Abstract
Impaired pulmonary gas exchange leading to arterial hypoxaemia is one of the most common problems in critically ill patients. This arterial hypoxaemia and, hence, an increased alveolar-arterial oxygen partial pressure difference (D(A-a)O2)—at a given fraction of inspired oxygen (FiO2) and a stable cardiac output—are mainly attributed to ventilation-perfusion mismatch (low VA/Q areas) and direct intrapulmonary right-to-left shunting. The discrimination of these two components has been of interest as their causes and treatment may be different (Bendixen 1964; Pesenti et al. 1983). Berggren (1942) tried to separate the two effects by calculating the venous admixture (QVA/QT) with and without nitrogen present in the inspired gas. In practice this method yielded contradictory results, both enhanced and decreased QVA/QT values being found (Quan et al. 1980; Shapiro et al. 1980; Suter et al. 1985), and evidence for absorption collapse of alveoli being observed (Dantzker et al. 1975; Wagner et al. 1974a). Moreover, increasing the oxygen tension in mixed venous blood by pure oxygen breathing may increase the right-to-left shunt (Bishop and Cheney 1983) by reversing hypoxic pulmonary vasoconstriction in unventilated lung areas (Domino et al. 1983).
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Bendixen H (1964) Atelectasis and shunting. Anesthesiology 25:595–596.
Berggren S (1942) The oxygen deficit of arterial blood caused by non-ventilating parts of the lung. Acta Physiol Scand [Suppl] 11:1–92.
Bishop M, Cheney F (1983) Effects of pulmonary blood flow and mixed venous O2 tension on gas exchange in dogs. Anesthesiology 58:130–135.
Canfield R, Rahn H (1957) Arterial-alveolar N2 gas pressure difference due to ventilation perfusion variation. J Appl Physiol 10:165–172.
Dantzker D, Wagner P, West J (1975) Instability of lung units with low VA/Q ratios during O2 breathing. J Appl Physiol 38:886–895.
Domino K, Wetstein L, Glasser S et al. (1983) Influence of mixed venous oxygen tension (PvO2) on blood flow to atelectatic lung. Anesthesiology 59:428–434.
Farhi L, Edwards A, Homma T (1963) Determination of dissolved N2 in blood by gas chromatography and (a-A) N2 difference. J Appl Physiol 18:97–106.
Klocke F, Rahn H (1960) The arterial-alveolar inert gas pressure difference. In: Studies in Pulmonary Physiology. Wright Air Development Center Technical Report 60–1, pp 66–90.
Klocke F, Rahn H (1961a) A method for determining inert gas (“N2”) solubility in urine. J Clin Invest 40:279–285.
Klocke F, Rahn H (1961b) The arterial-alveolar inert gas (“N2”) difference in normal and emphysematous subjects by the analysis of urine. J Clin Invest 40:286–294.
Lenfant C (1963) Measurement of ventilation/perfusion distribution with alveolar-arterial differences. J Appl Physiol 18:1090–1094.
Lenfant C (1965) Effect of high FiO2 on measurement of ventilation perfusion distribution in man at sea level. Ann NY Acad Sci 121:797–808.
Markello R, Winter P, Olszowka A (1972) Assessment of ventilation-perfusion inequalities by arterialalveolar nitrogen differences in intensive care patients. Anesthesiology 37:4–15.
Markello R, Schuder R, Border J (1974) Arterio-alveolar N2 differences documenting ventilation-perfusion mismatching following trauma. J Trauma 14:423–426.
Pesenti A, Riboni A, Marcolin R, Gattinoni I (1983) Venous admixture (QVA/QT) and true shunt (QS/QT) in ARF patients: effects of PEEP at constant F1O2. Intensive Care Med 9:307–311.
Quan S, Kronberg G, Schlobohm R, Feeley T, Don H, Lister G (1980) Changes in venous admixture with alterations of inspired oxygen concentration. Anesthesiology 52:477–482.
Rahn H, Farhi L (1964) Ventilation, perfusion and gas exchange—the VA/Q concept. In: Handbook of physiology, section 3, Respiration I. American Physiological Society, Washington DC, pp 735–766.
Shapiro B, Cane R, Harrison R, Steiner M (1980) Changes in intrapulmonary shunt with administration of 100% oxygen. Chest 77:138–141.
Suter P, Fairley B, Schlobom R (1975) Shunt, lung volume and perfusion during short periods of ventilation with oxygen. Anesthesiology 43:617–627.
Van Slyke D, Neill J (1924) The determination of gases in the blood and other solutions by vacuum extraction and manometric measurement. J Biol Chem 61:523–573.
Wagner P, Saltzmann H, West J (1974a) Measurement of continuous distributions of ventilation-perfusion ratios. J Appl Physiol 36:588–599.
Wagner P, Laravuso R, Uhl R, West J (1974b) Continuous distributions of ventilation-perfusion ratios in normal subjects breathing air and 100% O2. J Clin Invest 54:54–68.
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1988 Springer-Verlag Berlin Heidelberg
About this chapter
Cite this chapter
Radermacher, P., Falke, K.J. (1988). The Arterial-Alveolar Nitrogen Difference for the Assessment of Ventilation-Perfusion Mismatch. In: Kox, W., Bihari, D. (eds) Shock and the Adult Respiratory Distress Syndrome. Current Concepts in Critical Care. Springer, London. https://doi.org/10.1007/978-1-4471-1443-7_10
Download citation
DOI: https://doi.org/10.1007/978-1-4471-1443-7_10
Publisher Name: Springer, London
Print ISBN: 978-1-4471-1445-1
Online ISBN: 978-1-4471-1443-7
eBook Packages: Springer Book Archive