We have examined the mechanisms of abnormal gas exchange in seven patients with chronic obliteration of the pulmonary vascular bed secondary to recurrent pulmonary emboli or idiopathic pulmonary hypertension. All of the patients had a widened alveolar-arterial oxygen gradient and four were significantly hypoxemic with arterial partial presssures of oxygen less than 80 torr. Using the technique ...

We have investigated the following pulmonary related parameters in 22 patients with Crohn's disease who were free of clinical pulmonary symptoms and had normal chest roentgenograms and in 25 controls: serum angiotensin converting enzyme, pulmonary function tests, bronchoalveolar lavage (lymphocyte count and subpopulations, macrophage viability and superoxide anion release by macrophages) and pu...

The effects of slow intravenous infusion of three different respiratory stimulants (dimeftine, nikethamide and prethcamide) on minute and alveolar ventilation, blood gases and pH were studied in 18 patients with chronic pulmonary emphysema and chronic respiratory failure. For a more accurate assessment of the results of the double blind controlled trial, a factorial design in a Youden square sc...

Pulmonary embolism (PE) is a common condition. The central aim of this study was to describe the use of volumetric capnography (VCap) before and after fibrinolytic treatment of major PE. Lung scintigraphy was used as a base of comparison for the results of this treatment. We describe the cases of two conscious and spontaneously breathing patients (20- and by 24-year-old women) with major PE und...

We report a complicated case of acute respiratory distress syndrome (ARDS) from severe sepsis, in which we measured the ratio of physiologic dead space to tidal volume (V(D)/V(T)) with volumetric capnography prior to, during, and after therapy with human recombinant activated protein C. Previous studies hypothesized that early in ARDS, elevated V(D)/V(T) primarily reflects increased alveolar V(...

The measurement and interpretation of "diffusing capacity" by either single-breath or steady-state methods are complicated by both technical and conceptual difficulties. The CO uptake fraction is less complex but, as originally described, it is unacceptably sensitive to dead-space ventilation. A modification (the "alveolar CO uptake fraction", UA) largely removes this factor. We have measured U...

BACKGROUND When shared by people who inject drugs, needles and syringes with different dead space may affect the probability of HIV and hepatitis C virus (HCV) transmission differently. METHODS We measured dead space in 56 needle and syringe combinations obtained from needle and syringe programs across 17 countries in Europe and Asia. We also calculated the amounts of blood and HIV that would...

We propose an emergency department (ED) pulmonary embolism rule-out protocol based on pretest probability assessment coupled with either a negative D -dimer assay result or a negative D -dimer assay result plus a normal alveolar dead-space measurement. We examine the safety, efficiency, and feasibility of such a protocol, paying special attention to implicit and explicit strategies of pretest p...

This is the first report of a patient submitted to chemical thrombolysis due to massive pulmonary embolism (PE) during the postoperative period of neurosurgery, in whom due to the lack of adequate clinical conditions, no imaging assessment was performed. Clinical, gasometric and capnographic data allowed the decision to perform the thrombolysis with safety. The P(a-et)CO2 gradient decreased fro...