Choosing the Best Oxygen Source for Your Veterinary Practice

What Oxygen Source Does Your Veterinary Hospital Utilize: Concentrator-Generated, Cylinder-Stored, or Piped Oxygen?

Have you ever thought about what works best in your veterinary hospital?

Have you become accustomed to switching small oxygen cylinders on the regular, hoofing them about the practice, trying not to think too hard about what may result from one dropped on the ground?

Well, there are alternatives out there. So, if you’re rethinking how your practice should deliver oxygen to patients, read on; we’ve collated the pros and cons of each system so that you can make an educated judgment call for you and your colleagues.

Oxygen Cylinders for Veterinary Hospitals

One of the most traditional methods of oxygen storage and delivery within the veterinary hospital or clinic is through the use of oxygen cylinders, particularly the smaller ones designed to attach to individual anesthetic machines.

The patient caseload determines the lifespan of these cylinders, ranging from one to a few days before necessitating replacement.

However, the replacement process not only adds to the workload of the veterinary team but also poses potential dangers associated with handling and moving compressed gas.

It is crucial to equip staff with purpose-designed trolleys for safely transporting these cylinders. In the event of a drop and subsequent damage, a compressed gas leak could literally blow a hole in the operating theatre wall.

Effective administration is essential for managing small oxygen cylinders, ensuring that spares are consistently available. Ideally, anesthetic machines should feature two docks, allowing for a seamless transition from one cylinder to the next when needed.

Human error is a potential concern in this system, requiring accurate labeling of cylinders as "full," "in use," or "empty." Prompt replacement of empty cylinders is vital to maintaining a state of preparedness. Additionally, robust ordering processes must be in place to prevent running out of this critical veterinary consumable.

Considerations also extend to the cost of cylinder rental, contributing to the overall expenses of operating a veterinary practice, subsequently reflected in client bills.

Despite these challenges, there are positive aspects to using oxygen cylinders in veterinary care.

Purpose-built, portable anesthetic tables with small cylinders enable uninterrupted anesthesia for patients in transit.

Moreover, in the event of a power outage, anesthetic machines continue to function, with many modern devices equipped to be powered by compressed gas through mini-Schrader sockets during emergencies.

Piped oxygen for veterinary hospitals

Piped gas is sleek in appearance, giving a professional and ‘thought-out’ look to a clinic.

Gas outlets (sockets, usually Shrader-type) are placed at convenient spots around the practice (for example at prep room and theatre anesthetic stations, and near oxygen kennels inwards).

Hoses are secured into these outlets, extending into the room to attach to anesthetic machines.

The wall outlets are fed from an oxygen distribution line that extends outside and connects to an oxygen source, most commonly bulk supply oxygen cylinders.

These large oxygen cylinders are generally situated externally to the practice, making for convenient replenishment of supplies since gas delivery companies can be given a key or combination to a safety gas storage ‘cage’.

Oxygen concentrators can also be purchased as an alternative to bulk gas cylinders, the associated money-saving of which could well offset the cost of having a piped system installed.  

Veterinary piped oxygen tends to utilize flexible hosing for the transportation of the gas throughout the building.

These hoses are not only easy to fit retrospectively (and can therefore be fitted to existing veterinary practice fabric, not just new builds), but also allow amendments and changes to be made over time.

Veterinary practices tend not to be static entities; they grow and develop to meet the ever-changing and developing needs of pet owners, so having the ability to easily add to and amend facilities is extremely useful.

It is overall a flexible system that can be tweaked as necessary to suit the individual practice.

The list of benefits of piped gas is short but important. Many practices find piped gas to be the best option simply for the level of convenience and safety for staff; it reduces or even eradicates the number of cylinder changes compared to traditional small gas cylinders.

Even where large cylinders are used, changing empty cylinders is quick and simple since they do not need to be moved.

The downside is, of course, that the cylinder still needs to be replaced periodically. In some very cold climates, there may be a risk of the connections freezing in mid-winter – but this can easily be mitigated with good design.

