The STOP-BANG questionnaire is a validated, eight-item screening tool for obstructive sleep apnoea (OSA) in adult patients, developed by Frances Chung and colleagues at the University of Toronto and published in Anesthesiology in 2008. OSA is characterised by repetitive partial or complete collapse of the upper airway during sleep, resulting in hypoxaemia, sleep fragmentation, and excessive daytime sleepiness, with a prevalence of 15–24% in adult men and 5–9% in adult women — the majority of whom remain undiagnosed. OSA is a significant perioperative risk factor because of its association with difficult intubation, postoperative respiratory complications, and sensitivity to opioids and sedatives. The STOP-BANG acronym stands for: Snoring (Do you snore loudly?), Tired (Do you often feel tired, fatigued, or sleepy during the daytime?), Observed apnoeas (Has anyone observed you stop breathing during sleep?), Pressure (Do you have or are you being treated for high blood pressure?), BMI >35, Age >50 years, Neck circumference >40 cm, and Gender male. Each item is scored yes=1 or no=0, giving a total of 0–8. A score of 0–2 indicates low OSA risk, 3–4 intermediate risk, and 5–8 high OSA risk. STOP-BANG has a sensitivity of >90% for detecting moderate-to-severe OSA and is endorsed by the American Society of Anesthesiologists (ASA) and multiple anaesthesia and sleep medicine guidelines as a preoperative screening tool. Positive screening should trigger polysomnography (sleep study) referral or perioperative OSA management protocol activation.
STOP-BANG Score = Snoring(0/1) + Tired(0/1) + Observed(0/1) + Pressure(0/1) + BMI>35(0/1) + Age>50(0/1) + Neck>40cm(0/1) + Gender male(0/1); 0–2=low, 3–4=intermediate, 5–8=high OSA risk
- 1Step 1 — Snoring (S): Ask 'Do you snore loudly (louder than talking, or loud enough to be heard through closed doors)?' Score 1 for yes.
- 2Step 2 — Tired (T): Ask 'Do you often feel tired, fatigued, or sleepy during the daytime (such as falling asleep while driving)?' Score 1 for yes.
- 3Step 3 — Observed apnoeas (O): Ask 'Has anyone observed you stop breathing during your sleep?' Score 1 if yes.
- 4Step 4 — Pressure (P): Ask 'Do you have or are you being treated for high blood pressure?' Score 1 for yes.
- 5Step 5 — BMI (B): Measure or record BMI. Score 1 if BMI >35 kg/m².
- 6Step 6 — Age (A): Score 1 if patient is older than 50 years.
- 7Step 7 — Neck circumference (N): Measure neck circumference. Score 1 if >40 cm (approximately shirt collar size >17 inches).
- 8Step 8 — Gender (G): Score 1 if patient is male. Calculate total (0–8) and assign risk category.
Very high risk — anaesthesia review required; consider sleep study pre-operatively; CPAP if known OSA
All 8 criteria positive. This patient is at maximum STOP-BANG risk. Suspected severe OSA must be addressed perioperatively — postoperative monitoring, avoid opioid-sedative combinations, consider CPAP.
Intermediate risk — consider sleep study referral; monitor perioperatively for desaturation events
Snoring=1, tired=1, age>50=1. Total=3. Intermediate risk. Women with STOP-BANG ≥3 may be at similar risk to men with ≥4 due to systematic underdiagnosis of OSA in women.
Low OSA risk — no specific perioperative measures beyond standard monitoring required
All criteria negative in a young healthy non-obese woman. OSA risk is very low. Standard anaesthetic management is appropriate.
Consider that some studies use ≥4 as threshold for high risk in male patients; sleep study referral reasonable
Pressure=1, age>50=1, neck>40=1, male=1. Total=4. Upper boundary of intermediate risk in the standard scale. Many anaesthesia guidelines treat STOP-BANG ≥4 as high risk.
