Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2017 Jan-Feb;34(1):47-60.
doi: 10.4103/0970-2113.197116.

Mechanisms of hypoxemia

Malay Sarkar  1 , N Niranjan  2 , P K Banyal  3
Affiliations
Review

Mechanisms of hypoxemia

Malay Sarkar et al. Lung India. 2017 Jan-Feb.

Erratum in

  • Erratum: Mechanisms of hypoxemia.
    [No authors listed] [No authors listed] Lung India. 2017 Mar-Apr;34(2):220. doi: 10.4103/0970-2113.201292. Lung India. 2017. PMID: 28360486 Free PMC article.

Abstract

Oxygen is an essential element for life and without oxygen humans can survive for few minutes only. There should be a balance between oxygen demand and delivery in order to maintain homeostasis within the body. The two main organ systems responsible for oxygen delivery in the body and maintaining homeostasis are respiratory and cardiovascular system. Abnormal function of any of these two would lead to the development of hypoxemia and its detrimental consequences. There are various mechanisms of hypoxemia but ventilation/perfusion mismatch is the most common underlying mechanism of hypoxemia. The present review will focus on definition, various causes, mechanisms, and approach of hypoxemia in human.

Keywords: Diffusion limitation; hypoxemia; shunt; ventilation-perfusion mismatch.

PubMed Disclaimer

Conflict of interest statement

There are no conflicts of interest.

Figures

Figure 1
Figure 1
The low ventilation/perfusion ratio. Ventilation is reduced but perfusion is normal
Figure 2
Figure 2
The mechanism of hypoxic pulmonary vasoconstriction. Hypoxia causes closure of voltage-gated potassium channel, leading to K+ accumulation intracellularly. It leads to depolarization of the cells, opening of voltage-gated calcium channel and calcium-mediated pulmonary vasoconstriction
Figure 3
Figure 3
High ventilation/perfusion ratio in a patient with pulmonary embolism
Figure 4
Figure 4
Shunt where ventilation is zero but perfusion normal
Figure 5
Figure 5
The calculation of shunt
Figure 6
Figure 6
Various mechanisms and differentiating features of hypoxemia
See this image and copyright information in PMC

References

    1. Greene KE, Peters JI. Pathophysiology of acute respiratory failure. Clin Chest Med. 1994;15:1–12. - PubMed
    1. Aviado DM, Daly MD, Lee CY, Schmidt CF. The contribution of the bronchial circulation to the venous admixture in pulmonary venous blood. J Physiol. 1961;155:602–22. - PMC - PubMed
    1. Sorbini CA, Grassi V, Solinas E, Muiesan G. Arterial oxygen tension in relation to age in healthy subjects. Respiration. 1968;25:3–13. - PubMed
    1. Belda JF, Soro M, Ferrando C. Pathophysiology of respiratory failure. Trends Anaesth Crit Care. 2013;3:265–9.
    1. Glenny RW. Teaching ventilation/perfusion relationships in the lung. Adv Physiol Educ. 2008;32:192–5. - PubMed