NERO: a pilot study but important step towards comprehensive management of obesity hypoventilation syndrome

The assessment and management of obstructive sleep apnoea-hypopnoea syndrome and obesity hypoventilation syndrome in obesity

Obesity is associated with respiratory dysfunction. It is a key risk and contributory factor in the sleep related breathing disorders, obstructive sleep apnoea/hypopnoea syndrome (OSAHS) and obesity hypoventilation syndrome (OHS). Weight management is an integral part of the management of these disorders, in addition to continuous positive airways pressure (CPAP) and non-invasive ventilation (NIV). Untreated, these conditions are associated with a high disease burden and as treatment is effective, early recognition and referral is critical. Best practice in on-going care is multidisciplinary.

Obesity hypoventilation syndrome

Obesity hypoventilation syndrome (OHS) is defined as a combination of obesity (body mass index ≥30 kg·m-2), daytime hypercapnia (arterial carbon dioxide tension ≥45 mmHg) and sleep disordered breathing, after ruling out other disorders that may cause alveolar hypoventilation. OHS prevalence has been estimated to be ∼0.4% of the adult population. OHS is typically diagnosed during an episode of acute-on-chronic hypercapnic respiratory failure or when symptoms lead to pulmonary or sleep consultation in stable conditions. The diagnosis is firmly established after arterial blood gases and a sleep study. The presence of daytime hypercapnia is explained by several co-existing mechanisms such as obesity-related changes in the respiratory system, alterations in respiratory drive and breathing abnormalities during sleep. The most frequent comorbidities are metabolic and cardiovascular, mainly heart failure, coronary disease and pulmonary hypertension. Both continuous positive airway pressure (CPAP) and noninvasive ventilation (NIV) improve clinical symptoms, quality of life, gas exchange, and sleep disordered breathing. CPAP is considered the first-line treatment modality for OHS phenotype with concomitant severe obstructive sleep apnoea, whereas NIV is preferred in the minority of OHS patients with hypoventilation during sleep with no or milder forms of obstructive sleep apnoea (approximately <30% of OHS patients). Acute-on-chronic hypercapnic respiratory failure is habitually treated with NIV. Appropriate management of comorbidities including medications and rehabilitation programmes are key issues for improving prognosis.

Efficacy of bilevel ventilatory support in the treatment of stable patients with obesity hypoventilation syndrome: systematic review and meta-analysis

OBJECTIVE

To systematically review the effects of bilevel ventilatory support (BVS) in patients with Obesity Hypoventilation Syndrome (OHS).

METHODS

A search of databases (MEDLINE accessed by PubMed, Cochrane CENTRAL, EMBASE and LILACS) was conducted from inception to June 2018. Randomized trials comparing BVS to other therapeutic modalities such as lifestyle counseling, continuous positive airway pressure (PAP) or BVS with average volume assured pressure support for the treatment of patients with OHS were included. The primary outcome was a change in daytime arterial carbon dioxide levels (PaCO₂). Secondary outcome measures included arterial partial pressure of oxygen (PaO₂), blood bicarbonate (HCO₃), percentage of total sleep time (TST) with oxygen saturation <90%, transcutaneous pressure of carbon dioxide (PtcCO₂), Epworth Sleepiness Scale (ESS), Medical Outcome Survey Short Form (SF36), Functional Outcomes of Sleep Questionnaire (FOSQ), Severe Respiratory Insufficiency Questionnaire (SRI), compliance with treatment, and weight loss.

RESULTS

Of 176 articles identified, seven studies were included. When BVS was compared to lifestyle counseling, the intervention was superior in improving PaCO₂ (-2.90 mmHg; 95%CI -4.28 to -1.52), PaO₂ (2.89 mmHg; 95%CI 0.33 to 5.46), HCO₃ (-2.55 mmol/L; 95%CI -3.28 to -1.81), percentage of TST<90% (-30.55%; 95%CI -37.98 to -23.12), ESS (-2.52; 95%CI -4.16 to -0.88) and FOSQ (6.33; 95%CI 1.78 to 10.88). However, when BVS was compared to other PAP modalities, there was no difference in any of the outcomes evaluated.

CONCLUSIONS

Treatment using BVS therapy is superior to lifestyle counseling. Different PAP modalities appear to be equally effective in improving outcomes. CRD42017065326.

Ventilatory support or respiratory muscle training as adjuncts to exercise in obese CPAP-treated patients with obstructive sleep apnoea: a randomised controlled trial

BACKGROUND

Obstructive sleep apnoea (OSA) and obesity are interdependent chronic diseases sharing reduced exercise tolerance and high cardiovascular risk.

INTERVENTION

A 3-month intervention with innovative training modalities would further improve functional capacity and cardiovascular health than usual cycle exercise training in already continuous positive airway pressure (CPAP)-treated obese patients with OSA.

METHODS

Fifty three patients (35

MEASUREMENTS AND MAIN RESULTS

All training modalities increased 6 min walking distance without differences between groups (P=0.97). ERGO+NIV and ERGO+RMT led to significantly higher improvement in VO2peak compared with ERGO (3.1 (95% CI 1.6 to 4.6) vs 2.3 (0.8 to 3.7) vs 0.5(-1.0 to 1.9) mL/min/kg, respectively, P=0.04) and ERGO+NIV significantly reduced self-measured blood pressure compared with ERGO+RMT and ERGO (systolic: -9.5 (95% CI -14.1 to -4.9) vs -13 (-5.8 to 3.1) vs -0.7 (-5.1 to 3.8) mm Hg, respectively, P=0.01). Waist and neck circumferences were reduced after ERGO+NIV compared with ERGO+RMT and ERGO (P=0.01).

CONCLUSIONS

Combining RMT or NIV with cycling exercise training failed to provide further improvement in functional capacity as compared with cycling exercise training alone. However, the combination of NIV and exercise training demonstrated superiority for improving cardiometabolic risk factors in obese CPAP-treated patients with OAS.

TRIAL REGISTRATION NUMBER

Results, NCT01155271.

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Key Words

• pulmonary rehabilitation
• respiratory muscles
• sleep apnoea

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Affiliation(s)

Isabelle Vivodtzev HP2 Laboratory, Centre Hospitalier Universitaire Grenoble Alpes, INSERM U1042, Grenoble Alps University, Grenoble, France Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Harvard Medical School, Cambridge, Massachusetts, USA
Renaud Tamisier HP2 Laboratory, Centre Hospitalier Universitaire Grenoble Alpes, INSERM U1042, Grenoble Alps University, Grenoble, France
Marilie Croteau Centre de Recherche, Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec, QC, Canada
Jean-Christian Borel HP2 Laboratory, Centre Hospitalier Universitaire Grenoble Alpes, INSERM U1042, Grenoble Alps University, Grenoble, France
Angélique Grangier HP2 Laboratory, Centre Hospitalier Universitaire Grenoble Alpes, INSERM U1042, Grenoble Alps University, Grenoble, France
Bernard Wuyam HP2 Laboratory, Centre Hospitalier Universitaire Grenoble Alpes, INSERM U1042, Grenoble Alps University, Grenoble, France
Patrick Lévy HP2 Laboratory, Centre Hospitalier Universitaire Grenoble Alpes, INSERM U1042, Grenoble Alps University, Grenoble, France
Caroline Minville Centre de Recherche, Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec, QC, Canada
Frédéric Sériès Centre de Recherche, Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec, QC, Canada
François Maltais Centre de Recherche, Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec, QC, Canada
Jean-Louis Pépin HP2 Laboratory, Centre Hospitalier Universitaire Grenoble Alpes, INSERM U1042, Grenoble Alps University, Grenoble, France

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