Hot topic: Understanding medical oxygen

Some reports suggest shortages are either in-progress or imminent, but gasworld understands this is not yet the case and should not be in the future either.

Hot topic: Oxygen supply shortages?

The global industrial gases business is doing everything it can to maximise and prioritise oxygen supply to the healthcare sector. During uncertain times, this is one thing we can be certain of.

What is perhaps less understood for many other there is, what exactly is medical oxygen? Here, gasworld explains all.

Production

Oxygen is one of the core air gases, and the bulk of it is produced via the air separation process in an ASU (air separation unit).

Generally speaking, the air all around is comprised of 78% nitrogen, 21% oxygen (approx.) and 1% of argon and other constituents (rare gases like krypton, neon and xenon, for example). An ASU takes this abundant atmospheric air and, through several stages of separation and distillation, splits it out into those individual components (oxygen, nitrogen, argon).

Oxygen produced by the cryogenic process is typically produced at greater than 99% purity so that it can be used for essentially all applications, including for medical purposes. It does still, however, have to go through further stages of purification and certification.

So why? Well, medical oxygen is essentially the same oxygen as that produced for industrial use in the ASU as described above, but in the healthcare system it is considered as a drug or pharmaceutical product. Medical oxygen is taken, literally, from the same plant as that industrial oxygen, but must be further purified and as free from contaminants as possible – because lives literally depend on it.

To be able to sell medical oxygen, plants must have the required licenses and ensure the stringent specifications to be met – something of a red tape process, but nonetheless fundamental to its safe use for the patient.

How is it used?

Oxygen is one of the most important, life-saving gases used in medicine today. It has been used in medicine since the 1800s and has come a long way in terms of both its application and delivery systems.

Medical oxygen is used to restore tissue oxygen tension in conditions such as respiratory arrest, cardiac arrest, shock, carbon monoxide poisoning, and severe haemorrhaging, and has applications in both the hospital and pre-hospital (accident response) settings.

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. 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.

In this pandemic of Covid-19, we understand oxygen is being used in its most critical form in the medical sector – in respiration, incident response and life support. It’s about that getting that oxygen into patients and keeping their vital functions active.

How is it supplied or administered?

Oxygen in the medical field has traditionally been produced centrally at the ASU(s) and then distributed in liquid form, or as a gas via cylinders, to the customer.

An alternative and increasingly popular means of oxygen generation exists in the medical market, however, in the form of pressure swing adsorption (PSA). We’ll come back to this point later in this article and in more depth in an additional hot topic.

European hospitals have typically relied upon these 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.

Bulk supply via storage tanks and pipeline into the wards is generally the most popular or required means of supply, such is the volume of medical oxygen required. However, it is not uncommon to find a combination of bulk and cylinder supply – and especially so during these circumstances of pandemic, whereby the amount of oxygen required could feasibly outstrip the capabilities of the pipelines to deliver it. Cylinder supply can both complement the piped capacity and also provide a relatively mobile means of supply.

Oxygen cylinders come in a variety of sizes to provide continuous or demand flow of oxygen, while alleviating discomfort associated with these conditions. Hospitals often use these cylinders to ensure ease of deployment throughout the hospital, whether at the patient bedside, in operations or procedural areas, in MRI rooms or even integrated into mobile equipment. This flexibility to be used in various medical applications has not only resulted in oxygen cylinders becoming commonplace in the hospital environment, gasworld understands, but could also be crucial in responding to the messes of patients infected with coronavirus at any one time.

It is commonly reported that hospitals are having to set up makeshift wards in corridors and non-essential rooms, or governments are having to establish improvised facilities in conference buildings to deal with the sheer volume of patients, both of which would benefit from the portability of cylinder supply.

Medical oxygen cylinders are also used by first responders – those paramedics and emergency services personnel that are on the frontline of this crisis. Ambulances, for example, will often use fixed, lightweight oxygen cylinders to service the variety of medical equipment in the vehicle; small medical oxygen cylinders used by emergency personnel are the norm when responding to emergency situations and treating patients. First responders working in makeshift holding wards outside of the hospital or in town and city areas will also be dependent upon these cylinders.

Medical oxygen cylinders have been the subject of significant advances through the years, and the healthcare sector has naturally demanded ever-efficient vessels coupled with higher pressures and improved delivery systems. Valving systems and associated accessories such as hoses and face-masks have all made major advances too.

Special feature: The four Ps of medical oxygen cylinders

Right now, the emphasis is arguably more on getting the required cylinders than it is on advancing them, and gasworld understands that it may be possible for some of the ‘red tape’ around medical cylinder certification and registration to be temporarily relaxed if the crisis and need is such that this action requires.

Onsite generation

Back to that third, alternative means of medical oxygen supply – onsite generation.

Though commercialised in the 1970s, PSA oxygen concentrators for the supply of medical gas distribution systems have grown on the worldwide market in the last 20 years in particular. As the oxygen is produced onsite, without delivery and storage, medical oxygen generators have convinced many hospitals and healthcare facilities in North America, Africa, Middle East, Asia, and in recent years Europe, that they are able to supply medical oxygen at a competitive price compared to liquid oxygen or cylinders.

Read more: Advances in onsite oxygen generation 

PSA systems utilise commonly available components that can greatly reduce the initial capital required compared to the cryogenic production of oxygen, for example, and offer the kind of mobility that address the varying requirements of the hospital and healthcare sector; their rise in this area has been facilitated by ‘monographs’ that deem the use of oxygen in the range of 90-96% purity acceptable.

Read more: An introduction to PSA medical oxygen generators 

Part of this family of independent oxygen generation are oxygen concentration. The global medical oxygen market has seen the introduction of better, safer and more efficient portable oxygen concentrators in recent years – giving patients with respiratory problems a new lease on life and the freedom to be in their own homes.

Portable oxygen concentrators have helped to alleviate the pressures experienced by hospitals, managing to free up beds and see more people on an out-patient basis. Even the integration of gas sensor technology into portable oxygen concentrators has assisted in patient care, with individuals better able to monitor their own oxygen levels.