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\begin{document}

\title{Analysis of droplet splatter patterns during Coblation tonsil surgery in
the Covid-19 pandemic}



\author[1]{Grace Khong}%
\author[1]{Jaya Bhat}%
\author[1]{Ravi Sharma}%
\author[2]{Samuel Leong}%
\affil[1]{Alder Hey Children's NHS Foundation Trust}%
\affil[2]{Liverpool University Hospitals NHS Foundation Trust}%


\vspace{-1em}



  
  \date{May 16, 2024}


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\selectlanguage{english}
\begin{abstract}
Objectives: To assess droplet splatter around the surgical field and
surgeon during simulated Coblation tonsil surgery to better inform on
mitigation strategies and evaluate choice of personal protective
equipment. Design: Observational study Setting: Operation theatre suite
at a tertiary hospital Participants: Life size head model was used to
simulate tonsil surgery using fluorescein-soaked strawberries to mimic
tonsils Main outcome measures: The Coblation wand was activated over the
strawberries for 5 minutes. This was repeated 5 times with 2 surgeons
(total of 10 data sets). The presence of droplet around the surgical
field and anatomical subsites on the surgeon was assessed in binary
fashion: present or not present. The results were collated as frequency
of droplet detection and illustrated as a heatmap; 0 = white, 1-2 =
yellow, 3-4 = orange and 5 = red. Results: Fluorescein droplets were
detected in all four quadrants of the surgical field. The frequency of
splatter was greatest in the upper (nearest to surgeon) and lower
quadrants. There were detectable splatter droplets on the surgeon; most
frequently occurring on the hands followed by the forearm. Droplets were
also detected on the visor, neck, and chest albeit less frequently.
However, none were detected on the upper arms. Conclusion: Droplet
splatter can be detected in the immediate surgical field as well as on
the surgeon. Although wearing a face visor does not prevent splatter on
the surgical mask or around the eyes, it should be considered when
undertaking tonsil surgery as well as a properly fitted goggle.%
\end{abstract}%



\sloppy


\textbf{Introduction}

Tonsillectomy is a common ENT procedure commonly undertaken for
recurrent tonsillitis or sleep disordered breathing. Blood splatter
contamination occurring on the surgeon during tonsil surgery is well
recognised in the literature11Keogh IJ, Hone SW, Colreavey M, Walsh M.
Blood splash and tonsillectomy: an underestimated hazard to the
otolaryngologist. J Laryngol Otol. 2001
Jun;115(6):455-6.\textsuperscript{,}22Hanna BC, Thompson P, Smyth C,
Gallagher G. Blood splash from different diathermy instruments during
tonsillectomy. J Laryngol Otol. 2006; 120(11): 927 -- 31.. In fact,
tonsillectomy was the procedure most commonly resulting in patient's
blood and secretions being detected on the surgeon's face33Lakhani R,
Loh Y, Zhang TT, Kothari P. A prospective study of blood splatter in
ENT. Eur Arch Otorhinolaryngol. 2015 Jul;272(7):1809-12..

The current Covid-19 pandemic has highlighted many routine ENT
operations, including tonsillectomy, as being an aerosol-generating
procedure (AGP). The issue of AGP has been at the forefront of concerns
raised by healthcare professionals and patient-focused groups alike
because the coronavirus is in the oral and nasal cavities44Kowalski LP,
Sanabria A, Ridge JA, Ng WT, de Bree R, Rinaldo A, Takes RP, M\selectlanguage{ngerman}äkitie AA,
Carvalho AL, Bradford CR, Paleri V, Hartl DM, Vander Poorten V, Nixon
IJ, Piazza C, Lacy PD, Rodrigo JP, Guntinas-Lichius O, Mendenhall WM,
D'Cruz A, Lee AWM, Ferlito A. COVID-19 pandemic: Effects and
evidence-based recommendations for otolaryngology and head and neck
surgery practice. Head Neck. 2020 Jun;42(6):1259-1267.. Procedures
undertaken in these anatomical areas on patients who carry the virus may
cause aerosolisation of the virus thereby posing a relative risk of
transmission to the clinical team.

