Snoring & OSA Algorithm · Reasoning GP

Safety

Red Flags — High-Risk OSA & Driving Safety

Done

Untreated OSA is a driving risk — advise to stop driving if excessive daytime sleepiness present. Document this advice.

Falling asleep at the wheel / near-miss Immediately stop driving. Notify DVLA. 7× increased road traffic accident risk with untreated OSA. Mandatory documentation of advice.

Commercial / HGV / PSV driver + sleepiness Must stop driving immediately. DVLA Group 2 licence requires OSA to be treated and ESS <9 before relicensing. Occupational implications — notify employer.

Severe oxygen desaturation Nocturnal SpO2 <80% on oximetry → severe OSA / obesity hypoventilation syndrome → urgent sleep medicine referral

Witnessed prolonged apnoeas Apnoeas >10 seconds multiple times/night + morning headache + cognitive impairment → moderate-severe OSA → sleep study urgently

Pulmonary hypertension signs OSA + RV heave + elevated JVP + peripheral oedema → cor pulmonale (PHTN from chronic hypoxia) → same-day hospital

Newly diagnosed resistant hypertension + snoring OSA causes hypertension in 30–50% of cases — often treatment-resistant until OSA treated. Secondary hypertension screen.

Child with snoring + behaviour problems / ADHD Paediatric OSA causes neurocognitive impairment, school performance decline, growth retardation → paediatric ENT for adenotonsillectomy assessment

Obesity hypoventilation syndrome BMI >35 + daytime hypercapnia (confused, morning headache) + hypoxia → arterial blood gas + urgent respiratory referral. Life-threatening.

Untreated OSA increases road traffic accident risk 7-fold — it is a public safety issue as well as a personal health issue. DVLA regulations (2023) require Group 1 drivers (car/motorcycle) to notify DVLA if OSA causes excessive daytime sleepiness affecting driving, and Group 2 drivers (HGV/PSV) must stop driving until OSA is confirmed treated (ESS <9, minimum 1 month of CPAP compliance). GPs have a legal obligation to advise patients about driving restrictions and document this advice. Obesity hypoventilation syndrome (OHS — Pickwickian syndrome) is a distinct, life-threatening condition — it requires both CPAP/BiPAP and aggressive weight management and carries 50% 5-year mortality without treatment.

Diagnose

History — STOP-BANG & Symptom Screen

Done

STOP-BANG score

Snoring loud? Tired during day? Observed apnoeas? Pressure (hypertension)? BMI >35? Age >50? Neck >40 cm (M) / 35 cm (F)? Gender male? Score 0–2 = low risk, 3–4 = intermediate, ≥5 = high risk for OSA.

Epworth Sleepiness Scale

8 situations (reading, watching TV, as passenger, lying down, sitting talking, sitting after lunch, in car stopped, sitting in traffic). Score 0–24. ≥10 = excessive daytime somnolence requiring investigation. ≥16 = severe.

Witnessed apnoeas

Partner history is essential — do you stop breathing during sleep? How many times per night? How long? Gasping/choking on waking. Partner's observations are more reliable than patient's self-report.

Daytime impact

Refreshing sleep (non-restorative)? Morning headache (CO2 retention)? Cognitive impairment, memory problems, concentration? Mood changes, irritability, depression? Performance at work?

Nocturia

Waking to pass urine ≥2 times/night is common in OSA — atrial natriuretic peptide released in response to negative intrathoracic pressure from obstructed breathing. OSA is a reversible cause of nocturia.

Cardiovascular risk

Hypertension (especially resistant), AF, heart failure, type 2 diabetes, stroke/TIA — all associated with OSA. Treating OSA may improve blood pressure control by 3–5 mmHg.

STOP-BANG has 94% sensitivity for moderate-severe OSA (AHI >15) when score ≥3, making it the recommended primary care screening tool. However, specificity is low (35%) — many patients with positive scores will not have significant OSA on polysomnography. This is acceptable in screening, where sensitivity is prioritised. Nocturia as a presenting complaint of OSA is frequently missed — approximately 30% of men with nocturia have underlying OSA as a contributing factor. Morning headache (frontal, dull, improves within 1–2 hours of waking) reflects CO2 retention from overnight hypoventilation — it is a clinical indicator of moderate-severe OSA or obesity hypoventilation.

Diagnose

Differential Diagnosis — Snoring Spectrum

Done

Primary (simple) snoring

Snoring without apnoeas, without daytime sleepiness, without cardiovascular impact. Partner disturbed but patient well. ESS <10. No CPAP indication — lifestyle measures + MAD if social impact severe.

