Chest
Clinical InvestigationsSleep and BreathingNocturnal Hypoxemia Is Common in Primary Pulmonary Hypertension
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Materials and Methods
Patients with PPH who underwent a comprehensive polysomnogram study (polysomnography) in our institution were included in the study. Pulmonary hypertension was confirmed by right heart catheterization and was defined as a mean pulmonary artery pressure of > 25 mm Hg at rest or > 30 mm Hg during exercise. PPH was diagnosed according to the standard criteria provided by the National Registry of Primary Pulmonary Hypertension1 in 30 patients evaluated by one of the authors (A.C.A.). In brief,
Results
We studied 13 patients with PPH (12 women and 1 man) with a mean age of 44.7 ± 18.2 years and a mean BMI of 30.1 ± 7.3 kg/m2. Other characteristics are shown in Table 1. Three patients were receiving daytime resting oxygen supplementation, and six patients needed oxygen only when walking.
Our patients slept an average of 297.0 ± 48.1 min, with REM sleep making up 13 ± 5.3% of TST (Table 1). Snoring was noted in 85% of patients. All study patients had a normal apnea index (ie,< 5 episodes per
Discussion
The most important finding of the study is that 77% of the patients with PPH had significant nocturnal hypoxemia. Severe oxygen desaturation occurred independently of the presence of apneas or hypopneas. This study is important as well because it suggests that monitoring nocturnal oxygen saturation might be beneficial for patients with PPH.
Nocturnal hypoxemia occurred in 77% of our study population, and all nocturnal desaturators who did not undergo oxygen titration spent> 25% TST-Spo2 < 90%.
Conclusion
A high percentage of patients with PPH have significant nocturnal hypoxemia that is unrelated to apneas and hypopneas. Nocturnal desaturation occurs more frequently in patients with higher P(A-a)O2 values and lower FEV1, resting arterial Pao2 and Spo2, and walking Spo2 values.
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2021, Respiratory Medicine and ResearchCitation Excerpt :Some authors have studied breathing during sleep in patients with pre-capillary PH and these studies are summarized in Table 3. First of all, in 2001, in a small cohort of 13 patients with severe PAH (mPAP 60.8 ± 15 mmHg), Rafanan et al. found very few apneas or hypopneas measured during polysomnography but nocturnal hypoxemia in 10/13 patients (characterized by a saturation < 90% for at least 10% of the sleep time) [44]. Sleep hypoxemia is the most common SBD in PAH with a prevalence of 21% to 83%, independently of sleep apnea, and it has been recently associated with a poor prognosis in PAH [45].