Arterial Oxygen Unsaturation Research Articles

Behavior of the Pulmonary Circulation in the Grossly Obese Patient: Pathogenesis of Pulmonary Arterial Hypertension at an Altitude of 2,240 Meters

Twenty persons living at an altitude of 2,240 meters were studied in order to examine the relative roles of passive and active factors in the genesis of pulmonary arterial hypertension in obesity (overweight, 75 +/- 39 percent). Pulmonary arterial hypertension was present in 80 percent (16) of the patients (mean pulmonary arterial systolic pressure, 45 +/- 17 mm Hg). In 95 percent (19) of the 20 patients, resistance to pulmonary flow at the end of diastole was increased (estimated mean pulmonary arteriolar resistance, 210 +/- 144 dynes.sec.cm-5; mean pulmonary arterial diastolic-pulmonary wedge pressure gradient 7.86 +/- 1.40 mm Hg). The mean arterial oxygen pressure was 50 +/- 9 mm Hg, the arterial carbon dioxide tension was 37 +/- 6 mm Hg and the arterial pH was 7.42 +/- 0.08. Since the pulmonary arterial systolic pressure has been reasonably predicted (r = 0.91; P < 0.001), it would appear that the compliance of the elastic pulmonary arteries in obese patients follows a normal pattern. The behavior of the right ventricular end-diastolic pressure at rest (mean change, 4.6 mm Hg; P < 0.001) and of the pulmonary wedge pressure (mean change, 4.7 mm Hg; P < 0.001) during passive lifting of the legs was indirect evidence of the increase in pulmonary blood volume. The presence of an abnormal resistance to pulmonary blood flow at the end of diastole is suggestive of a decrease in the distention of the pulmonary microcirculation. The pulmonary arterial diastolic-pulmonary wedge pressure gradient and the pulmonary arterial diastolic pressure were related to arterial oxygen unsaturation (r = 0.70; P < 0.05) but not to the concentration of hydrogen ions; thus hypercapnic acidemia appears as a secondary factor in the genesis of pulmonary arterial hypertension at high atitudes. The explanation could be the relative hyperventilation of high altitudes, with a compensatory metabolic alkalosis. The increased pulmonary blood volume and the alveolar hypoxia are the main causes in the pathogenesis of pulmonary arterial hypertension in the grossly obese patient at this altitude.

Respiratory Failure and Pulmonary Tuberculosis

We thank Kaplan for his interest in our article. 1 Agarwal ME Muthuswamy PP Banner AS et al. Respiratory failure in pulmonary tuberculosis. Chest. 1977; 72: 605-609 Abstract Full Text Full Text PDF PubMed Scopus (29) Google Scholar Kaplan suggests that the cause of our patients severe hypoxemia was the shunting which has been described in patients with cirrhosis, and he refers to his own interesting article entitled “Cirrhosis of the Liver: An Unusual Cause of Severe Hypoxemia;” 2 Kaplan AL Laguarda R Cirrhosis of the liver: An unusual cause of severe hypoxemia. Respiration. 1972; 29: 180-190 Crossref PubMed Google Scholar however, tins is not pertinent, because none of our patients clinically had cirrhosis, and cirrhosis was not found at the autopsies of those who died. Several other reports 3 Daoud FS Reeves JT Schaefer JW Failure of hypoxic pulmonary vasconstriction in patients with liver cirrhosis. J Clin Invest. 1972; 51: 1076-1080 Crossref PubMed Scopus (91) Google Scholar , 4 Emirgil C Soboi BJ Heymann B Pulmonary function in alcoholics. Am J Med. 1974; 57: 69-77 Abstract Full Text PDF PubMed Scopus (35) Google Scholar , 5 Rodman T Sobel M Close HP Arterial oxygen unsaturation and the ventilation-perfusion defect of Laennec's cirrhosis. N Engl J Med. 1960; 263: 73-77 Crossref PubMed Scopus (34) Google Scholar of hypoxemia and cirrhosis have emphasized that the oxygen tension of such patients is not very low: abnormal functioning communications may exist between the portal and pulmonary venous systems through the paraesophageal, mediastinal, azygous and bronchial venous systems in patients with portal hypertension. Except in rare cases, the arterial oxygen unsaturation is slight and probably of little clinical significance.5(P77)

