PARIS, Oct 6, 2020 (BSS/AFP) – Procedures like inserting or removing
breathing tubes, which were thought to pose a serious danger of Covid-19
transmission to health workers, produce less aerosols than a normal cough,
according to new research published Tuesday.
A particular concern for doctors and nurses during the pandemic has been
that intubation — when a tube is placed in the patient’s airway to help them
breathe — could create a fine mist of viral particles and create an
infection danger for hospital staff.
This has caused health authorities in Britain to classify them as ‘aerosol
generating procedures’, meaning health workers need respirators and high
level personal protective equipment and the operating rooms are cleaned using
a special technique to remove aerosols. Researchers say using this technique
has “dramatically” slowed surgery and contributed to long hospital waiting
lists.
But a new study published in Anaesthesia, the journal of the Association of
Anaesthetists, found that both intubation and the removal of the breathing
tube after surgery produce much less aerosol than had previously been
assumed.
While the research was not performed on patients with Covid-19 for safety
reasons, the authors from the University of Bristol and hospitals in Bristol
and Bath called for the risk levels of the procedures to be reassessed.
“The results suggest that during anaesthesia tube insertion should not be
considered a high-risk procedure,” the authors said.
“We detected no increases in aerosolised particles during face-mask
ventilation, airway suction or repeated attempts at intubation,” they wrote.
“This reflects typical clinical practice by anaesthetists with a range of
experience, providing further reassurance regarding the low level of aerosol
generation.”
– Coughs are riskier –
The researchers worked to quantify the aerosols generated during various
anaesthesia procedures for insertion and removal of tubes from patients’
airways, as well as other breathing assistance, in real clinical settings.
They looked at 19 tube insertions and 14 tube removals and found — against
expectations — that tube insertion generated approximately one thousandth of
the aerosol generated by a single cough.
Tube removal produced more aerosol, especially when accompanied by a weak
cough, which sometimes occurs when patients resume breathing on their own.
But researchers said this was still less than 25 percent of that produced
by a voluntary cough.
The authors note that their study was limited because they were unable to
directly study the risk of transmission of the new coronavirus, adding their
“interpretation rests on the widely accepted link between aerosol generation
and infection risk”.
They said the research could have implications for the distribution of
protective equipment in hospitals, which is allocated on the basis of how
risky a given situation is considered.