205
REVIEW ARTICLE
The efficacy of an aerosol box to prevent infections during aerosol-generating procedures
Copyright (c) 2022 Slovenian Medical Journal. This work is licensed under a
Creative Commons Attribution-NonCommercial 4.0 International License.
The efficacy of an aerosol box to prevent infections 
during aerosol-generating procedures
Učinkovitost aerosolne škatle za preprečevanje okužb pri posegih, pri katerih  
nastajajo aerosoli
Luka Pušnik,1 Matej Serdinšek,2 Tatjana Stopar Pintarič,2,3 Nejc Umek3
Abstract
The new risks faced by healthcare workers in the COVID-19 pandemic have inspired the development of new forms of 
personal protective equipment (PPE). Such a novel PPE is an aerosol box modified and adapted to facilitate safer intu-
bation of patients infected with SARS-CoV2. Hitherto, the idea of a protective aerosol box has found clinical application 
in anaesthesiology and many other fields of medicine and dentistry. However, numerous criticisms of the original design 
have led to the evolution of new forms that gradually improved the original shortcomings. The present modified design 
improves the safety and simplicity of use while reducing the operator’s hindrance during interventions. Operator training 
is also extremely important for the correct and safe use of the aerosol box in clinical practice. Aerosol box does significantly 
affect the speed of intubation therefore it is not recommended in urgent cases. Many authors have been able to prove that 
the use of the original box, as well as its later modifications, adequately protects healthcare workers from large and small 
water droplets. However, the use of the original form increases the risk of infection with aerosol particles.
Izvleček
Izpostavljenost okužbi zdravstvenih delavcev zaradi pandemije covida-19 je privedla do razvoja novih oblik osebne va-
rovalne opreme. Ena od njih je aerosolna škatla, ki je bila zasnovana z idejo, kako varneje vstaviti dihalno cevko v sapnik 
bolnikom, okuženim z virusom SARS-CoV2. Uporaba aerosolne škatle ne sega samo v področje anesteziologije, ampak 
tudi v druga področja medicine. Številne kritike na račun prvotne zasnove so vodile v izdelavo novih oblik, ki postopoma 
izboljšujejo prvotne pomanjkljivosti. Razvoj se usmerja predvsem v okoliščino, kako zmanjšati oviranost kirurga (ali iz-
vajalca) pri posegih ter kako zagotoviti varnejšo, enostavnejšo in hitrejšo možnost uporabe. Številnim avtorjem je uspelo 
pokazati, da uporaba aerosolne škatle pomembno vpliva na hitrost vstavitve dihalne cevke v sapnik, zato v urgentnih 
1 Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
2 Department of Anaesthesiology and Intensive Therapy, University Medical Centre Ljubljana, Ljubljana, Slovenia
3 Institute of Anatomy, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
Correspondence / Korespondenca: Luka Pušnik, e: luka.pusnik7@gmail.com
Key words: personal protective equipment; COVID-19; water droplets; safety; tracheal intubation
Ključne besede: osebna varovalna oprema; covid-19; vodne kapljice; varnost; vstavitev dihalne cevke v sapnik
Received / Prispelo: 29. 10. 2020 | Accepted / Sprejeto: 1. 5. 2021
Cite as / Citirajte kot: Pušnik L, Serdinšek M, Stopar Pintarič T, Umek N. The efficacy of an aerosol box to prevent infections during 
aerosol-generating procedures. Zdrav Vestn. 2022;91(5–6):205–14. DOI: https://doi.org/10.6016/ZdravVestn.3187
eng slo element
en article-lang
10.6016/ZdravVestn.3187 doi
29.10.2020 date-received
1.5.2021 date-accepted
Anaesthesiology, intensive care Anesteziologija, intenzivna nega discipline
Review article Pregledni znanstveni članek article-type
The efficacy of an aerosol box to prevent infec-
tions during aerosol-generating procedures
Učinkovitost aerosolne škatle za preprečevanje 
okužb pri posegih, pri katerih nastajajo aerosoli article-title
The efficacy of an aerosol box to prevent infec-
tions during aerosol-generating procedures
Učinkovitost aerosolne škatle za preprečevanje 
okužb pri posegih, pri katerih nastajajo aerosoli alt-title
personal protective equipment, COVID-19, 
water droplets, safety, tracheal intubation
osebna varovalna oprema, covid-19, vodne ka-
pljice, varnost, vstavitev dihalne cevke v sapnik kwd-group
The authors declare that there are no conflicts 
of interest present.
