Copyright ©ERS Journals Ltd 2007 The influence of patent foramen ovale on oxygen desaturation in obstructive sleep apnoea1 Sahlgrenska University Hospital/Östra, and 2 Sahlgrenska University Hospital/Sahlgrenska, Gothenburg, and 3 Dept of Community Medicine, Lund University, Malmö, and 4 Skaraborg Institute, Skövde, Sweden. CORRESPONDENCE: M. C. Johansson, Dept of Clinical Physiology, Sahlgrenska University Hospital/Östra, SE-416 85 Gothenburg, Sweden. Fax: 46 31846334. E-mail: Magnus.C.Johansson{at}vgregion.se Keywords: Echocardiography, heart septal defects, hypoxia, obstructive sleep apnoea, patent foramen ovale
Received: March 13, 2006
Obstructive sleep apnoea (OSA) is associated with oxygen desaturation to a varying degree. A patent foramen ovale (PFO) may allow interatrial right-to-left shunting. The hypothesis of the current study was that oxygen desaturation will occur more often, in proportion to the frequency of respiratory disturbances, in OSA subjects with PFO than in those without.
In a group of 209 subjects diagnosed with OSA, the proportion of desaturation to respiratory events was calculated as the ratio of oxygen desaturation index (ODI)/apnoeahypopnoea index (AHI). A total of 15 cases with high proportional desaturation (ODI/AHI
The prevalence of large PFO was nine out of 15 (60%) in the high proportional desaturation group versus two out of 15 (13%) in the low proportional desaturation group. The median number of passing bubbles was positively correlated to minimum oxygen saturation among those with PFO.
In conclusion, oxygen desaturation occurs more often, in proportion to the frequency of respiratory disturbances, in obstructive sleep apnoea subjects with a patent foramen ovale than in those without.
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