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A method of heparinless, oxygenatorless, left heart bypass perfusion rewarming following surface hypothermia, with the use of a closed circuit with 130 ml. prime volume including heat exchanger, has been devised. The use of polyurethane-polyvinyl-graphite (PPG)-coated tubing has previously been reported. In this text, the use of an athrombogenic coating with cetyl-pyridinium chloride (CPC) as a regional heparin carrier was studied in dogs, comparing groups with PPG tubing and total systemic heparinization or plain polyvinyl tubing without systemic heparinization. Heparin compounded in the CPC coating eluted into the blood and caused mild transient whole-body heparinization during rewarming from 20 degrees to 25 degrees C., as evidenced by prolongation of the thrombin time. Alterations of hematologic parameters in all three groups were similar to those during surface rewarming except for those affected by heparinization. The left heart bypass method was found useful for hypothermic open-heart surgery when utilized with an athrombogenic surface coating or total body heparinization. It was concluded that the CPC coating is superior to the PPG coating since no cracking surface develops, it is translucent, and it provides a more effective athrombogenic surface.

To facilitate perfusion rewarming without the use of total body heparinization or an oxygenator following open-heart correction with surface hypothermia, we devised a pump circuit. The circuit, totally primed with 100 c.c. of saline, consists of polyurethane-polyvinyl-graphite (PPG) coated Tygon tubes (with one end tapered by heat treatment) and a copper-coil heat exchanger. A roller pump was used to achieve partial bypass from the left atrium to the ascending aorta with flow rates up to 70 c.c. per kilogram per minute. Experiments in dogs resulted in rapid rewarming, immediate return of cardiac function, and hematologic alterations similar to those noted during surface rewarming. The safety of the method was also demonstrated. Prothrombin time, partial thromboplastin time, and platelet values returned to control levels upon rewarming, and no thromboemboli or bleeding problems were noted. Six clinical experiences were accumulated. Details of the method, hematologic and blood chemical analyses in dogs, and the first clinical trial in a 3-month-old infant with transposition of the great vessels are reported.

Based on instrumental conditioned avoidance responses, the effect of difficulty of visual task and that of the number of preoperative post-criterional trials as overtraining were studied on the degree of visual impairment following bilateral ablation of the neocortex in gyrus temporalis inferior and polus temporalis. Eleven dogs were trained on either a more difficult problem a or an easier problem β, concerning discrimination of flickering rate. Each dog was then given either 900 or 460 post-criterional trials as overtraining. Following bilateral inferotemporal ablation, the dogs were retrained to the criterional level on the same problem as before operation. The data obtained indicate that (1) the more difficult the discrimination tasks, the greater the relearning scores, (2) the greater the number of trials as overtraining, the less the relearning scores and (3) the visual performance of the preoperatively learned discrimination was not affected in the control dogs which received bilateral ablation of gyrus ectosylvius or unilateral removal of the inferotemporal lobe. It is obvious from the above findings that both factors, overtraining and difficulty of tasks, are important in evaluating the effect of ablation of the inferotemporal lobe on the visual deficit. We wish to thank Prof. K. Motokawa for his invaluable discussion and suggestion throughout the course of the experiment and the preparation of the manuscript.

A dye-dilution study was carried out by injecting dye into the right and left atria through the dwelling polyvinyl tubings after open heart surgery and especially after the radical operation for tetralogy of Fallot. In every instance time factors in both left and right atrial dye-dilution curves showed marked increase immediately after operation or on the first postoperative day. Subsequently they decreased first rapidly and later gradually. The changes were more marked in the right atrial dye-dilution curves than in the left ones. Increase in all the time factors was apparently larger in tetralogy of Fallot than in ventricular or atrial septal defect. Particularly, disappearance time (tpd), time constant of exponential decay of the curve (ts) and mean transit time (_??_R) in the right atrial dye-dilution curves were markedly prolonged and furthermore a remarkable increase occurred in the right heart-pulmonary circulation time (_??_R-_??_L) and right heart-pulmonary blood volume (VRP). Cardiac output after the operation was lower in Fallot's tetralogy than in other heart diseases. In two-thirds of the cases of Fallot's tetralogy, however, postoperative cardiac output exceeded 3.0l/min/m2 and attained a normal range. The characteristic findings of the dye-dilution curves in tetralogy of Fallot were most closely related to the extent of residual pulmonary stenosis. This was indicated by a large systolic pressure gradient between the right ventricle and the pulmonary artery at the end of open heart correction.

Various operative techniques have been developed for correction of partial anomalous pulmonary venous return into the right superior vena cava. Among these, external partitioning is our procedure of choice. Up to December 1966, 137 cases of ostium secundum atrial septal defect were operated upon at the Second Department of Surgery, Tohoku University Hospital, and 4 of these 137 were associated with partial anomalous pulmonary venous return. In 3 of the 4, an abnormal right pulmonary vein drained into the right superior vena cava and all but one were operated upon by utilizing external partitioning. Although most of this type of anomaly are associated with high secundum atrial septal defect, the atrial septum may be intact in rare instances. We have encountered a case in which the atrial septum was intact, and complete correc-tion was successfully carried out by external partitioning and creation of atrial septal defect.