Avtorji so izjavili, da ne obstajajo nobeni 
konkurenčni interesi. conflict
year volume first month last month first page last page
2022 91 5 6 205 214
name surname aff email
Luka Pušnik 1 luka.pusnik7@gmail.com
name surname aff
Matej Serdinšek 2
TatjanaPintarič Stopar Pintarič 2,3
Nejc Umek 3
eng slo aff-id
Faculty of Medicine, University 
of Ljubljana, Ljubljana, Slovenia
Medicinska fakulteta, Univerza v 
Ljubljani, Ljubljana, Slovenija 1
Department of Anaesthesiology 
and Intensive Therapy, 
University Medical Centre 
Ljubljana, Ljubljana, Slovenia
Klinični oddelek za 
anesteziologijo in intenzivno 
terapijo operativnih strok, 
Univerzitetni klinični center 
Ljubljana, Ljubljana, Slovenija
2
Institute of Anatomy, Faculty 
of Medicine, University of 
Ljubljana, Ljubljana, Slovenia
Inštitut za anatomijo, Medicinska 
fakulteta, Univerza v Ljubljani, 
Ljubljana, Slovenija
3
Slovenian Medical Journallovenian Medical Journal
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ANAESTHESIOLOGY, INTENSIVE CARE
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1 Introduction
The COVID-19 pandemic posed an additional risk 
to healthcare workers, exacerbated by a possible lack of 
personal protective equipment (PPE). SARS-CoV-2 is 
spread mostly via droplets from the upper respirato-
ry tract, but aerosol transmission is also possible (1). 
The particles with which the virus is transmitted are 
of different sizes and can be defined as large droplets 
with a diameter of 60 µm and more, small droplets 
with a size of 10 - 60 µm, and aerosols, particles that 
are smaller than 5 µm. Large droplets can reach sur-
faces up to two metres away, small water droplets reach 
distances even greater than two meters, and aerosols 
can remain airborne for three hours after formation 
(2-4). Therefore, protection during aerosol-generating 
procedures is crucial as healthcare workers performing 
these procedures are at increased risk from infection 
(1,3,4). Other measures, such as reducing the number 
of staff in the area where interventions are carried out, 
sterilization and disinfection of equipment and PPE 
use are also effective in reducing aerosol transfer (4,5). 
Endotracheal intubation and extubation, non-invasive 
ventilation, tracheotomy, oropharyngeal/tracheal aspi-
ration, bronchoscopy, oesophagogastroduodenoscopy, 
transoesophageal echocardiography and surgery in 
the head and neck area are counted among the aerosol 
generating procedures (AGP) (3,6). The World Health 
Organization (WHO) and Centers for Disease Control 
and Prevention (CDC) have defined the lists of proce-
dures for which PPE use is mandated, consisting of a 
hair cover, protective goggles, N95 mask, gloves and a 
gown with long sleeves (7-9). High levels of workload 
and limited access to technology and materials for pa-
tient care encourage the development of strategies to 
improve personal protection in countries with less de-
veloped health systems (10). In the latter, the risk of 
aerosol transfer is increased due to a number of addi-
tional risk factors, such as inadequate ventilation, per-
forming procedures in rooms where negative pressure 
cannot be established, lack of rooms to prepare for pro-
cedures, hospital rooms with multiple patients and in-
adequate sealing of doors and windows (4,11-14). Due 
to an increased risk of infection during AGP, forms of 
primerih odsvetujejo uporabo aerosolne škatle. Ob primerni uporabi ter ustreznem urjenju zdravstvenega delavca pa se je 
izkazala kot učinkovita osebna varovalna oprema, ker zdravstvene delavce dobro zaščiti pred velikimi in majhnimi vodnimi 
kapljicami. Pravilno posodobljena oblika aerosolne škatle dobro varuje tudi pred aerosolnimi delci, medtem ko uporaba 
izvorne oblike lahko tveganje za okužbo zdravstvenega delavca z aerosolnimi delci še poveča.
