01Principles and purposeThe professional or clinical skill and the decisions it supports.
Assess airway and breathing first. Obtain reliable saturation, respiratory rate, work, consciousness and oxygen history while calling for help in critical illness. Oxygen treats hypoxaemia, not breathlessness alone. Carbon-monoxide exposure and other special circumstances have separate guidance, but urgent life-saving resuscitation is not delayed.
Prepare the prescribed source, flowmeter, interface, tubing, oximeter and fire-safety environment. Confirm cylinder content for transport, secure cylinders and keep oil, flame and smoking away. Check tubing continuity, device integrity and size. Humidification is not automatic and should follow indication and local system guidance.
BTS guidance targets 94–98% for most acutely ill adults and 88–92% for known COPD or other hypercapnic-risk states pending blood gases. COPD does not prove carbon-dioxide retention and never justifies leaving severe hypoxaemia untreated. An established patient-specific range or gas result may change the target.
Typical BTS starting flows are nasal cannulae 2–6 L/min, simple mask 5–10 L/min and reservoir mask 15 L/min. Never run a simple mask below 5 L/min. Controlled hypercapnic-risk examples are 24% Venturi at 2–3 L/min or 28% at 4 L/min; follow the actual valve’s printed minimum and meet respiratory demand. Maintain reservoir inflation and confirm the patient’s response.
Apply the interface, set the correct flow and observe saturation and breathing continuously in instability. Titrate to target rather than maximal saturation. If target is not reached, check patient, airway, source, connectors and interface and escalate; do not turn up an unsuitable device indefinitely. Inspect pressure points and dryness.
Obtain urgent blood gases in hypercapnic risk. Repeat after 30–60 minutes, or sooner with deterioration, to detect rising PaCO2 or falling pH. Critical illness, shock or peri-arrest deterioration can require initial reservoir oxygen at 15 L/min even with COPD while resuscitation and gases guide treatment. If excessive oxygen is contributing to hypercapnia, step delivery down to the target instead of abruptly withdrawing it; acidosis or drowsiness requires urgent ventilatory assessment.
When stopping oxygen, reduce and observe on air according to plan, recording symptoms and saturation. During transfer, hand over target, device, flow and cylinder duration. Oxygen tubing is a trip hazard. An empty cylinder, kink or disconnected line requires immediate alternative supply and incident review.
Inhaler assessment uses the exact device in the patient’s hand, prescription and dose counter. Ask for an unprompted demonstration. Observe preparation, orientation, exhalation, seal, inspiratory manoeuvre, breath hold, second-dose spacing, closure and cleaning. Verbal confidence does not establish deposition in the lungs.
For a pMDI, remove cap, inspect mouthpiece and shake when the product requires. Exhale gently away, seal lips and begin a slow deep breath while pressing once; continue to full inspiration, hold up to ten seconds as comfortable, then exhale away. Repeat after the product-specified interval if another puff is prescribed.
For a valved holding chamber, assemble and inspect the valve, insert the pMDI, shake, make a seal, actuate one puff and inhale slowly and deeply with breath hold, or take the product-recommended tidal breaths. Do not fire several puffs together. Clean and air-dry according to manufacturer instructions because wiping can increase static.
A DPI is device-specific. Load without wasting a dose, keep the specified orientation, exhale fully away, seal and inhale quickly and deeply enough to disperse powder, then hold breath. Do not exhale into it, shake unless instructed or wash a powder device. Check counter, discard interval and storage.
Breath-actuated and soft-mist devices have different steps. Select a device the patient can generate flow for and manipulate. During severe acute breathlessness, coordination or inspiratory flow may fail; follow the acute plan instead of repeating an unsuitable device and attributing failure to behaviour.
After inhaled corticosteroid, rinse and spit or brush teeth where product instructions advise; a pMDI spacer reduces oropharyngeal deposition. Discuss priming after non-use, mouthpiece cleaning, counter and replacement. Preventer underuse and frequent reliever use prompt clinical review rather than technique teaching alone.
Teach in cycles: explain purpose, demonstrate, ask the patient to demonstrate, correct one error and repeat. Use accessible materials or interpreters and involve carers with consent. Recheck after any change and at reviews, exacerbations and poor control. Document device, errors corrected and final observed ability.
Non-invasive ventilation, high-flow nasal oxygen, tracheostomy oxygen, home-oxygen installation, nebulised medicine and paediatric systems require additional competencies. Delegated application and teaching need local training and support. Clinicians must remain able to summon help and monitor deterioration while teaching any device.
Key points
- Oxygen is a medicine: prescribe target and device except in immediate emergencies, then titrate and record response.
- BTS uses 94–98% for most acutely ill adults and 88–92% pending gases for known COPD or other hypercapnic risk, then individualise.
- Reservoir bags must remain inflated; simple masks have manufacturer minimum flows; Venturi valves require their specified flow.
- Never withhold resuscitation oxygen while waiting for a prescription, but retitrate once reliable monitoring is available.
- Match inhaler to inspiratory ability, dexterity, cognition and preference; environmental benefit cannot rescue an unusable device.
- pMDI technique uses slow deep inhalation coordinated with actuation; a spacer reduces coordination demand.
- Many DPIs require loading, exhalation away and a quick deep inhalation; moisture and exhaling into the device impair delivery.
- Teaching is complete only when the patient demonstrates every step and explains maintenance, counter, mouth care and escalation.
