CPAP not working? An AU guide to optimising sleep apnoea treatment

CPAP: between prescription and benefit lies a gap

Being prescribed CPAP for obstructive sleep apnoea is not the same as benefiting from it. Research consistently shows that more than half of patients fail to reach the AASM definition of adequate adherence — at least 4 hours of use per night on 70% or more of nights — and many abandon treatment altogether within the first few months.

This article is written for the patient who already has a CPAP machine but is not yet getting the benefit they were promised. If you are still being investigated for sleep apnoea, the starting point is a referral to a sleep physician or Sleep Health Foundation-affiliated service for a diagnostic sleep study.

A. Core clinical — the AU general-practice framework

Who this applies to

There are three common entry points for CPAP troubleshooting:

Non-starter. The machine is sitting unused. The fitting appointment felt overwhelming, the pressure was uncomfortable on the first night, or daily life made it easy to procrastinate. The 30-day acclimatisation window matters — what happens in the first few nights predicts long-term use.

Drop-out. There was initial use, but adherence fell off at 1–6 months. Mask leak, skin marks, dry nose, partner disruption, or simply not feeling different enough to bother.

Adherent but undertreated. Consistent nightly use, but daytime sleepiness persists, BP remains difficult to control, or the download shows residual AHI above 5/h. The machine is on, but not doing its job.

Therapy targets: what the download should show

Pull the device download before making any clinical decision. Cloud platforms from ResMed (myAir, AirView), Philips (Care Orchestrator), and Fisher & Paykel (InfoSmart) make this straightforward. The four numbers that matter:

• Usage: ≥4 h/night on ≥70% of monitored nights — the operational AASM adherence definition
• Residual AHI: target <5/h — above this, something is wrong with mask seal or pressure settings
• Mask leak (95th centile): target <24 L/min (ResMed convention); leak above threshold invalidates the AHI reading
• 95th-centile pressure: for APAP, persistent >18 cmH₂O suggests bilevel consideration

The week-one-to-four rescue workflow

The first month is where most adherence loss occurs, with the first few days being the highest-risk period. Triage problems in this order:

1. Mask fit. This is the dominant failure mode. The mask hierarchy exists because no single mask suits every patient:

• Nasal pillows — smallest footprint, least claustrophobic, preferred first try; best for lower pressures (up to ~10 cmH₂O) and patients who tolerate a chinstrap for mouth breathing
• Nasal mask — second tier; covers the nose only but with better seal stability at pressures 10–14 cmH₂O
• Oronasal (full-face) mask — third tier; for mouth leak that does not respond to a chinstrap, severe nasal obstruction, or very high pressures

A sleep technician refit is the single highest-yield intervention. Most CPAP providers offer a free 30-day mask-swap window — exploit it before declaring failure.

2. Pressure intolerance. If the patient describes “I can’t breathe out against it”:

• Switch fixed CPAP to APAP — Smith 2012 Cochrane meta-analysis showed equivalent AHI and Epworth score with about 11 extra minutes per night compliance
• Enable the ramp function (starts at 5 cmH₂O, rises over 20–45 min while the patient falls asleep)
• Turn on expiratory pressure relief (EPR 1–3 on ResMed; Flex 1–3 on Philips)

3. Aerophagia. Gut bloating, belching, and morning distension usually indicate over-pressurisation. Shift to nasal pillows if possible (less swallowed air), encourage a lateral sleep position, and consider dropping the APAP upper pressure limit.

4. Mouth leak. Try a chinstrap first. If that fails, move to an oronasal mask. Screen for and treat underlying nasal obstruction — allergic rhinitis (intranasal corticosteroid), deviated septum or nasal polyps (ENT referral).

5. Dry mouth and nasal congestion. Titrate the heated humidifier up; add a heated tube if available (ResMed Climate-LineAir, Philips Heated Tube) to reduce rainout. Saline nasal rinse before bed; intranasal corticosteroid for concurrent rhinitis.