Studies focusing on bipolar cautery during tonsil surgery have
demonstrated not only aerosolisation of particles originating from the
oral cavity but also deposition of blood droplets around the surgeon's
eyes55Carr MM, Patel VA, Soo JC, Friend S, Lee EG. Effect of
Electrocautery Settings on Particulate Concentrations in Surgical Plume
during Tonsillectomy. Otolaryngol Head Neck Surg. 2020
Jun;162(6):867-872.\textsuperscript{,}66Keogh IJ, Hone SW, Colreavey M,
Walsh M. Blood splash and tonsillectomy: an underestimated hazard to the
otolaryngologist. J Laryngol Otol. 2001 Jun;115(6):455-6.. Coblation is
a popular method because it purportedly causes less pain than other
surgical methods77Pynnonen M, Brinkmeier JV, Thorne MC, Chong LY, Burton
MJ. Coblation versus other surgical techniques for tonsillectomy.
Cochrane Database Syst Rev. 2017 Aug
22;8(8):CD004619.\textsuperscript{,}88Daskalakis D, Tsetsos N,
Karagergou S, Goudakos J, Markou K, Karkos P. Intracapsular coblation
tonsillectomy versus extracapsular coblation tonsillectomy: a systematic
review and a meta-analysis. Eur Arch Otorhinolaryngol. 2020 Jul 4. doi:
10.1007/s00405-020-06178-2. Online ahead of print.. However, in the
light of the current pandemic it is unknown if Coblation tonsillectomy
results in detectable droplet splatter on the surgeon. The aim of this
study was to assess droplet splatter around the surgical field and
surgeon during simulated tonsil surgery in order to better inform on
mitigation strategies and evaluate choice of personal protective
equipment.

\textbf{Methods}

\emph{Ethical considerations}

This was an observational study on simulated surgery which did not
involve patients, healthy volunteers or utilised patient-derived
clinical data. Following review by the Director of Research at
{[}removed for blind peer review{]}, formal ethics committee approval
was not required. The reporting guideline we used was the Strengthening
the Reporting of Observational Studies in Epidemiology (STROBE)
checklist for observational studies.

\emph{Experimental setup}

A life-size, anatomically realistic model of the head (AirSim®. TruCorp®
Co. Armagh, Northern Ireland, U.K) was used in this study (Figure 1a).
All simulations of tonsil surgery were undertaken in the operating
theatre suite at {[}removed for blind peer review{]}. The hospital is a
recent construction (2015) incorporating modern airflow techniques in
each of its operating theatres. The model was placed at the top edge of
the operating table in an extended neck position, akin to the
conventional way of doing a tonsillectomy in a patient, with an
appropriately sized Boyle--Davis mouth-gag which was supported by
Draffin rods (Figure 1a). Pillows were placed at the bottom of the model
to simulate the chest and upper abdomen of a patient. The model and
surgical setup was then covered by an impervious black square sheet.

Fresh strawberries cut in half and soaked overnight in nontoxic
fluorescein dye (1mg in 25mL. Monument Tools, MAP UK (TA Tool Chimp)
Ltd. Essex, U.K) was used to simulate tonsils (Figure 1b). The
Coblation\textsuperscript{TM} Procise\textsuperscript{TM} EZ wand
(Smith\&Nephew Ltd. Hull, U.K) was used in default energy settings
(Coblate = 7, coagulate = 3). Diluted fluorescein dye was also added to
the irrigation bag; 1g dye diluted in 250mL irrigation fluid. (Figure
1c).

Tonsil surgery was undertaken by two trained members of the team
({[}removed for blind peer review{]}) who undertook five experiments
each, wearing standard personal protective equipment (PPE).

\emph{Quantification of fluorescein droplets and reporting of data}

Each surgeon undertook five simulated tonsil procedures. The Coblation
wand was activated on the strawberries for five minutes (Figure 1d)
before the surgical field and surgeon was assessed for fluorescein
droplet deposition using an ultraviolet (UV) lamp. The presence of
droplet was assessed in binary fashion: present or not present. The
results were collated as frequency of droplet detection and illustrated
as a heatmap; 0 = white, 1-2 = yellow, 3-4 = orange and 5 = red.

