introduction: capnography, is an easy, fast and practical method which its application in the diagnosis of pulmonary thromboendarterectomy (pte) has recently been studied. this study aimed to assess the diagnostic value of end-tidal co2 (etco2) and the alveolar dead space (avds) in the diagnosis of patients suspected to pte who have been referred to the emergency department. materials and metho...

OBJECTIVES Physiologic dead space is associated with mortality in acute respiratory distress syndrome, but its measurement is cumbersome. Alveolar dead space fraction relies on the difference between arterial and end-tidal carbon dioxide (alveolar dead space fraction = (PaCO2 - PetCO2) / PaCO2). We aimed to assess the relationship between alveolar dead space fraction and mortality in a cohort o...

BACKGROUND Volumetric capnography dead-space measurements (physiologic dead-space-to-tidal-volume ratio [VD/VT] and alveolar VD/VT) are considered more accurate than the more readily available time-based capnography dead-space measurement (end-tidal alveolar dead-space fraction [AVDSF]). We sought to investigate the correlation between volumetric capnography and time-based capnography dead-spac...

CONSIDERABLE UNCERTAINTY existed regarding the magnitude of pulmonary dead space in the immediate post-World War II era. The dead space concept was originated by Bohr (2), who viewed total ventilation as composed of two distinct, but homogeneous, components—alveolar ventilation that participated fully in gas exchange and dead space ventilation in which no respiratory exchange occurred. With kno...

CONSIDERABLE UNCERTAINTY existed regarding the magnitude of pulmonary dead space in the immediate post-World War II era. The dead space concept was originated by Bohr (2), who viewed total ventilation as composed of two distinct, but homogeneous, components—alveolar ventilation that participated fully in gas exchange and dead space ventilation in which no respiratory exchange occurred. With kno...

BACKGROUND This study was undertaken to determine whether alveolar dead space increases during intramedullary nailing of femoral shaft fractures and whether alveolar dead space predicts postoperative pulmonary dysfunction in patients undergoing intramedullary nailing of a femoral shaft fracture. METHODS All patients with a femoral shaft fracture were prospectively enrolled in the study unless...

BACKGROUND Respiratory dead-space is often increased in lung disease. This study evaluates the effects of increased alveolar dead-space (Vd(alv)), pulmonary shunt, and abnormal ventilation perfusion ratio (/) distributions on dead-space and alveolar partial pressure of carbon dioxide (Pa(co(2))) calculated by various methods, assesses a recently published non-invasive method (Koulouris method) ...

Introduction Physiology of Carbon Dioxide PACO2 PaCO2 The Concept of Dead Space Measurement of Dead Space Bohr Enghoff Langley Alveolar Ejection Volume Causes of Elevated Dead Space in Mechanically Ventilated Patients Pulmonary Embolism COPD ARDS Effects of Mechanical Ventilation on Dead Space Effect of VT Effect of PEEP Effect of Inspiratory Flow Waveforms and End-Inspiratory Pause Prone Posit...

An elevated physiological dead space, calculated from measurements of arterial CO2 and mixed expired CO2, has proven to be a useful clinical marker of prognosis both for patients with acute respiratory distress syndrome and for patients with severe heart failure. Although a frequently cited explanation for an elevated dead space measurement has been the development of alveolar regions receiving...