Obstructive sleep apnoea

Repetitive upper airway collapse during sleep (partial = hypopnoea, complete = apnoea). AHI (apnoea-hypopnoea index): mild 5–14/hr, moderate 15–29/hr, severe ≥30/hr. CPAP indicated for moderate-severe or symptomatic mild.

Upper airway resistance syndrome

Increased respiratory effort without discrete apnoeas — EEG arousals, daytime sleepiness, snoring. AHI normal on sleep study. Diagnosed on polysomnography. CPAP effective.

Obesity hypoventilation syndrome

BMI >35 + daytime hypercapnia (PaCO2 >6 kPa) + sleep-disordered breathing. 90% have co-existing OSA. BiPAP often required. High cardiovascular and respiratory mortality.

Central sleep apnoea

Apnoeas without respiratory effort (vs obstructive which has effort). Associated with heart failure (Cheyne-Stokes), opioid use, high altitude, brainstem pathology. Adaptive servo-ventilation (ASV) — specialist initiated.

Nasal obstruction

Deviated nasal septum, chronic rhinitis, nasal polyps, adenoid hypertrophy (children) — all cause or worsen snoring. Nasal steroids + refer ENT if significant obstruction.

Central sleep apnoea in heart failure (Cheyne-Stokes respiration) is critically important — it worsens prognosis in heart failure and was previously treated with adaptive servo-ventilation (ASV) until the SERVE-HF trial (2015) showed ASV increased cardiovascular mortality in heart failure patients with reduced ejection fraction. ASV is now contraindicated in HFrEF — this is an important safety point. Simple snoring (without apnoeas or daytime symptoms) does not need CPAP — CPAP is expensive and has significant side effects. Mandibular advancement devices are an effective alternative for primary snoring and mild-moderate OSA who cannot tolerate CPAP.

Diagnose

Targeted Examination

Done

BMI + weight + waist

BMI >30 strongly associated with OSA. Waist >94 cm (M) / >80 cm (F) = abdominal obesity. Weight loss of 10% reduces AHI by 25–30%. Track at every consultation.

Neck circumference

>40 cm (M) / >35 cm (F) = independent OSA risk factor. Measure at thyroid cartilage level. Fat deposition around pharynx narrows airway.

Blood pressure

Bilateral BP measurement — hypertension is both caused by and worsened by OSA. Resistant hypertension (BP uncontrolled on ≥3 agents including diuretic) → screen for OSA.

Oropharyngeal exam

Mallampati score (visualisation of posterior oropharynx with mouth open, tongue out, not phonating — class III/IV = reduced airway). Tonsillar size (grade 1–4). Retrognathia (small jaw — OSA risk).

Nasal airway

Anterior rhinoscopy — septal deviation, inferior turbinate hypertrophy, polyps. Assess nasal patency. Nasal obstruction worsens OSA.

Cardiovascular

Assess for cor pulmonale (RV heave, loud P2, raised JVP, peripheral oedema, hepatomegaly) in severe/longstanding OSA. AF rhythm assessment.

Mallampati class III/IV (posterior oropharynx and soft palate not visible) indicates a narrow upper airway and correlates with OSA severity. The Mallampati score is also used by anaesthetists to predict difficult intubation — patients with high Mallampati scores and OSA are high-risk for anaesthetic airway complications and must have this documented. Retrognathia (posterior displacement of the mandible) significantly reduces the airway dimensions and is a non-modifiable OSA risk factor — mandibular advancement devices are particularly effective in retrognathic patients as they advance the jaw and tongue base anteriorly, enlarging the airway.

Diagnose

Investigations

Done

Home overnight oximetry

Overnight pulse oximetry — GP-arranged in many regions. Identifies oxygen desaturation index (ODI — dips >4% per hour). ODI >15 = significant. Sensitivity 80% for moderate-severe OSA. First-line before sleep study.

Bloods

TFTs (hypothyroidism worsens OSA) · FBC (polycythaemia from chronic hypoxia — raised Hb) · HbA1c (OSA + DM2 co-morbidity) · Fasting lipids (metabolic syndrome screen) · BMI + BP documented

ABG (severe cases)

Arterial blood gas — if obesity hypoventilation suspected (BMI >35 + morning headache + hypoxia). Daytime PaCO2 >6.0 kPa = OHS diagnostic. Hospital or respiratory clinic arranged.

Polysomnography (PSG)

Gold standard — full overnight sleep study. AHI, sleep stages, arousal index, limb movements, CPAP titration. Arranged by sleep medicine clinic after oximetry/clinical assessment. Not routinely needed in straightforward OSA.

NOT routinely

Home sleep testing device (limited channel) — available in some NHS sleep centres instead of full PSG. Acceptable for uncomplicated suspected OSA. Avoid in suspected complex sleep disorders (central, parasomnias).