Respiratory Failure and Pulmonary Tuberculosis

The conclusions concerning the frequency of respiratory failure and the types of abnormalities of pulmonary function that were reached in the article entitled “Respiratory Failure in Pulmonary Tuberculosis” by Agarwal et al 1 Agarwal MK Muthuswamy PP Banner AS et al. Respiratory failure in pulmonary tuberculosis. Chest. 1977; 72: 605-609 Abstract Full Text Full Text PDF PubMed Scopus (29) Google Scholar are premature and are not supported by adequate data. Fifteen of the 16 patients had hepatic disease or alcoholism which might have contributed to the hypoxemia noted. 2 Kaplan AL Laguarda R Cirrhosis of the liver: Unusual cause of hypoxemia. Respiration. 1972; 29: 180-190 Crossref PubMed Google Scholar Only those cases with alveolar hypoventilation manifested by hypercapnea can be attributed unquestionably to respiratory failure secondary to pulmonary disease. All of the other patients could have had all or part of their hypoxemia secondary to shunting, which has been well documented in hepatic disease. 3 Abelmann WH Kramer GE Verstraeten JM et al. Cirrhosis of the liver and decreased arterial oxygen saturation. Arch Intern Med. 1961; 108: 34-40 Crossref PubMed Scopus (13) Google Scholar , 4 Rodman T Sobel M Close HP Arterial oxygen unsaturation and the ventilation-perfusion defect of Laennec's cirrhosis. N Engl J Med. 1960; 263: 73-79 Crossref PubMed Scopus (32) Google Scholar Studies of shunting using 100 percent oxygen could have eliminated absolute shunting (both intrapulmonary and extrapulmonary) as a significant factor in the reported cases with respiratory failure. In the absence of such information, the conclusions about the frequency and mechanism of respiratory failure in patients with pulmonary tuberculosis are merely speculative.

Arterial oxygen unsaturation and hemodynamic changes in cirrhosis of the liver (author's transl)

Arterial oxygen unsaturation and hemodynamic changes in cirrhosis of the liver (author's transl)

The use of Bohr integral isopleths in the study of arterial oxygen saturation in chronic pulmonary tuberculosis.

Data are presented from a group of 8 patients with respiratory insufficiency due to pulmonary tuberculosis. An improved method, using Bohr integral isopleths, was used for assessing the diffusing capacity of the differently ventilated and perfused lung spaces. Arterial oxygen unsaturation, when it occurred while the patient was breathing air, was due to inadequate oxygenation of blood in the slow space that washes out nitrogen slowly when oxygen is breathed. This in turn was due to either a low diffusing capacity, a low ventilation-perfusion ratio, or a combination of both in this space. The fast space of the lung did not contribute to arterial oxygen unsaturation in any of these patients. The alveolar-arterial oxygen tension gradients while the patient was breathing air were large, and were almost entirely due to disturbance of function in the slow space and not to shunting of blood.

Regional ventilation and perfusion in silicosis and in the alveolar-capillary block syndrome

Eleyen patients selected on the basis of bilateral, diffuse linear and/or nodular densities in their chest roentgenograms were studied by a battery of pulmonary function tests, including quantitative measurements of regional ventilation and perfusion with radioactive xenon (Xe 133 ). Two groups were separated according to the presence of arterial oxygen unsaturation following a one minute standard step test. Group A, without arterial oxygen unsaturation following exercise, consisted of six patients with minimal nodular uncomplicated silicosis. Group B, with arterial oxygen unsaturation following exercise, consisted of four patients with diffuse interstitial pneumonitis and one with silicosis which was also nodular and uncomplicated but with larger and more extensive involvement than those in group A. The patients in group B demonstrated the physiologic characteristics associted with the alveolar-capillary block syndrome. Regional ventilation measurements in both groups A and B were not significantly different from those in a control group of eleven normal subjects. Regional perfusion was also found to be normal in group A so that the normally decreasing ventilation-perfusion ratios from apex to base of the lungs was maintained. However, the evenly distributed perfusion in group B resulted in more uniform ventilation-perfusion ratios from upper to lower lung zones. This finding is interpreted as support for the concept that the arterial oxygen unsaturation after exercise demonstrated by patients with the alveolar capillary-block syndrome results from the reduced diffusing capacity of the lung rather than from an imbalance between alveolar ventilation and perfusion.

