell to between 33 per cent and 25 per cent of normal at 25° C. and 

 that these animals could withstand periods of anoxia four times greater than the 

 average survival period at 37° C. 



This paper deals with the clinical aspects and evaluation of hypothermia in 

 neurosurgery. 



We have operated upon 40 patients using hypothermia. Thirty-two have had 

 berry aneurysms, four arteriovenous malformations, one resection of internal 

 carotid artery, two cerebral tumors, and one hemispherectomy^ (table I). 



METHODS 



Pre-operative medication consisted of the intramuscular injection of 50 mg. each 

 of Largactil (chlorpromazine), Phenergan and Demerol the night preceding opera- 

 tion, and again in the morning of operation. Lightly anesthetized (N2O in Trilene) 

 and intubated, the patients were placed in a bath on the operating table (fig. 1). 

 Electroencephalograi)hic, electrocardiographic, and multiple thermocouple leads 

 were connected with the patient. A Cournand needle was placed in the radial artery 

 to measure the mean blood pressure. The neck was dissected with exposure of the 

 carotid and vertebral arteries bilaterally in order to allow occlusion as might be 

 needed (fig. 2). The bath was filled with ice water and the patient cooled. The 

 patients were allowed to breathe spontaneously and were not hyperventilated. 



Hypothermia has greatly facilitated and reduced the risk of local surgical treat- 

 ment of intracranial aneurysms and certain arteriovenous malformations.* 



The advantages afforded by hypothermia in the surgical management of recently 

 ruptured intracranial aneurysms include reduction of the oxygen demand of the 



TABLE I 



Hypothermic Cases 



Hemispherectomy 1 



Brain tumour 2 



Arteriovenous malformations 4 



Aneurysms 32 



Resection int. carotid 1 



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