Treatment of obstructive sleep apnea in high risk pregnancy: a multicenter randomized controlled trial.

BACKGROUND: Obstructive sleep apnea (OSA) during pregnancy is a risk factor for preeclampsia possibly through a link to placental physiology. This study evaluates the efficacy of continuous positive airway pressure (CPAP) on the modulation of blood pressure and the reduction in preeclampsia in women with high-risk pregnancy and OSA. METHODS: A multicenter open-label, randomized controlled trial comparing CPAP treatment versus usual antenatal care was conducted in three academic hospitals in Bangkok, Thailand. Participants included singleton pregnant women aged older than 18 years with any high-risk condition (i.e., chronic hypertension, obesity, history of preeclampsia or gestational diabetes in the previous pregnancy, or diabetes), and OSA (respiratory disturbance index 5-29.99 events/hour by polysomnography), who presented either in the first trimester (gestational age, GA 0-16 weeks) or subsequently developed OSA during the 2nd trimester (GA 24-28 weeks). The primary endpoint was blood pressure during antenatal care. Secondary endpoints included the incidence of preeclampsia. An intention-to-treat analysis was performed with additional per-protocol and counterfactual analyses for handling of nonadherence. RESULTS: Of 340 participants, 96.5% were recruited during the first trimester. Thirty participants were later excluded leaving 153 and 157 participants in the CPAP and usual-care groups for the modified-intention-to-treat analysis. CPAP adherence rate was 32.7% with average use of 2.5 h/night. Overall, CPAP treatment significantly lowered diastolic blood pressure (DBP) by - 2.2 mmHg [95% CI (- 3.9, - 0.4), p = 0.014], representing approximately - 0.5 mmHg per hour of CPAP use [95%CI (- 0.89, - 0.10), p = 0.013]. CPAP treatment also altered the blood pressure trajectory by continuously lowering DBP throughout pregnancy with mean differences (95% CI) of - 3.09 (- 5.34, - 0.93), - 3.49 (- 5.67, - 1.31) and - 3.03 (- 5.20, - 0.85) mmHg at GA 18-20, 24-28, and 32-34 weeks, respectively compared to 0-16 weeks. Preeclampsia rate was 13.1% (20/153 participants) in the CPAP and 22.3% (35/157 participants) in the usual-care group with a risk difference (95% CI) of - 9% (- 18%, - 1%, p-value = 0.032) and a number-needed-to-treat (95% CI) of 11 (1, 21). CONCLUSIONS: CPAP treatment in women with even mild-to-moderate OSA and high-risk pregnancy demonstrated reductions in both DBP and the incidence of preeclampsia. CPAP treatment also demonstrated a sustained reduction in DBP throughout gestation. Trial registration ClinicalTrial.GovNCT03356106, retrospectively registered November 29, 2017.

Expiratory air trapping during asthma exacerbation: Relationships with clinical indices and proximal airway morphology.

OBJECTIVES: To semi-quantitatively assess expiratory air trapping (AT(exp)) and structural changes in the proximal airways in asthma during asthma exacerbation (AE) and to explore the relationships among AT(exp), clinical indices, and proximal airway changes. METHODS: Paired inspiratory-dynamic forced expiratory CT scans of 36 asthmatics (30 women, 6 men; mean age, 49.2±18.9 years) performed during AE were retrospectively reviewed for the total AT(exp) score (summed scores [extent grading (0-4)×pattern grading (1-4)] of the twelve lung zones), morphologic parameters and expiratory bronchial collapse (BC(exp)) of the proximal airways. The relationships of the score with clinical indices and proximal airway morphology (normalized by body surface area [BSA]) were analyzed. A p value of <0.05 was considered statistically significant. RESULTS: The mean total AT(exp) score was 110.1±43.4 (range, 8-166). It was higher in the lower zones and in patients older than 60 years, having BMI of <27.5 kg/m(2), and peak expiratory flow rate (PEFR) of <60% predicted. Correlation existed between the score and age (r=0.331), BMI (r=-0.375), BSA (r=-0.442), % predicted PEFR (r=-0.332), right upper lobe apical segmental bronchus (RB1)-wall area (WA)/BSA (r=0.467), %RB1-WA (r=0.395), and RB1-bronchial wall thickness (BWT)/BSA (r=0.378). The score showed no correlation with BC(exp) and other morphologic bronchial parameters. Area under receiver-operating-characteristic curve 0.724 (95% CI) showed that the score of 110 could discriminate patients with PEFR of <60% predicted from those with PEFR of ≥60% predicted. CONCLUSION: During AE, there was a high prevalence of extensive AT(exp) which was correlated with patient's age, BMI, BSA, AE severity and RB1 morphology but not correlated with BC(exp).