Changing attitudes towards the management of surgical smoke

By Daniel S Hill¹, Joseph P V Natale², Anthony J Paluch³ and Jonathan Keenan⁴

¹Higher Surgical Trainee, University Hospitals Plymouth
²Core Surgical Trainee, University Hospitals Plymouth
³Trauma and Orthopaedic SHO, University Hospitals Plymouth
⁴Consultant Orthopaedic Surgeon, University Hospitals Plymouth

Corresponding author e-mail: [email protected]

Published 02 September 2021

Traditionally theatre teams have been exposed to air pollution from the aerosol generated through thermal tissue destruction, with electrocautery (diathermy) being the most common source.  The aerosol created represents a chemical (carcinogenic smoke by-products of combustion) and biological hazard (vapourised biological tissues and particles).  The comparison with exposure to passive cigarette smoke is obvious, with surgical smoke being equally mutagenic^1-3.   One series reported that an average of 30 cigarettes per day would need to be smoked to generate an equivalent passive air pollution in an operating theatre⁴.  The pandemic has raised concerns around potential biological hazards posed by surgical smoke aerosol^3,5-8, with almost half of COVID-19 positive patients having the virus detectable in their blood⁹.  Despite this, there remains a paucity of quality evidence surrounding the risk of healthcare worker exposure to the surgical smoke aerosol¹⁰, and the efficacy of methods to reduce the airborne hazard¹³.  Our aim was to investigate the availability and use of purpose-designed surgical smoke extraction systems in orthopaedic trauma units, and to determine if the COVID-19 pandemic has changed practices. 

National Survey

A telephone survey was conducted to ascertain the availability and use of surgical smoke extraction systems in the operating theatres of orthopaedic trauma units before and during the COVID-19 pandemic.  A list of 157 British orthopaedic trauma units was obtained from the National Hip Fracture Database (www.nhfd.co.uk).  The authors contacted members of the orthopaedic theatre team at each unit.  We specifically asked “was a purpose designed surgical diathermy smoke extractor system available for use in your trauma theatre prior to March 2020” and “since the COVID-19 pandemic has a purpose designed surgical diathermy smoke extractor system been introduced.”  Probing questions were asked in order to avoid confusion between the use of a purpose-designed surgical smoke extractor system and the use of standard suction tubing.   If the answer was ‘yes’ to either question, we then asked how often the system was used.  A small number of units requested email confirmation of our enquiry.  Each department was contacted on up to three occasions in order to achieve the most complete picture. Results were analysed using Microsoft Excel. 

All 157 British orthopaedic trauma units responded.  Prior to the first COVID-19 lockdown in March 2020, 38% (60/157) of orthopaedic trauma units had a surgical smoke extractor system available for use, which increased to 56% (88/157) by the third lockdown in January 2021 (Table 1). 

This represented a percentage increase of 37%.  There was a significant difference in the observed availability between the two timepoints (McNemar X²=28.0, p<0.01).  Across all responses regarding frequency of use, for those units where a smoke extractor system was available, there were only three different answers repeatedly given (Table 2).

Prior to the pandemic, in the 38% of units who had the device available, it was used depending on the surgeon’s preference in 53%.  The proportion of units using the device for every case involving diathermy increased from 42% (n=25) to 81% (n=71) as the COVID pandemic unfolded.  Notwithstanding the COVID-19 pandemic there remains regional variation (Table 3).

Surgical smoke as a chemical hazard

Historically most surgeons were unaware of the risks posed by the surgical smoke plume¹³, which has been shown to be as mutagenic as cigarette smoke^1-3, and to cause visible changes in the lungs of exposed rats¹⁴.  Despite the theoretical risks the evidence supporting causality of healthcare workers developing respiratory symptoms and disease due to exposure of this nature is limited.  The best safety guidance pre-dating the COVID-19 pandemic is from the Control of Substances Hazardous to Health Regulations (COSHH) 2002, and state “If exposure to diathermy emissions cannot be prevented then it should be adequately controlled.  This is usually achieved by effective local exhaust ventilation (LEV). Typically this takes the form of extraction incorporated into the electrosurgery system to remove emissions at source, known as ‘on-tip’ extraction¹⁰.”  Currently, there is insufficient published literature to appraise the effectiveness of surgical smoke extractor systems in reducing the levels of smoke exposure for healthcare workers.  Despite the Health Act 2006 protecting people in the workplace by making smoking in enclosed public and work places illegal, there is no legal requirement for hospitals to install surgical smoke extractor systems in operating theatres. 

