SAFIRA® Giving anaesthetists control

Minimising the risks of nerve injection pressure with new technology

May 2021

Innovative technology is transforming regional anaesthesia to reduce a patient’s risk of nerve damage and change the exacting procedure into a quicker, one-person process.
The newly-developed SAFIRA® uses in-built control and safety features to ensure patients can benefit from the faster recovery times and fewer side effects offered by regional anaesthesia, whilst minimising the risks associated with nerve injection pressure during the procedure.

The advantage for the anaesthetist is the ability to work independently and use SAFIRA® to precisely control the injection of small doses of anaesthetic confident in the knowledge it is delivered at a consistent, safe level of pressure.

As an increasingly common procedure, there are more than 20 million regional anaesthetic nerve blocks performed each year throughout the EU and US(1). The process involves anaesthetic being injected near a specific nerve, or bundle of nerves, to block sensations of pain from a specific area of the body, more commonly for surgery on the arms or hands, the legs or feet, or the face. It means patients can stay awake but remain pain-free during invasive surgery without requiring a general anaesthetic. Peripheral nerve blocks are one of the most common types of regional anaesthesia.

As well as offering patients fast recovery times and few side effects compared to general anaesthesia, there is also no need for an airway device during a regional block. Traditionally these procedures have required two operators. The anaesthetist holds an ultrasound probe in one hand and uses this to guide the needle tip placement with the other hand.
An assistant then injects the anaesthetic solution using their judgement to assess if the pressure in the syringe is at a safe level before the injection is made.

However, studies have shown that the assistant can find it difficult to judge the pressure correctly and less than 4% of anaesthetists are confident their assistants are applying the correct pressure(2). High pressures have been shown to damage the nerve fascicles and can cause serious nerve damage(3).

Also, research shows that whilst complications, such as transient nerve damage resulting from regional anaesthesia procedures, are small when they do occur they can have significant implications for patients, leading to severe pain or permanent paralysis of the area involved(4). Meanwhile, transient nerve damage, though less severe, can involve additional costs from follow-up appointments and further tests. There is also the potential for negligence cases to be raised in more extreme cases.

Studies have shown that injection of regional anaesthesia at pressures of 20psi can result in transient or serious nerve damage (transient nerve damage in up to 8% of cases(5) and serious nerve damage in up to 1% of cases).

In addition, injection feel is highly subjective and varies between individuals. Studies consistently show 40-70% of injections occur above 20psi with a significant portion above 30psi(6).

It was the challenging issue of varying ‘syringe’ feel that brought together the SAFIRA® (SAFer Injection for Regional Anaesthesia) group of clinicians to address the problem. Consultant anaesthetists Dr Peter Young, Dr Emad Fawzy, Dr Joseph Carter and Dr John Gibson from the Queen Elizabeth Hospital King’s Lynn NHS Foundation Trust worked together with medical device development company Medovate to work on a solution.

SAFIRA® consists of three components; a sterile syringe, a driver and a foot pedal. Easy to assemble, it allows the anaesthetist to hold the block needle in one hand, the ultrasound probe in the other and then control the aspiration and injection using the foot pedal operator. The device will not allow the injection to proceed if the pressure within the syringe goes above 20psi. If the pressure gets too high, SAFIRA® will stop working and the anaesthetist can then make necessary checks and adjustments as required (such as needle placement) before resetting the SAFIRA® system and continuing with the block. By enabling a consultant to work alone to administer regional anaesthesia, SAFIRA® represents a fundamental change to current procedures but, at the same time, it is intuitive to use and, easily integrates into existing practice.

As well as the clinical benefits, there are considerable financial efficiencies. Using SAFIRA® saves up to five minutes per procedure (therefore saving valuable theatre time) and limits the costs associated with extra operators(1). It also eliminates any communication issues between the anaesthetist and the assistant. As the distributor for SAFIRA® in the UK and Europe, Vygon anticipates high demand for the system.

“SAFIRA® has the potential to transform regional anaesthesia because it is the first device that makes the procedure suitable for a single operator. It gives the anaesthetist total control to precisely deliver small doses of local anaesthetic secure in the knowledge that the pressure is at the right level to reduce the chance of accidental nerve damage in patients.
There are benefits for the clinician and the patient as well as efficiencies for the hospital. It is very welcome technology on so many levels.”
Sam Kirby
Business Unit Manager, Vygon UK

Interested to find out more about SAFIRA? Visit our SAFIRA product page to find out more, or get in touch with your Vygon UK representative.

1. Fong-Soe-Khioe R. Health Economic report Medovate commissioned written by a health economist from the University of East Anglia (UEA)
2. Health Enterprise East (HEE): Research results using a cohort of volunteer anaesthetists
3. Borgeat A, Blumenthal S. Nerve injury and regional anaesthesia [Internet]. Vol. 17, Current Opinion in Anaesthesiology. 2004 (cited 2020 Mar31)
p.417–21. Available from: http://www.ncbi.nlm.nih. gov/pubmed/17023899
4. Important Complications of Anaesthesia. Information | Patient
5. Jeng CL, Torrillo TM, Rosenblatt MA. Complications of peripheral nerve blocks. Br J Anaesth [Internet]. 2010 [cited 2020 Mar 31];105(S1):97–107.
Available from: article-abstract/105/suppl_1/i97/235950
6. Heij R, Eldin E, Young P, Carter J, Gibson J, Ali A, et al. Regional Anesthesiology Injection Pressures comparing Skilled Assistants with SAFIRA in a Simulated Ultrasound Guided Technique. In: The Anesthesiology annual meeting [Internet]. 2013 [cited 2020 Mar 31]. Available from:

Published 22nd September 2021

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