Ventilation-perfusion mismatch pathophysiology: Difference between revisions
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==Pathogenesis== | ==Pathogenesis== | ||
In the upright position of the normal [[lung]], the amount of [[ventilation]] and [[perfusion]] is higher in the [[Base of lung|base of the lung]] compare to [[Apex of lung|apex of the lung]]. Although ventilation and perfusion are low in the apex of the lung, the perfusion is lower than ventilation in the apex. So, the V/Q is higher in the apex of the lung compare to the base. In a normal lung V/Q is 0.8 which means 4 liters of oxygen and 5 liters of blood transfer in the lung per minute. V/Q mismatch is one of the reason of hypoxemia in patients with [[lung]] disease like [[Obstructive lung disease|obstructive lung]] diseases, pulmonary vascular diseases, and [[Interstitial lung disease|interstitial diseases]] . Usually hypoxemia due to V/Q mismatch will resolve by [[Oxygen therapy|oxygen therapy.]] | In the upright position of the normal [[lung]], the amount of [[ventilation]] and [[perfusion]] is higher in the [[Base of lung|base of the lung]] compare to [[Apex of lung|apex of the lung]]. Although ventilation and perfusion are low in the apex of the lung, the perfusion is lower than ventilation in the apex. So, the V/Q is higher in the apex of the lung compare to the base. In a normal lung V/Q is 0.8 which means 4 liters of oxygen and 5 liters of blood transfer in the lung per minute. V/Q mismatch is one of the reason of hypoxemia in patients with [[lung]] disease like [[Obstructive lung disease|obstructive lung]] diseases, pulmonary vascular diseases, and [[Interstitial lung disease|interstitial diseases]] . Usually hypoxemia due to V/Q mismatch will resolve by [[Oxygen therapy|oxygen therapy.]] | ||
In normal condition when there is a low ventilation, the body tries to keep this ratio in a normal range by restricting the perfusion in that specific area of the lung. This unique mechanism is called hypoxic pulmonary vasoconstriction. If this process happens for a long time it can cause pulmonary hypertension<ref name="pmid6410061">{{cite journal |vauthors=Orchard CH, Sanchez de Leon R, Sykes MK |title=The relationship between hypoxic pulmonary vasoconstriction and arterial oxygen tension in the intact dog |journal=J. Physiol. (Lond.) |volume=338 |issue= |pages=61–74 |date=May 1983 |pmid=6410061 |pmc=1197181 |doi= |url=}}</ref>. | |||
==Associated Conditions== | ==Associated Conditions== | ||
Revision as of 18:59, 30 July 2018
Template:Ventilation-perfusion mismatch
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Aida Javanbakht, M.D.
Overview
Any disruption between blood flow and ventilation is called V/Q mismatch.
Pathogenesis
In the upright position of the normal lung, the amount of ventilation and perfusion is higher in the base of the lung compare to apex of the lung. Although ventilation and perfusion are low in the apex of the lung, the perfusion is lower than ventilation in the apex. So, the V/Q is higher in the apex of the lung compare to the base. In a normal lung V/Q is 0.8 which means 4 liters of oxygen and 5 liters of blood transfer in the lung per minute. V/Q mismatch is one of the reason of hypoxemia in patients with lung disease like obstructive lung diseases, pulmonary vascular diseases, and interstitial diseases . Usually hypoxemia due to V/Q mismatch will resolve by oxygen therapy.
In normal condition when there is a low ventilation, the body tries to keep this ratio in a normal range by restricting the perfusion in that specific area of the lung. This unique mechanism is called hypoxic pulmonary vasoconstriction. If this process happens for a long time it can cause pulmonary hypertension[1].
Associated Conditions
Some conditions that cause decrease in V/Q are:
Some conditions that cause increase in V/Q are: