The lungs normally are ventilated with enough air to dilute the carbon dioxide produced by metabolism, so that the partial pressure of carbon dioxide (Pco,) in the alveoli is kept remarkably close to 40 mm. Hg. It is the alveolar ventilation and not the total amount of air going in or out of the mouth (or 'minute-volume') that determines the Pco2 because a varying proportion of the total ventil...

Background. Respiratory dead-space is often increased in lung disease. This study evaluates the effects of increased alveolar dead-space (VDalv), pulmonary shunt, and abnormal ventilation perfusion ratio ( _ V= _ Q) distributions on dead-space and alveolar partial pressure of carbon dioxide (PACO2) calculated by various methods, assesses a recently published non-invasive method (Koulouris metho...

We have developed an exercise designed to give students practice calculating arterial O2 content, O2 delivery, physiological dead space, dead space and alveolar ventilation, and alveolar partial pressure of O2 and CO2. The exercise is in the form of a "murder mystery" in which students are required to make these calculations to identify the murderer.

INTRODUCTION Alveolar dead space reflects phenomena that render arterial partial pressure of carbon dioxide higher than that of mixed alveolar gas, disturbing carbon dioxide exchange. Right-to-left shunt fraction (Qs/Qt) leads to an alveolar dead space fraction (VdAS/VtA; where VtA is alveolar tidal volume). In acute respiratory distress syndrome, ancillary physiological disturbances may includ...

Purpose: To determine the value of alveolar dead space as a predictor of weaning failure in mechanically ventilated COPD patients admitted to the intensive care units. Design: A prospective, observational cohort study conducted from 1 March 2014 to 31 August 2014. Setting: general Intensive care unit of Alexandria main University Hospitals. Patients: Eighty COPD patients requiring mechanical ve...

Fowler ( 1 ) estimated the respiratory dead space in man by recording simultaneously and continuously the nitrogen concentration and the volume flow at the mouth during a single expiration, following a breath of oxygen. Such an expiration may be divided into three phases. In the first part of expiration there is virtually no nitrogen. This is followed by an S-shaped rise in nitrogen concentrati...

The aims were to examine the gas exchange and arterial blood gas abnormalities among patients with scoliosis, and the correlation of these abnormalities with age and severity of deformity. Means among 51 patients were as follows: age 25.4 +/- 17.5 yr, angle of scoliosis 80.2 +/- 29.9 (SD), vital capacity 1.94 +/- 0.91 (SD) (i.e. 60.6 +/- 19.2% of predicted), PaO2 85.8 +/- 12.0 (SD), PaCO2 42.4 ...

BACKGROUND Little is known about the alveolar dead-space fraction after the first week of acute respiratory distress syndrome (ARDS). We measured the dead-space fraction in the early phase (first week) and the intermediate phase (second week) of ARDS, and evaluated the association of dead-space fraction with mortality. METHODS We prospectively measured dead-space fraction and other variables ...

Citation: Mosing M, Böhm SH, Rasis A, Hoosgood G, Auer U, Tusman G, Bettschart-Wolfensberger R and Schramel JP (2018) Physiologic Factors Influencing the Arterial-ToEnd-Tidal CO2 Difference and the Alveolar Dead Space Fraction in Spontaneously Breathing Anesthetised Horses. Front. Vet. Sci. 5:58. doi: 10.3389/fvets.2018.00058 Physiologic Factors influencing the arterial-To-end-Tidal cO2 Differe...

LmLEJOHN, A. & BOWLES, FELICITY, 1982. Studies on the physiopathology of c~~r?nic obstructive pulmonary disease in the horse. VI. The alveolar dead space. Onderstepoon Journal ofVetenMry Research, 49. n..:n (1"982!. The alveolar dead space (VDalv) as a percentage of tidal volume was calculated in horses by substituting the values for partial pressure of carbon dioxide in end-expiratory gas (PE'...