Surgical smoke as a biological hazard

The recent focus around surgical smoke is whether COVID-19 particles are present, viable, transmissible, and virulent^3,7–11.  Currently there is no evidence suggests that COVID-19 is transmissible through surgical smoke, although this is biologically plausible.  Previous studies have demonstrated the presence of different viruses in surgical smoke including; Human Papilloma Virus (HPV)^15–19, Polio-virus²⁰, Human Immunodeficiency Virus (HIV)^21,22, and Hepatitis B²³.  The potential for transmission through the surgical smoke aerosol does exist, but reported cases are rare^18,24. 

COVID-19 guidance

Guidance from the Royal College of Surgeons (RCS) around good practices for surgeons and surgical teams during the COVID-19 pandemic details recommended infection prevention measures and protection of the surgical workforce within the operating theatre, but failed to make any reference to the surgical smoke aerosol and the risks this represents²⁵.  This is in contrast to the American College of Surgeons guidance around surgeon protection during the COVID-19 pandemic recommending “smoke evacuator use when electrocautery is used”²⁶.  Intercollegiate guidance specific to General Surgery has defined surgical smoke generation as high-risk, and recommend that “smoke evacuation for diathermy” be used for all cases²⁷.  The British Orthopaedic Association (BOA) guidance on Aerosol Generating Procedures (AGP’s)²⁸ has evolved in line with that from Public Health England²⁹, with neither making reference to the risk posed by the surgical smoke aerosol to healthcare workers in the operating theatre. 

Measures to reduce the risk of surgical smoke

The measures to reduce the risk from surgical smoke consist of minimising the generation, managing the smoke aerosol, and barrier methods to prevent inhalation. 

The smoke aerosol can be captured close to the source of generation using purpose designed local extraction devices, therefore minimising exposure of theatre teams.  Although there are recommendations from the RCS for their use during the pandemic for all cases where diathermy is used, this is variable in British orthopaedic trauma theatres.  Other factors to consider in the context of purpose-designed surgical smoke extractor systems are sufficient suction rates, the ability to vary flow rate and noise level, the useability and ergonomics, and the costs of purchasing the device and consumable filters.    

Laminar air flow systems are common place within certain surgical disciplines providing a continuous flow of ultra-clean air and can have a 99% efficiency in removing airborne particles of 0.3 µm and larger.  This would imply effectiveness in clearing COVID-19 particles, pushing them towards the floor and away from the surgical team. The RCS advice is that “the rapid dilution of these aerosols by operating theatre ventilation will protect operating room staff and that “air passing from operating theatres to adjacent areas will be highly diluted and is not considered to be a risk”²⁵, although we were unable to identify any evidence base to substantiate this.

There has been mass media attention on all aspects of Personal Protective Equipment (PPE). A standard surgical mask will not protect the surgeon from the potential hazards of the surgical smoke aerosol. The PPE recommendation from the RCS is that FFP3 masks or  should be worn when performing any AGPs on a patient with suspected or confirmed COVID‐19²⁵, however surgical diathermy is not included in the list of AGPs.

Exposure, causality, and future research

There is a risk of surgical smoke aerosol presenting a hazard to healthcare workers however epidemiological data does not currently support causality of the chemical hazard causing respiratory symptoms or disease, nor the biological hazard resulting in infectious disease transmission.  The challenge is clearly defining a population (i.e. healthcare workers) of sufficient size to prove a statistically robust association between exposure (i.e. surgical smoke aerosol), and outcome (i.e. chronic respiratory disease or contracting COVID-19) while controlling for the myriad number of confounding factors (i.e. healthcare workers smoking or living in polluted city, or working in a hospital during the COVID-19 pandemic).   

Conclusion

The use of purpose designed surgical smoke extraction systems in British orthopaedic trauma theatres has increased significantly, as a result of the COVID-19 pandemic, from 38% to 56%.  Variation exists both within regions of the provision of these devices and also, where available, in their frequency of use.  Guidance on surgical diathermy smoke extractor use should be implemented in a standardised way to protect healthcare workers.

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