Pre-operative anaesthetic assessment to identify OSA risk and plan perioperative airway and analgesia management, representing an important application area for the Stop Bang in professional and analytical contexts where accurate stop bang calculations directly support informed decision-making, strategic planning, and performance optimization
Primary care screening of patients with resistant hypertension, type 2 diabetes, or atrial fibrillation for occult OSA, representing an important application area for the Stop Bang in professional and analytical contexts where accurate stop bang calculations directly support informed decision-making, strategic planning, and performance optimization
Sleep medicine clinics as the entry-point screening tool before formal polysomnography referral, representing an important application area for the Stop Bang in professional and analytical contexts where accurate stop bang calculations directly support informed decision-making, strategic planning, and performance optimization
Cardiology assessment of AF, heart failure, and hypertension patients where OSA is a modifiable comorbidity, representing an important application area for the Stop Bang in professional and analytical contexts where accurate stop bang calculations directly support informed decision-making, strategic planning, and performance optimization
Occupational health screening of commercial vehicle drivers, pilots, and shift workers for OSA-related impairment, representing an important application area for the Stop Bang in professional and analytical contexts where accurate stop bang calculations directly support informed decision-making, strategic planning, and performance optimization
Morbidly Obese Patients
STOP-BANG is particularly important pre-bariatric surgery, where OSA is associated with significantly increased perioperative mortality. Pre-operative sleep study and CPAP optimisation should be considered standard care before elective bariatric surgery in STOP-BANG high-risk patients.'}
Patients with Cardiac Arrhythmias
{'title': 'Patients with Cardiac Arrhythmias', 'body': 'OSA is an independent risk factor for atrial fibrillation, hypertension, and heart failure. In patients with new atrial fibrillation, resistant hypertension, or unexplained right heart failure, OSA should be actively screened with STOP-BANG. Treatment of OSA with CPAP has been shown to reduce AF recurrence rates after cardioversion.'}
Paediatric OSA
In the Stop Bang, this scenario requires additional caution when interpreting stop bang results. The standard formula may not fully account for all factors present in this edge case, and supplementary analysis or expert consultation may be warranted. Professional best practice involves documenting assumptions, running sensitivity analyses, and cross-referencing results with alternative methods when stop bang calculations fall into non-standard territory.
Pregnancy and OSA
{'title': 'Pregnancy and OSA', 'body': 'OSA prevalence increases during pregnancy due to weight gain, mucosal oedema, and positional changes. Third-trimester OSA is associated with gestational hypertension, pre-eclampsia, and fetal growth restriction. STOP-BANG has not been formally validated in pregnancy but can be used as a screening prompt for referral to obstetric sleep medicine clinics.'}
| Criterion | Yes (1pt) | No (0pt) |
|---|---|---|
| S — Snoring | Loud snoring (louder than talking / heard through walls) | No or quiet snoring |
| T — Tired | Frequent daytime fatigue or sleepiness | Not fatigued |
| O — Observed | Witnessed apnoeas during sleep | None reported |
| P — Pressure | Hypertension (treated or untreated) | No hypertension |
| B — BMI | BMI >35 kg/m² | BMI ≤35 |
| A — Age | Age >50 years | Age ≤50 |
| N — Neck | Neck circumference >40 cm | Neck ≤40 cm |
| G — Gender | Male | Female |
| Risk category | 0–2 = Low; 3–4 = Intermediate; 5–8 = High |
What is the sensitivity of STOP-BANG for OSA?
STOP-BANG has a sensitivity of approximately 93–100% for moderate-to-severe OSA (AHI ≥15) at a cutoff of ≥3. This high sensitivity means it rarely misses significant OSA. Specificity is lower (~30–50%), meaning many STOP-BANG positive patients will not have confirmed OSA on formal sleep study — but this is acceptable for a screening tool.
What is AHI and how is OSA classified?
The Apnoea-Hypopnoea Index (AHI) measures sleep-disordered breathing events per hour of sleep, confirmed by polysomnography. AHI 5–14 = mild OSA; 15–29 = moderate OSA; ≥30 = severe OSA. The standard treatment for moderate-to-severe OSA is CPAP (continuous positive airway pressure). Mild OSA may be treated with positional therapy, weight loss, or mandibular advancement devices.
