From the Guidelines
Acute oxygen desaturation, or hypoxemia, is most commonly caused by conditions such as pulmonary embolism, pneumothorax, severe bronchospasm, pulmonary edema, atelectasis, pneumonia, airway obstruction, and ventilation-perfusion mismatch, as well as equipment issues and hypoventilation from sedative medications or neurological conditions. The top causes of acute oxygen desaturation can be categorized into several key areas, including:
- Respiratory conditions: pulmonary embolism, pneumothorax, severe bronchospasm, pulmonary edema, atelectasis, pneumonia
- Equipment issues: disconnected oxygen, kinked tubing, ventilator malfunctions
- Hypoventilation: sedative medications, opioids, neurological conditions
- Other causes: acute respiratory distress syndrome (ARDS), ventilation-perfusion mismatch According to the BTS guideline for oxygen use in adults in healthcare and emergency settings 1, hypoxaemia can be caused by a number of mechanisms, including V/Q mismatch, poor aeration of areas of lung, or abnormalities of gas exchange within the lung during serious illnesses such as pneumonia. The Society of Critical Care Medicine clinical practice guidelines for rapid sequence intubation in the critically ill adult patient 1 also highlights the importance of preoxygenation to prevent desaturation, and notes that high-flow nasal oxygen (HFNO) can be an effective method for preoxygenation in critically ill patients. In terms of treatment, the BTS guideline recommends an initial target saturation range of 94-98% for most patients, unless they have COPD or other risk factors for hypercapnic respiratory failure, in which case a saturation of 88-92% may be more appropriate 1. Overall, prompt identification and treatment of the underlying cause of acute oxygen desaturation is crucial to prevent further deterioration and organ damage from hypoxemia.
From the Research
Causes of Acute Oxygen Desaturation (Hypoxemia)
The top causes of acute oxygen desaturation (hypoxemia) can be identified from various studies, including:
Pathophysiology of Acute Respiratory Distress Syndrome (ARDS)
ARDS is characterized by acute lung inflammation and increased pulmonary vascular permeability, leading to hypoxemic respiratory failure and bilateral pulmonary radiographic opacities 6, 3. The syndrome is thought to occur when a pulmonary or extrapulmonary insult causes the release of inflammatory mediators, promoting inflammatory cell accumulation in the alveoli and microcirculation of the lung 3.
Etiology of ARDS
The etiology of ARDS is multifactorial, and can be caused by both direct lung triggers (such as pneumonia or aspiration) and extrapulmonary reasons (such as sepsis or trauma) 2, 3. The diagnosis of ARDS is based on the presence of acute onset of respiratory symptoms, profound hypoxemia, bilateral pulmonary opacities on radiography, and inability to explain respiratory failure by cardiac failure or fluid overload 3.