For the surgical field, a 10cm diameter circle was cut out of the
epicentre of the black square sheet to allow access into the oropharynx.
A 30cm line was drawn to each corner of the square to divide it into
four quadrants representing areas within the immediate surgical field.
Another black square sheet measuring 42cm x 42cm was placed over the
pillow (Figure 2a). The surgeon was assessed based on anatomical
subsites (Figure 2b): hands, forearm, upper arm, chest, neck, face visor
and the area under the visor (mask and upper face).

The surgical field was then cleaned and re-checked with the UV lamp.
Remnant strawberries were carefully removed and replaced with fresh
fluorescein-soaked pieces. The Coblation wand was cleaned and activated
externally to ensure both irrigation and suction was functioning
properly. The surgeon's PPE was also cleaned and where necessary,
changed.

\textbf{Results}

Each surgeon completed five experiments, providing a total of 10 data
sets for analysis. For both simulated surgeons, the distance between tip
of nose (surgeon) and upper lip (model) was 35cm. Fluorescein droplets
were detected in all four quadrants of the surgical field. The frequency
of splatter was greatest in the upper and lower quadrants (Figure 3).
The upper quadrant corresponded to the area nearest the surgeon.

There were detectable splatter droplets on the surgeon; most frequently
occurring on the hands followed by the forearm (Figure 4). Droplets were
also detected on the visor, neck and chest albeit less frequently.
However, none were detected on the upper arms.

\textbf{Discussion}

Simulated tonsil surgery using Coblation technology results in
detectable splatter around the surgical field and on the surgeon. The
most common area in the surgical field to be contaminated were the
quadrants anterior and posterior to the oral cavity. There was reduced
frequency of splatter in both lateral quadrants (Figure 3). This is due
to the position of the surgeon's hand within the surgical field which
corroborates with the finding of splatter on both hands (Figure 4).
Splatter was detected on the face visor but interestingly, was also
found on the mask and around the eyes which were areas under the visor.
The results of this study, and in the light of the current pandemic,
emphasises the importance of appropriate PPE and strict donning and
doffing practice.

We were unable to undertake the splatter assessments during real-life
surgery due to the suspension of elective surgery throughout the spring
and summer of 2020. We believe that our experiments on a life-like model
simulated real surgery and provided a consistent and repeatable platform
to undertake the experimental observations. The strawberries were
saturated in fluorescein dye which was also added to the saline
irrigation bag (Figure 1b,c) to facilitate detection of droplet
splatter. While excepting that fresh strawberries were not a substitute
for tonsils, it is frequently used to simulate tonsils at instructional
courses. We decided not to use porcine or bovine soft tissue due to the
health and safety issues of utilising the operating theatre suite in our
institution.

It was an arbitrary decision to activate the Coblation wand for 5
minutes during each experiment. Appreciating that different surgical
styles and practices exist, we felt that 5 minutes was an average
duration required to complete a unilateral tonsillectomy and that the
duration mimicked our clinical practice.

This is the first study to assess for droplet splatter contamination
around the surgical field and on the surgeon after Coblation
tonsillectomy. Previous studies, undertaken during actual surgery, have
focused on either the monopolar or bipolar diathermy which clearly
demonstrated splatter contamination on the surgeon's
face\textsuperscript{1,2,3}. The latter diathermy resulted in greater
splatter. These studies were published following concerns that
transconjunctival exposure was a potential route of transmission for
hepatitis viruses and the human immunodeficiency virus in health care
workers. The consensus from these studies was for surgeons to wear
goggles during tonsil surgery in order to mitigate the risk of
transconjunctival contamination.

A recent study on monopolar tonsillectomy demonstrated greater spread of
the surgical plume at higher energy settings11O'Brien DC, Lee EG, Soo
JC, Friend S, Callaham S, Carr MM. Surgical Team Exposure to Cautery
Smoke and Its Mitigation during Tonsillectomy. Otolaryngol Head Neck
Surg. 2020 Sep;163(3):508-516.. The authors concluded that the addition
of a suction catheter held by a surgical assistant reduced the
detectable spread of the surgical plume. We did not alter the settings
on the Coblation power console but elected to use the default settings
which are recommended by the manufacturer and reflects our clinical
practice. Furthermore, our experiments did not consider the introduction
of an additional suction as we wanted to demonstrate the splatter
patterns from Coblation tonsillectomy which is routinely undertaken
without an assistant bearing in mind that the wand has a built-in
suction port.