Home overnight oximetry is available in many GP practices or via community equipment services and represents a significant first-line investigation that avoids a 6–12 month wait for formal sleep study in most patients. An ODI >15/hr (oxygen desaturation index — number of >4% dips per hour) has 85% sensitivity and 80% specificity for moderate-severe OSA and can be used to justify urgent sleep study referral. Polycythaemia (elevated Hb) secondary to chronic nocturnal hypoxia is a reversible complication of severe OSA — effective CPAP treatment normalises Hb over months. Hypothyroidism can both cause and significantly worsen OSA through weight gain and pharyngeal tissue myxoedema — TFTs are mandatory.

Refer

Referral Pathways

Done

Same-day hospital

Suspected cor pulmonale from OSA (RV failure, peripheral oedema, polycythaemia), suspected OHS with daytime hypercapnia, acute desaturation with cardiovascular compromise

Urgent sleep clinic

Commercial driver (Group 2 licence) — cannot return to work until assessed and treated. ESS ≥16 (severe sleepiness). Witnessed prolonged apnoeas. STOP-BANG ≥5 + ESS ≥10.

Routine sleep clinic

STOP-BANG ≥3 + ESS ≥10, or overnight oximetry ODI >15. Via respiratory / sleep medicine. Includes CPAP titration, follow-up and compliance monitoring.

ENT

Simple snoring with significant nasal obstruction (deviated septum, polyps), tonsillar hypertrophy grade 3–4, retrognathia considered for MAD, paediatric OSA (adenotonsillectomy)

Tier 3 weight management / bariatric

BMI >35 + OSA + metabolic comorbidities. Weight loss of 15–20% can eliminate mild-moderate OSA. Bariatric surgery reduces AHI by 60–80% on average.

Simple snoring — no referral

STOP-BANG <3, ESS <10, no witnessed apnoeas, no cardiovascular impact → lifestyle measures first. Review at 3 months. Refer if not improving or snoring significantly impacting relationship.

Commercial drivers (Group 2 — HGV, PSV, taxi) represent an urgent occupational safety priority — they cannot legally drive until OSA is confirmed treated with documented CPAP compliance and Epworth score <9. GPs must document this advice clearly. Bariatric surgery achieves remission of OSA in 80% of patients — weight loss is the only intervention that can cure (rather than just treat) OSA. NICE TA228 recommends CPAP for moderate-severe OSA — the cost-effectiveness is very high given CPAP's impact on cardiovascular risk reduction, road accident prevention, and quality of life (QALY gain of 0.14/year at £3,000/QALY, well within NICE threshold).

Treat

Treatment by Severity

Done

Moderate-severe OSA

CPAP therapy

Continuous positive airway pressure — provided by sleep clinic with mask fitting and titration. Therapeutic pressure typically 8–12 cmH2O. Required ≥4 hours/night for clinical benefit. Reduces AHI to <5/hr. NICE TA228.

Mild OSA / snoring

Mandibular advancement device

Titratable MAD — advances mandible 5–10 mm, enlarges posterior airway. Custom-fitted via dentist/ENT. 70–80% efficacy for mild-moderate OSA. Alternative for CPAP-intolerant. NHS-funded via some sleep clinics.

Nasal obstruction component

Mometasone nasal spray

Mometasone 200 mcg/spray, 2 sprays each nostril OD. Reduces nasal mucosal oedema — improves nasal breathing, reduces mouth breathing (worsens OSA). Nasal dilator strips (Breathe Right) — OTC, modest benefit for primary snoring.

Positional OSASupine-predominant OSA — positional therapy (tennis ball in back of pyjamas, positional alarm devices, sleep position trainer). Effective when AHI in lateral position is 50% of supine AHI.

Hypothyroidism-relatedLevothyroxine replacement → may significantly improve or resolve OSA. Reassess with oximetry/sleep study after 3–6 months of euthyroid state before permanent CPAP prescription.

CPAP intoleranceAddress: mask fit (try different mask types — nasal pillow, full-face, nasal), heated humidifier attachment (reduces dryness), pressure ramp-up, auto-titrating CPAP (APAP — adjusts to breathing needs). 70% achieve compliance with support.

CPAP compliance (>4 hours/night) is required for cardiovascular benefit — sub-therapeutic compliance (2–3 hours) improves symptoms but does not reduce cardiovascular risk. Sleep clinics track compliance via CPAP data card download — this is shared with the GP for monitoring. CPAP reduces systolic BP by 3–5 mmHg (as effective as adding one antihypertensive agent), reduces AF recurrence post-cardioversion, and improves insulin sensitivity in type 2 diabetes. Mandibular advancement devices are preferred by patients for lifestyle reasons (travel, portability) but are slightly less effective than CPAP for severe OSA — they are an acceptable alternative for mild-moderate OSA with preference.