Electrocardiographic patterns of right atrial overloading in some congenital heart conditions

This study analyzes 116 electrocardiograms of patients with congenital heart disease that had some hemodynamic effect on the right atrium. A correlation between the P wave changes and the hemodynamic and radiographic data was attempted. The mean right atrial pressure, the systolic pressure within the right ventricle, the a wave of the right atrium, the peripheral arterial blood oxygen saturation, the age of the patient and the radiographically determined size of the right atrium were analyzed and correlated with the voltage, configuration, duration, axis and other features of the P wave. In congenital lesions characterized by a difficulty in emptying the right atrium the voltage of the P wave was related to the integrity of the atrial septum. In the presence of such difficulty, an atrial septal defect decreased the systolic overloading of the right atrium. Arterial oxygen unsaturation was not related to the voltage of the P wave. No relation was found between the mean right atrial pressure and the changes of the P wave. The a wave in valvular pulmonic stenosis, tricuspid atresia, Ebstein's disease and total anomalous pulmonary venous connection had some relation, although it was not linear, with the P wave alterations. In valvular pulmonic stenosis with intact atrial and ventricular septa the P wave was related to the degree of systolic overloading of the right ventricle, but this was not true in trilogy of Fallot. The greatest voltages of the P wave were seen in valvular pulmonic stenosis, anomalous pulmonary venous connection and tricuspid atresia. In tetralogy of Fallot P wave changes were frequent but not as marked as in the previously mentioned defects. They consisted almost exclusively of peaking of the P wave. The size of the right atrium determined radiologically was generally related to the P wave changes in these congenital defects, but the relation was not linear. In atrial septal defect the P wave changes were slight, consisting almost exclusively of notching and slurring, slowing of the ascending branch of the P wave and, exceptionally, an increase in voltage. It is difficult to attribute P wave changes in different congenital lesions with hemodynamic involvement of the right atrium, to a single factor. In each disease one or a group of factors predominates. The most important one seems to be the resistance encountered by the right atrium in emptying its contents and the integrity of the interatrial septum.

Arterial oxygen unsaturation in sickle cell disease.

Arterial oxygen unsaturation in sickle cell disease.

Persistent left superior vena cava draining into the left atrium without arterial oxygen unsaturation

A 36 year old noncyanotic white man with coarctation of the aorta was found to have a left superior vena cava terminating in the left atrium on catheterization. A right to left shunt was demonstrated by dye-dilution studies; but, except for a mild decrease in the amount of dissolved oxygen in the plasma, there was no peripheral arterial oxygen unsaturation. Only one other case with this combination of anomalies has been reported, and this patient was found to have a shunt from the left to the right atrium via the two venae cavae and the connecting left innominate vein. These two cases are exceptional since in most of the other reported cases (listed in Table I) patients have been cyanotic. Mechanisms which may possibly determine the direction of blood flow in a persistent left superior vena cava terminating in the left atrium are discussed.

Pulmonary hypertension with muscular exercise in the newborn calf

Two types of pulmonary hypertension occur with muscular exercise (walking) in the calf on the day of birth: a) Pulmonary arterial pressure increased in all calves during exercise. The increase was greatest in the youngest calves. Pulmonary arterial pressures did not rise to systemic levels and arterial oxygen saturations remained normal. Pulmonary hypertension subsided in 2 min after stopping exercise. Pulmonary arterial pressure rose again when exercise was repeated. Both an increased pulmonary flow and pulmonary vasoconstriction may have contributed to the increased pulmonary arterial pressure during exercise. b) Pulmonary hypertension was observed in five calves for 30-50 min after exercise ceased. When pulmonary arterial pressure exceeded aortic pressure, arterial oxygen unsaturation occurred. This pulmonary hypertension which occurred only once per calf resembled"spontaneous" pulmonary vasoconstriction observed in resting calves on the day of birth. It is postulated that some substance remaining in the lung after fetal life, rather than the acutely reduced oxygenation of mixed venous blood, initiated this pressor response. hypoxia; pulmonary vasoconstriction Submitted on May 11, 1964

MEASUREMENT OF BLOOD FLOW THROUGH PORTOPULMONARY ANASTOMOSIS IN PORTAL HYPERTENSION.

