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Intrapulmonary arteriovenous anastomoses in humans – response to exercise and the environment
Author(s) -
Lovering Andrew T.,
Duke Joseph W.,
Elliott Jonathan E.
Publication year - 2015
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2014.275495
Subject(s) - medicine , hyperoxia , pathophysiology , hypoxia (environmental) , supine position , lung , disease , arteriovenous anastomosis , adverse effect , cardiology , anastomosis , physiology , surgery , chemistry , organic chemistry , oxygen
Intrapulmonary arteriovenous anastomoses (IPAVA) have been known to exist in human lungs for over 60 years. The majority of the work in this area has largely focused on characterizing the conditions in which IPAVA blood flow ( Q ̇ IPAVA ) is either increased, e.g. during exercise, acute normobaric hypoxia, and the intravenous infusion of catecholamines, or absent/decreased, e.g. at rest and in all conditions with alveolar hyperoxia ( F I O 2 = 1.0). Additionally, Q ̇ IPAVA is present in utero and shortly after birth, but is reduced in older (>50 years) adults during exercise and with alveolar hypoxia, suggesting potential developmental origins and an effect of age. The physiological and pathophysiological roles of Q ̇ IPAVA are only beginning to be understood and therefore these data remain controversial. Although evidence is accumulating in support of important roles in both health and disease, including associations with pulmonary arterial pressure, and adverse neurological sequelae, there is much work that remains to be done to fully understand the physiological and pathophysiological roles of IPAVA. The development of novel approaches to studying these pathways that can overcome the limitations of the currently employed techniques will greatly help to better quantify Q ̇ IPAVA and identify the consequences of Q ̇ IPAVA on physiological and pathophysiological processes. Nevertheless, based on currently published data, our proposed working model is that Q ̇ IPAVA occurs due to passive recruitment under conditions of exercise and supine body posture, but can be further modified by active redistribution of pulmonary blood flow under hypoxic and hyperoxic conditions.