Do oom ai empe a u e and human ac i i y a ec he pa icle
concen a ion unde eal su gical p ocedu es in ope a ing
ooms wi h mixing en ila ion? - An expe imen al s udy a S .
Ola s hospi al
Yang Bi1
*
, Tomáš Feče 2, Runa Lundøy1, Tina Kazemi alachi3, Li Inge S ens ad4, Sa a Ed a dsen4, and Guangyu
Cao1
1 Depa men o Ene gy and P ocess Enginee ing, No wegian Uni e si y o Science and Technology - NTNU, No way
2 Facul y o Ci il Enginee ing, B no Uni e si y o Technology, B no, Czech Republic
3 Mechanical and Indus ial Enginee ing depa men , No wegian Uni e si y o Science and Technology - NTNU, No way
4 S . Ola s Hospi al, T ondheim, No way
Abs ac . The objec i e o his s udy is o explo e he e ec s o di e en oom empe a u es and di e en
ypes o ac i i ies on he indoo ai quali y in he ope a ing oom du ing su ge y. Th ee mock-up su ge ies
we e pe o med a 21 ℃, 23 ℃, and 25 ℃ a S . Ola s hospi al in No way. The e ec s o he su geon’s
ac i i y and nu se's mo emen on he concen a ion o pa icula e ma e a he su gical si e and ins umen
able we e compa ed. The esul s show ha he concen a ions o pa icles a bo h he su gical si e and he
ins umen able a e he lowes a oom empe a u e o 23 ℃. The ac i i y o he su geon was he main ac o
leading o he inc ease in he concen a ion o pa icula e ma e wi h he size 0.3-0.5 μm a he su gical si e,
while he nu se mo emen led o he inc ease in he concen a ion o pa icula e ma e wi h he la ge size.
A all oom empe a u es, he mo emen o he dis ibu ion nu se had a g ea e e ec han he ac i i y o he
su geon on he inc ease o he concen a ion o pa icles a he ins umen able. In addi ion, he in ensi y o
he pa icula e sou ce may be ac o s a ec ing he concen a ion o pa icula e ma e . The e o e, i is
ecommended ha dis ibu ion nu ses should a oid unnecessa y ac i i ies du ing he ope a ion.
1 In oduc ion
Ai bo ne bac e ia ha en e open wounds du ing su ge y
can cause pos -ope a i e in ec ions, commonly known
as su gical si e in ec ions (SSI). SSI is he mos common
heal hca e-associa ed in ec ion among pa ien s [1].
Acco ding o Wo ld Heal h O ganiza ion (WHO)
guidelines o sa e su ge y, he incidence o se ious
complica ions in pa ien s unde going inpa ien su ge y
in de eloped coun ies is 11.8% (1.2-23.6%), Ex a
hospi al s ay a ibu able o SSI was 9.7 days wi h
inc eased cos s o US$ 20 842 pe admission [2].
Ai cleanliness in he ope a ing oom (OR) is one o he
impo an ac o s a ec ing he incidence o SSI [3]. The
s udy showed ha skin scales on he su gical eam we e
he main sou ce [4]. O he s udies seem o ha e ound a
linea ela ionship be ween CFU and he concen a ion
o 5-10 μm pa icles o a speci ic size in he OR [5]. A
p esen , he OR uses high en ila ion olume, lamina
en ila ion, and high-e iciency il a ion de ice o make
he indoo ai can achie e a cleane s a e. These
measu es ha e been p o ed o be e ec i e in imp o ing
indoo ai quali y and educing he SSI a e o a ce ain
ex en .
*
Co esponding au ho : [email p o ec ed]
In addi ion o some equipmen and en ila ion
pa ame e s, some human ac i i ies in OR a e also
hough o a ec ai quali y in he ope a ing oom.
P e ious s udies on in luencing ac o s o ai quali y in
he OR summa ized he ollowing impo an ac o s: 1.
Ac i i ies o he su gical eam [6], 2. Doo opening [7,
8], 3. The mo emen o he dis ibu ion nu se [9], 4.
Clo hing [10], 5. Ai change a e [11, 12]. Al hough
some s udies ha e discussed hese in luencing ac o s
quali a i ely, he e is no quan i a i e analysis ye .
In addi ion, a ecen s udy [13] showed ha he su gical
lamp i adia es he su gical si e which c ea es a he mal
plume abo e i may p e en pa icula e ma e om
se ling. This phenomenon may ha e a p o ec i e e ec
on he su gical si e, and he g ea e he eloci y o he
he mal plume, he s onge he p o ec i e e ec . The
in ensi y o he he mal plume is ela ed o oom
empe a u e, and he lowe he oom empe a u e is, he
s onge he he mal plume is [14]. The ela ionship
be ween oom empe a u e and ai quali y a he su gical
si e has no been desc ibed. The e o e, his s udy aims
o e eal he in luence o oom empe a u e changes and
pe sonnel ac i i ies on he ai quali y o he su gical si e
and ins umen able.