Abstract A method was developed for the measurement of blood flow through the portopulmonary anastomosis in portal hypertension. After the same quantity of radioactive krypton and T-1884 dye were injected into the spleen and into the peripheral vein, blood was continuously sampled at a constant rate for 50 seconds from the pulmonary and brachial arteries. From continuous measurement of the radioactivity of blood and the concentrations of T-1824 dye in the brachial arterial blood taken 2 minutes after the injections, the blood flow through the portopulmonary anastomosis was calculated. Calculated values of 7 controls were in the vicinity of zero. Among 12 patients with portal hypertension, 2 patients had increased (14.4 per cent and 11.3 per cent) blood flow through the portopulmonary anastomosis. Three other patients had slightly elevated anastomotic flow, and 7 patients had normal values. There was no signifiant correlation between the calculated blood flow and the arterial oxygen saturation. It is suggested that the portopulmonary anastomosis does not play an important role as the came of the arterial oxygen unsaturation in portal hypertension.

Pulmonary Dysfunction in Rheumatoid Arthritis and Systemic Lupus Erythematosus

Pulmonary function was studied in 13 cases of rheumatoid disease and eight of systemic lupus erythematosus associated with roentgenographic evidence of pulmonary involvement. The most common abnormality noted was a reduction of lung volumes associated frequently with arterial oxygen unsaturation. These changes posibly were due to pleural effusion, restrictive pleuritis, parenchymal involvement, or any combination of these. Corticosteroid administration was attended by variable results.

HYPOXIA IN POLYCYTHEMIA VERA.

Excerpt It is generally considered that the demonstration of arterial oxygen unsaturation in a patient with polycythemia indicates a secondary rather than a primary cause for the increase in red ce...

HEMODYNAMIC AND VENTILATORY EFFECTS OF EXERCISE IN THE UPRIGHT POSITION IN PATIENTS WITH LEFT-TO-RIGHT SHUNTS.

Nine patients having ventricular septal defect or patent ductus arteriosus performed bicycle exercise of moderate intensity in the upright position while oxygen consumption and pulmonary and systemic blood flows and pressures were being measured. Resting pulmonary vascular resistance (PVR) was normal in five patients and elevated in four. Right-to-left shunt became apparent or increased during exercise in patients with elevated PVR. The rise of pulmonary "wedge" pressure and of right atrial pressure during exercise was not related to the resting PVR. Both ventilation and pulmonary artery pressure increased more rapidly during exercise in patients with high PVR than in the normal PVR group. Left atrial blood remained fully saturated during exertion in three patients with high PVR and arterial oxygen unsaturation.

Regional blood flow and cardiac output during acute hypoxia in the anesthetized dog.

The circulatory effects of breathing low concentrations of oxygen were studied in ten anesthetized dogs. Simultaneous measurements were made of cardiac output (indicator dilution technique) and blood flow to the head, kidney, and hind limb (electromagnetic flowmeters). Four experiments were performed with the addition of succinylcholine to inhibit the ventilatory response to hypoxia and maintain pCO2 constant. A rise in cardiac output and mean arterial pressure occurred which was significantly correlated to the decrease in arterial oxygen saturation. No threshold for these responses was found. Blood flow tended to increase during hypoxia in the regions studied but the responses were variable and only the change in renal blood flow had a significant correlation to arterial oxygen unsaturation. Systemic and regional vascular resistances during hypoxia varied both in direction and magnitude of change. The preponderant effects of hypoxia influence cardiac output more than peripheral vascular resistance.

The effect of acetylcholine upon arterial saturation

1. 1. Infusion of acetylcholine into the pulmonary artery or right ventricular outflow tract in a dose of 1.6 to 4.0 mg. per minute (20 to 75 μg per minute per kilogram) in the patients studied was associated with the following changes: (a) a decrease in mean arterial saturation; (b) an increase in mean cardiac index and a decrease in mean calculated total pulmonary resistance and total systemic resistance but no significant change in mean pulmonary arterial pressure, mean brachial arterial pressure, or mean pulse rate; (c) a slight increase in minute ventilation, with no significant change in mean oxygen consumption or respiratory exchange ratio and no statistically significant increase in mean ventilation equivalent. 2. 2. Inhalation by the patient of 99.6 per cent oxygen for 5 minutes while acetylcholine was being infused reversed the arterial unsaturation produced by the infusion of acetylcholine, but 5 or 10-minute periods of breathing oxygen during the infusion of acetylcholine did not usually produce a full 100 per cent oxygen saturation of arterial hemoglobin. 3. 3. The mechanism of the systemic arterial oxygen unsaturation produced by acetylcholine is discussed, and it is assumed that acetylcholine produces arterial unsaturation by decreasing the protective local vasoconstriction which is thought to occur normally in areas of the lung which are poorly ventilated.