PPE have been developed during the COVID-19 pan-
demic, the aerosol box among them. It is a transparent 
box made of acrylic or polycarbonate, which covers the 
patient’s head and has two ports that allow the opera-
tor to access the airway, handle devices and allows for 
endotracheal intubation or extubation (15). The first 
design for the box was published in March 2020 by the 
Taiwanese anaesthesiologist Lai Hy with the purpose 
of safer endotracheal intubation. The original aerosol 
boxes were designed as transparent boxes measuring 50 
x 50 x 40 cm with two circular ports 10 cm in diameter 
for the operator’s hands (Figure 1). The original design 
sought to maximize reusability. It used materials that 
are resistant to higher temperatures, and its price was 
estimated at $67 for one aerosol box (1,16-20). Trans-
parent acrylic or polycarbonate panels, 5-6 mm thick, 
were most often used to make the aerosol box, while 
newer aerosol boxes also use thicker acrylic, up to 9.5 
mm thick, or thinner acrylic, 3 mm thick, a large dif-
ference in final weight (17,20-24). The advantages of 
acrylic material are permanent transparency, free and 
wide availability and low price. It is also easy to cut 
and bend at higher temperatures (25). The quality of 
the original model has deteriorated in some places after 
only three to five uses, while the version with thicker 
acrylic allows up to eight weeks of intensive clinical use 
and numerous disinfections (17). The time to make an 
aerosol box is estimated at four hours and the setup 
time for clinical use is 5-7 minutes (24,26).
Numerous criticisms of the original aerosol box 
design and the increase in infections among health-
care professionals during a general PPE shortage have 
spurred the rapid development of the original aerosol 
box, which has undergone many improvements (22). 
The usefulness of the aerosol box is not limited to in-
terventions to provide a patent airway, but also extends 
to other areas of medicine. To date, the possibility of 
its use has also been described in the field of (a) der-
matology for facial procedures, (b) ophthalmology 
for surgery, (c) gastrointestinal surgery for emergency 
surgery, (c) gastroenterology for oesophagogastroduo-
denoscopy, and (d) neonatology for AGP of neonates 
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REVIEW ARTICLE
The efficacy of an aerosol box to prevent infections during aerosol-generating procedures
whose mothers are infected with SARS-CoV2 virus. 
The authors also mention the use in dentistry and oto-
rhinolaryngology (3,7,23,24,26-30).
2 Drawbacks of the original aerosol box 
design
The simple design of the original aerosol box has 
been frequently criticized, so many researchers are try-
ing to address these shortcomings. First and foremost, 
the aerosol box has been shown to complicate vital pro-
cedures that need to be carried out extremely quickly, 
making it less useful for emergencies (31). The pro-
longed set up time can significantly prolong the time 
to the emergency procedure’s start, and at the same 
time further impede the operator’s access to the patient 
(24,26,32). The two most common subjective problems 
with handling an aerosol box are discomfort with han-
dling the bougie and laryngoscope and mentally taxing 
the operator, which has often led to the abandonment 
of aerosol box use in many hospitals (1). In addition 
to the shortcomings already mentioned, there are often 
problems due to: (a) inadequate size, especially in over-
weight and short-necked patients (18,32); (b) insuffi-
cient aerosol box height, which does not allow proper 
handling of the elastic bougie, making the procedure 
more difficult, particularly for operators of lower stat-
ure, and (1,22,32); (c) too small or excessive diameter 
of the hand ports or the absence of the ports for nurse’s 
assistance (1,24). The original design of the aerosol box 
has also received considerable criticism for: (d) inad-
equate design of the panel facing the patient’s feet, as 
this does not protect staff located near the open panel 
(8,17,33,34); (e) the lower part, which tends to slide and 
requires the assistance of staff in stabilizing the aerosol 
box (27,28); (f) the inability to safely and quickly re-
move the box in case of airway problems (22,32); (g) the 
inability to maintain negative air flow and prevent the 
air and aerosols from escaping (7,26); (h) heavy weight 
and rigidity in handling; (i) short lifespan and (j) prob-
lems with storage and cleaning (17,33,35). Opinions 
about cleaning and disinfecting the aerosol box differ 
greatly. Some cite the ease of disinfection as an advan-
tage, while others cite the difficulty of disinfection as 
one of its main drawbacks (21,31). A 70% alcohol solu-
tion is recommended for disinfection, which can be re-
placed by a 0.5% hypochlorite solution (20,21,28). Due 
to the alleged shortcomings, there have been a number 
of updates and improvements to the boxes, which try to 
eliminate errors and increase their usability.
