Dr R Marshall-Roberts, University Hospitals Plymouth,
rachelroberts2@nhs.net, 01752 202082; Dr J Braschi, University Hospitals
Plymouth.
Abstract
Laparoscopy has been found to result in aerosolization of blood borne
viruses and so a more cautious approach has been taken during the
pandemic and more attention given to safe deflation of the
pneumoperitoneum. We have used a heat and moisture exchange filter to
deflate the abdomen as an alternative to a smoke evacuation device.
These filters are known to reduce the transmission of microbes and other
particulate matter in breathing systems and are readily available in the
anaesthetic room.
Over the last two months clinicians have had to reconsider every aspect
of our practice to identify clinical events and procedures which could
expose staff and patients to increased risk of contracting COVID-19. For
the foreseeable future, we will be compelled to adapt the way we work
due to the risks presented by this virus.
A joint statement from the RCOG and BSGE (1) in March 2020 advised on
how to minimise the potential risk of virus transmission during minimal
access surgery. Though most Trusts across the UK are now performing
COVID-19 testing on all patients admitted for elective surgery, this
will not be possible in all cases and also a false negative rate as high
as 30% is quoted (2). Therefore, as well as emergency surgery on known
positive patient, the transmission risks must be considered in all
cases.
The COVID-19 virus has been detected in non-respiratory specimens in
infected individuals, including stool, blood, and ocular secretions,
with the highest levels detected in stool. Currently, the potential for
transmission via these fluids is uncertain. The well recognised benefits
of laparoscopy over open surgery, including shorter hospital stays and
speedier recovery, are particularly desirable in the current climate.
However previous research has revealed that laparoscopy can lead to
aerosolization of blood borne viruses in surgical smoke (3). Therefore
it has been extrapolated that laparoscopic gas could also be
contaminated with Coronavirus from infected blood, stool or peritoneal
fluid. Due to this theoretical risk, laparoscopies with higher risk of
bowel involvement have been deferred where possible, or if urgent,
performed by laparotomy.
The splattering of blood from port sites is avoided by careful insertion
and removal of specimens and trocars.
Smoke extraction devices and vacuum suction units have been provided to
enable enclosed release of gas from the abdomen, permitting laparoscopic
procedures to continue safely. However we have found that staff have
been unfamiliar with this equipment and have failed to use them
effectively, either resulting in incomplete evacuation of the
pneumoperitoneum or leakage into the environment. Another method
trialled in the hospital involves evacuating the pneumoperitoneum by
expelling the gas via tubing attached to a port directly into a bowl of
betadine. This may minimise the explosive dispersion into the air that
frequently occurs, but whether virus could be released at the surface of
the fluid is unknown and it did not seem a convincing method for long
term use.
In the light of these unsatisfactory methods, a novel suggestion is
proposed here, using a standard Heat and Moisture Exchanger (HME) filter
as pictured below; these filters reduce the transmission of microbes and
other particulate matter in breathing systems with 99.99% effectiveness
according to their manufacturers (3) and are included in the Difficult
Airway Society Consensus guidelines for managing the airway in patients
with COVID‐19 (5)
The HME filter is simply attached to the end of the gas tubing
(previously inserted onto the gas delivery system on the stack), once
the gas intake channel on the port has been closed. An adapter is
required to allow the filter to fit the gas tubing and for this a size 6
endotracheal tube connector was utilised (see figure 1). Once the gas
channel on the port is opened, the pneumoperitoneum deflates quickly and
fully through the filter which can then be disposed of like any other
contaminated waste
Though it will be difficult to acquire a solid evidence base, for just a
few pounds this simple and rapid method may be one that has the
potential to lower infection risk further for staff working in operating
theatres during laparoscopic procedures.
We warmly invite comments from readers.
Ethical approval: not required
Disclosure of interests: nil
Funding: nil
Dr Marshall-Roberts utilised the equipment as above during multiple
laparoscopies and wrote the article which was contributed to by Dr
Braschi.
Acknowledgements: Dr Geoff Smith, anaesthetist at UHP, who suggested
this method during a laparoscopy in the early days of the pandemic.
- Joint RCOG / BSGE Statement on gynaecological laparoscopic procedures
and COVID-19
https://mk0britishsociep8d9m.kinstacdn.com/wp-content/uploads/2020/03/Joint-RCOG-BSGE-Statement-on-gynaecological-laparoscopic-procedures-and-COVID-19.pdf
- Watson J, Whiting P et al. Interpreting a covid-19 test result. BMJ
2020; 369 m1808 (published 12 May 2020)
- Kwak HD, Kim S, Seo YS, et al.Detecting hepatitis B virus in surgical smoke emitted during
laparoscopic surgery. Occupational and Environmental
Medicine 2016;73:857-863.
(https://oem.bmj.com/content/73/12/857)
- https://www.intersurgical.com/info/filtrationandhumidification
- Cook T, El-Boghdadly K, McGuire B, et al. Consensus guidelines for
managing the airway in patients with COVID‐19 : Guidelines from the
Difficult Airway Society, the Association of Anaesthetists the
Intensive Care Society, the Faculty of Intensive Care Medicine and the
Royal College of Anaesthetists Anaesthesia 2020; 75:785-799