The results of our study demonstrate that a face visor is insufficient
to prevent splatter on the surgeon's face. It must be assumed that if
splatter droplets could be detected in our study, that there will be
smaller droplets deposited on the surfaces which were undetectable or
remain aerosolised. This study confirms that Coblation tonsil surgery is
an AGP. Given that coronaviruses are approximately 0.125\selectlanguage{greek}μ\selectlanguage{english}m in size and
are frequently carried in respiratory droplets, it is possible that
surgical techniques regarded as aerosol generating may risk airborne
transmission of SARS-CoV-2 during surgery. The small particle size of
the virus and the extent airborne aerosols may travel has highlighted
the need for specific PPE to protect against inhaled transmission.

This study cannot determine if N97 surgical masks and goggles are
sufficient protection from the risk of viral transmission. Air-purifying
respirators systems and hoods may seem to be the obvious choice, but it
should be remembered that extended use of these PPE is uncomfortable and
restricts communication between staff in the operating suite22Verbeek
JH, Rajamaki B, Ijaz S, Sauni R, Toomey E, Blackwood B, Tikka C,
Ruotsalainen JH, Kilinc Balci FS. Personal protective equipment for
preventing highly infectious diseases due to exposure to contaminated
body fluids in healthcare staff. Cochrane Database Syst Rev. 2020 May
15;5:CD011621.\textbf{Succinct key points:}The Covid-19 pandemic has
highlighted tonsillectomy as an aerosol generating procedure (AGP). This
is the first study to assess for droplet splatter contamination around
the surgical field and on the surgeon during Coblation tonsillectomy.
Droplets were detected in all four quadrants of the surgical fields with
the greatest in the upper (nearest to surgeon) and lower quadrants.
Splatter droplets were most frequently occurring on the hands of the
surgeon followed by the forearm, and less frequently on the visor, neck,
and chest. Although wearing a face visor does not prevent splatter on
the surgical mask or around the eyes, it should be considered when
undertaking tonsil surgery as well as a properly fitted
goggle.\textbf{Legend to tables and figuresFigure 1.} Experimental
setup: (a) Head model with Boyle--Davis and Draffin rods in-situ. (b)
Fluorescein-soaked strawberries used to mimic tonsils. (c) Fluorecein
infused into saline irrigation bag and tubing connected to Coblation
pump. (d) Close-up of simulated tonsil surgery using the Coblation
Procise wand. Note the hole in the black sheet covering the model but
providing access to the oropharynx.\textbf{Figure 2} . a) Quadrants of
surgical field b)Anatomical subsites of surgeon (Right and left hands,
forearms and arms, chest, neck and face) including face
shield\textbf{Figure 3} . Frequency of detected droplet spread around
the surgical field by individual (a and b) and average (c); 0 = white,
1-2 = yellow, 3-4 = orange and 5 = red.\textbf{Figure 4} . Heatmap of
anatomical areas of each surgeon (a and b) including face shield.. The
need for better protection must be balanced between user comfort,
ability to communicate effectively more complicated donning or doffing
procedures, and ultimately compliance to PPE recommendations.

\textbf{Conclusion}

Coblation tonsillectomy is an aerosol-generating procedure. Droplet
splatter can be detected in the immediate surgical field as well as on
the surgeon. Although wearing a face visor does not prevent splatter on
the surgical mask or around the eyes, it should be considered when
undertaking tonsil surgery as well as a properly fitted goggle.

\textbf{Conflict of interest:} none

\textbf{Financial support:} none

\textbf{Data availability statement:} The data that support the findings
of this study are available from the corresponding author upon
reasonable request.

\textbf{References}

{[}1{]} Keogh IJ, Hone SW, Colreavey M, Walsh M. Blood splash and
tonsillectomy: an underestimated hazard to the otolaryngologist. J
Laryngol Otol. 2001 Jun;115(6):455-6.

{[}2{]} Hanna BC, Thompson P, Smyth C, Gallagher G. Blood splash from
different diathermy instruments during tonsillectomy. J Laryngol Otol.
2006; 120(11): 927 -- 31.

{[}3{]} Lakhani R, Loh Y, Zhang TT, Kothari P. A prospective study of
blood splatter in ENT. Eur Arch Otorhinolaryngol. 2015
Jul;272(7):1809-12.