Figure 1: Aerosol box.
The original design of the aerosol box has six sides. The upper and lateral sides are without ports; the operator side has two 
hand ports; the feet-facing side and lower side are open. The centre of the port is 25 cm removed from the lower border and 10 
cm from the lateral border of the aerosol box, per Lai HY, 2020 (20).
Operator side
Cover
Operator hand 
ports
Operator side
Cover
Operator hand
ports
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3 Improvements to the original aerosol 
box design
Several improvements to the aerosol box have already 
been proposed in an attempt to address the shortcom-
ings of the original design (Figure 2). The most common 
update is the added side port or more ports that make 
it easier to give and use instruments (1,7,16,28,32). The 
ports are normally circular, 10–12.5 cm in diameter, but 
can also be square in shape, up to 27 x 27 cm in size 
(3). They are commonly free to open, but can be cov-
ered with removable acrylic material, neoprene or nitrile 
rubber, which can be discarded after use (2,10,20,32,36). 
Frequently, an air outlet is added (1,27). A polypropyl-
ene drape covering the chest can be attached to the sur-
face facing the legs; the side surfaces of the aerosol box 
may be tilted upwards towards the operator. Due to the 
different patient sizes, the width and curvature of the lat-
eral surfaces can be adjusted, allowing easier access to 
patients with higher body weight and wider shoulders. 
Frequent updates also include the increased aerosol box 
height, which makes it easier to handle instruments, and 
the changed inclination of the upper surface with an an-
gle between 8° and 30°, which allows a more comfort-
able position for the operator and less difficulty handling 
bougies, laryngoscopes and other longer instruments. 
The slope can cover the entire upper side or only part of 
it. A belt can also be added to stabilize the aerosol box 
and reduce the need for additional stabilization during 
procedures (10,22,27,28,32,37-39) (Table 1).
To facilitate handling of the aerosol box, plastic spac-
ers may be added on its upper surface to allow easier 
storage when the box is not in use; side handles for quick 
removal in emergencies; staples holding the suction de-
vice and laryngoscope; and a waste bag (10,22). Some 
aerosol boxes are also foldable to take up less space when 
not in use (35,38). The specially designed KS-type acryl-
ic aerosol box (Kojima/Sugimura) also allows more free-
dom in handling instruments. It is similar in design to 
the original aerosol box, but without sides next to the 
operator. A transparent plastic cover is required for in-
stallation, into which ports are cut with scissors before 
use, and the operator’s hands are wrapped with adhe-
sive tape to additionally seal the opening (40). Table 1 
summarizes the main features of some updated aerosol 
boxes. Other forms of protective equipment have also 
been described as a substitute for the aerosol box, e.g. 
single-use drapes in the form of a tent (33).
4 The effect of the aerosol box on the 
speed and success of endotracheal 
intubation
PPE should not endanger the safety of the patient or 
staff (22), but at the same time it should enable quick 
access to the patient in case their vital functions rapidly 
worsen (37). Several studies have evaluated the impact 
of an aerosol box on the speed and success of endo-
tracheal intubation (Table 2). The results uniformly 
show that the use of an aerosol box in its original or 
Figure 2: Frequent updates to the original aerosol box.
Taller box 
with sloped cover
Waste area
Additional protection at the patient's feet
Assistant ports
Air extraction 
port Larger operator hand ports
Longer, wider 
box
Tubing access port
Operator side
Assi
stan
t sid
e
Cover
Tub
ing 
acc
ess 
por
t
Operator hand 
ports Assi
stan
t po
rts
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The efficacy of an aerosol box to prevent infections during aerosol-generating procedures
updated form affects the endotracheal intubation speed 
(1,19,37,38,41). Begley et al. have found that the endo-
tracheal intubation time is lengthened by 38.3 second 
with the use of the original aerosol box design and 9.3 
seconds with the updated design (19). The other au-
thors cite values between the previous ones (37,38,41-
44). A meta-analysis by Lim et al. summarized that the 
endotracheal intubation time is significantly length-
ened (>4 seconds) with the use of an aerosol box (43). 