E3S Web o Con e ences 356, 05005 (2022)
ROOMVENT 2022
h ps://doi.o g/10.1051/e3scon /202235605005
© The Au ho s, published by EDP Sciences. This is an open access a icle dis ibu ed unde he e ms o he C ea i e
Commons A ibu ion License 4.0
(h p://c ea i ecommons.o g/licenses/by/4.0/).
2 Me hods
2.1 The eal ope a ing oom
The mock su ge ies we e conduc ed in an ac ual OR
wi h Mixing en ila ion (MV) in he Eme gency, Hea
and Lung Cen e a S . Ola s Hospi al in T ondheim,
No way, as shown in Fig.1. The OR has an a ea o 53
m2 and a heigh o 2.9 m. The OR is equipped wi h ou
adial ai di use s loca ed in he ceiling in each co ne
o he oom (Figu e 1). The e a e ou exhaus g ills in
his OR. Two exhaus g ills a e ins alled on he wall o
he en ance doo , wi h one exhaus g ill close o he
loo and one close o he ceiling. The o he wo exhaus
g ills a e ins alled in he same manne on he opposi e
wall. The o al supply ai low a e was 3701 m3/h, and
he a e age ai low a e in he exhaus was 3288 m3/h.
The ai change a e o he OR was 24 ai changes pe
hou (ACH). The h ee mock su ge ies we e pe o med
a 21℃ ( he lowes oom ai empe a u e), 23℃ ( oom
ai empe a u e du ing no mal su ge y), and 25℃ ( oom
ai empe a u e du ing su ge y o in an s).
Fig. 1. The layou o he OR
2.2 Measu emen p ocedu e and equipmen
Abdominal su ge y is he mos common ype o su ge y,
such as caesa ean deli e ies, appendec omy, colon
su ge y, lapa oscopic su ge y. The e o e, he su gical
si e loca ion in his s udy was abdomen [15]. Fi e
expe imen e s simula ed i e di e en oles in he OR,
which includes wo su geons, a s e ile nu se, a
dis ibu ion nu se, and an anes hesiologis . A 4 kg po k
ib was placed on he ope a ing able o simula e he
pa ien . Among hem, wo su geons and he s e ile nu se
wo e a non-wo en polyes e / u ed Su gical gown,
Ful illing he Requi emen s o EN13795-2:2019, Wo n
o e a clean ai sui , oge he wi h a Su gical ace Mask
(EN 14683 Type II app o ed). The dis ibu ion nu se
and anes hesiologis wea a clean ai sui and su gical
ace mask, and a co ec ly posi ioned su gical hood.
Each mock ope a ion is di ided in o ou s ages, a o al
o 60 minu es, di ided in o: 20 minu es o s a ic, 10
minu es o su geon ac i i y, 20 minu es o s a ic, 10
minu es o nu se mo emen . The su geon cu and
su u ed he ib while he su geon ac i i y and he nu se
walk a ound he ope a ing able while he nu se mo ed.
The pu pose o 20 mins immobili y is o s abilize he
concen a ion o indoo pa icula e ma e . This p e en s
he in luence o p e-ope a i e pe sonnel ac i i ies on he
esul s, as well as he in luence o su geon ac i i ies on
he esul s o nu se mo emen . O e 1 hou was
a anged be ween each mock su ge y o wai o he
s abili y o he empe a u e.
The measu ing poin s we e he su gical si e and
ins umen able. The measu emen de ice is Ae o ack
9306, which suppo s o de ec he concen a ion o
pa icles o six di e en pa icle sizes. Flow a e 0.1
CFM (2.83 LPM) Accu acy ±5% / pa icle size ange
0.3 o 15 µm . The sampling in e al used in his s udy is
10s.
Fig. 2. TSI Ae o ack 9306
3 Resul s and discussion
We scheduled 20 minu es o inac i i y a he beginning
o each simula ed ope a ion. Since all he su geons a e
wai ing ou side be o e he ope a ion, hei clo hes can
ca y a la ge amoun o dus . As we can see om he
Fig.3., du ing hese 20 minu es, we obse ed he
concen a ion o pa icula e ma e d op o be ween 1/12
and 1/5 o i s ini ial le el, wi h he inal pa icula e
concen a ion below 5000 numbe s /m3. We obse ed
signi ican inc eases in pa icula e ma e concen a ions
in bo h su geon ac i i y and nu se mo emen .
Fig.3. The d op in pa icle concen a ion a su gical si e
du ing i s 20 minu es o e e y mock-up su ge y
Fig. 4. shows he concen a ion esul s o pa icula e
ma e quan i y a he su gical si e a di e en oom
empe a u es and di e en ac i i ies. As can be seen
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om he igu e, on he whole, he concen a ion o
pa icula e ma e a he su gical si e when he nu se
mo ed was g ea e han ha when he su geon ac i i y.