A fivemonth-old female with tricuspid atresia was successfully treated by Rashkind and Miller's balloon septostomy after banding of the pulmonary artery.

In order to correct severe metabolic acidosis, peritoneal dialysis was attempted in 2 cases of cyanotic babies. The condition was markedly improved in both of them by peritoneal dialysis with buffer solution, though they died finally of cardiac failure. It could be concluded from our experiences that peritoneal dialysis was effective in the correction of severe metabolic acidosis in newborn babies with marked cyanosis.

The behavior of the recruiting response during hypothermia was investigated, and the following results were obtained. 1. Recruiting response was recorded from the frontal area by stimulation of the nucleus ventralis anterior or the anterior pole of the reticular nucleus in rat. The brain temperature was lowered gradually till 18°C. and then raised slowly to normal temperature. All the changes to be stated below were reversible. 2. Spontaneous background EEG was decreased in amplitude, and slowed in rate as the brain temperature was lowered, and flattened at 18°C. Dominant spindle bursts of high amplitude and low frequency appeared between 29°C.-25°C. 3. The optimal frequency of stimulation was determined for each temperature. There was linear relationship between the logarithm of the optimal frequency and the brain temperature in a range from 36°C. to 18°C. 4. A value of temperature characteristic (μ) 7500 cal. was obtained from the law of Arrhenius applied to the data. 5. Large and small responses appeared alternately when the frequency of stimulation was somewhat higher than the optimal one, and only small ones appeared when the frequency was much higher. The mechanism of alternation was discussed. I wish to thank Prof. K. Motokawa for his invaluable discussion and suggestion throughout the course of the experiment and the preparation of the manuscript.

The corrected transposition of the great arteries with pulmonary stenosis was completely repaired in a 5 1/2-year-old boy. To relieve the stenosis of the pulmonary valve ring which was located posterior to the aorta and heart chambers, the valve-bearing tube-graft made of the pericardium was implanted as a bypass graft between the right-sided ventricle and the pulmonary trunk. Postoperative hemodynamics and cineangiographic findings were satisfactory. The use of the viable autologous tissue such as the pericardium is definitely more advantageous than that of the other homografts, since the former requires neither sterilization nor long-term preservation.

The effect of halothane-100% oxygen anesthesia on oxygen consumption was studied in 10 dogs subjected to surface-induced deep hypothermia with 30 minutes of circulatory arrest. The results were compared with previous oxygen consumption data under ether-100% oxygen anesthesia. Low cardiac output, especially during the rewarming period, low Pa02, and a large arteriovenous oxygen difference during rewarming were significantly different in the halothane group, despite identical oxygen consumption in both groups. These differences could not elucidate the exact cause of postoperative motor disturbances associated with 30 minutes of circulatory arrest in the halothane group. The possibility that there was higher oxygen consumption under halothane anesthesia is discussed.

A total of 216 cases underwent open-cardiac operations up to December 1963. The hypothermia was applied for 121 instances, while 95 individuals were operated upon by means of heart-lung machine. On the basis of the above clinical experiences, advantages and disadvantages of hypothermia and heart-lung machine have been described and our current point of view about operative indications has been presented. Furthermore, detailed account has been made on history and development of hypothermia and heart-lung machine for open-heart surgery in our department. Some improved points which may contribute to widening indications of hypothermia, in particular, have been discussed.

In normal postnatal development, physiological regression of the muscular coat is accomplished to the major part in the first 6 months. Thereafter, the medial thickness still continues slowly to diminish and practically attains the level of normal adults in 4 years. With the present histometrical method, the medial thickness at an arterial radius of 100 μ was estimated at 9.8 μ immediately after birth, was reduced to 6.8 μ in 6 months, to 6.5 μ in a year and to 5.9 μ in 4 years, while the value for normal adults was 5.4 μ. In patients with ventricular septal defect (VSD), physiological medial regression does not take place, and the muscular coat retains or increases its neonatal thickness. The medial thickness is correlated with pulmonary blood pressure level and can be expressed by an exponential function of blood pressure. Pulmonary hypertension in VSD is correlated with the dimension of septal defect. Medial hypertorphy in VSD is probably associated with increased vascular resistance of pulmonary circulation.

This is a follow-up study of the second consecutive series of 71 infants during the year of 1965 through 1970. Over-all mortality rate was 15.5 per cent. In the last two years, the result has improved markedly as exemplified by only one death occuring in 33 patients (3 per cent) operated. The striking decrease in the mortality rate during this period was mainly due to the intensive care of postoperative respiratory dysfunction and prevention of low cardiac output especially in infants under one year of age. Permanent heart block and complications of the central nervous system have not been observed in this series. In conclusion, patients with VSD and pulmonary hypertension should be advised to undergo radical operation even in early stage of infancy.