Anaesthesia procedures may not pose as much risk of COVID-19 transmission as had been feared, according to a British study.
The conclusion comes from a detailed study of aerosol emissions during intubation and extubation in ultra-clean operating theatres.
Researchers say it suggests that hospitals could resume routine operations much more rapidly than had been thought.
According to the study, the aerosols produced represent a fraction of those generated by a cough.
It involved 19 intubations and 14 extubations. The researchers found that intubation produced a thousandth of the level generated by a cough. Extubation was equivalent to about a quarter of a cough.
The research, published in Anaesthesia, involved hospitals in Bristol and Bath, UK, and the Bristol University aerosol research centre.
The researchers say that the detail of the study shows which anaesthetic procedures pose a risk and which do not.
The researchers, led by Dr Jules Brown, of the North Bristol NHS Trust, write: "The precautions many hospitals worldwide have introduced to mitigate the risks posed by viral aerosols have reduced operating theatre turnover, decreased hospital productivity and increased waiting times for elective and cancer surgery.
“A further important consideration relates to the cost and limited supply of PPE which has to be targeted to appropriate healthcare settings on the basis of risk. Our results raise important questions about the need for these precautions at the start and end of anaesthesia.”
They add: "The results suggest that during anaesthesia tube insertion should not be considered a high-risk procedure," say the authors. "We detected no increases in aerosolised particles during face-mask ventilation, airway suction or repeated attempts at intubation. This reflects typical clinical practice by anaesthetists with a range of experience, providing further reassurance regarding the low level of aerosol generation.
“The risk of aerosol exposure for staff can be further reduced by using techniques that reduce coughing or by the anaesthetist simply stepping away, as our study showed much reduced particle numbers behind the patient’s head compared to above their face."
Anaesthesia 6 October 2020
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