Oxygen concentrators play a vital role in the operations of a veterinary hospital or clinic.

They serve as ingenious devices that harness air as a natural resource to generate medical-grade oxygen.

Functioning by extracting air from the surroundings, these concentrators meticulously filter out elements like nitrogen, producing purified oxygen readily available for patients around the clock.

Available in various sizes, they cater to diverse needs, ranging from individual anesthetic stations to comprehensive applications that serve an entire veterinary practice through a piped gas delivery system.

This method of oxygen generation proves highly convenient, requiring minimal intervention once the equipment is activated.

Veterinary practices stand to benefit in two significant ways: firstly, for environmentally conscious practices, the use of concentrators helps diminish their ecological footprint by reducing the need for oxygen delivery vans on the road.

Secondly, there's a substantial cost-saving advantage, potentially cutting gas bills by up to 90%. It is advisable, however, to maintain a spare oxygen cylinder as a precaution in case of equipment failure.

In summary, the cost-effectiveness of utilizing an oxygen concentrator in conjunction with a piped gas system makes it a valuable investment for veterinary hospitals, regardless of their size.

This holds particularly true for mid to large-sized practices, where the financial advantages are substantial.

Moreover, the convenience offered by these systems contributes to enhanced staff morale.

Even in smaller veterinary practices where the installation of a piped gas system might not be financially justifiable, the adoption of one or more compact concentrators can prove advantageous not only in terms of finances but also in promoting staff well-being and environmental considerations.

Low Flow Anesthesia in a Veterinary Practice. Do's / Don'ts

Low Flow Anesthesia in a Veterinary Practice: Key Do's and Don'ts

The Benefits of Low-Flow Anesthesia for Veterinary Practices.

There was once a time when anesthetic was all about just keeping the patient ‘asleep’ so that a procedure could be carried out.

If we are being responsible practitioners and business owners, we should be striving to reduce the use of some of these inhalants.

Using injectable anesthetic protocols eliminates the volatile gas element altogether, but there is still a carbon footprint associated with the production of the drug, the electricity needed to power the syringe driver, drug wastage, and so on.

We also need to be careful not to compromise patient safety.

Low-flow anesthesia helps to provide the compromise we need, allowing us to continue with inhalants but at lower levels than we are traditionally used to.

What is low-flow anesthesia?

Simply put, low-flow anesthesia is the minimum safe gas flow you can use during the maintenance phase of a patient’s anesthetic, that still supplies them with enough oxygen to continue with normal metabolic functions.

It is defined as a fresh gas flow (FGF) of 0.5-1 L/min. 

Minimal flow (which is 0.25 – 0.5 L/minute) or closed-circuit techniques (< 0.25 L/minute) also exist, but care must be taken to ensure your patient doesn’t become hypoxic.

This is made riskier if nitrous oxide is used, so this would not be recommended. It’s also important to remember that many general-purpose vaporizers do not operate reliably below 0.5L/min.

Many practices have conventionally used comparatively high FGF rates, usually much more than is actually required for our patients.

This has many downsides, including being wasteful of oxygen and inhalational anesthetics. This not only impacts the environment but also costs money. There is an increased risk of unnecessarily exposing the veterinary team to anesthetic agents with this method too.

For our patients, there is also the downside of having lots of unnecessary cooling gases entering the airways, which is not ideal for a small animal under anesthesia. Hypothermia is a real risk, particularly for animals under 10kg, so re-breathing warm gases in low-flow anesthesia can be very helpful.

What are the dos and don’ts of low-flow anesthesia in a veterinary clinic?

Most of the problems faced in low-flow anesthesia are due to inappropriate equipment which we will cover here.

Dos:

Do use a veterinary vaporizer that can deliver precise fresh gas flows down to 200ml/min and make sure that it has been calibrated and tested for low flow rates.

