THE POSSIBLE RELATIONSHIP BETWEEN PATENT FORAMEN OVALE AND DECOMPRESSION SICKNESS: A REVIEW OF THE LITERATURE

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Authors
  1. Saary, M.J.
  2. Gray, G.W.
Corporate Authors
Defence and Civil Inst of Environmental Medicine, Downsview ONT (CAN)
Abstract
There continues to be a controversy about the possible significance of patent foramen ovale (PFO) in the pathophysiology of tyhpe II decompression sickness (DCS with neurologic symptoms). PFO's are a common finding in normal persons, being present in up to a third of the population. The potential for right-to-left shunting of venous gas emboli (VGE) which are known to occur in even no-decompression dives is a theoretical concern, yet the incidence of type II DCS is remarkably low given the prevalence of PFO. Altitude decompression is analagous to decompression from a saturation dive, and VGE are observed above 15,000 fet (4572m). The potential for PFO shunting of VGE is a particular concern for space extra-vehicular activity (EVA) where the pressure in the US EVA suit is 4.3 PSI, equivalent to 30,000 feet. This paper reviews the literature with respect to the potential for right-to-left embolization through a PFO, relation of PFO to DCS, screening techniques for PFO, and treatment options. The literature supports a relationship between the presence and size of PFO and cryptogenic stroke (stroke, generally in younger individuals with not other identifiable risk factors). The weight of evidence also favours an increased realtive risk of type II DCS with a PFO, although the absolute increase in risk accrued is small. TRUNCATED
Keywords
Foramen Ovale
Report Number
DCIEM-TR-1999-001 — Technical Report
Date of publication
01 Jan 1999
Number of Pages
39
DSTKIM No
99-00455
CANDIS No
510504
Format(s):
Hardcopy;Document Image stored on Optical Disk

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