MEDICAL GAS SYSTEMS ‘‘
Although the surgeon is at most risk of exposure, due to their proximity, the plume can disperse throughout the operating theatre, and thereby affect everyone in the room
flow. Is there with this burgeoning market an opportunity to include a chapter in the HTM on medical gases for veterinary care and surgery?
The surgical plume
Electrosurgery units, surgical lasers, and ultrasound devices, are widely used in operating theatres for a range of surgical procedures. However, an inevitable consequence of employing these devices is the generation of surgical plume or smoke. Surgical plume is a gaseous product that is created when heat- generating procedures are employed to cut through and dissect structures in the body. The smoke often produced is the only visible evidence, and is accompanied by the unpleasant odour; these are the two aspects of the plume we can detect with our senses. The plume also contains toxin, and infectious and carcinogenic material, which research has shown can be harmful. Exposure to the surgical plume has been linked to numerous health problems with the eyes, nose, and throat. Although the surgeon is at most risk of exposure, due to their proximity, the plume can disperse throughout the operating theatre, and thereby affect everyone in the room. The plume can even affect the patient, who would effectively be breathing in their own surgical waste.
Surgical smoke extractors Surgical smoke extractors have been introduced, and are designed to capture and remove the plume, thereby minimising the danger to the staff and patient. The majority of the original designs, although portable, were noisy, and were often left unused for that reason. However, modern units are much quieter. Furthermore, we have seen the introduction, for new or refurbished theatre suites, of central pipeline systems for plume evacuation, which convey the plume to outside of the building through appropriate filtering. The benefits of dedicated central systems are that they can be both powerful and quiet in operation, and reduce the clutter in the operating theatre. This raises the question of whether the requirements for these should also be incorporated in the HTM, in a similar way to AGSS or vacuum. Interestingly, it has been found that, unlike AGSS, the capture velocity is a better measure of effectiveness than the flow of air, and a capture velocity of 100-150 feet per minute at the inlet nozzle is generally
62 Health Estate Journal January 2022 recommended,8 although most units
specify the flow rate dependant on the bore of the tubing e.g. 7/8 in (22 mm) → 780 L/min, or approximately 25 CFM.
What next?
From the discussion above it is clear that there are several opportunities moving forward to both update the HTM, and bring it in line with current clinical practice and medical technologies, but also to broaden its scope, if desired, to include veterinary gases and surgical plume extraction. There is an opportunity now for hospitals to review the MGPS to see if additional resilience should be installed to mitigate the risks many have experienced during the pandemic over the past 18 months. Should we, for example, now consider further changes also in our hospital by providing Critical Care Unit expansion capacity in adjacent areas with oxygen-diversified flows capable of meeting the needs of ventilated patient and pandemic expansion wards for a larger intake of patients on high flow nasal oxygen or CPAP? What is important for any revision to the MGPS is the role of the Authorising Engineer as an independent subject matter expert.
References 1 Shaoul, J. Egyptian hospitals run out of oxygen, killing COVID-19 patients in ICU wards. International Committee of The Fourth International 2021 [
https://tinyurl.com/3yex2zsn].
2 BBC News online. Covid-19: Brazil hospitals ‘run out of oxygen’ for virus patients. 15 January 2021 [
https://tinyurl.com/v29d75uy].
3 Department of Health. HTM 02-01: Medical Gas Pipeline Systems Part A: Design, validation and verification. The Stationery Office, 2006.
4 Institute of Physics and Engineering in Medicine. Advice Notice: Converting Anaesthesia machines from Oxygen driven to Air driven for use in intensive care V1.1. York: IPEM, 2020.
5 NHS England and NHS Improvement. Delivering a ‘Net Zero’ National Health Service. NHS England and NHS Improvement; 2020
[
https://tinyurl.com/kecjm28c].
6 Ryan SM, Nielsen CJ. Global warming potential of inhaled anaesthetics: application to clinical use. Anesth Analg 2010; 111: 92–98.
7 Mosing M, Waldmann AD, Raisis A, Böhm SH, Drynan E, Wilson, K. Monitoring of tidal ventilation by electrical
impedance tomography in anaesthetised horses. Equine Vet J 2019; 51: 222–6.
8 National Institute of Occupational Health and Safety. Control of Smoke for Lasers/Electric Surgical Procedures No 96-128. NIOSH; 1996 [
https://tinyurl.com/3a7wrsn6].
Dr Scott Brown hej
Dr Scott Brown PhD, MEd, CEng, CSci, MIPEM, MCGI, is a Chartered Engineer and Chartered Scientist with over 30 years’ experience in hospital and biomedical engineering. He is also registered as a Clinical Scientist with the Health and Care Professions Council, and has gained certification in MGPS (AP) and Essentials for Authorising Engineers. During his career he has played an active role by sitting on a number of IPEM committees, including Council, Engineering Group Board, and the Clinical Engineering Special Interest Group, and being a City & Guilds Visiting Assessor. In his role within the NHS, Scott Brown sits on two medical gas committees, and during the first wave of COVID-19 was a key member of the Oxygen assurance group.
Health Tech Solutions was established in 2014. and offers consultancy services to the healthcare sector, along with engineer and user training on medical, dental, and medical gas equipment, both classroom-based and remotely. During the COVID-19 pandemic he has provided expert advice to the groups involved in setting up the London ExCeL Nightingale hospital, as well as VentilatorChallengeUK. He has published widely on hospital and biomedical engineering, including contributing to four textbooks, and is regularly an invited speaker at national conferences. The business continues to grow, and is now establishing international links.
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