When analyzing studies, it should be borne in mind 
that these have been simulated and do not account for 
all the factors that occur in real circumstances, so the 
time may actually be even longer. Factors such as lack 
of experience, operator’s mental overload, procedural 
problems and reduced visibility can further prolong the 
endotracheal intubation time, which is particularly im-
portant in critically ill patients with severe COVID-19 
who have significantly reduced tolerance to lack of 
oxygen (1,43-46). Trujillo et al. have noted that the 
use of an aerosol box significantly lengthens the endo-
tracheal intubation time in infants and children (47). 
Researchers have also found that the aerosol box has 
less effect on the endotracheal intubation time when 
using the videolaryngoscope when compared to the la-
ryngoscope (38,41). Most authors also did not find dif-
ferences in the first attempt at endotracheal intubation 
with or without the use of an aerosol box. Nevertheless, 
some authors reported up to 6% lower success rate at 
the first attempt at endotracheal intubation with the use 
of an aerosol box (1,19,37,38,41,46,48).
Opinions about the use of an aerosol box during in-
tubation in clinical practice are divided. Numerous au-
thors recommend their use (19,35,37,41,47), but Malik 
et al. advise against the use of the original aerosol box in 
emergency intubation due to reduced manoeuvrability, 
which can affect the intubation speed. They mention a 
Table 1: Comparison of the original aerosol box design with updated designs (10,20,21,24,26,27,38,39).
Legend: AC – aerosol contamination; SU – sloped upwards in the direction of the operator; SD – sloped upwards in the direction 
of the operator; ND – no data; OP – for the operator; PE – polyethylene; PP – polypropylene; LS – on the lateral side; TA – 
transparent acrylic; TP – transparent polycarbonate; T – on the top.
Size (cm) Material Shape Access ports Feet-facing 
side
Air 
extraction 
system
AC risk
Original aerosol 
box (20) 40 x 50 x 50 TA rectangular 2 ports: 2 OP open NO high
Aerosol box with 
negative air flow 
(26)
43 x 53 x 53 TA rectangular – upper side ND
6 ports: 2 OP, 
4 LS
slosed with 
synthetic 
material
YES low
Aerosol box for 
dentistry (27) 50 x 60 x 60 ND
rectangular – 
upper side ND, 
lower side SU
4 ports: 2 OP, 
2 LS open NO ND
Neobox – box 
for neonates 
(24)
42 x 42 x 56 TP rectangular – upper side ND
6 ports: 2 OP, 
4 LS open or PE NO ND
Aerosol box 2.0 
(10) NP
TA, nitrile 
rubber
rectangular – 
upper side ND
4 ports: 2 OP, 
2 LS 
covered with 
plastic drape YES ND
SLACC – 
suction-assisted 
local aerosol 
containment 
chamber (39)
NP NP Irregular hexagonal 
5 ports: 2 OP, 2 
LS, 1 T
covered with 
plastic drape YES low
Aerosol box 
Serdinšek et al. 
(38)
NP
TA, 
aluminium, 
neoprene
rectangular 4 ports: 2 OP, 2 LS PP drape YES ND
»Endoprotector« 
box (21) 40 x 45 x 50 TA rectangular
3 ports: 2 OP, 
1 LS open YES ND
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number of procedures when the patient’s safety is not 
endangered as much, thus allowing for the use of an 
aerosol box – e. g. tracheal extubation, nasogastric tube 
insertion, tracheal tube exchange and patient transfers 
(22). It can be summarized that the time of endotrache-
al intubation is significantly lengthened with the use of 
an aerosol box, so its use is not recommended in emer-
gencies. We must also be aware that the aerosol box is 
an additional physical barrier that affects the way inter-
ventions and procedures, which the operator is already 
experienced with, are performed.
5 Aerosol box safety
The risk of introducing new equipment or protocol 
must always be balanced by proven effectiveness. The 
procedure must protect the provider and other health-
care staff and be safe for the patient at the same time 
(49). To confirm the protective function of the box, 
several studies have shown that the use of an upgrad-
ed aerosol box with an active air extraction system can 
effectively reduce contamination of the operator and 
assistant with both large and small water droplets. At 
the end of the procedure, the aerosol box and the con-
tents of the box remain contaminated, which can lead 
to additional infections if not handled properly and 
disinfected (4,5). It is important to be aware that trans-
mission can also occur after the procedure, especially 
during the removal of the aerosol box (48). Serdinšek et 
al. have shown that when the hands contaminated with 
large droplets are removed from an aerosol box with 
neoprene covered ports, the outside of the box remains 
uncontaminated (38). All the research published so far, 
which studied the contamination with water droplets, 
showed a significant reduction in the operator’s and 
environment’s contamination when using an aerosol 
box (Table 3) (8,21,50,51). Fried et al. also showed the 
importance the patient’s position plays during endo-
tracheal intubation, which also affects the healthcare 
worker’s exposure. The latter is lowest at the slight re-
verse Trendelenburg position, which, however, is not 
optimal for direct laryngoscopy (51).
