抄録
Between October, 1964, and December, 1966, 32 patients with various congenital diseases underwent open heart surgery under normothermic condition with the aid of extracorporeal circulation, using Kay-Cross rotating disc oxygenator and rollar pomp. The cases were consisted of atrial septal defect 17, ventricular septal defect 8, atrial and ventricular septal defect 2, tetralogy of Fallot 3, pentalogy of Fallot 1, and aortic insufficiency with ventricular septal defect 1. The rate of perfusion was 2.2 1/min.
There was one operative death in 32 cases, which was a case of tetralogy of Fallot died suddenly 15 days after the operation. The cause of death was considered to be thrombosis of pulmonary artery.
The time of perfusion ranged from 13 minutes to 3 hours 40 minutes but no case showed cerebral or renalc omplications following the perfusion. Artificial aortic valve of Kay-Shiley type was replaced to one case of aortic insufficiency with ventricular septal defect, in which the defect was closed at the same time. The postoperative course was uneventful.
Because of the difficulty in obtaining the large amount of fresh blood, we have adopted the deep hypothermia for means of open heart surgery, and 12 cases were operated since June, 1966, to December, 1966. The cases were consisted of 9 cases of atrial septal defect and 3 cases of ventricular septal defect. There was one operative death in this group. The method of deep hypothermia was similar to that of Okamura's method except for minor difference in premedication. The lowest rectal temperature ranged from 24°C to 26°C. The time of occlusion ranged from 11 to 20 minutes, averaging 16 minutes. The time of cardiac massage averaged about 8 minutes. The case of operative death was a 19 years old with ventricular septal defect, who was failed to be resuscitated following the release of occlusion. The cause of death remained unknown. The rest of the cases were uneventful postoperatively.
The comparative study was made between the extracorporeal circulation and deep hypothermia as to time of operation, and anesthesia, the amount of bleeding during and post-operative period, time of perfusion and occlusion.
At first, time of operation was 1 hour shorter in hypothermia, than in extracorporeal circulation, averaging 3 hours 1 minute and 4 hours 8 minutes respectively. The time of anesthesia was on the contrary, hypothermia took about 2 times that of extracorporeal circulation, namely 11 hours 46 minutes and 6 hours 4 minutes respectively. This was considered to be the shortage of hypothermia. The amount of bleeding during the operation was larger in hypothermia than in extracorporeal circulation. This was against our expectation, and probably due to the fact that intracardiac blood aspirated at the time of cardiotomy was counted as bleeding. However, the actual amount of blood used for operation was much less in hypothermic group than in extracorporeal circulation, averaging about 1100c. c. in former and 6000 to 8000 c. c. in the latter including the heparinized blood used in the pump-oxygenator. The amount of bleeding postoperatively was about same in both groups averaging 13 to 14 c. c./kg. The time of occlusion averaged 16.4 minutes, and time of perfusion was 24.8 minutes in average.
As a conclusion, the advantages of hypothermia are as follows: the necessary blood was small in amount, no expensive apparatus is necessary, operation is simple because cannulation for venous drainage or arterial perfusion are not necessary, and slow beating heart under hypotension and dry quiet intracardiac field enable operation easy and comfortable. The numbers of surgeons and nurses are also economized.
The shortcomings of hypothemia are as follows: time of anesthesia takes long time compared to the extracorporeal circulation, the occlusion time is limitted depending on the temperature, namely 20 minutes at 27°C, 40 minutes at 24°C, and 1 hour at 20°C. The longer