6. Claustrophobia. Structured desensitisation — daytime mask wear without pressure for 30 minutes (watching television), then with pressure while sitting, then to sleep. Nasal pillows offer the least facial coverage. Refer to a sleep psychologist for graded exposure in severe cases.

7. Bed-partner disturbance. Modern devices are quieter than a whisper at the pillow. If the partner hears a whistling sound, it is nearly always a mask seal issue, not the machine itself. The ResMed AirSense 11 (integrated humidifier, reduced size) and Philips DreamStation 2 are the current AU flagships. Note that the original Philips DreamStation 1 was subject to a TGA recall in June 2021 for degradation of its polyurethane foam — the DreamStation 2 uses redesigned silicone foam and is not affected. Anyone still using a DreamStation 1 should be transitioned.

When to re-investigate

Recheck a home sleep study at 3 months if the download shows residual AHI persistently >5/h despite adequate adherence and leak control. MBS item 12250 covers a follow-up diagnostic sleep study. If residual AHI remains >10/h despite good adherence and correct mask, refer for in-laboratory polysomnography and bilevel titration (MBS item 12207).

The escalation menu when CPAP rescue fails

• Mandibular advancement device (MAD) — custom-fitted by an accredited dentist; effective for AHI <30; appropriate as an adjunct or CPAP substitute in genuinely intolerant patients; costs ~$1,000–3,000; regular dental review required
• Hypoglossal nerve stimulator (Inspire) — TGA-listed implant for AHI 15–65 in CPAP-intolerant patients; not PBS-funded; costs >$30,000 out-of-pocket; available at selected AU tertiary centres
• Upper-airway surgery — tonsillectomy where adenotonsillar enlargement drives the problem; UPPP largely outdated as monotherapy; maxillomandibular advancement for selected anatomies
• Weight loss + GLP-1 receptor agonist + bariatric pathway — 10% weight reduction produces roughly a 25% AHI reduction; tirzepatide and semaglutide achieve larger effects; MBS items 31572/31575 underwrite bariatric surgery at BMI ≥40 or ≥35 with major comorbidity including OSA

B. Evidence and controversies

CPAP and hard cardiovascular outcomes

The SAVE trial (McEvoy NEJM 2016) enrolled over 2,700 patients with moderate-to-severe OSA and established cardiovascular disease. At a mean follow-up of 3.7 years, CPAP did not reduce the composite of cardiovascular death, MI, stroke, or hospitalisation — with a mean CPAP use of only 3.3 hours per night.

Per-protocol analyses in adherent subgroups do show nocturnal BP reduction and AF-burden improvements. The clinical interpretation: treat OSA for symptoms, sleepiness, nocturnal BP, and road safety. Do not position CPAP as primary cardiovascular event prevention, and do not use the SAVE result to dismiss CPAP for symptomatic patients.

APAP versus fixed CPAP

Smith 2012 — a Cochrane-updated systematic review and meta-analysis — found equivalent AHI suppression and Epworth sleepiness scores between APAP and fixed CPAP, with APAP producing about 11 minutes per night more adherence. Fixed CPAP had marginally better minimum SpO₂. APAP is the pragmatic default; fixed pressure is appropriate when APAP tolerance is poor.

Myofunctional therapy

Camacho 2015 (SLEEP meta-analysis) — 9 studies across 120 adults — found oropharyngeal exercises reduced AHI by approximately 50% in mild-to-moderate disease. Effect is modest but meaningful as an adjunct for motivated patients who want an active role. Requires daily practice for 3+ months.

