BACKGROUND Anatomic dead space (also called airway or tracheal dead space) is the part of the tidal volume that does not participate in gas exchange. Some contemporary ventilation protocols, such as the Acute Respiratory Distress Syndrome Network protocol, call for smaller tidal volumes than were traditionally delivered. With smaller tidal volumes, the percentage of each delivered breath that i...

This review provides an overview of the relationship between ventilation/perfusion ratios and gas exchange in the lung, emphasising basic concepts and relating them to clinical scenarios. For each gas exchanging unit, the alveolar and effluent blood partial pressures of oxygen and carbon dioxide (PO2 and PCO2) are determined by the ratio of alveolar ventilation to blood flow (V'A/Q') for each u...

Deformation of the alveolar epithelial basement membrane with lung inflation has been implicated in blood-gas barrier breakdown during the development of ventilator-induced lung injury. To determine the vulnerability of alveolar epithelial cells to deformation-induced injury, we developed a cell-stretching device that subjects cells to cyclic, equibiaxial strains. Alveolar epithelial type II ce...

UP TO THE BEGINNING Of the present century, operations within the thoracic cavity were greatly hampered by the "pneumothorax problem." When the chest was opened, the lung collapsed and the patient made vigorous efforts to breathe. The mediastinal structures moved violently and surgery was very diflficult. Hypoxia rapidly occurred and unless the chest was soon dosed, death occurred due to asphyx...

The aim of this study was to determine what the influence of different designs of face masks and different noninvasive ventilator modes would be upon total dynamic dead space. Using a spontaneous breathing model, total dynamic dead space was measured when using 19 commercially available face masks and a range of ventilators in various ventilation modes. Total dynamic dead space during spontaneo...

either group. In 8 of the 32 individuals (4 with COPD and 4 without) the changes in V/Q were of sufficient magnitude to cause a significant decrease in PaOz, averaging 10.4 mm Hg decrease immediately after smoking; there were no changes in PaCO:! or pH. In six of these eight, the response was primarily in the airways as indicated by increased A-a, Q S / Q ~ and alveolar shunting. In two of the ...

INTRODUCTION Dead-space fraction (Vd/Vt) has been shown to be a powerful predictor of mortality in acute lung injury (ALI) patients. The measurement of Vd/Vt is based on the analysis of expired CO2 which is not a part of standard practice thus limiting widespread clinical application of this method. The objective of this study was to determine prognostic value of Vd/Vt estimated from routinely ...