Updates
A general consensus exists on coronavirus diffusion by droplet
transmission, especially the aerosolisation during hospital procedures
like intubation or bronchoscopy might represent a big concern, exposing
other patients and health-care staff to an increased risk of infection
In this context, the general otolaryngology procedures may determine an
aerosolisation with nosocomial amplification of the infection.
In particular flexible and/or rigid nasolaryngoscopy may include some
maneuvers such as puffing out your cheeks, talking, swallowing some
coloured water or poking out your tongue. Further, the introduction of
the endoscope may cause sneezing and cough.
These risks can increase when in-office surgical procedures are applied
to cure urgent and emergent pathologies such as epistaxis, removal of
foreign bodies in upper aero-digestive tract, cricothyroidotomy as well
as elective procedures such as biopsies, inferior turbinoplasty etc.
Based on the available evidence, it appears that SARS-CoV-2 can be
transmitted by asymptomatic carriers, which contributes to its basic
reproduction number and pandemic potential1.
Zou et al2 showed higher viral loads after symptom
onset, with higher viral loads detected in the nose than in the throat.
Further in the asymptomatic patients, the viral load was similar to
symptomatic patients, which suggests the transmission potential of
asymptomatic or minimally symptomatic patients.
The common work-load of a ENT are symptoms related to upper airways
inflammations or infections. Sore throat with or without fever,
sneezing, hoarseness may be prodromic symptoms of a COVID-19 infection
in the incubation period3. Moreover, the coughing
patients with a negative chest X-ray is one of the most consultation
required.
Direct contact of droplet spray produced by coughing, sneezing or
talking involves relatively large droplets containing organisms and
requires close contact usually within 1 m 4. Indirect
contact may take place after the droplets are removed from the air by
surface deposition5.
Han et al6 studied the dynamic features of
bio-aerosolisation by sneezing. The velocity of the airflow exhaled by
sneeze is much larger than that of breath and cough. Moreover, the total
number of droplets generated during sneeze is also larger than that of
other respiratory activities. According to the study on flow dynamics
and characterization of cough, the maximum velocity of exhaled airflow
can be found at t = 57–110 ms for different persons which is most
likely to occur at 100 ms. Usually, sneeze lasts 0.3–0.7 s, so t = 100
ms is in the duration of the sneeze. As the velocity of the airflow
exhaled by sneeze is really high, it can be assumed that the droplets
that are exhaled at t =0–100 ms will not re-enter the measurement zone
before t=100 ms. The high-speed airflow and corresponding turbulence
produced by sneeze may also lead to a large number of droplets, i.e. the
number of the droplets generated by sneeze is about 18 times larger than
that of cough. Further, the size of sneezing droplets is 341.5–398.1 µm
for unimodal distribution and 73.6–85.8 µm for bimodal distribution.
After the droplets are exhaled into the indoor environment, the
evaporation effects will strongly influence the size and mass of the
droplets. The final equilibrium diameter of expiratory droplets after
evaporation is highly dependent upon the temperature and relative
humidity of the environment. In the indoor environment, the relative
humidity and temperature are much lower than those in the respiratory
tract. So the volatile content of these droplets will keep evaporating
and result in the shrinkage of the droplets.
Definitively, these findings demonstrate that the routine activities of
an otolaryngologist are constantly at high risk of contagion in COVID-19
epidemic areas.
Taking a look at the current Italian situation, the experience of the
region Veneto demonstrated that the application of COVID-19 screening
also in asymptomatic people can reduce the contagion spreading. Thus, it
seems clear that extend the screening to all health-workers included
otolaryngologists could be a valid strategy to reduce the onset of a
worst case scenario, the hospital outbreak.
In conclusion, the professional exposure to SARS-CoV-2 is really high
for the otolaryngologist and nurse staff, even in in-office settings.
Personal protective equipments are strongly recommended as well as for
health-workers in close contact with infected patients.
REFERENCES
Zhu W, Xie K, Lu H, Xu L, Zhou S, Fang S. Initial clinical features of
suspected Coronavirus Disease 2019 in two emergency departments outside
of Hubei, China. J Med Virol. 2020 Mar 13. doi: 10.1002/jmv.25763.
[Epub ahead of print]
Zou L, Ruan F, Huang M et al. SARS-CoV-2 Viral Load in Upper Respiratory
Specimens of Infected Patients. N Engl J Med. 2020 Feb 19. doi:
10.1056/NEJMc2001737. [Epub ahead of print]
Lauer SA, Grantz KH, Bi Q et al. The Incubation Period of Coronavirus
Disease 2019 (COVID-19) From Publicly Reported Confirmed Cases:
Estimation and Application. Ann Intern Med. 2020 Mar 10. doi:
10.7326/M20-0504. [Epub ahead of print]
Leder K, Newman D. Respiratory infections during air travel. Intern Med
J. 2005 Jan;35(1):50-5.
Chao CYH, Wan MP, Sze To GN. Transport and removal of expiratory
droplets in hospital ward environment. Aerosol Sci Technol 2008;42, 377
– 394.
Han ZY, Weng WG, Huang QY. Characterizations of particle size
distribution of the droplets exhaled by sneeze. J R Soc Interface. 2013
Sep 11;10(88):20130560.