The provision of oxygen – and its supply chain – has been at the forefront of the fight against Covid-19. Yet it has always been one of the most important, life-saving gases used in medicine, since the 1800s in fact – so what is ‘supplemental oxygen’ and how is it used?
Put simply, supplemental oxygen – or oxygen therapy – is the use of oxygen as a medical treatment. In short-term procedures or treatments, this might include the use of oxygen to remedy low blood oxygen levels, to overcome carbon monoxide poisoning or to maintain a patient’s oxygen levels while under an anaesthetic during an operation.
In long-term cases, oxygen treatment has been increasingly called upon in the fight against known and ongoing respiratory diseases like COPD (chronic obstructive pulmonary disorder) or other lung diseases where chronically low oxygen levels are restrictive at best and life-endangering at worst. Portable oxygen delivery devices to meet these needs have been a fast-growing application for those in the gas and equipment business.
On a more technical level, oxygen is required for normal or healthy cell metabolism, the set of life-sustaining chemical reactions in organisms. For humans, the intake of oxygen from the air is the essential purpose of respiration – the inhalation of oxygen from the outside environment to the cells within tissues and the exhalation of carbon dioxide in the same process – so oxygen supplementation is used in various branches of medicine. Treatment not only increases oxygen levels in the patient’s bloodstream, but has the secondary effect of decreasing resistance to blood flow in many types of diseased lungs, easing the workload on the heart. Oxygen saturation is key and can vary on the treatment being given; just as oxygen is required for core functions and to overcome the presence of carbon dioxide or carbon monoxide in a given circumstance, excessively high concentrations can cause oxygen toxicity or lung damage.
During the pandemic of Covid-19, oxygen has been used in its most critical form – in assisted respiration, incident response and life support. It has been very much about getting that oxygen into patients struggling to breathe and suffering from dangerously low oxygen levels, and keeping their vital functions active.
Oxygen has come a long way in terms of both its application and delivery systems, and we are still seeing important innovations in the delivery of oxygen to patients across a range of technologies.
The use of medical oxygen extends outside of the hospital setting, with thousands of people dependent on portable medical oxygen technologies to function in their day-to-day lives (think of those living with COPD as described above). In addition, medical oxygen is critical in accident response units, first aid, resuscitation and life support equipment – even modern anaesthetic techniques rely on medical oxygen.
Hospitals have typically had two choices for supplying medical oxygen to their medical gas network: depending on their consumption they could either purchase liquid oxygen stored in on-site in bulk cryogenic tanks and fed into the facility via its pipelines; or purchase cylinder supply and the regular refills required. Once in the medical setting, this supplemental oxygen may be delivered via positive airway pressure ventilators and the use of a face mask, or other means such as a humidified high flow nasal canula which enables oxygen flows exceeding a person’s peak inspiratory flow demand to be delivered. In most such instances, the oxygen will first pass through a pressure regulator to control the high pressure of oxygen delivered to a lower pressure, which would then be further controlled by a flow meter.
In many first aid or first responder scenarios, oxygen delivery might be achieved via a bag-valve-mask (BVM), a familiar sight in the form of a face mask attached to a malleable bag or balloon, which is manually manipulated by the responder to replicate the rhythmic cycle of respiration – pushing oxygen into the lungs.