Robert H. Goetz

Some Aspects of the Cardiovascular System in the Giraffe

* Now at the Department of Surgery, Albert Einstein College of Medicine, New York 61, N. Y. † From the Departments of Surgical Research and Anatomy, University of Cape Town, South Africa. ‡ Now at the Department of Physiology, University of Brisbane, Australia. § The 16-mm. color film, The Giraffe and its Circulation, has been included in the film library of the American Heart Association and is available on loan. INTRODUCTION

Circulation of the Giraffe

Observations on the circulatory functions of 4 giraffes are recorded. Both the right and the left heart were catheterized under local anesthesia with a miniature manometer. Cardiac output was determined by employing both indicator dilution method and the Fick principle. Other parameters, such as the circulation time, blood volume, velocity, right and left ventricular pressure ascent as well as the changes in blood pressure occurring with changes in the Posture of the head were recorded. The difficulties of the experiments created certain limitations in their interpretation. The arterial blood pressure is high by human standards and adequate to maintain cerebral perfusion without other means of support. The arterial pressure pulse contour suggests a relatively lax vascular bed with considerable reserve distensibility. Values for cardiac output and blood volume were roughly comparable to those recorded in domestic cattle of the same approximate weight.

CARDIORESPIRATORY DYNAMICS IN THE OX AND GIRAFFE, WITH COMPARATIVE OBSERVATIONS ON MAN AND OTHER MAMMALS*

Comparative mammalian physiology not only is important as an intellectual discipline in its own right, but it also provides a perspective which can contribute to the understanding of physiological processes in a given species. As an example, those functions of the organism which appear related to body weight or to body surface area can be studied over a wide range of animal size, providing more extensive data for the precise analysis of relationships than could be obtained from investigations confined to members of a single species. In recent years a strong increase in interest in physiological studies on large mammals has been evident.’-6 The discussion which follows is based on circulatory and respiratory observations obtained on four giraffe in South Africa a t an elevation of 2375 feet and on 26 domestic cows studied a t three centers in the United States a t 400 feet or less above sea level, as well as on data reported from other investigative groups. I n certain areas comparison of the findings in giraffe and cattle is made with those in man, dog, and other mammals. In the choice of material considerable selection has been exercised and preference given to findings providing new viewpoints for discussion or permitting direct comparison between species. The species of primary interest in this presentation-domestic cattle (cows) and giraffe-are large ruminants of approximately comparable body weight, namely, 650 to 1,450 pounds (295 to 659 kg.). Both of these animal groups belong to the same suborder (Pecora) but to different families, the Bovidae and Giraffidae, respectively. Although giraffe sometimes attain a height of 16 feet and are said to reach 20 feet rarely, the tallest animal in the present group was approximately 12 feet in height. FIGURE 1 shows this animal and a domestic cow of comparable weight in proper scale relationship. I t can be seen that although there is a striking difference in height (11’7.5” versus 4’6”) the position of the heart is roughly halfway between hoof and head in both animals. The heights of the other three giraffe, as measured

Unidirectional intraaortic balloon pumping in cardiogenic shock and intractable left ventricular failure

Abstract Intraaortic balloon pumping effectively interrupts the vicious circle of cardiogenic shock by increasing coronary blood flow and decreasing left ventricular work and myocardial oxygen requirements. Clinical experience with intraaortic balloon pumping in 4 patients with intractable cardiogenic shock and in 1 patient with intractable left ventricular failure from myocardial infarction is reported. Four of the 5 comatose anuric patients were returned to the coronary care unit alert and in a hemodynamically stable state after an average of 12 hours of pumping. Since the fate of the patient in cardiogenic shock from myocardial infarction depends upon the balance between myocardial oxygen supply and demand, it is believed that the primary aim of intraaortic balloon pumping should be directed toward increasing coronary blood flow. A dual-chambered balloon mounted on a single lumen catheter is described which, in contrast to the conventional single-chambered balloon, pumps the blood unidirectionally toward the root of the aorta and markedly increases coronary and cerebral blood flow. A safety chamber is interposed between the intraaortic balloon and driving unit, which permits use of carbon dioxide, instead of helium, and a vacuum to assist deflation of the balloon, to assure maximal decrease in left ventricular afterload by facilitating ventricular ejection. Intraaortic balloon pumping is shown to be an innocuous procedure which is easily instituted at the bedside. A plea is made for earlier referral of patients. Although intraaortic balloon pumping by itself may not salvage these patients with shock, it effectively prepares them for more definitive surgical therapy, such as coronary artery bypass or infarctectomy. One such patient was successfully supported and referred for infarctectomy.

