EM · Respiratory failure (type 1 & 2)
Respiratory failure (type 1 and type 2)
Also known as Type 1 respiratory failure · Type 2 respiratory failure · Hypoxaemic respiratory failure · Hypercapnic respiratory failure
Respiratory failure — the type 1 (hypoxaemic) and type 2 (hypercapnic) classification from the arterial blood gas, the oxygen targets (94 to 98 per cent for most, 88 to 92 per cent for the CO2 retainer), the oxygen device ladder with inspired fractions, the mechanism by which excess oxygen worsens the CO2 (the Haldane effect and the loss of hypoxic pulmonary vasoconstriction), and the escalation to non-invasive ventilation (BiPAP for type 2, CPAP for type 1 pulmonary oedema) and invasive ventilation. ACEM-primary, globally tagged.
Practise this topic
On this page
Study tools
Your progress
Saved on this device.
Target exams
Red flags
- A rising PaCO2 in a previously type-1 patient signals fatigue and impending respiratory arrest — escalate to ventilatory support without delay
- A CO2 retainer given uncontrolled high-flow oxygen may develop CO2 narcosis — target 88 to 92 per cent, not 94 to 98 per cent
- A patient who is becoming drowsy, slowing their respiratory rate, or losing the accessory-muscle effort is tiring — prepare for ventilation
- A normal chest radiograph does not exclude respiratory failure — the ABG is the defining test
- Naloxone 400 micrograms intravenously reverses the opioid-induced type 2 respiratory failure — titrate to avoid the acute withdrawal
Meet the patient
A 68-year-old with known COPD is brought in drowsy and slow. The ambulance crew gave him high-flow oxygen on scene for low saturations — the right call for almost anyone else, the wrong call for him. His gas: pH 7.28, PaCO₂ 8.2 kPa, PaO₂ 7.6 kPa, bicarbonate 32. That is acute-on-chronic type 2 respiratory failure, and the high-flow oxygen has pushed his CO₂ higher still.[1]
The two questions that decide his next hour are the two that decide every respiratory failure: what type is it? (the ABG answers in three minutes) and what oxygen target does that type demand? For him, 88–92 per cent — never 94–98. The Austin trial showed high-flow oxygen raises mortality in prehospital COPD, so your first move is to take it off and reach for the Venturi mask.[9]
References10ShowHide
- [1]O'Driscoll BR, Howard LS, Earis J, et al. BTS guideline for oxygen use in adults in healthcare and emergency settings Thorax, 2017.PMID 28507176
- [2]Matthay MA, Arabi Y, Arroliga AC, et al. A New Global Definition of Acute Respiratory Distress Syndrome Am J Respir Crit Care Med, 2024.PMID 37487152
- [3]Brower RG, Matthay MA, Morris A, et al. Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome N Engl J Med, 2000.PMID 10793162
- [4]Guérin C, Reignier J, Richard JC, et al. Prone positioning in severe acute respiratory distress syndrome N Engl J Med, 2013.PMID 23688302
- [5]Bellani G, Laffey JG, Pham T, et al. Epidemiology, Patterns of Care, and Mortality for Patients With Acute Respiratory Distress Syndrome in Intensive Care Units in 50 Countries JAMA, 2016.PMID 26903337
- [6]Brochard L, Mancebo J, Wysocki M, et al. Noninvasive ventilation for acute exacerbations of chronic obstructive pulmonary disease N Engl J Med, 1995.PMID 7651472
- [7]Plant PK, Owen JL, Elliott MW. Early use of non-invasive ventilation for acute exacerbations of chronic obstructive pulmonary disease on general respiratory wards: a multicentre randomised controlled trial Lancet, 2000.PMID 10859037
- [8]Ram FSF, Picot J, Lightowler J, Wedzicha JA. Non-invasive positive pressure ventilation for treatment of respiratory failure due to exacerbations of chronic obstructive pulmonary disease Cochrane Database Syst Rev, 2004.PMID 15266518
- [9]Austin MA, Wills KE, Blizzard L, Walters EH, Wood-Baker R. Effect of high flow oxygen on mortality in chronic obstructive pulmonary disease patients in prehospital setting: randomised controlled trial BMJ, 2010.PMID 20959284
- [10]Frat JP, Thille AW, Mercat A, et al. High-flow oxygen through nasal cannula in acute hypoxemic respiratory failure N Engl J Med, 2015.PMID 25981908