This phenomenon is ob ious in pa icle size ange la ge
han 0.3 μm. Fo pa icles smalle han 0.3 mic ons, he
e ec o su geon ac i i y is g ea e . This may be because
su geons end o ha e small mo emen s, such as wa ing,
bending, and u ning. In con as , nu ses ha e a la ge
ange o mo emen s. Al hough he ac i e a ea is mo e
han 1m away om he ope a ing able, he ai low o
he su gical mic oen i onmen may be dis u bed by i .
The su gical lamp shines on he su gical si e o a long
ime, hea ing i and c ea ing an upwa d plume o hea .
The upwa d ai low will p e en he deposi ion o
pa icles abo e he su gical si e, so i has a p o ec i e
e ec on he su gical si e. Tu bulence in he ai low may
des oy i and lea e i unp o ec ed.
The concen a ion o pa icula e ma e a ies g ea ly a
di e en oom empe a u es. I was obse ed ha a
oom empe a u e o 23℃, he pa icle concen a ion o
any size was below 24000 numbe s /m3. When he oom
empe a u e was 21℃, he concen a ion o pa icula e
ma e was he highes . The concen a ion o 0.3 μm
pa icles is abou 48000 numbe s /m3.
Fig. 4. Pa icle concen a ion a he su gical si e
The Fig. 5. shows he concen a ion esul s o pa icula e
ma e quan i y a he su gical si e a di e en oom
empe a u es and di e en ac i i ies. The impac o he
nu se mo emen is g ea e han ha o su geon ac i i ies.
The ela i e di e ence was g ea es a 25℃, wi h he
concen a ion du ing he nu se mo emen being wice as
much as he concen a ion o he su geon ac i i y. This
could be in e p e ed as he ac ha he nu se, who is a
sou ce o he pa icles, is close o he ins umen able
han he su geon du ing he nu se mo emen .
By compa ing he esul s o di e en empe a u es, we
ound ha he pa icle concen a ion was he lowes a
oom empe a u e o 23℃. The pa icle concen a ions
o all pa icle sizes we e lowe han 24000 numbe s /m3.
This phenomenon is simila o he concen a ion o
pa icula e ma e a he su gical si e. Combined wi h he
esul s o pa icle concen a ion a he su gical si e, we
belie e ha he di e ence concen a ion unde di e en
oom empe a u e may be caused by di e en emission
sou ce in ensi ies. Be o e he mock ope a ion a 21℃,
all he expe imen e s s ayed ou side o a long ime.
A e he s a o mock ope a ion, pa icula e ma e was
g adually dilu ed and emo ed by en ila ion. Howe e ,
be o e he mock su ge y a 25℃, he expe imen e s le
he OR again o a longe ime han be o e he mock
su ge y a 23℃, ca ying mo e pa icles. In addi ion, he
in luence o he mal plumes on he esul s can be uled
ou , because he e is no he mal plume abo e he
ins umen able, bu he wo measu emen poin s show
simila esul s a di e en oom empe a u es. The e o e,
u he s udies a e needed o e eal he di ec
ela ionship be ween oom empe a u e and pa icula e
concen a ion.
Fig. 5. Pa icle concen a ion a he ins umen able
4 Conclusion
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In his s udy expe imen al measu emen s we e
pe o med in simula ed ope a ion p ocedu es in a eal
OR. This s udy in es iga ed he in luence o oom ai
empe a u e and di e en su gical ac i i ies on he
dis ibu ion o he concen a ion o pa icula e ma e in
he su gical si e and ins umen able. A ew conclusions
may be made as ollowing:
1) Indoo pa icula e ma e concen a ions can be
educed o 1/12 o 1/5 o he ini ial alue by 20 minu es
wi h e y low ac i i y le el. The e o e, i is
ecommended o educe he mo emen o pe sonnel in
he OR o a leas 20 minu es be o e he incision.
2. The sou ce o pa icula e ma e in he OR is medical
s a , and he elease a e o pa icula e ma e sou ce
may ha e a c ucial impac on he concen a ion o
pa icula e ma e in he su gical si e and ins umen s.
3) The mo emen o he nu se inc ease he concen a ion
o pa icula e ma e a he su gical si e and ins umen
able when he oom empe a u e is highe . The e o e, i
is an e ec i e measu e o educe he concen a ion o
pa icula e ma e a he su gical si e and ins umen
able by adop ing a lowe oom empe a u e and
a oiding unnecessa y mo emen o ci cula ing nu ses as
a as possible.
Acknowledgmen
The au ho s a e g a e ul o he China Schola ship
Council o he inancial suppo o Yang Bi (CSC
s uden ID: 2020090210006).
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