Why is neck circumference included in STOP-BANG?
Upper airway anatomy, particularly neck circumference, is a strong predictor of OSA. A larger neck circumference correlates with increased pharyngeal fat deposition and reduced airway calibre. Neck circumference >40 cm (approximately 17-inch collar size) is the threshold used in STOP-BANG. It is an objective anatomical measurement that can be taken quickly in any clinical setting.
How does OSA affect perioperative risk?
OSA patients are at increased risk of: difficult mask ventilation and intubation (due to redundant pharyngeal tissue), postoperative respiratory depression (heightened sensitivity to opioids and sedatives), hypoxic events on the ward, and postoperative pulmonary complications. They benefit from: opioid-sparing multimodal analgesia, careful positioning (semi-recumbent), supplemental oxygen monitoring, and CPAP continuation perioperatively.
Can STOP-BANG be used for non-surgical patients?
Yes — STOP-BANG is widely used in sleep medicine clinics, primary care, cardiology, and any clinical setting where OSA screening is indicated. Patients with resistant hypertension, heart failure, atrial fibrillation, or type 2 diabetes have particularly high OSA prevalence and should be screened. A positive screen in any setting warrants referral for polysomnography or home sleep apnoea testing.
What is the difference between STOP-BANG and Epworth Sleepiness Scale?
The Epworth Sleepiness Scale (ESS) measures subjective daytime sleepiness across 8 common situations (e.g., watching TV, sitting reading, as a car passenger). A score ≥11 suggests excessive daytime sleepiness. ESS is a symptom severity measure rather than an OSA screening tool — many OSA patients do not feel sleepy despite significant overnight hypoxaemia. STOP-BANG is more sensitive for OSA detection; ESS better quantifies symptom burden.
Does gender scoring in STOP-BANG underserve women?
Yes — the male gender criterion (1 point) reflects the higher OSA prevalence in men, but this can lead to systematic underdiagnosis in women. Women with OSA often present differently (more fatigue, insomnia, depression) rather than classic loud snoring and apnoeas. Modified thresholds have been proposed: STOP-BANG ≥3 in women or men, rather than ≥3 for men and ≥4 for women, to reduce gender bias in screening.
Should patients with known OSA on CPAP still be screened with STOP-BANG?
Known OSA patients are automatically classified as high risk for perioperative purposes regardless of STOP-BANG score. The key clinical information is: Is their OSA well controlled? Are they CPAP compliant? Do they have their CPAP machine available perioperatively? CPAP should be continued through the perioperative period — patients should bring their machine to hospital.
Pro Tip
Use STOP-BANG at the pre-operative assessment clinic for every patient undergoing any procedure requiring sedation or general anaesthesia. For STOP-BANG ≥5, discuss OSA management plan with the anaesthetist before the procedure: CPAP availability, opioid-sparing analgesia plan, post-operative monitoring location (HDU versus general ward), and patient education about OSA risks.
Did you know?
The STOP-BANG questionnaire was published in 2008 and has since become the most widely used OSA screening tool worldwide, with over 500 peer-reviewed validation studies. Its eight binary questions can be completed in under 2 minutes by patients themselves in waiting rooms. Remarkably, it was developed because studies showed that anaesthesiologists correctly predicted OSA risk by clinical gestalt only about 50% of the time — no better than chance — prompting the need for a systematic, evidence-based screening approach.
References
- ›Chung F et al. — STOP Questionnaire: A Tool to Screen Patients for OSA (Anesthesiology 2008)
- ›Nagappa M et al. — Validation of STOP-BANG Questionnaire — Systematic Review (PLoS ONE 2015)
- ›ASA Practice Guidelines for the Perioperative Management of Patients with OSA (2014)
- ›NICE — Obstructive Sleep Apnoea/Hypopnoea Syndrome in Adults (NG202, 2021)
- ›LITFL STOP-BANG Questionnaire Reference