J.Jpn. Surg. Soc.. 58(12): 1867-1881, 1958

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STUDIE'S OF PROFOUND HYPOTHERMIA
1) RESEARCH CONCERNED WITH THE METHOD OF ANESTHESIA, COOLING, REWARMING AND BIOLOGICAL CHANGES IN DEEP HYPOTHERMIA.
2) INVESTIGATION OF CARDIAC RESUSCITATION AFTER LONG CESSATION OF TOTAL BLOOD FLOW TO THE HEART UNDER PROFOUND HYPOTHERMIA AND ITS USE FOR CARDIOVASCULAR SURGERY.

Bigelow reported for the first time that the interruption of circulation could last for about 10 minutes under hypothermia without using heart-lung apparatus. This proved to be enough to repair some cardiac anomalies under direct vision. Since then several cases of successful repair of atrial septal defect were reported. But the lower the body temperature became, the more danger of ventricular fibrillation increased and the more often the difficulties of defibrillation occurred. So it was universally believed that the profound hypothermia was not preferable to both cardic function and haemodynamics.Therefore, the investigators of profound hypothermia diminished in number. According to my examinations concerned with the relationship between the cerebral function, and the rectal temperature exposed by circulatory arrest, the first was that the permissable time of circulatory arrest was 3 ~ 5 minutes as far as normothermia, but the lower the body temperature become, the longer the permissible time was found to be prolonged. And what was noticeable was that the permissible time became longer and longer in inverse proportional to the decrease of oxygen consumption. Therefore, I thought that if the body temperature lowered below 20°C, the prolonger time of circulatory arrest, say 1 ~ 2 hours, might be possible. And finally I succceeded in resuscitation after the circulatory arrest of 2 hours and 40 minutes at rectal temperature around 12°C. During these experiments, E.K.G., E.E.G., oxygen consumption rate, hemodynamics, electorolyte change, blood gas etc. were examined. Now, we have 6 to 40 cases of permanent-survivaldog-resuscitation after 1 to 1.5 hours circulatory arrest under profound hypothermia.
In section 1. described the method as to how to reduce the body temperature, how to maintain the respiration in cooling and rewarming. And in what kind of state were the function of the various organs in such profound hypothermia was discussed.
In section 2. chiefly described the method of r esuscitation after long cessation of cardiac flow.
Conclusions :
(1)
i) In warm-blooded animals ether anesthesia is the most desirable in cooling and rewarming.
ii) As to cooling and rewarming, the slow method is preferable, especially in rewarming. These reasons are discussed.
iii) Respiration maintained spontaneously by pure oxygen connected with the anesthetic apparatus until respiration ceases, but it is needed to keep hyperventilation below 20°C.
iv) Variable biological reactions are observed in cooling, but they are all reversible functionally in rewarming.
v) Besides, these conclusions, I should like to insist the hypothermia might be used in safe not only cardiovascular surgery and even a profound hypothermia might be applied to clinical use in future.
(2)
i) The details of cardiac resuscitation after long cessation of circulation under profound hypothermia were described as follows: Together with rewarming, the heart massage was continued until 28°C and the respiration was maintained by hyperventilation. It took 1 ~ 2 hours to rewarm the dogs until 28°C ~ 30°C, but defibrillation was never attempted until rectal temperature rose above 28°C. At this level of rectal temperature, counter shock was applied immediately after noradrenalin injection to the left ventricle. After that 5 ~ 15 cc of 2% CaCl₂ solution was injected intravenously to promote in the heart action. This method was very effective and almost all the cases were successful to restoring the nodal rhythm by only one or two single electro-shock. Then the chest was closed.
ii) We have several successful cases of both cardiotomy under direct vision and aortic arch homograft transplanlation under deep hypothermia, as was preliminarily reported by us.
iii) This report may give a wishful thinking about the resuscitation of human beings frozen to death.
(author's abstract)

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