Lifestyle

Weight, Sleep Position & Risk Factor Modification

Done

Weight loss Most impactful intervention — 10% weight loss reduces AHI by 25–30%. 15% reduction can eliminate mild OSA entirely. Caloric restriction + exercise programme. Refer Tier 3 weight management if BMI >35 + comorbidities.

Lateral sleep position Side-sleeping reduces OSA severity by 50% in positional OSA (60% of all OSA patients). "Sleep on your side" is simple, free, and effective. Positional alarm devices available commercially.

Alcohol cessation Alcohol relaxes upper airway musculature — even 2 units before bed increases AHI by 25% and worsens oximetry. Avoid alcohol for 4 hours before bed minimum. AUDIT-C screen.

Smoking cessation Smoking causes upper airway mucosal inflammation, increases nasal congestion, and worsens OSA. Cessation reduces AHI in smokers. NHS Stop Smoking Service referral.

Avoid sedatives / hypnotics Benzodiazepines, Z-drugs, and opioids relax upper airway muscles, worsen apnoeas, and blunt the arousal response to hypoxia. Avoid or use with extreme caution in confirmed OSA.

Head of bed elevation Raising head of bed 30° (wedge pillow or bed tilt) reduces tongue/soft palate prolapse by gravity. Particularly effective in mild OSA and patients who cannot tolerate lateral positioning.

Nasal hygiene Saline nasal irrigation (Neilmed) clears nasal secretions, reduces rhinitis, and improves nasal airflow — improves CPAP tolerance and OSA severity. Daily use in patients with nasal congestion.

Exercise Regular aerobic exercise improves OSA severity independently of weight loss — reduces pharyngeal fat deposition and improves upper airway tone. 150 minutes/week moderate exercise (NHS guidelines).

A landmark study (Tuomilehto et al., NEJM 2009) showed that intensive lifestyle intervention (dietary restriction + exercise) achieving 10% weight loss eliminated OSA in 63% of obese patients — significantly outperforming sham control. This makes lifestyle modification more effective for mild-moderate OSA than any pharmacological intervention. Opioid medications are particularly dangerous in OSA — they blunt the arousal response to hypoxia (the mechanism that wakes the patient to restore breathing) and increase the duration and severity of apnoeas. Prescribing opioids to patients with untreated severe OSA can cause fatal nocturnal respiratory arrest.

Safety

Follow-Up, CPAP Compliance & Driving

Done

CPAP — 4–6 weeks

Sleep clinic reviews compliance (data download — hours/night, AHI, leak data). ESS reassessment. If ESS still ≥10 after 4 weeks of adequate CPAP → review mask fit, pressure, or reconsider diagnosis.

CPAP — 6 months

Annual CPAP review — compliance maintained? Weight change affecting pressure needs? Any new symptoms? Mask replaced (every 6 months). Sleep clinic responsibility, GP monitors cardiovascular risk factors.

Driving reassessment

Group 1: may return to driving once symptoms controlled and ESS <9 — no formal DVLA notification required unless still symptomatic. Group 2 (HGV/PSV): DVLA medical review required before relicensing after confirmed OSA diagnosis.

Weight monitoring

Monthly weight review in obese OSA. 10% weight loss → repeat oximetry to reassess OSA severity — may allow step-down or cessation of CPAP.

Cardiovascular monitoring

Annual BP check, HbA1c, lipids — OSA is an independent cardiovascular risk factor. Effective CPAP reduces 10-year cardiovascular risk — QRISK score improvement.

999 safety-net

Acute hypoxic episode at home (SpO2 <88% on pulse oximeter), suspected cor pulmonale deterioration, respiratory arrest symptoms, acute confusional state with cyanosis

Same-day GP

New morning headaches (CO2 retention worsening), cognitive deterioration in known OSA, CPAP-related side effects causing inability to use (nasal bridge sores, severe dry mouth, persistent claustrophobia)

CPAP compliance data monitoring is essential — patients who use CPAP <4 hours/night get only partial benefit and retain significant cardiovascular risk. Sleep clinics provide downloaded compliance reports (via built-in CPAP modem technology) — GPs should request these at annual reviews. Weight loss in obese OSA patients can completely resolve the condition — this should be actively pursued as it represents the only true cure. Annual repeat oximetry after significant weight loss (≥10%) allows CPAP to be safely discontinued in some patients, improving quality of life. Driving regulations for OSA are often misunderstood — the key point is that it is SYMPTOMS (excessive sleepiness) not the diagnosis that triggers the DVLA obligation, though known OSA must be disclosed when renewing Group 2 licence.