{[}4{]} Kowalski LP, Sanabria A, Ridge JA, Ng WT, de Bree R, Rinaldo A,
Takes RP, M\selectlanguage{ngerman}äkitie AA, Carvalho AL, Bradford CR, Paleri V, Hartl DM,
Vander Poorten V, Nixon IJ, Piazza C, Lacy PD, Rodrigo JP,
Guntinas-Lichius O, Mendenhall WM, D'Cruz A, Lee AWM, Ferlito A.
COVID-19 pandemic: Effects and evidence-based recommendations for
otolaryngology and head and neck surgery practice. Head Neck. 2020
Jun;42(6):1259-1267.

{[}5{]} Carr MM, Patel VA, Soo JC, Friend S, Lee EG. Effect of
Electrocautery Settings on Particulate Concentrations in Surgical Plume
during Tonsillectomy. Otolaryngol Head Neck Surg. 2020
Jun;162(6):867-872.

{[}6{]} Keogh IJ, Hone SW, Colreavey M, Walsh M. Blood splash and
tonsillectomy: an underestimated hazard to the otolaryngologist. J
Laryngol Otol. 2001 Jun;115(6):455-6.~

{[}7{]} Pynnonen M, Brinkmeier JV, Thorne MC, Chong LY, Burton MJ.
Coblation versus other surgical techniques for tonsillectomy. Cochrane
Database Syst Rev. 2017 Aug 22;8(8):CD004619.

{[}8{]} Daskalakis D, Tsetsos N, Karagergou S, Goudakos J, Markou K,
Karkos P. Intracapsular coblation tonsillectomy versus extracapsular
coblation tonsillectomy: a systematic review and a meta-analysis. Eur
Arch Otorhinolaryngol. 2020 Jul 4. doi: 10.1007/s00405-020-06178-2.
Online ahead of print.

{[}9{]} O'Brien DC, Lee EG, Soo JC, Friend S, Callaham S, Carr MM.
Surgical Team Exposure to Cautery Smoke and Its Mitigation during
Tonsillectomy. Otolaryngol Head Neck Surg. 2020 Sep;163(3):508-516.

{[}10{]} Verbeek JH, Rajamaki B, Ijaz S, Sauni R, Toomey E, Blackwood B,
Tikka C, Ruotsalainen JH, Kilinc Balci FS. Personal protective equipment
for preventing highly infectious diseases due to exposure to
contaminated body fluids in healthcare staff. Cochrane Database Syst
Rev. 2020 May 15;5:CD011621.

~

\textbf{Succinct key points:}

1.~~~~ The Covid-19 pandemic has highlighted tonsillectomy as an aerosol
generating procedure (AGP).

2.~~~~ This is the first study to assess for droplet splatter
contamination around the surgical field and on the surgeon during
Coblation tonsillectomy.

3.~~~~ Droplets were detected in all four quadrants of the surgical
fields with the greatest in the upper (nearest to surgeon) and lower
quadrants.

4.~~~~ Splatter droplets were most frequently occurring on the hands of
the surgeon followed by the forearm, and less frequently on the visor,
neck, and chest.

5.~~~~ Although wearing a face visor does not prevent splatter on the
surgical mask or around the eyes, it should be considered when
undertaking tonsil surgery as well as a properly fitted goggle.

\textbf{Legend to tables and figures}

\textbf{Figure 1.} Experimental setup: (a) Head model with Boyle--Davis
and Draffin rods in-situ. (b) Fluorescein-soaked strawberries used to
mimic tonsils. (c) Fluorecein infused into saline irrigation bag and
tubing connected to Coblation pump. (d) Close-up of~ simulated tonsil
surgery using the Coblation Procise wand. Note the hole in the black
sheet covering the model but providing access to the oropharynx.

~

\textbf{Figure 2}. a) Quadrants of surgical field b)Anatomical subsites
of surgeon (Right and left hands, forearms and arms, chest, neck and
face) including face shield

~

\textbf{Figure 3}. Frequency of detected droplet spread around the
surgical field by individual (a and b) and average (c); 0 = white, 1-2 =
yellow, 3-4 = orange and 5 = red.

\textbf{~}

\textbf{Figure 4}. Heatmap of anatomical areas of each surgeon (a and b)
including face shield.

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