The association between asthma and obstructive sleep apnea (OSA): A systematic review.

OBJECTIVE: Bronchial asthma and obstructive sleep apnoea (OSA) are common respiratory disorders that can co-exist. The strength of this association, and also the impact of OSA on asthma-related clinical outcomes remain unclear. DATA SOURCES: Literature review was performed in EMBASE and MEDLINE databases. Studies up to and including 2016 were selected. STUDY SELECTION: Studies were included if they contained; 1) a population with asthma AND 2) a prevalence of OSA reported using either polysomnography or validated questionnaires such as the Sleep Apnoea Scale of the Sleep Disorders Questionnaire (SA-SDQ), STOP BANG or the Berlin questionnaire. RESULTS: Nineteen studies were identified. Thirteen questionnaire-based studies met the inclusion/exclusion criteria and twelve of these demonstrated a prevalence of OSA in asthma of 8-52.6%, with one study showing no association between the two conditions. Six studies using polysomnography demonstrated a high prevalence of 19.2-60%; which was higher at 50-95% in severe asthma. Two polysomnography and four questionnaire studies found worse asthma-related clinical outcomes with co-existing OSA. One polysomnography and two questionnaire studies showed no difference. CONCLUSION: This systematic review suggests that there is a high prevalence of OSA in asthma, particularly within severe asthma populations and that co-diagnosis of OSA in asthma patients is associated with worse clinical outcomes. However this outcome was not uniform and the number of studies using polysomnography to confirm OSA was small. This weakens the conclusions that can be drawn and prompts the need for adequately powered and well-designed studies to confirm or refute these findings.

Biomarkers of oxidative stress and antioxidants in severe asthma: A Prospective Case-Control Study.

BACKGROUND: Bronchial airway inflammation is the hallmark of asthma, which may be driven by an imbalance between oxidative stress and antioxidant defenses. Antioxidants deficiency may play a role, but this has remained unconfirmed. OBJECTIVE: To evaluate the oxidative stress burden and antioxidants defenses in patients with increasing asthma severity. METHODS: This prospective case-control study compared fractional exhaled nitric oxide (FeNO), exhaled breath condensate nitrite/nitrate (EBC-NOx), spirometry, and serum vitamins and trace elements among patients with and without asthma. RESULTS: Sixty participants were recruited (30 with severe asthma number; 23 women [76.7%]; mean age, 41.4 years; mean forced expiratory volume in 1 second [FEV1], 2.2 L [72.2% predicted]; mean inhaled corticosteroid dosage, 2,540 µg/d; 18/30 [60%] receiving maintenance oral corticosteroids; 15 with mild asthma; all corticosteroids naïve; 9 women [60%]; mean age, 34.6 years; mean FEV1, 3.48 L [100.5% predicted]; 15 healthy controls; 12 women [80%]; mean age, 37.6 years; and mean FEV1, 3.53 L [111.7% predicted]). The mean FeNO levels increased significantly with increasing asthma severity (P = .01), but the EBC-NOx levels did not change significantly (P = .90). Paradoxically, vitamin A and vitamin E increased with increased disease severity, with vitamin E levels increasing significantly (P = .07 and P < .001, respectively). There was no significant difference between groups in the levels of copper (P = .37), zinc (P = .97), or selenium (P = .90). CONCLUSION: FeNO but not EBC-NOx is increased significantly with asthma severity with no evidence of vitamins or trace elements deficiency in severe asthma. Impaired oxidative stress defenses in severe asthma may be driven by factors other than vitamins or trace elements deficiency.

The Preventative Effect of Hydrocolloid Dressings on Nasal Bridge Pressure Ulceration in Acute Non-Invasive Ventilation.

BACKGROUND: Non-invasive ventilation (NIV) is a valuable treatment in the management of acute hypercapnic respiratory failure. NIV is not without risks. One such adverse effect is the development of pressure ulcers over the nasal bridge which have an incidence of up to 20% of patients requiring NIV in this setting. The role of medical devices in the development of hospital acquired pressure ulcers has been increasingly recognised with 10-35% of all hospital acquired ulcers attributed to medical devices. Guidelines on acute NIV use suggest good skin care strategies. However, data on the magnitude of the problem of nasal bridge pressure ulceration and the effect of proactive preventative steps remains scant. METHOD: A quality improvement project was designed to reduce the incidence of nasal bridge pressure ulcers during acute NIV. Hydrocolloid dressings were placed over the nasal bridge in all patients requiring NIV between 30th October 2015 and the 29th October 2016. Tissue viability was assessed daily with new pressure ulceration defined as grade 2 or above. Rates of nasal bridge pressure ulcers were compared to all patients requiring NIV in the 12-month period prior to intervention. RESULTS: In Group 1, there were 161 admissions and 9 grade 2 pressure ulcers from 666 NIV bed-days. In Group 2 there were 134 admissions and 0 pressure ulcers from 718 NIV bed-days. There was a statistically significant reduction in grade 2 pressure ulceration rates (p= 0.0013) in Group 2 compared to Group 1. CONCLUSION: Application of an early prophylactic pressure-relieving hydrocolloid nasal dressing reduces the risk of developing grade 2 pressure ulcers in patients in patients requiring acute NIV.

Does Continuous Positive Airway Pressure (CPAP) treatment of obstructive sleep apnoea (OSA) improve asthma-related clinical outcomes in patients with co-existing conditions?- A systematic review.

INTRODUCTION: A high prevalence of OSA has been observed in asthma populations, with detrimental impact on clinical outcomes. AIM: To determine if CPAP treatment of co-existing OSA improves asthma-related symptoms and quality of life. METHODS: Literature review of EMBASE and MEDLINE databases prior to July 2017. Study populations included asthmatics with co-existing OSA treated with CPAP, and ≥1 asthma-related clinical outcome measure. RESULTS: 12 studies; 8 prospective quasi-experimental and 4 observational. Mean CPAP duration; 19.5 (2-100) weeks. Meta-analysis demonstrated significant improvement in mean Asthma Quality of Life Questionnaire scores (AQLQ and mini-AQLQ); 0.59 (95%CI; 0.25, 0.92), p = 0.0006. No significant improvement was demonstrated in forced expiratory volume in 1 s (FEV1)% predicted; 0.32 (95%CI; -2.84, 3.47), p = 0.84. Asthma Control Test/Asthma Control Questionnaire improved in 2 studies, with no improvement in 1 study. 4 studies demonstrated improvement in asthma daytime/night-time symptoms, and 3 studies showed improved asthma severity. CONCLUSION: Asthmatics with co-existing OSA can experience improved quality of life with CPAP treatment. This effect appears more pronounced in severe OSA or poorly controlled asthma.