Obesity (BMI ≥30) with Daytime Hypercapnia and No or Mild OSA: Management After First-Line PAP Therapy Has Not Corrected Hypercapnia

Clinical scenario: Patient with obesity (BMI ≥30 kg/m²), daytime hypercapnia (PaCO&sub2; ≥45 mmHg), and sleep disordered breathing without severe obstructive sleep apnoea (AHI <30 events/h — no or mild OSA). Other causes of alveolar hypoventilation have been excluded.

Previous Treatment — Failure Condition

First-line noninvasive ventilation (NIV) with bi-level pressure settings and PAP titration — as part of a multimodality approach combining PAP with weight reduction and increased physical activity — did not achieve the primary goals at approximately 2 months: reduction in daytime PaCO&sub2; and correction of daytime hypercapnia with an increase in arterial oxygen tension. This protocol also applies when the patient is intolerant of PAP therapy.

Next-Step Approach

In patients intolerant of PAP, the approach involves a class of respiratory stimulants that augment ventilation, administered under close monitoring by specialised centres. The specific agents, selection criteria, and monitoring requirements are detailed in the full protocol.

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References

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.

Noninvasive ventilation (NIV) should be considered as first-line therapy for OHS patients with no OSA or milder forms of OSA.

The remaining patients have non-obstructive sleep hypoventilation with no or mild OSA.

There are case report data and a small RCT assessing the role of respiratory stimulants, such as medroxyprogesterone and acetazolamide, which augment ventilation in patients with OHS and can be considered in patients intolerant of PAP.

DOI: 10.1183/16000617.0097-2018 View source ↗