C. CPAP in Australian practice

MBS items relevant to CPAP management

• Standard GP consultation (items 23, 36, 44) for CPAP review
• GP-initiated home sleep study (item 12203) — for high-pretest-probability moderate-to-severe OSA
• Sleep-physician-referred polysomnography (item 12207) — for complex cases or bilevel titration
• Repeat diagnostic sleep study (item 12250) — 3-month check if residual AHI suspected
• Chronic Disease Management Plan (items 965/967) — covers OSA plus comorbidities (replaced 721/723/732 from 1 July 2025)
• Bariatric surgery (items 31572/31575) — for BMI ≥40 or ≥35 with major comorbidity

CPAP cost and access reality

CPAP is not PBS-subsidised in Australia. Typical out-of-pocket costs: device $1,500–3,500; mask $200–400 (replace every 6–12 months). NDIS only funds when sleep apnoea is directly linked to an approved primary disability, not for OSA alone. Private health insurance “Medical Appliances” and “Sleep Apnoea” benefits vary substantially between funds — verify before purchase. DVA Gold Card covers CPAP for eligible veterans. Rent-to-buy pathways through major manufacturers reduce the upfront barrier.

Commercial and heavy-vehicle drivers

Austroads 2022 §8 requires documented treatment efficacy before commercial driving can resume — specifically, a CPAP download confirming ≥4 h/night on ≥70% of nights, residual AHI <10/h, and no significant residual sleepiness. Annual review is required. Private licence holders have a self-report obligation; healthcare providers may notify the licensing authority if a patient refuses to act on advice.

D. Special populations

Aboriginal and Torres Strait Islander patients. OSA prevalence is elevated in many Aboriginal and Torres Strait Islander communities. Telehealth sleep medicine is Medicare-rebatable and can reduce access barriers in regional and remote areas. Sleep Health Foundation publishes patient resources in plain English.

Patients with atrial fibrillation. CPAP reduces post-cardioversion AF recurrence burden and may lower nocturnal BP in resistant hypertension. Re-engagement framing around these specific gains is often more motivating than generic “treat your apnoea” advice.

Patients with type 2 diabetes. Some evidence suggests insulin sensitivity improves with adherent CPAP therapy. Include OSA management in the diabetes care plan.

Older adults. CPAP is as beneficial in older adults as in younger patients; humidification and mask choice may need greater attention. Falls risk from nocturnal hypoxia is a relevant motivator for adherence.

Positional OSA. If the diagnostic study showed supine AHI ≥2 times the lateral AHI, adding positional therapy (NightBalance vest, vibrotactile Snoreshirt, body pillow) allows CPAP at lower pressures and may improve adherence. Confirm the positional phenotype on the study before recommending.

When to escalate

Refer to a sleep physician or sleep-medicine service when:

• Residual AHI >5/h on the download despite adequate mask seal and adherence — further titration or bilevel assessment needed
• 95th-centile pressure consistently >18 cmH₂O on APAP — bilevel required
• Suspected hypoventilation (bicarbonate elevation, morning headaches, daytime hypercapnia) — bilevel with a backup rate or non-invasive ventilation may be indicated
• Genuine CPAP intolerance after full rescue cycle — for MAD or Inspire assessment
• Unexplained persistent daytime sleepiness despite confirmed adequate CPAP therapy — consider narcolepsy, PLMD, or central hypersomnia
• Commercial driver unable to achieve documented adherence required for recertification

What this article is and is not

This is general health information drawn from Australasian Sleep Association, Sleep Health Foundation, Therapeutic Guidelines (eTG), AASM, and current literature. It is not personal medical advice and does not replace assessment and management by your own GP, sleep physician, or sleep technician.

For AU consumer resources: Sleep Health Foundation, HealthDirect — Sleep apnoea, Better Health Channel.

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Sources cited

1. Australasian Sleep Association
2. Sleep Health Foundation
3. Therapeutic Guidelines (eTG)
4. AASM — CPAP adherence measure (MIPS #279, 2025)
5. SAVE trial — McEvoy NEJM 2016
6. Smith 2012 — APAP vs fixed CPAP meta-analysis
7. Sawyer 2022 — Adherence to PAP therapy review
8. Camacho 2015 — Myofunctional therapy for OSA (SLEEP)
9. TGA — Philips CPAP recall action (Jun 2021)
10. Austroads — Assessing Fitness to Drive 2022
11. NDIS / CPAP subsidy — Sleep Testing Australia
12. MBS Online — Item 12203
13. MBS Online — Item 12207
14. MBS Online — Item 12250
15. HealthDirect — Sleep apnoea