J. Francis Dammann

THE COST OF RESPIRATORY EFFORT IN POSTOPERATIVE CARDIAC PATIENTS.

The Engstrom volume-controlled respirator is used routinely in patients after open-heart surgery as a short-term prophylaxis to avoid hypoxia, respiratory acidosis, and excessive fatigue. The respirator should be discontinued when pulmonary function is improved sufficiently to the point where the work of breathing is no longer excessive. With a spirometer designed for the Engstrom respirator, we have determined oxygen consumption and cardiac output in the spontaneously breathing patient and while assisted by the respirator. The difference between the two measurements reflects the oxygen cost of breathing and thus the work that can be spared the heart, by proper mechanical ventilation, during the period of acute postoperative stress. We havedemonstrated that the work of breathing, even in good risk patients, is appreciably increased postoperatively, that it is maximal immediately and then falls. These data lend objective support for the prophylactic use of respiratory assistance in patients after cardiac surgery. A similar application to other debilitated surgical and medical patients should be investigated.

COR TRIATRIATUM AS A PROBLEM OF ADULT HEART DISEASE.

The occurrence of severe pulmonary venous obstruction due to the congenital anomaly known as cor triatriatum in a 19-year-old furniture mover is described. Relentless and massive hemoptysis led to pulmonary edema, and an attempt at surgical correction under unfavorable conditions was not successful.Seven other cases of cor triatriatum in adults are reviewed. The hemodynamic abnormalities closely resemble mitral stenosis, except that pressures in the true left atrium were normal in the presence of elevated pulmonary capillary pressures. The availability of flow across the obstructing membrane during systole as well as diastole is probably the major element in the surprisingly good tolerance of severe degrees of anatomic obstruction for long periods of time. Slow increase in the degree of obstruction could also be a factor.The clinical picture in these patients very closely resembles mitral stenosis. Hemoptysis appeared to be more frequent in cor triatriatum. Features suggestive of the correct diagnosis would include the absence of an opening snap, the absence of a typical murmur of mitral stenosis, regular rhythm, and lesser evidence of left atrial enlargement in the presence of obvious pulmonary hypertension. Five of these patients have undergone successful correction of their disease by operation.Representative films from the first knownangiograms in this condition in an adult are reproduced and discussed.

Simultaneous determinations of cardiac output by thermal dilution, fiberoptic and dye-dilution methods.

Abstract A total of 225 simultaneous dye-dilution and thermal dilution and 176 dye-dilution and fiberoptic dilution cardiac output curves were obtained from 14 mongrel dogs at basal levels and after the injection of isoproterenol or angiotensin. The analog signal was digitized with an Ambilog 200 computer, and the data were analyzed with a Burroughs B5500 digital computer. Experience gained with this analysis has led to an on-line program for cardiac output determinations with digital readout using the Ambilog 200. Results indicate (1) that the fiberoptic technique is sufficiently accurate and desirable for acute studies but until the long-term risk of clot formation on the catheter tip is thoroughly evaluated, the use of this technique in chronic studies of patients under intensive care is questionable and (2) that thermal dilution cardiac output determinations correlate well with those of the other techniques studied and that the thermal method is uniquely attractive for use in the long-term monitoring of cardiac output necessary to the management of the critically ill patient.

Successful Treatment of Pseudomonas aeruginosa Septicemia Following Total Aortic Valve Replacement

The successful treatment of Pseudomonas aeruginosa septicemia in a 24-year-old patient by antibiotic therapy, reoperation, and insertion of a new aortic valve prosthesis three weeks after total aortic valve replacement is reported. This patient also presented other interesting features. She had a Hufnagel valve inserted for severe aortic insufficiency in December, 1955; a Teflon subcoronary, tricuspid, cage prosthesis replaced her destroyed aortic valve in April, 1960; and two Starr-Edwards aortic valve prostheses were inserted during September and October, 1963. The patient is clinically well 12 months after her last operation.

