From the Guidelines
High oxygen levels can cause several side effects, including oxygen toxicity, absorption atelectasis, and suppression of respiratory drive, which require careful management to prevent morbidity and mortality. The main side effects of high oxygen levels include:
- Oxygen toxicity, which can damage the lungs and central nervous system
- Absorption atelectasis, which is the collapse of lung tissue
- Suppression of respiratory drive in patients with chronic CO2 retention
- Retinopathy of prematurity in premature infants
- Oxidative stress leading to cellular damage
Management of these side effects involves:
- Titrating oxygen therapy to maintain target saturation levels (typically 94-98% for most patients, or 88-92% for those with COPD or risk of hypercapnic respiratory failure) 1
- Using the lowest effective oxygen concentration
- Implementing controlled oxygen weaning
- Regular monitoring of arterial blood gases and oxygen saturation
- Utilizing high-flow systems or non-invasive ventilation when appropriate
- For patients experiencing oxygen toxicity, immediate reduction of FiO2 (fraction of inspired oxygen) is necessary, while maintaining adequate oxygenation 1
In hospital settings, oxygen should be prescribed with clear target ranges and regularly reassessed 1. The underlying mechanism of oxygen toxicity involves the formation of reactive oxygen species that damage cellular components when oxygen levels exceed physiological needs 1. Understanding these mechanisms helps clinicians balance the benefits of oxygen therapy against potential risks. It is essential to carefully measure respiratory rate and heart rate, as tachypnoea and tachycardia are more common than a physical finding of cyanosis in hypoxaemic patients 1.
Key recommendations for oxygen therapy include:
- Target saturation range of 94-98% for most patients, or 88-92% for those with COPD or risk of hypercapnic respiratory failure 1
- Use of the lowest effective oxygen concentration
- Implementation of controlled oxygen weaning
- Regular monitoring of arterial blood gases and oxygen saturation
- Utilization of high-flow systems or non-invasive ventilation when appropriate
- Immediate reduction of FiO2 for patients experiencing oxygen toxicity, while maintaining adequate oxygenation 1
From the Research
High Oxygen Side Effects
- High oxygen levels, also known as hyperoxia, can have harmful effects on the body, including peripheral and coronary vasoconstriction, and direct cellular toxicity through the production of reactive oxygen species 2.
- Hyperoxia is associated with adverse clinical outcomes, and it is essential to titrate oxygen therapies to specific goals to avoid these effects 2, 3.
- The current evidence base suggests that PaO2 > 300 mmHg (40 kPa) should be avoided, but it remains uncertain whether there is an "optimal level" which may vary for given clinical conditions 3.
- Even moderately supra-physiological PaO2 may be associated with deleterious side effects, and it seems advisable to titrate O2 to maintain PaO2 within the normal range, avoiding both hypoxaemia and excess hyperoxaemia 3.
Management of High Oxygen Side Effects
- To prevent potential complications from oxygen administration, it is recommended to use the lowest effective dose of oxygen and to monitor patients closely for signs of hyperoxia 4.
- The use of periodic reminders and decision support may facilitate implementation of more precise oxygen titration at the bedside of critically ill patients 5.
- Automated oxygen administration devices might reduce dyspnea during exercise and COPD exacerbations, and could help to optimize supplemental oxygen therapy (SOT) 6.
- A conservative approach to SOT can reduce side effects compared with higher concentration oxygen regimens, and current recommendations for SOT need to be revised to focus on patients who respond best and benefit most from this therapy 6.