The changes in the circulation of patients with heart disease and with emphysema have been studied many times when the patient was at bed rest. There is little information as to the changes produced when the circulatory requirements exceed the resting level. This information is probably of more importance than resting measurements as the greater part of existence is one of activity. Chronic emphysema produces changes in the heart in many patients. Congestive failure leads to water logging of the lungs. It was felt that simultaneous measurements of the cardiac output and pulmonary arterial pressure in normal persons and in those with emphysema and heart failure would aid in the understanding of the alterations of cardiac and pulmonary functions occurring in these diseases. The purpose of this paper is to present these data and to discuss their significance. METHODSIntracardiac catheterization was performed in the usual manner (1). The catheter was passed for a distance of 1 to 2 inches into the right or left main branch of the pulmonary artery. Pulmonary arterial pressures were recorded by a Hamilton manometer and mean pressures determined by planimetric integration, covering a period of at least 2 respiratory cycles. Atrial pressures were determined either in the same fashion, using a sufficiently sensitive Hamilton manometer, or by the use of a saline manometer. Systemic arterial pressures were measured in most cases from the brachial artery, using a Hamilton manometer. The point of zero reference was 5 cm. beneath the fourth left costochondral junction. Mixed venous blood samples were taken from the pulmonary artery in nearly all cases; otherwise, they were from the ventricle or atrium. Arterial samples were taken through an in-lying needle, usually in the brachial artery but occasionally in the radial or femoral arteries.
The development of a technique of intravenous catheterization and its application to the sampling of renal venous blood (1) have made possible the study of the metabolic activity of the kidney in the unanesthetized human subject. We have used this method of investigation in conjunction with the usual clearance procedures in an attempt to determine the oxygen consumption of the normal kidney and its variation in disease. METHODSAll subjects were studied at rest and in the postabsorptive state. Inulin and sodium para-aminohippurate (PAH) clearances were performed as described by Goldring and Chasis (2), urine being collected by bladder catheterization. Following the injection of the priming doses and the starting of the sustaining infusion of inulin and PAH, a modified ureteral catheter was introduced into an antecubital vein of the opposite arm, and passed under fluoroscopic visualization through the right atrium and inferior vena cava and into the right renal vein. The rotation of the curved tip of the catheter posteriorly, and other details of technique have been described by Bradley (3), and by Warren, Brannon, and Merrill (1). Urine was collected at accurately ,timed intervals of 10-30 minutes, and at approximately the midpoint of each urine collection period blood samples were obtained from a femoral artery and the right renal vein. There was usually an interval of one or two minutes between the withdrawal of these samples. A portion of each sample was collected anaerobically, either under mineral oil, or in an oiled heparinized or citrated syringe, and the oxygen content determined by the method of Van Slyke and Neill (4). The remainder of the samples were oxalated and centrifuged as soon as possible for the determination of the plasma inulin and PAH content by the methods of Corcoran and Page (5) and Smith et al. (6). From two to six urine collection periods and a corresponding number of pairs of arterial and renal venous blood samples were obtained from each subject. In addition, paired samples of heparinized and oxalated whole blood were obtained from each subject for hematocrit and oxygen capacity determinations. University School of Medicine, Atlanta, Georgia.Clearances of inulin and PAH were calculated in the usual manner from the rate of urinary excretion and the arterial levels of these substances. The percentage extraction of PAH was determined by the formula AAR X 100, where A and R represent the PAH concentrations in arterial and renal venous plasma, respectively, and the renal plasma flow obtained by dividing the clearance of PAH by the extraction: RPF = CPA AH-A discusExt. PAH' sion of the calculation of renal plasma flow in this manner is presented in a separate publication (7). This figure was corrected for the hematocrit reading to obtain the renal blood flow. The difference in oxygen-content between arterial and renal venous blood (renal oxygen extraction), expressed as volume of 02 per cc., was multiplied by the renal blood flow to obtain the renal oxygen consumption: Renal oxygen consump...
In a previous communication (1) evidence was presented for a "forward failure" hypothesis of edema in patients who have low cardiac outputs at rest. These patients have a low renal blood flow, apparently accompanied by renal efferent arteriolar constriction. This seems to be directly related to the level of the cardiac output and is entirely unrelated to the height of the venous pressure. As the renal blood flow falls, a consequent reduction in filtration rate occurs. This results in a decrease in the amount of salt and water filtered, and, since the tubules continue to reabsorb salt and water almost completely, there is a net retention of the latter which produces edema. It is. recognized that other factors may be involved in the rate of reabsorption. We emphasized that the patients studied were those who formed edema at rest, since the data were collected on resting subjects. Many patients who are compensated at rest form edema with activity. The reason for this can be ascertained only by studying patients in the exercising state. This paper is a report on the effect of exercise on the renal plasma flow and filtration rate of normal and cardiac subjects. METHODSSubjects were selected most of whom, at rest in the hospital, responded readily to routine therapeutic procedures. In this way it was hoped to obtain patients with relatively normal resting filtration rates. Controls consisted primarily of patients with asymptomatic neurosyphilis who were -receiving penicillin therapy. Since other techniques are not suitable to demonstrate brief changes in renal plasma flow and filtration rate, the methods of Smith, Goldring and Chasis (2) were employed utilizing sodium para-amino hippurate for renal plasma flow and inulin for filtration rate.As accurate results necessitate maintenance of a constant blood level of these materials, forms of exercise 1 Aided by grants from the Life Insurance Medical Research Fund and Smith, Kline and French Laboratories.were used in which a constant intravenous infusion could be given. At first, studies were made on recumbent patients with simple alternate flexion of each leg. As it became obvious that so little exercise was insufficient, the patients were required to step up and down two steps, each 121/ inches high, approximately 40 times. These patients were relatively free of edema as a result of mercurial diuresis before exercise was undertaken. Still later, in the recumbent position, pedals were pushed which, through two single pulley arrangements, raised two 22-pound weights alternately through a distance of 8 inches. Finally, as indicated in the table, 22-pound weights were raised through a distance of 12 inches. After allowing 30 minutes to acquire a constant blood level, a 12-minute exercise period was preceded by two 15-minute control periods and followed by sometimes one, usually two, 15-minute control periods. In most gases the normal subjects were required to do more work than the cardiac subjects. All results are corrected to a body surface area of 1.73 square meters.In L. ...
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