Numerous studies have confirmed that the use of an 
aerosol box limits the macroscopic contamination of 
the operator; however, concerns about aerosol exposure 
remain (34). With dynamic analysis of air flow, Dallin 
et al. showed increased air leakage during deep breath-
ing and coughing with the original aerosol box. The 
completely open surface facing the patient’s legs is par-
ticularly exposed. When using the drape, the air does 
Table 2: The effect of the aerosol box on the speed and success of endotracheal intubation (1,19,37,38,44).
Legenda: AB – aerosol box; mAB – modified aerosol box; DL – direct laryngoscopy; ND – no data; VL – videolaryngoscopy; s – 
second.
Study Begley 
et al. (1)
Clariot 
et al. (37)
Serdinšek 
et al. (38)
Wakabayashi 
et al. (19)
Turner 
et al. (44)
Number of 
endotracheal 
intubations
36 94 144 108 96
Number of operators 12 47 36 18 48
AB
Original and modified 
AB (upper and lateral 
port)
Modified AB 
(upper side 
sloped forward)
Modified AB 
(Table 1) Original AB Original AB
Time to successful 
endotracheal 
intubation without AB 
42.9 s DL 48 s DL 23 s DL25 s VL
14 s DL
14 s VL 12.2 s VL
Lengthening of 
time required 
for endotracheal 
intubation 
+38 s AB
+9 s mAB +5 s DL
+4 s DL
+9 s VL
+3 s DL
+1 s VL +8.4 s VL
Success rate of 
first attempt at 
endotracheal 
intubation
100% without AB
75% AB
83% mAB
100% 
95.4% without 
AB
94.4% mAB
100% without 
AB 
100% AB
ND
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The efficacy of an aerosol box to prevent infections during aerosol-generating procedures
not escape from the box (31). By analyzing the removal 
of aerosols from a box covered with a plastic drape and 
an air extraction system, the researchers found that the 
half-life of the particles in the box is reduced. The lat-
ter was reduced from 3.4 minutes without the use of 
an air extraction system, and to less than 17 seconds 
when using it. In this way, the authors showed a signif-
icant reduction in the possibility of contamination us-
ing an active air extraction system (36). Simpson et al. 
also studied aerosol contamination by simulating five 
scenarios involving coughing. Particles with a diameter 
of 0.3 to 5 µm were measured with a meter placed in 
front of the operator’s head. They compared the use of 
the original aerosol box design with the surface which 
faced the patient’s feet covered with a plastic drape, and 
an updated aerosol box with an active air extraction 
system and a particulate filter. Compared to the absence 
of all protective equipment, greater contamination was 
found when using the original aerosol box, as aerosols 
reached the operator through the large hand ports. The 
use of an aerosol box with an active air extraction sys-
tem, filters and ports that were completely sealed with 
neoprene showed that the number of particles in the 
air near the operator’s head was consistently similar to 
pre-contamination values. However, they have shown 
that the use of an unsuitable aerosol box can increase 
exposure to aerosol particles in the air (2). Therefore, 
the term “aerosol” box is incorrect, as the original box 
does not protect the operator and other healthcare staff 
from aerosol particles without updates, while an up-
dated box with an active air extraction system can be a 
suitable part of PPE (2,52).
Table 3: Studies comparing droplet contamination with or without an aerosol box (8,21,50).
Study Aerosol box Study description The result with an 
aerosol box
The result without an 
aerosol box
Canelli 
et al. (50)
Original 
aerosol box
The operator was in the standard 
position for endotracheal intubation. 
A cough was simulated with balloon 
cuff rupture. A balloon cuff with 10 
mL of fluorescent fluid was inserted 
in the manikin’s hypopharynx and 
inflated with oxygen until it burst. 
This simulated a cough, neglecting the 
direction, speed and turbulence of a 
real cough.
