Use of athrombogenic tubing for perfusion rewarming following surface-induced deep hypothermia.

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.

Internodal conduction. Immediate and long-term effects of transverse circular incision of right atrium including atrial septum.

Immediate and long-term effects of a transverse circular incision of the entire right atrium, including the atrial septum, on internodal conduction were studied in 7 dogs. Electrocardiograms were followed up to 35 weeks, and the atrial epicardial excitation sequence was evaluated in all 7 dogs. The findings were compared with data from 3 normal dogs and 3 other dogs which underwent total atrial transverse incisions. All dogs with total atrial separation developed complete atrioventricular (A-V) block immediately after the operation and died within 3 days. All dogs with right atrial interruption exhibited persistent sinus rhythm with slight extension of P-R intervals and a normal QRS immediately after the operation. The mean P-R interval reached its maximum at the fourth day (50 per cent increase), remained prolonged through the first week, but returned to near control valves after 12 weeks. Three days later developed transient arrhythmia; sinus arrhythmia; sinus arrhythmia in 2 dogs and second-degree block in 1 appeared between the tenth and fourteenth postoperative days. Postoperative P vectors migrated toward the left. Atrial excitation sequence studies demonstrated prolongation of atrial epicardial conduction intervals (2.3 times) between the sinus node and distal right atrial wall. The presence of an interatrial conduction mechanism (whether by specific pathways or not), through which sinus node excitation was transmitted to the A-V node was demonstrated.

Heparinless, oxygenatorless perfusion rewarming following surface-induced deep hypothermia for open-heart surgery.

To facilitate perfusion rewarming without the use of total body heparinization or an oxygenator following open-heart correction with surface hypothermia, we divised 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.

Current practice of coronary artery bypass surgery. Results of a national survey.

A survey of techniques used in coronary artery bypass graft (CABG) surgery by 400 experienced cardiac surgeons is presented. These surgeons performed 41,000 CABG operations in 1975. A seventy-question survey form was answered by each surgeon on their techniques for cardiopulmonary bypass and myocardial preservation, choice of bypass conduit, and grafting techniques. We found that extracorporeal circulation is almost always used in CABG surgery. A wide divergence of practice exists in the use of left ventricular vents and in methods of myocardial protection during coronary artery grafting. A spectrum of graft suture techniques is employed, the most common being a running double-ended suture anastomosis with the end of the vein initially fixed only at its heel to the coronary artery. Only 23 surgeons (6 per cent) prefer the internal mammary artery (IMA) rather than saphenous vein, when feasible, as the bypass conduit of choice for CABG surgery.

Prefabricated Dacron baffle for use in correction of transposition of the great arteries.

Interatrial venous transposition for correction of transposition of the great arteries (TGA) is facilitated by using a premolded Dacron baffle. Fine-mesh Dacron is easily fashioned to the desired shape in a metallic brass mold at 200 degrees C. The resultant baffle material can be autoclaved without losing its shape or altering the fabric characteristics of flexibility and porosity. This premolded baffle has been used in our last 7 patients with TGA over the past two years without complication, and the use of Dacron in 13 survivors over the past seven years has shown no pulmonary or venous obstructions related to the material.

Electrocardiographic changes during surface-induced deep hypothermia. The influence of ether, halothane, carbon dioxide, and perfusion rewarming.

The influence of halothane, ether, carbon dioxide, and perfusion rewarming on the electrocardiogram was studied in 37 dogs subjected to surface-induced deep hypothermia. Significant anesthetic-related differences in P-R, QRS, Q-T and R-R intervals during cooling were not apparent; however, reduced arterial pressure, ventricular fibrillation, and a greater tendency for bradycardia requiring supportive measures were noted at low temperatures with halothane anesthesia. The use of 95% O2/5% CO2 significantly reduced the QTc at low temperatures; Other phenomena, including the occurrence and significance of J waves, are discussed. The relationship of the electrocardiogram to clinical and pathological results was evaluated and indicates that (1) properly managed resuscitation (manual massage and defibrillation) is not a serious hazard, (2) ether in 100% oxygen is the agent of choice for surface-induced deep hypothermia with prolonged circulatory arrest, and (3) halothane may be used in a procedure combining surface cooling and perfusion rewarming if given in a mixture of oxygen and carbon dioxide.

The use of Forane anesthesia for surface-induced deep hypothermia.

The effects of Forane anesthesia for deep surface hypothermia with 30 minutes of total circulatory occlusion were evaluated. With 100% O2 6 of 7 dogs developed motor disorders postoperatively, while 3 of 5 with 98% O2/2% CO2 and none with 95% O2/5% CO2 developed motor disorders. Cooling was uneventful except for 1 episode of ventricular fibrillation in the 5% CO2 group at 23 degrees C. Resuscitation was easy, but the early rewarming period was characterized by repeated episodes of ventricular fibrillation and delayed recovery of cardiac function, especially in the 100% O2 group. Blood lactate levels remained low during cooling and gradually increased during rewarming in all groups, with the highest levels in the 100% O2 group and the lowest in the 5% CO2 group. It is concluded that Forane can be used for surface hypothermia with 30 minutes' circulatory occlusion when administered in 95% O2/5% CO2. A Comparison of these results with previously reported series indicates that Forane is inferior to ether but may be superior to halothane for surface hypothermia.

Gel foam embolization of a functioning pheochromocytoma.

For the first time, to our knowledge, a patient with a functioning pheochromocytoma was subjected to gel foam embolization for physiologic destruction of the tumor. The operation, 24 hours later, provided an uneventful anatomic removal of the infarcted tumor. Observation was considered as a possible alternative to surgical excision. Experience gained may allow testing of the validity of a nonoperative approach in selected cases.

Outcome analysis of surgical therapy for patients with angina pectoris.

Surgical therapy for coronary artery disease results in improved survival rates for selected groups of patients, particularly those with left ventricular dysfunction and/or severe coronary artery disease as evidenced by involvement of two or more vessels. Successful augmentation of coronary blood flow as shown by patient saphenous vein graft is associated with improved exercise tolerance when compared with patients in whom the grafts are occluded. Patients with impaired left centricular function as a result of their coronary artery disease appear to experience an improvement in this function with the augmentation of coronary blood flow by patent saphenous vein bypass grafts. In patients with occluded grafts and impaired left ventricular function, the left ventricular function is unchanged. Ptients with normal left ventricular function who sustain occlusion of their grafts will probably experience a reduction in their systolic ejection fraction.