INTRODUCTION Different blood gas criteria have been used in the diagnosis of hepatopulmonary syndrome (HPS). PATIENTS AND METHODS Arterial blood gases were prospectively evaluated in 194 cirrhotic candidates for liver transplantation (LT) in the supine and seated position. Three blood gas criteria were analyzed: classic (partial pressure of oxygen [PaO2] < 70 mmHg and/or alveolar-arterial gra...

The various methods described in recent years for determining the cardiac output of man consist essentially either 1, in an application of the Fick principle, or 2, in measuring the rate with which either a normally present gas (nitrogen) or a foreign gas (nitrous oxide, ethyl iodide or ethylene) is exchanged during the passage of the blood through the lungs. Results obtained by the carbon diox...

The mechanisms governing pulmonary gas exchange were heavily debated at the start of the 20th century when Christian Bohr provided measurements of lung and blood gases as well as rational arguments in favour of oxygen being secreted actively from the lung gas to the blood within vertebrate lungs. The concept of active transport was studied by August Krogh in his doctoral dissertation on the par...

The lung exists for gas exchange, that is, the transfer of oxygen from the air to the blood and carbon dioxide from the blood to the air. Its basic structural unit is the alveolus—a roughly polygonal gas-filled tissue “bubble” whose walls are filled with capillaries. The human lung contains some 300 million alveoli, and their diameters average about 300 m. The strategy of dividing the lung up i...

The solubility of nitrous oxide in blood at body temperature was determined by Siebeck (1) with considerable accuracy as early as 1909. In his experiment, the blood was placed with a gas mixture in a tonometer of 3 liters capacity and equilibrated at 38” and atmospheric pressure. After an equilibrium had been attained, samples of both blood and gas were analyzed for nitrous oxide content. A blo...

Arterial blood gas analysis, the focus of this article, provides a fuller and more accurate ”gold standard” assessment of blood oxygenation status. It allows generation, not only of oxygen saturation (in arterial blood) sO2(a), but a number of further oxygen-related parameters, including the partial pressure of oxygen in arterial blood, pO2(a) and the total oxygen concentration of arterial bloo...

An experimental silicone hollow fiber membrane oxygenator for long-term extracorporeal membrane oxygenation (ECMO) was developed in our laboratory using an ultrathin silicone hollow fiber. However, the marginal gas transfer performances and a high-pressure drop in some cases were demonstrated in the initial models. In order to improve performance the following features were incorporated in the ...