Only the inside of the box, 
including the operator’s 
gloves and forearms, 
was contaminated. 
Macroscopic 
contamination outside 
the aerosol box was not 
observed.
The gloves, clothes, 
face mask, glasses, hair, 
neck, ears and shoes 
of the operator were 
contaminated. The floor 
was contaminated within a 
radius of one metre, and a 
monitor two metres away 
was also contaminated.
Campos 
et al. (21)
Modified 
aerosol box – 
endoprotector 
The operator was in the same position 
as in the previous study. The assistant 
was standing at the lateral side of the 
aerosol box. Both had PPE on and 
hands in the box’s ports. A balloon 
cuff with 10 mL of fluorescent fluid 
was inserted in the manikin’s pharynx 
and inflated with oxygen until it 
burst.
Only the contents of the 
box were contaminated, 
including the hands and 
forearms that were inside 
the box.
The operator’s and 
assistant’s gloves, 
clothing, face mask and 
neck were contaminated. 
Within a radius of 
two metres, the 
following surfaces were 
contaminated: floor, bed, 
wall and computer.
Branecki 
et al. (8)
Modofied 
aerosol box 
with open feet-
facing side 
The operator’s hands were inside the 
box’s ports. In the first part of the 
experiment, a cough was simulated 
with a syringe, filled with 5 mL of 
normal saline with fluorescent 
plastic particles, connected 
to a catheter that led to the 
hypopharynx. 
The second part of the experiment 
was performed in a similar way, except 
that 10 mL of ordinary fluorescent 
solution and a nebulizer were used, 
generating smaller droplets and 
aerosols.
Contamination was 
limited to the inside of 
the aerosol box - the 
operator’s hands and PPE 
inside the box. Due to the 
opening on the lower side 
of the box, the manikin’s 
chest and the lower limbs 
were contaminated at a 
distance of 1.2 metres 
from the aerosol box.
PPE and unprotected areas 
- the operator’s ear and 
neck - were contaminated. 
Surfaces and instruments 
were contaminated within 
a radius of 1.8 metres. 
When using the nebulizer, 
the dispersion of the 
droplets was lower.
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6 Drape as a replacement for an aerosol 
box
The aerosol box is receiving more attention in coun-
tries with less developed healthcare systems, while the 
reception is more varied in developed countries. Some 
authors report complications in procedures that need 
to be performed quickly and therefore advise against 
use (31). Their impracticality is also described in the 
USA, where it has been replaced by plastic drapes or 
sheets in some locations. Enami et al. have developed a 
drape to prevent disease transmission during endotra-
cheal intubation. It consists of a clear plastic sheet with 
hand insertion ports placed closely around the patient 
(33,53). Preparation time takes five minutes, which is 
comparable to an aerosol box, and the cost of produc-
tion is much lower at about $2 (54). The drape should 
be disposed after each use. One of the major advantag-
es of the drape is that is allows for manual dexterity as 
it can be moved. It also protects other healthcare staff 
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Drapes can be placed in different ways. The use of 
non-sealing horizontal and vertical drapes protects the 
operator from macroscopic drops but not from aero-
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7 Conclusion
From the results of research to date, we can conclude 
that a properly updated aerosol box reduces the health-
care worker’s exposure to water droplets and aerosols. 
On the other hand, an improperly designed aerosol box 
can only divert aerosols and cause even greater expo-
sure of healthcare workers, while giving them a sense of 
false security. An aerosol box is also not suitable for use 
in situations where swift action is required. It is more 
useful in procedures where the extension of time is less 
important, e. g. endotracheal extubation. The impor-
tance of operator training should be stressed, including 
additional training with an aerosol box, as it is an ad-
ditional physical barrier, which, due to limitations and 
changes in visibility, may affect the way interventions 
and procedures, which the operator is already experi-
enced with, are performed. It is the author’s opinion 
that no form of the aerosol box can reliably replace 
PPE. Its usefulness is seen mainly in reducing room 
and equipment contamination, e.g. endoscopy tower or 
microscope, which would allow better treatment of pa-
tients infected with SARS-CoV-2. Before it can be used 
it regular clinical practice, further improvements are 
required to ensure that the aerosol box is less restrictive 
for operators and easier and safer to use.
Conflict of interest
None declared.
213
REVIEW ARTICLE
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