Arterial oxygen tension during sleep in the third trimester of pregnancy.

BACKGROUND: Changes during pregnancy include reduced functional residual capacity (FRC) and residual volume (RV), increased alveolar difference for oxygen and, in the supine position, reduced cardiac output. In conjunction with sleep-related disturbances, these changes could lead to maternal oxygen desaturation during sleep. OBJECTIVES: Because of conflicting data from respiratory sleep studies in pregnancy, we performed complete polysomnography on 21 pregnant women at the 36th week of gestation and again postpartum. We also measured the partial pressure of oxygen in the arterial blood (PaO2) in the supine and sitting positions. METHODS: We tested 21 healthy pregnant women at the 36th week of gestation. Arterial samples were taken in the sitting position. Complete polysomnography was performed in all of the pregnant women. Before the polysomnography arterial samples were taken in the supine and sitting positions and then every 2 h until termination of the study. RESULTS: We did not find any correlation between SaO2/PaO2 levels and apnea, hypopnea or percent of rapid eye movement (REM) sleep. The frequency of apnea and hypopnea was significantly lower during pregnancy (5.81 +/- 2.1 apneas or hypopneas per hour of sleep) than postpartum (12.1 +/- 2.7 apneas or hypopneas per hour of sleep) (p < 0.001), which may be due to the raised level of progesterone. The PaO2 levels in the supine position were significantly lower than in the sitting position at 36 weeks of gestation (p < 0.001). No differences were found between PaO2 levels in the sitting and supine positions postpartum (p < 0.5). CONCLUSIONS: According to our results we conclude that 1) the frequency of apnea and hypopnea in pregnancy was significantly lower than postpartum, and 2) a significant difference in PaO2 levels in the sitting and supine positions was observed at 36 weeks of gestation.

Endothelin-1 levels in the pathophysiology of chronic obstructive pulmonary disease and bronchial asthma.

BACKGROUND: Endothelin-1 (ET-1) has been implicated in the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD). The ET-1 levels are elevated during exacerbations of asthma and COPD in bronchoalveolar lavage, serum, and sputum and fails with treatment of the exacerbations. Hypoxemia stimulates ET-1 secretion. OBJECTIVE: The aim of this study was to examine the serum ET-1 levels in stable asthmatic and COPD patients. MATERIALS AND METHODS: We examined 48 COPD and 26 asthmatic patients and 34 normal subjects. We collected arterial samples to measure baseline ET-1 levels in all patients and in the control group, during the day. All the patients underwent formal polysomnography (EEG, ECG, airflow, respiratory muscle movement, oximeter) to detect the presence of nocturnal, nonapneic, and oxyhemoglobin desaturation. Twelve of the COPD patients and six of the asthmatic patients were disqualified because of inadequate sleep or sleep apnea syndrome. Nineteen of the COPD patients desaturated below a baseline sleep saturation of 90% for 5 min or more, reaching a nadir saturation of at least 85%. We collected arterial samples to measure ET-1 levels, 5 min after the first period of desaturation in each of the 19 desaturators COPD patients. None of the 20 asthmatic patients exhibited oxyhemoglobin desaturation during sleep. RESULTS: Baseline arterial ET-1 levels during the day were significantly higher in "desaturators" COPD patients (2.08+/-0.28 pg/ml) compared to "non-desaturators" COPD patients (1.38+/-0.16 pg/ml) (P<0.001) and to asthmatics (0.7+/-0.85 pg/ml) (P<0.001). ET-1 Levels in normal subjects were 1.221+/-0.02 pg/ml. In "desaturators" COPD patients ET-1 levels during the night, 5 min after the first oxyhemoglobin desaturation, were significantly higher (4.28+/-1.10 pg/ml) compared to those during the day (2.08+/-0.28 pg/ml) (P<0.001). A significant negative correlation was observed between ET-1 levels and degree of desaturation during the day (P=0.005, r=0.632) and during the night (P<0.001, r=0.930) in "desaturators" COPD patients. CONCLUSION: According to our results: (1) ET-1 levels were significantly higher in "desaturators" COPD patients than in "non-desaturators" COPD and in asthmatics; (2) ET-1 levels were significantly higher during the night than during the day in "desaturators" COPD patients; (3) the degree of desaturation correlated negatively with the ET-1 levels in "desaturators" COPD patients, both during daytime and nighttime. These findings are consistent with the hypothesis that ET-1 is implicated in the pathophysiology of asthma and COPD, especially if nocturnal, nonapneic, oxyhemoglobin desaturation exists.

Abnormal origin of the left common carotid artery by innominate artery: a case of enlargement mediastinum.

An abnormal origin of the left common carotid artery is rare. A 71-year-old male was presented with a cough, fever and dyspnea. A chest radiography revealed a widening of the superior mediastinum. An abnormal origin of the left common carotid artery by innominate artery was diagnosed by angiography.

Evaluation of arterial endothelin-1 levels, before and during a sleep study, in patients with bronchial asthma and chronic obstructive pulmonary disease.

BACKGROUND: Endothelin (ET)-1 has been implicated in the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD). The ET-1 levels are elevated during exacerbations of asthma and COPD in bronchoalveolar lavage, serum, and sputum, falling with treatment of the exacerbations. OBJECTIVE: The aim of this study was to examine the ET-1 blood levels in stable asthmatic patients and stable COPD patients during alertness and sleep. MATERIALS AND METHODS: We examined 48 COPD and 20 asthmatic patients. All underwent forced spirometry, measurement of SaO2 and of arterial ET-1 levels and nocturnal polysomnography. ET-1 levels were also determined during nocturnal oxyhaemoglobin desaturation. RESULTS: The daytime SaO2 level of our asthmatic patients was higher than that of our COPD patients (p < 0.001). Daytime SaO2 level of our non-desaturator COPD patients was higher than that measured in desaturator COPD patients. Nightime SaO2 level in our asthmatic patients was higher than that in our desaturator COPD patients (p < 0.001). Daytime ET-1 levels in desaturator COPD patients were higher than those observed in normal individuals, in non-desaturator COPD patients and in asthmatic patients. The COPD desaturator patients had higher levels of ET-1 during nighttime than during daytime (p < 0.001). CONCLUSION: Asthmatic patients did not exhibit desaturation of haemoglobin during the night. ET-1 levels are significantly higher in desaturator COPD patients compared with non-desaturator COPD patients, both during the day and during the night. ET-1 levels in stable COPD patients are significantly higher than in patients with stable asthma. These findings are consistent with the hypothesis that ET-1 is implicated in the pathogenesis of COPD and asthma.