Surgical Relief of Aortic Insufficiency by Direct Operation on the Aortic Valve

The natural history of patients with aortic insufficiency and the previous experimental and clinical operations devised for its relief are reviewed. Methods that have been used at the University of Virginia Hospital for treatment of aortic insufficiency are reported. These procedures include the release of the fixed valve leaflet and removal of calcium from it, aortic valve leaflet extension with suture of a small piece of compressed polyvinyl sponge or Teflon fabric to the edge of one of the leaflets, excision and replacement of a portion of the valve with a synthetic leaflet, and complete subcoronary replacement of the valve with a prosthesis. To relieve isolated rheumatic aortic insufficiency, an annulus has been constricted or a bicuspid aortic valve has been created. Insufficiency resulting from perforation of one or more valve leaflets by subacute bacterial endocarditis has been treated by closure of the perforations. Nineteen patients underwent 21 operations for the correction of aortic insufficiency. All had been in, or were in, heart failure, and several had significant coronary artery disease or multivalvular disease. Eleven of the 19 patients are well or markedly improved. Eight died during or after the operative procedure. It is concluded that a direct attack upon the insufficient aortic valve is the procedure of choice at the present time.

Reflections on the Evolution of Cardiopulmonary Bypass

The concept of cardiopulmonary bypass is more than a century old. Although the first clinical application occurred in 1953, there were great deficits in knowledge and materials that had to be overcome before we could achieve the outcomes of cardiac surgery that we have today.

Experimental pulmonary arterial hypertension

Abstract A brief review of previously described methods of producing experimental pulmonary hypertension has been presented. Three technics that we have used in attempting to induce pulmonary arterial disease are described. These technics were: (1) creation of interventricular septal defects in fetal puppies, (2) the administration of serotonin to newborn rats, and (3) systemic-lobar-pulmonary arterial anastomoses in dogs. The systemic-lobar-pulmonary arterial anastomoses proved to be the most satisfactory technic and produced pulmonary arterial lesions similar to those seen in man in the majority of survivors in this group of animals. The reversibility of these changes was determined by histologic study of the lung following anastomotic restoration of the pulmonary artery to the involved lobe. Those animals showing both medial hypertrophy and intimal hyperplasia demonstrated a significant increase in the cross-sectional area of the pulmonary arteries following the reversal operation. Medial hypertrophy alone or with minimal intimal sclerosis appeared to regress at a slower rate but in no instance did a progression of the observed changes occur.

Evaluation of myocardial contractility in man

Abstract In 53 patients studied at cardiac catheterization, the relationship between the maximal rate of rise of the left ventricular pressure and the integrated isovolumetric stress was observed to be an excellent index of contractility. A clearer separation of patients with evidence of myocardial disease was possible with this index than with other parameters assessed. The ejected fraction (fiber-shortening) was noticed to be an inverse function of the peak systolic tension (afterload) as expected from extensive experimental work. The highest reciprocity was observed in patients with myocardial disease, indicating the probable deleterious effect of an increasing peripheral resistance in this type of patient. End-diastolic stress was found to be significantly higher in patients with evidence of myocardial damage, due to a relatively thinner myocardial wall in this group.

INDICATIONS FOR TRACHEOSTOMY.

Respiratory insufficiency is a frequent complication of major abdominal and thoracic surgery, although it is difficult to recognize. Its presence can only be established by an analysis of the arterial oxygen and carbon dioxide tensions. After open‐heart surgery, the patients demands are usually increased significantly. This occurs at a time when pulmonary function is usually impaired and the energy necessary to breathe is significantly increased. Our studies in postoperative patients after open‐heart surgery indicate that the work of breathing in most patients is increased many fold and in some patients may be sufficient to produce acute congestive failure. Therefore, we advocate the use of controlled ventilation leaving an oral endotracheal tube in place, to treat respiratory insufficiency or excessive and compromising work of breathing. Occasionally, such therapy must be instituted prior to definitive surgery in order to rest the patient and give the patient enough reserve to withstand a major surgical procedure. If respiratory insufficiency has not been abolished within 72 hours after surgery, we advocate that a tracheostomy be performed and that respirator treatment be continued until respiratory insufficiency is eliminated and the work of breathing no longer places an intolerable work load on the cardiovascular system.

Mitral stenosis associated with partial anomalous pulmonary venous return (with intact atrial septum). An unsolved question.

Abstract In a patient with severe mitral stenosis, intact atrial septum and venous drainage of the left lung into the left innominate vein, increased values for pulmonary capillary wedge pressure and flow in the abnormally draining left lung equaled those found in the normally draining right lung. The possible mechanisms for this discrepancy are discussed. Total surgical correction of these lesions was successful.