Oxygen Therapy Targets and Management of Breathlessness

Oxygen Saturation Targets

For patients without risk of hypercapnic respiratory failure, aim for an oxygen saturation of 94 %–98 %. This target applies to the general breathless population receiving supplemental oxygen. 1
For patients with risk of hypercapnic respiratory failure, aim for an oxygen saturation of 88 %–92 % to minimise CO₂ retention. 2

Risk factors that warrant the lower‑target (88 %–92 %) strategy include:
In patients with COPD who develop respiratory acidosis from excessive oxygen (PaO₂ > 10 kPa / 75 mm Hg), do not discontinue oxygen abruptly. Instead, step down to a Venturi mask delivering 28 %–35 % oxygen or to 1–2 L/min via nasal cannula, targeting the 88 %–92 % saturation range. This gradual reduction avoids rapid falls in oxygenation while allowing CO₂ to clear. 2

A hand‑held fan should be offered as first‑line therapy for breathlessness when the patient’s SpO₂ is ≥94 %, and before initiating supplemental oxygen. The airflow on the face reduces the sensation of dyspnoea. 3

Low‑dose opioids are recommended for refractory breathlessness that persists despite optimal treatment of the underlying condition. Oral sustained‑release morphine may be started at 10 mg per day (e.g., 5 mg twice daily). 4
In dose‑escalation studies, 63 % of participants achieved a clinically important improvement; 67 % responded at the initial 10 mg/day dose, 25 % required escalation to 20 mg/day, and 8 % needed 30 mg/day. These data support titrating to the lowest effective dose. 4

In chronically hypoxemic patients experiencing an exacerbation with a ≥3 % drop in SpO₂ on their usual oxygen regimen, arrange hospital assessment with arterial blood‑gas analysis to evaluate for severe hypoxaemia. 5

The American Heart Association recommends beginning by ensuring scene safety, checking responsiveness, and immediately assessing for life-threatening causes requiring resuscitation, then measuring oxygen saturation and vital signs to guide oxygen therapy and determine the need for urgent intervention 6, 7
The American Heart Association suggests tapping the patient's shoulder and shouting "Are you all right?" to assess responsiveness, and simultaneously checking for absent or abnormal breathing (gasping does not count as normal breathing) 6, 8
If unresponsive with no breathing or only gasping, the American Heart Association recommends activating emergency response and beginning CPR immediately, and healthcare providers should check for a pulse, taking no more than 10 seconds—if no definite pulse is felt, start chest compressions 6

The American College of Physicians recommends measuring oxygen saturation using pulse oximetry immediately in all patients presenting with breathlessness, and checking respiratory rate, heart rate, and blood pressure to assess severity 7
For patients without risk of hypercapnic respiratory failure, the British Thoracic Society recommends starting oxygen via nasal cannula (1-4 L/min) or simple face mask (5-10 L/min) targeting 94-98% saturation 7
For patients with risk of hypercapnic respiratory failure, the British Thoracic Society suggests targeting oxygen saturation of 88-92% using controlled oxygen via Venturi mask (24-28%) 7

The British Medical Journal recommends sitting the patient upright to increase peak ventilation and reduce airway obstruction, and having the patient lean forward with arms bracing a chair or knees with upper body supported to improve ventilatory capacity 9, 7
The British Medical Journal suggests teaching pursed-lip breathing: inhale through nose for several seconds with mouth closed, then exhale slowly through pursed lips for 4-6 seconds, and instructing patient to relax and drop shoulders to reduce the hunched posture associated with anxiety 9

The British Medical Journal recommends opening airway using head tilt-chin lift maneuver: place hand on forehead and gently tilt head back while lifting chin with fingertips, and avoiding head tilt if trauma to the neck is suspected 8
The British Medical Journal suggests giving 2 effective rescue breaths after ensuring head tilt and chin lift, pinching nose closed, and creating a good seal around the mouth, and each breath should take 1.5-2 seconds and make the chest rise 8

The American College of Physicians recommends recording oxygen saturation, delivery system, and flow rate on patient monitoring charts, and reassessing frequently if breathlessness persists despite interventions 7
The American College of Physicians suggests seeking medical advice if: patient appears to need increasing oxygen therapy, there is a rising National Early Warning Score (NEWS), or signs of respiratory deterioration are present 7