From the Guidelines
The primary purpose of oxygen is to support life by enabling cellular respiration, the process by which cells convert nutrients into energy, as emphasized in the BTS guideline for oxygen use in adults in healthcare and emergency settings 1.
Importance of Oxygen
Oxygen is essential for human survival as it allows our cells to produce adenosine triphosphate (ATP), the molecule that powers nearly all cellular activities. When we breathe, oxygen enters our lungs, binds to hemoglobin in red blood cells, and is transported throughout the body to tissues and organs. There, it participates in metabolic reactions that break down glucose and other nutrients to release energy. Without adequate oxygen, cells cannot function properly, leading to hypoxia and potentially cell death.
Medical Use of Oxygen
In medical settings, supplemental oxygen is administered to patients with conditions that impair oxygen delivery or utilization, such as respiratory diseases, heart failure, or during surgery. The normal atmospheric concentration of oxygen is about 21%, which is sufficient for healthy individuals under normal circumstances. However, patients with hypoxaemia require oxygen therapy to increase their PaO2 and decrease the work of breathing necessary to maintain a given PaO2, as stated in the BTS guideline 1.
Target Saturation Ranges
The guideline recommends aiming to achieve normal or near-normal oxygen saturation for all acutely ill patients apart from those at risk of hypercapnic respiratory failure or those receiving terminal palliative care. A desirable target saturation range of 94–98% is suggested, which mirrors the normal range for UK adults with a wide margin of safety above the 90% threshold, as discussed in the BTS guideline 1.
Key Points
- Oxygen is a treatment for hypoxaemia, not breathlessness, as emphasized in the BTS guideline 1.
- The amount of oxygen carried in the blood is often expressed in terms of how saturated circulating haemoglobin is with oxygen (SO2) 1.
- Sudden exposure to low SaO2 levels (below about 80%) can cause impaired mental functioning even in healthy participants 1.
- The use of supplemental oxygen should be guided by a target saturation range and monitored closely to avoid hyperoxia or hypoxia, as recommended in the BTS guideline 1.
From the Research
Purpose of Oxygen
The purpose of oxygen is to provide cells with the necessary oxygen for adequate organ function 2. Oxygen transport in the blood is achieved through binding to haemoglobin and physical dissolution in plasma.
Importance of Oxygen in the Body
- Oxygen is essential for the proper functioning of organs and tissues in the body 2.
- The delivery of oxygen to different organs is determined by cardiac output and arterial oxygen content 2.
- Inadequate oxygenation can lead to tissue hypoxia and lactacidosis, particularly in cases of anaemia or hypovolemic shock 2.
Role of Oxygen in Treating Hypoxemia
- Oxygen therapy is a crucial treatment for hypoxemia, which is a common presentation in critically ill patients 3, 4, 5, 6.
- The management of hypoxemia involves ascertaining the severity of hypoxemia, determining the underlying diagnosis, and implementing the most appropriate treatment, which may include oxygen therapy, non-invasive ventilation, or mechanical ventilation 6.
- In severe cases of hypoxemia, specialist treatments such as extracorporeal membrane oxygenation may be necessary 3.