Despite claims, some vaporizers struggle with high resistance, an inability to respond quickly to setting changes, and inaccuracies in the delivery of inhalants (Kelly and Kong, 2011).

Don’t hesitate to speak to the manufacturer if you require specific advice about individual vaporizers.

Do use a precise oxygen flow meter which can be easily read and used to monitor fresh gas flow rates down to 200ml/minute.

Do use a low volume / low resistance circle absorber which can rapidly respond to changes in vaporizer settings at 200ml/min fresh gas flow. It should respond within 5 breaths ideally.

Some can be very slow (up to 20 minutes). Increasing your FGF during vaporizer setting changes can help, but may negate some of the benefits of using a low-flow system.

Do always leak-test your system before use. The soda lime in any rebreathing circuit needs daily checking too, as once exhausted the indicator can revert back to its original color if left in situ which can be misleading, severely compromising its carbon dioxide absorbing abilities.

Do use a higher FGF (2L/min) and vaporizer settings at the start of your anesthetic. Around 10-15 minutes is required to allow the anesthetic agent and oxygen concentrations to build to a sufficient level in the breathing system (Feldman, 2012).

Similarly at the end of your anesthetic increasing your FGF can help to remove any volatile agent more rapidly.

Do use appropriate analgesia and volatile agent-sparing techniques.

This includes using systemic analgesia as well as regional anesthesia techniques like epidurals, peripheral nerve blocks, and splash blocks. You could also consider total or partial intravenous anesthesia.

Do use capnography whenever you’re doing a low-flow protocol. It gives us a measure of how well a patient is ventilating and is the only reliable early measure of hypoxemia.

Don’ts

Don’t use repurposed human equipment for low-flow anesthesia in small animals. It is unlikely to be accurate enough for the patient sizes you will be dealing with.

Don’t try and use non-rebreathing systems that require high gas flows to expel expired CO2, such as Bain circuits or Ayres T-pieces.

Don’t use low-flow when nitrous oxide is being delivered unless there is in-circuit oxygen concentration monitoring. There is a risk of hypoxia in these patients.

Don’t expect staff to feel comfortable with new techniques without appropriate training, invest time in your team.

Don’t worry if you don’t have access to all the patient monitoring tools.

However, your patient will need to be observed very closely.

Most practices have a pulse oximeter though, which you should use as a minimum.

This tells us about hemoglobin saturation, which is essential in low-flow anesthesia.

Gas/anesthetic agent monitoring is ideal as it monitors inspired O2, as well as inspired and expired anesthetic agent concentrations, but this is expensive so many practices do not have access to this.

Summary

There are multiple benefits to low-flow anesthesia, and it should be considered by all veterinary hospitals. Ensuring you have the right equipment in place is key, as is spending time on staff training so that you can be sure you are providing the very best care for your patients.

References

Feldman, Jeffrey M. MD, MSE. Managing Fresh Gas Flow to Reduce Environmental Contamination. Anesthesia & Analgesia 114(5):p 1093-1101, May 2012. | DOI: 10.1213/ANE.0b013e31824eee0d

Jones, RS & West, E (2019) Environmental Sustainability in Veterinary Anaesthesia. Veterinary Anaesthesia and Analgesia 46 (4) 409-420

Kelly, J.M. & Kong, K.-L. Accuracy of ten isoflurane vaporizers in current clinical use. Anaesthesia, 2011; 66: 682–688

‘The whys and hows of low flow: an introduction to safe low-flow anesthesia’ by Simon Wheeler and Colin Dunlop, 14th June 2023

‘Low Flow Anaesthesia: Frequently Asked Questions, April 2020’ – Davies Veterinary Specialists, April 2020

‘Reducing anesthetic gas for environmental benefit’ - Ellie West MA Cantab VetMB CertVA DipECVAA AIEMA MRCVS, Clinical Anaesthetist, and Sustainability Lead at Davies Veterinary Specialists, 30th January 2020