Cyanotic syndrome of portal hypertension in hepatosplenic schistosomiasis and portal cirrhosis: Report of four cases ∗

The clinical, pathophysiologic and laboratory features of 4 cases with the chronic cyanotic syndrome of portal hypertension caused by visceral bilharziasis, 2 with complicating portal cirrhosis, are presented. In the presence of hepatosplenomegaly, chronic severe cyanosis is suggestive of pulmonary arteriovenous fistulas. On examination, the degree of cyanosis and clubbing with no significant clinical, laboratory or physiologic pulmonary and cardiac abnormalities is striking. The pathologic lesions responsible for the clinical picture consist chiefly of evidence of portal hypertension and widespread abnormal ramifications of both pulmonary arteries and veins, the great increase in the vascular bed of pulmonary parenchyma, and the presence of arteriovenous fistulas. There was no roentgenologic nor electrocardiographic evidence of pulmonary or cardiac disease. The liver function tests may show moderate impairment as in portal cirrhosis but may show no significant changes as happens in visceral schistosomiasis. Right heart catheterization and pulmonary function tests reveal normal pressure in the right side of the heart and associated great vessels, essentially normal pulmonary function studies and persistence of arterial oxygen unsaturation after administration of 100 per cent oxygen for 15 minutes. The differentiation of the cyanotic syndrome with clubbing of the fingers due to portal hypertension from congenital and acquired cyanotic diseases, pulmonary and cardiovascular, is of paramount importance. Further observations will enable us to learn more about the factors involved in the genesis of the pulmonary vascular findings, but portal hypertension, when present, seems to be an important factor. A similar syndrome in the absence of portal hypertension may be best explained by a vascular proliferative factor.

The respiratory defects in extreme obesity

Severely obese patients, including patients with normal lungs, myxedema and pulmonary emphysema, have been studied. Three of these patients had the hypoventilation syndrome at the time the studies were performed. All the patients exhibited marked reduction in expiratory reserve volume and a low maximal breathing capacity. Many patients had mild desaturation of the arterial blood. Unless concurrent thoracic disease was present, the oxygen cost of breathing and work of breathing were normal or near normal, and did not appear to be important in the pathogenesis of the hypoventilation syndrome. It is concluded that the basic respiratory defect in severe obesity is the low expiratory reserve volume and that the reduction of maximal breathing capacity and arterial oxygen unsaturation are a consequence of this. The hypoventilation syndrome occurring in occasional obese patients is due to a complex combination of factors that vary from case to case.

The demonstration of porta-pulmonary anastomoses in portal cirrhosis with the use of radioactive krypton (Kr85).

VENOUS anastomoses connecting the portal and pulmonary veins have been shown in cirrhotic patients by post-mortem injection,1 and there has been considerable speculation concerning their possible significance in life, particularly as a cause of arterial oxygen unsaturation and finger clubbing in patients with cirrhosis.2 3 4 5 Radioactive krypton (Kr85) solution, when injected into a peripheral vein, is blown off in the expired air as it reaches the alveolar surface of the lungs (Fig. 1). This has led to its use to demonstrate intrapulmonary arteriovenous shunts, which would allow krypton to bypass the alveoli and so reach a peripheral artery. In normal . . .

Physiologic Evaluation and Treatment of Kyphoscoliotic Patients

Article1 July 1961Physiologic Evaluation and Treatment of Kyphoscoliotic PatientsISRAEL BRUDERMAN, M.D., MYRON STEIN, M.D.ISRAEL BRUDERMAN, M.D.Search for more papers by this author, MYRON STEIN, M.D.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-55-1-94 SectionsAboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail ExcerptNew techniques of investigation have clarified the nature of the abnormalities of pulmonary function in patients with severe kyphoscoliosis. Restricted lung volumes, alveolar hypoventilation, hypercapnia, arterial oxygen unsaturation, and normal distribution of inspired air have been observed in these patients. However, arterial oxygen unsaturation when it occurs is unusually large for the degree of alveolar hypoventilation. Previous investigations have eliminated a diffusion abnormality (1) or atelectasis as a basis for this defect. The present study is concerned with the problem of arterial oxygen unsaturation and with the therapy of the acutely ill kyphoscoliotic patient.PATIENTS AND METHODSPATIENTSThree male...