The Predictors of Obesity Hypoventilation Syndrome in Obstructive Sleep Apnea

Background: As obesity increases, the frequency of obstructive sleep apnea and obesity hypoventilation syndrome increases also. However, obesity hypoventilation syndrome frequency is not known, as capnography and arterial blood gas analysis are not routinely performed in sleep laboratories. Aims: To investigate the frequency and predictors of obesity hypoventilation syndrome in obese subjects. Study Design: Retrospective clinical study Methods: Obese subjects who had arterial blood gas analysis admitted to the sleep laboratory and polysomnography were retrospectively analyzed. Subjects with restrictive (except obesity) and obstructive pulmonary pathologies were excluded. Demographics, Epworth-Sleepiness-Scale scores, polysomnographic data, arterial blood gas analysis, and spirometric measurements were recorded. Results: Of the 419 subjects, 45.1% had obesity hypoventilation syndrome. Apnea hypopnea index (p<0.001), oxygen desaturation index (p<0.001) and sleep time with SpO2<90% (p<0.001) were statistically higher in subjects with obesity hypoventilation syndrome compared to subjects with eucapnic obstructive sleep apnea. The nocturnal mean SpO2 (p<0.001) and lowest SpO2 (p<0.001) were also statistically lower in subjects with obesity hypoventilation syndrome. Logistic regression analysis showed that the lowest SpO2, oxygen desaturation index, apnea hypopnea index and sleep time with SpO2 <90% were related factors for obesity hypoventilation syndrome. Conclusion: Obesity hypoventilation syndrome should be considered when oxygen desaturation index, apnea hypopnea index and sleep time with SpO2 <90% are hig

Vocal Cord Paralysis and Hypercapnic Respiratory Failure in a Patient with Familial Amyloidotic Polyneuropathy

We herein report a patient case with familial amyloidotic polyneuropathy (FAP) who presented with vocal cord paralysis (VCP). A 60-year-old man with FAP (Gly89Gln) presented with hoarseness and snoring for the previous two years. A chest X-ray demonstrated cardiomegaly and bilateral diaphragmatic elevation. The findings of a restrictive pattern on spirometry and daytime hypercapnia were consistent with respiratory muscle weakness related to neuropathy [ forced expiratory volume (FEV1): 38%, forced vital capacity (FVC): 39%, FEV1/FVC: 77, partial pressure of arterial oxygen (PaO2): 80 mmHg, partial pressure of carbon dioxide in arterial blood (PaCO2): 52 mmHg]. An ear-nose-throat examination showed VCP. Polysomnography revealed severe obstructive sleep apnea (OSA). FAP may cause OSA by VCP and hypercapnic respiratory failure by respiratory muscle weakness. Therefore, an ear-nose-throat examination, spirometry, arterial blood gases analysis and polysomnography are important for these patients