02Situations and prioritiesThe context, relevant information and actions that matter most.
Low saturation with exhaustion, cyanosis, reduced consciousness or instability needs immediate support and senior help.
Drowsiness or acidosis in an at-risk patient needs urgent gas and ventilatory assessment.
Empty cylinder, kink, disconnection or collapsed reservoir can explain target failure.
Actuation outside slow inhalation reduces delivery and may improve with a spacer.
Slow weak inspiration may not disperse powder, especially during acute illness.
Dexterity, cognition, seal or inspiratory limitations can make a chosen inhaler ineffective.
03Assessment and interpretationHow to gather information, assess the situation and recognise uncertainty.
Consider the information, its meaning and its limitations before deciding what follows.
- 01
Pulse oximetry with signal check - Why
- Guide oxygen titration and detect hypoxaemia.
- Interpretation and limitations
- Confirm signal and clinical fit; target depends on hypercapnic risk and prescription.
- 02
Blood gas when indicated - Why
- Assess carbon dioxide and acid-base status.
- Interpretation and limitations
- Oximetry does not reveal hypercapnia; worsening acidosis may require ventilatory support.
- 03
Observed inhaler demonstration - Why
- Identify the specific technique errors preventing effective inhaled medicine delivery.
- Interpretation and limitations
- Record exact device and errors; verbal confidence does not prove correct technique.
- 04
Dose counter and adherence review - Why
- Compare reported use with doses and control.
- Interpretation and limitations
- Counter data supports discussion but does not prove inhalation or deliberate non-adherence.
04Worked approachesCases with ordered reasoning, an action and a check of the outcome.
01Worked case: COPD and saturation 82%Treat hypoxaemia while controlling targetAn alert adult with COPD has SpO2 82% on air, respiratory rate 26 and BP 132/78, without shock or exhaustion. The available 28% Venturi valve specifies 4 L/min.+
- 1Call for urgent clinical assessment and check ABCDE. Start the 28% Venturi at its specified 4 L/min immediately, with an initial 88–92% saturation target pending urgent blood gases.
- 2Check the source, tubing and fit while observing breathing and saturation; in this case SpO2 rises to 90%. Continue the controlled supply and treat the exacerbation. If target is not reached, escalate oxygen delivery and urgent clinical support rather than accepting hypoxaemia.
- 3The urgent gas shows pH 7.37 and PaCO2 6.5 kPa. With raised carbon dioxide but no acidaemia and a stable clinical response, maintain the 88–92% target and repeat gases after 30–60 minutes. A falling pH, worsening hypercapnia, exhaustion or reduced consciousness requires immediate senior ventilatory assessment.
- 4Document device, flow, target, gas and response. Reassess sooner for deterioration, maintain adequate supply during transfer and give a named handover. Critical illness would change this initial oxygen strategy and require resuscitation support.
02Teach pMDI with spacerOne puff and slow breathCoordination is poor with a pressurised inhaler.+
- 1Confirm medicine/device, inspect spacer and observe baseline demonstration.
- 2Demonstrate exhale away, one actuation, slow deep or instructed tidal breaths and breath hold.
- 3Have patient demonstrate, correct errors and document maintenance, mouth care and review.
03Teach a DPILoad dry and inhale forcefullyA dry-powder inhaler is prescribed and its suitability needs observed assessment.+
- 1Confirm inspiratory ability, dexterity, counter and exact instructions.
- 2Load, exhale away, seal, inhale quickly and deeply and hold; keep device dry.
- 3Use teach-back and reassess control, adherence and suitability.
05Feedback, follow-up and evidenceReview outcomes, seek feedback and identify what to improve.
- Continuously monitor unstable patients on oxygen and escalate worsening breathing or consciousness immediately.
- Record target, device, flow and response after changes.
- Repeat blood gases after 30–60 minutes in hypercapnic risk, sooner if the patient deteriorates.
- Inspect interface pressure areas, tubing continuity and adequate oxygen supply during each reassessment.
- Observe a complete inhaler demonstration after every device change and correct identified errors.
- Review symptoms, exacerbations, reliever use and counter.
06Special situationsVariants, exceptions and circumstances that change the usual approach.
Target beats maximum
Controlled oxygen aims for a prescribed range because hypoxaemia and unnecessary hyperoxia can both harm.
COPD still needs oxygen
Hypercapnic risk changes target and gas urgency, not treatment of severe hypoxaemia.
Device determines breath
pMDIs need slow coordinated inhalation while DPIs need sufficiently forceful inspiratory flow.
One puff per chamber
Separate spacer actuations preserve inhalable aerosol instead of depositing it in the chamber.
Demonstration proves learning
Teach-back exposes errors that agreement, leaflets and familiarity do not reveal.
07Common pitfallsFrequent interpretation and management errors.
- 01
Do not leave oxygen without a target after emergency prescribing is possible.
- 02
Do not withhold oxygen because of COPD.
- 03
Do not run a simple mask below manufacturer minimum flow.
- 04
Do not let a reservoir bag collapse.
- 05
NEWS2 Scale 2 requires hypercapnic respiratory failure confirmed by blood gases on the current or a previous admission, plus a competent clinician’s documented decision. COPD alone or an interim 88–92% oxygen target pending gases is insufficient; use Scale 1 otherwise.
- 06
Do not teach one breath for every inhaler.
- 07
Do not fire multiple puffs into a spacer.
- 08
Do not switch until ability is demonstrated.