Daytime PaO2 in OSAS, COPD and the combination of the two (overlap syndrome)

Abstract

Our data suggest that day-time hypoxemia in OSA patients is largely determined by the increase of body weight and severity of nocturnal hypoxia. However, CPAP therapy has been shown to improve daytime PaO(2) values both in OSAS and in OS.

SpCO: Let's Not Throw the Baby Out With the Bath Water—Reply

“…2,3 Lacedonia et al studied 720 patients with suspected OSA, of whom 168 had overlap syndrome, and 86 had COPD. 4 They found that the overlap syndrome group had lower daytime P aO 2 than the OSA group, and the diurnal P aO 2 in the overlap syndrome group correlated with age and with FEV 1 . 4 Overlap syndrome causes more severe nocturnal hypoxemia than either OSA or COPD alone.…”

“…4 They found that the overlap syndrome group had lower daytime P aO 2 than the OSA group, and the diurnal P aO 2 in the overlap syndrome group correlated with age and with FEV 1 . 4 Overlap syndrome causes more severe nocturnal hypoxemia than either OSA or COPD alone. 2,4 Therefore, overlap syndrome contributes to daytime hypoxemia and the embarrassing breathlessness, resulting in worsening anxiety and social phobia.…”

“…Furthermore, Weaver et al's findings were consistent with other studies of the RAD-57. [2][3][4] In response to Weaver et al's study, Dr McEvoy opines that these failures of the RAD-57 to report a S pCO consistent with the laboratory COHb measurement could have been due to technician technique. The concern has previously been raised by another industry representative, 5 in response to a prospective study that demonstrated wide limits of agreement and poor sensitivity of the RAD-57.…”

“…4 Overlap syndrome causes more severe nocturnal hypoxemia than either OSA or COPD alone. 2,4 Therefore, overlap syndrome contributes to daytime hypoxemia and the embarrassing breathlessness, resulting in worsening anxiety and social phobia.…”

“…However, we concur with Alkhuja that OSA is a disabling comorbid disease that may be a risk factor for anxiety. 4 The co-occurrence of OSA in COPD patients increases the frequency of oxygen desaturation, 4 defragments the quality or quantity of sleep due to hypoxemia and hypercapnia, and results in depression, somnolence, and daytime dreaming. 5 All these factors contribute to COPD patients' increasing burden and worsening prognosis of anxiety symptoms and dependence on their caregivers.…”