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Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.

Non-invasive ventilation

Respiratory · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

RapidFull
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Escalate

NIV must not delay intubation in a patient who cannot protect the airway, is peri-arrest, has severe worsening acidosis, uncontrolled vomiting, refractory hypoxaemia or haemodynamic instability. Call critical care early and document whether invasive ventilation is appropriate before the mask is applied.

Synopsis

Start, optimise and monitor acute NIV safely in patients with a reversible ventilatory failure, with a clear ceiling, failure criteria and route to invasive ventilation when needed.

  • For acute COPD, consider NIV when pH remains below 7.35 with PaCO2 above 6.5 kPa and tachypnoea after about 1 hour of optimal medical treatment.
  • NICE calls NIV the treatment of choice for persistent hypercapnic ventilatory failure during a COPD exacerbation despite optimal medical therapy.
  • Start acute NIV within 60 minutes of the qualifying blood-gas result and, for patients presenting with AHRF, within 120 minutes of hospital arrival where possible.
  • Before starting, treat reversible factors and document diagnosis, target SpO2, interface/settings, monitoring location, escalation to intubation and what to do if NIV fails.
  • Typical initial bilevel settings are IPAP 10–15 cmH2O and EPAP 4–5 cmH2O, with a backup rate around 12–16/min; titrate IPAP over 10–30 minutes toward 20–30 as needed and tolerated.
  • Increase pressure support (IPAP minus EPAP) to improve tidal volume and lower PaCO2; increase EPAP/FiO2 for persistent hypoxaemia while preserving adequate pressure support.
  • Repeat ABG about 1 hour after starting and after material setting changes, then around 4 hours; improving pH, PaCO2, respiratory rate and distress indicates response.
  • Continuous SpO2 and cardiac monitoring are expected early; trained staff, an appropriate NIV area and rapid access to blood gases are treatment requirements, not extras.
  • An undrained pneumothorax, fixed upper-airway obstruction, major facial injury/burn or inability to protect the airway makes NIV unsafe or impossible until the problem is corrected.
  • NIV is not routine for acute asthma or isolated hypoxaemic pneumonia; these groups need early critical-care assessment because failure can be abrupt.

Key red flags

Evidence-based COPD indication

Persistent pH below 7.35 and PaCO2 above 6.5 kPa with tachypnoea after controlled oxygen, bronchodilators, steroids and cause treatment.

Neuromuscular/chest-wall risk

Hypercapnia, rapid shallow breathing, vital-capacity decline or weak cough may justify NIV before severe acidosis; bulbar dysfunction and secretion load increase failure risk.

Immediate intubation concern

Respiratory arrest, inability to protect airway, worsening consciousness, severe haemodynamic instability, refractory hypoxaemia or rapidly worsening acidosis.

Technical NIV failure

Large mask leak, wrong circuit/exhalation port, poor synchrony, insufficient IPAP, blocked secretions or an untreated pneumothorax can mimic biological failure.

Investigation priorities

01
Pre-NIV ABGFirst step

Confirm acute hypercapnic failure and establish severity.

Management branches

PrepareOne-hour optimisation and decision

Suspected COPD-related acute hypercapnic respiratory failure.

  1. Give controlled oxygen to 88–92%, nebulised bronchodilators, systemic steroid and antibiotics when indicated; stop/reverse respiratory depressants and manage secretions.
  2. Obtain/repeat ABG after initial treatment. If pH remains below 7.35 with PaCO2 above 6.5 kPa and tachypnoea, decide on NIV promptly.
  3. Before the mask, document escalation/ceiling, treatment location, target SpO2, settings, ABG schedule and the clinician to call for failure.

Key medicines

Salbutamol nebuliser2.5 mg nebulised, increasing to 5 mg in severe bronchospasm and repeating according to response; use compressed air to drive in hypercapnia risk while oxygen is delivered separately to target.Tachycardia, tremor, hypokalaemia and lactate rise; review frequent dosing and cardiac rhythm.
Ipratropium bromide nebuliser500 micrograms nebulised, commonly every 4–6 hours during a severe COPD exacerbation, alongside short-acting beta2 agonist.Dry mouth, urinary retention and acute angle-closure glaucoma if aerosol reaches the eyes; not a treatment for ventilatory failure itself.
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Sources and review status5 sources · checked 27 Aug 2026 · clinical review pending+
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.

  • BTS/ICS guideline for ventilatory management of acute hypercapnic respiratory failurePatient selection, settings, monitoring and escalation.
  • BTS Quality Standards for acute NIVTiming, staffing, treatment area and review standards.
  • NICE NG115: COPD in over 16s—recommendationsNIV as treatment of choice in persistent hypercapnic COPD failure.
  • BTS adult NIV algorithmOperational settings, gas timings and failure triggers.
  • BTS enhanced emergency assessment pathways 2026Current COPD initial-treatment doses and acute NIV timing.

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateRapid draftClinical stateAwaiting reviewJurisdictionUnited Kingdom