Clinical Experience with the Unidirectional Dual-Chambered Intra-aortic Balloon Assist

A dual-chambered balloon mounted on a single-lumen catheter is described, consisting of a distal spherical occluding balloon and a narrower cylindrical pumping balloon. This balloon, in contrast to the conventional single-chambered balloon, pumps blood unidirectionally toward the aortic root in diastole, effecting a 66 to 100% greater increase in coronary blood flow. The implications of this concept are discussed, with particular reference to cardiogenic shock. Significant improvement in all measurable indices of ventricular work are demonstrated both clinically and experimentally. Results in patients are summarized.

The Differentiation of the Tetralogy of Fallot From Severe Pulmonary Stenosis With Intact Ventricular Septum and Right-To-Left Interatrial Shunt

Pulmonary stenosis was one of the first congenital anomalies described (1), and this malformation has continued to receive particular attention throughout the years (2). However, it is only since the development of cardiac catheterlzation, angiocardiography, and cardiac surgery that a better understanding of the syndromes associated with pulmonary stenosis have emerged. Fundamentally, the syndromes associated with pulmonary stenosis are dependent on the state of the ventricular septum and the aortic root (3). When there is a defect in the ventricular septum and the aorta arises partly from the right ventricle the entity is that of the tetralogy of Fallot. On the other hand, when the septum is intact and the aortic root normal, the condition is known as pulmonary stenosis with intact ventricular septum. Abrahams and Wood (3) in their excellent study of pulmonary stenosis with intact ventricular septum have emphasized the importance of the severity of the stenosis in determining the clinical picture and prognosis. When the stenosis is mild or moderate as is commonly found, there is little or no disability and no cyanosis. An associated foramen ovale will remain functionless and even if the auricular septum is defective the left-to-right shunt will not be reversed. When the stenosis is severe the disability is much greater and central cyanosis may develop. The latter is dependent on the condition of the atrial septum and the relative pressures in both atria. If this septum is intact and the foramen ovale

THE EFFECT OF 2-AMINO-2-HYDROXYMETHYL-1, 3-PROPANEDIOL ON THE ANURIA OF HYPOVOLEMIC STATES*

The anuria accompanying hypovolemic states in general and hemorrhagic shock in particular has been investigated by numerous authors. I t is generally held that anuria is the result of a disproportionate diminution of the renal blood flow and a cessation of glomerular filtration with mean blood pressures below 60 mm. Hg.ln2J Also it has been observed that the lowest renal blood flows are associated with the lowest pH, metabolic acidosis being the constant byproduct of poor perfusion? With the availability for physiological use of an amine buffer 2-amino2 hydroxymethyl 1,3 propanediol or tris(hydroxymethy1)aminomethane (THAM),3-4 which is a reversible hydrogen-ion acceptor forming compounds with carbonic and other acids, the problem of anuria in hypovolemia seems well worth investigating anew.

The Effect of Intra-arterial Injections of Hydergine and Dihydroergocornine on the Peripheral Circulation in Man

If given by the intra-arterial route, the immediate effect of the hydrogenated alkaloids of ergot is unpredictable. Vasodilation is obtained in some patients only. However, it was found that in those cases who do not react, the vessels respond more easily to the release of sympathetic tone, proving that, nevertheless, the drug has had an (potential) effect, probably on the neurovascular apparatus. This effect could be demonstrated for many hours and is, therefore, of considerable therapeutic interest. Even with the higher local concentrations possible by the intra-arterial route, the hydrogenated alkaloids of ergot still did not exhibit any adrenolytic action on the peripheral blood vessels in man.

Book Reviews: Die Behandlung peripherer Durchblutungsstörungen mit der Sauerstoffinsufflation. Theoretische Grundlagen und praktische Durchführung. By F. Scherer. Dm. 12.80. Springer-Verlag, Berlin, 1957

The Pathology and Surgery of the Veins of the Lower Limb. By Harry Dodd and Frank B. Cockett.

Fusiform Dilatation and Thrombosis of Arteries Following the Application of Methyl 2-Cyanoacrylate (Eastman 910 Monomer)*

12.50. Pp. 462. The Williams & Wilkins Company, Baltimore, 1956. This is one of the most complete and detailed books that has appeared on varicose veins to date. It is profusely illustrated with diagrams, photographs and venograms. The surgical aspects of varicose veins and ulcers are described in the greatest detail with a thorough discussion of the theory behind every operative approach. It is surprising to note that no mention is made of the relation-