From the Guidelines
For patients with pulmonary embolism, pulmonary congestion, and pneumonia, the target SpO2 range should be 94-98% for most patients, unless they are at risk of hypercapnic respiratory failure, in which case the target range is 88-92%. This recommendation is based on the British Thoracic Society (BTS) guideline for oxygen use in adults in healthcare and emergency settings 1. The guideline suggests that for acutely ill patients not at risk of hypercapnic respiratory failure, a target saturation range of 94–98% is recommended, while for patients with known chronic obstructive pulmonary disease (COPD) or other known risk factors for hypercapnic respiratory failure, a target saturation range of 88–92% is suggested pending the availability of blood gas results.
Some key points to consider when managing these patients include:
- Carefully measuring respiratory rate and heart rate, as tachypnoea and tachycardia are more common than a physical finding of cyanosis in hypoxaemic patients 1
- Allowing fully conscious hypoxaemic patients to maintain the most upright posture possible, unless there are good reasons to immobilise the patient 1
- Being aware that mental functioning becomes impaired if the PaO2 falls rapidly to <6 kPa (45 mm Hg, SaO2 <80%) and consciousness is lost at <4 kPa (30 mm Hg, SaO2 <56%) in normal participants 1
- Considering the use of pulse oximetry to aid in the detection of children with signs of severe respiratory distress, as SpO2 < 90% is predictive of mortality among children with pneumonia 1
It is essential to note that SpO2 alone cannot differentiate between pulmonary embolism, pulmonary congestion, and pneumonia, and diagnosis requires integration with clinical presentation, physical examination, laboratory tests, and imaging studies. Additionally, the BTS guideline recommends that the SaO2 should be maintained above 90% for seriously ill patients, with a target SaO2 (and SpO2) ≥94% for most hypoxaemic patients to ensure that the actual oxygen level remains above 90% for most of the time with a 4% margin of safety to allow for variability in oxygen saturation levels, their recordings and oximeter error 1.
From the Research
SpO2 in Patients with Pulmonary Embolism
- The studies provided do not directly address the relationship between SpO2 and pulmonary embolism, pulmonary congestion, and pneumonia 2, 3, 4, 5, 6.
- However, it is mentioned that patients with pulmonary embolism can present with shortness of breath and hypoxemia, which can affect SpO2 levels 3.
- A study on supplemental oxygen for pulmonary embolism (SO-PE) aims to investigate the mechanisms of supplemental oxygen in patients with acute PE, including its effects on pulmonary artery systolic pressure and right ventricular function 5.
Relationship Between SpO2 and Pulmonary Conditions
- Pulmonary embolism can lead to right ventricular dysfunction, which can cause hypoxemia and decreased SpO2 levels 2, 6.
- The use of supplemental oxygen can help reduce pulmonary artery pressure and improve right ventricular function in patients with acute PE 5.
- However, the optimal SpO2 target for patients with pulmonary embolism, pulmonary congestion, and pneumonia is not explicitly stated in the provided studies.
Clinical Management of Pulmonary Embolism
- The diagnosis and treatment of pulmonary embolism involve clinical assessment, laboratory tests, and imaging studies 2, 3, 4.
- Anticoagulant therapy, such as low-molecular-weight heparin or direct oral anticoagulants, is commonly used to treat pulmonary embolism 2, 3, 4.
- Supplemental oxygen may be used to support patients with pulmonary embolism, especially those with hypoxemia or right ventricular dysfunction 5.