Management of Acute Desaturations

Initial Oxygen Delivery Based on Severity

The British Thoracic Society recommends immediately initiating high-flow oxygen at 15 L/min via reservoir mask for any patient with SpO2 <85%, while simultaneously performing rapid clinical assessment to identify and treat the underlying cause 1
For patients with critical desaturation (SpO2 <85%), administer the highest possible inspired oxygen concentration using a reservoir mask at 15 L/min immediately, regardless of COPD status or hypercapnic risk until the situation stabilizes 1
The American Heart Association recommends giving the highest possible inspired oxygen during CPR until spontaneous circulation is restored for cardiac arrest or resuscitation scenarios 1
For moderate desaturation (SpO2 85-93%), start oxygen at 2-6 L/min via nasal cannulae or 5-10 L/min via simple face mask, and target SpO2 94-98% for most acutely ill patients 1
For patients with known COPD, morbid obesity, cystic fibrosis, chest wall deformities, neuromuscular disorders, or bronchiectasis with fixed airflow obstruction, target SpO2 88-92% instead 1

The British Journal of Anaesthesia recommends assessing for airway obstruction, tension pneumothorax, massive pulmonary embolism, and acute pulmonary edema as life-threatening causes requiring immediate intervention 2
Verify pulse oximetry signal quality and proper probe placement, and check that the waveform is adequate and correlates with pulse rate 1
Record vital signs comprehensively, including respiratory rate, heart rate and rhythm, blood pressure, mental status, and temperature 4, 5

The British Journal of Anaesthesia recommends using tight-fitting facemask with circuit capable of delivering CPAP (5-10 cm H2O) if oxygenation is impaired for patients requiring intubation 2
Apply nasal oxygen at 5 L/min during preoxygenation while awake, then increase to 15 L/min when consciousness is lost 2
Continue nasal oxygen at 15 L/min or high-flow nasal oxygen (HFNO) at 30-70 L/min during laryngoscopy to provide apneic oxygenation 2

The British Thoracic Society recommends never abruptly discontinuing oxygen, as this causes life-threatening rebound hypoxemia with rapid fall below baseline SpO2, and instead stepping down oxygen to the lowest level required to maintain SpO2 88-92% 5

The British Thoracic Society recommends recording oxygen delivery device and flow rate on the patient's monitoring chart, and reducing oxygen in stable patients with satisfactory saturation 1
Discontinue oxygen once the patient maintains saturation within or above target range on room air, but leave the prescription in place for potential deterioration 1

The American College of Cardiology recommends not routinely administering oxygen if SpO2 ≥94%, as supplemental oxygen in normoxemic ACS patients increases myocardial injury, infarction size, reinfarction rates, and cardiac arrhythmias, and only giving oxygen if SpO2 <94%, signs of heart failure, shock, or breathlessness are present 7
The American Heart Association recommends targeting SpO2 94-98% for major trauma, sepsis, or acute illness during pregnancy, and positioning in full left lateral position or using left lateral tilt to avoid aortocaval compression 5