A low Pa02 may result from an incomplete diffusion equilibrium, hypoventilation, or other alterations of Va/Q relationships, including intrapulmonary, extra-pulmonary, or postpulmonary shunt. The oxygen diffusion capacity has been found to be normal in patients with cirrhosis of the liver. Our patients also presented with hyperventilation leading to respiratory alkalosis, which is consistently observed in cirrhosis. The increased ventilation and the almost normal dead space effectively ruled out hypoventilation as a source of the Va/Q inequality. buy glucophage Read the rest of this entry »
Measured gas exchange and hemodynamic data are shown in Table 3. In these patients with severe hypoxemia, the Ve was increased, and Vo2 was raised, whereas the Pv02 was normal. Cardiac output and the Cl were extremely high, while the PVR and the SVR were extremely low. Finally, the P50 was increased (29.5 ±1.5 mm Hg), which was in agreement with other studies. The Va/Q distribution of ventilated and perfused units (Fig 1) was little altered. The hypoxemia was mainly due to the large amount of perfusion flowing through unventilated units for patients 1, 2, 4, and 6 and through unventilated and underventilated areas for patients 3 and 5 (Table 4). The Pa02 predicted from the distribution was always higher than measured values, and the difference between these two values was statistically significant (predicted Pa02 — measured Pa02= +9.27 ±5.9 mm Hg; p<0.01). Read the rest of this entry »
Preparation of Vtyients
Using a sterile introducer (Vygon Desilet No. 8), a No. 7F Swan-Canz catheter (Edwards Laboratories) was inserted percutaneously into a femoral vein and placed in the pulmonary artery under continuous electrocardiographic monitoring and fluoroscopic control. The tip of the catheter was positioned in the pulmonary artery to sample mixed-venous blood and to measure pulmonary capillary wedge and arterial pressure (Bentley-Trantec transducer model 800). A Seldicath catheter Plastimed No. 4F was introduced into a radial or a femoral artery for sampljpg arterial blood and measuring systemic pressures. A cannula was placed in the most convenient vein in the arm. Samples of blood were then collected for measurement of the partition coefficient of each inert gas and the P, obtained for each patient by using the tonometer on two samples of blood with gases containing 2.5 percent or 5.5 percent oxygen, both with 5.5 percent carbon dioxide. read more
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Arterial oxygen desaturation in patients with cirrho-L sis of the liver was first described by Snell in 1935; however, in spite of numerous studies, the mechanism of the alterations in gas exchange in these patients remains obscure. The diffusing capacity does not appear to be altered, and the shift to the right of the oxyhemoglobin dissociation curve is too small to account for the degree of desaturation; however, the increase in alveolar-arterial oxygen partial pressure difference and the moderate increase in blood saturation during oxygen breathing are in favor of venous admixture as the cause of arterial hypoxemia. Postmortem findings indicate the existence of intrapul-monary arteriovenous shunts or a portopulmonary venous bypass in some patients. More recently, it has been suggested that this abnormality in gas exchange is due to an inappropriate pulmonary blood flow relative to ventilation distribution,10 to an altered distribution of ventilation caused by an increase in closing volume,11 or to an impairment of HPY. In short, hypoxemia in patients with hepatic disease is common and is probably of multifactorial origin, but severe hypoxemia is unusual. This study was designed to investigate the mechanism of the alteration in gas exchange in severely hypoxemic cirrhotic patients using the multiple inert gas elimination technique to estimate Va/Q inequalities. read Read the rest of this entry »
4.1 Mortality Statistics
To obtain improvements in the quality of mortality statistics supplied to WHO, the following measures are recommended:
4.1.1: More rapid reporting from all countries using ICD coding system.
4.1.2: Standardization of death certificates.
4.1.3: New programs to teach the importance of death certificates and how to complete them.
4.1.4: More collection of data from developing countries. 4.1.5: Improvement of the ICD itself (eg, elimination of allergic alveolitis from the list of airways diseases). Read the rest of this entry »
The papers presented indicate that CAD is an important disease throughout the world, and a major cause of morbidity and mortality. This is lamentable because CAD can be controlled by a reduction in smoking and air pollution. The lack of reliable data probably reflects the failure of health authorities and of governments to recognize the magnitude of the problem. This point was brought out by Chaulet, who commented that in Africa there are well-developed programs to manage tuberculosis and acute respiratory infections, but little attention is being paid to CAD. It is essential to direct future research toward collecting accurate information of prevalence rates and risk factors in order that effective measures to prevent and control CAD can be implemented. Read the rest of this entry »
2.3 Morbidity (How Severe Is CAD?)
There is evidence that CAD places heavy demands on health care services. As reported in this symposium, Higgins estimates that in the USA, 1.3 percent of hospital discharges are from COPD; Holland estimates that, in the United Kingdom, respiratory diseases account for 25 percent of general practitioner consultations; Wojtyniak and Wysocld give evidence that 3.3 percent of hospitalizations in Poland are due to chronic bronchitis, emphysema, and asthma; and Utkin reports that 1.5 percent of outpatients attend clinic because of chronic bronchitis. Population studies conducted in Papua New Guinea (PNG) and in Australia show that up to 30 percent of elderly people in PNG and 10 to 12 percent of adults in Australia have CAL. Because there are very few data available about the prevalence of CAL in other countries, there is a great need to collect this information. Read the rest of this entry »
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