Discussion
Despite the best medical care, tracheotomy may be inevitable among a
small cohort of patients (6-13%) with severe COVID-19 associated
pneumonia and/or ARDS. (11) A tracheotomy confers less work of breathing
when compared to breathing through an endotracheal tube (ETT), offering
less resistance than the thermo-liable ETT which can deform the upper
airway, increasing ventilatory requirements. The lower resistance and
improved secretion clearance via a tracheotomy may also facilitate
weaning off the ventilator. Successful weaning of patients off
ventilators is likely to be beneficial in preventing complication such
as ventilator associated pneumonia. This would facilitate earlier
transfer out of ICU, and potentially freeing up precious bed space for
another patient who requires it. This is important in the era of
SARS/COVID-19, where judicious use of ICU resources is paramount in
managing a viral pandemic.
Looking at the overview of PPE recommendations, the consensus among
various articles has been fairly uniform in their recommendations of at
least standard PPE when dealing with COVID-19 positive patients, with
enhanced PPE being preferred whenever available. Recommendations
regarding adjunctive measures prior to definitive intervention have also
been congruent. Non-invasive ventilation devices such as CPAP/BiPAP are
discouraged, whereas HFNC use has been shown to potentially circumvent
rapid respiratory deterioration in COVID-19 patients.
There is limited literature on the optimal timing for tracheotomy among
patients with severe viral associated pneumonia with ARDS. Additionally,
existing studies and guidelines do not distinguish between the various
indications of tracheotomy in an ICU setting, and formalizing a specific
guideline on timing of tracheotomy will be based on anecdotal evidence
in the context of COVID-19 patients and ARDS patients.
Growing evidence has shown that the need for tracheotomy should be
assessed daily. Proponents of an early tracheotomy argue that
unnecessary delays in tracheotomy among patients with prolonged
endotracheal intubation risk the development of
post-intubation tracheal stenosis of between 10-22%. Additionally,
around 1 to 2% of these patients develop symptomatic tracheal
stenosis. (12) In one study among ARDS patients who had open-lung biopsy
performed after 5 days of ventilation, around half (53%) demonstrated
significant pulmonary fibrosis on histopathology. (13) These
observations suggest that a decision for tracheotomy in COVID-19
positive patients with ARDS should be considered as early as within 4 to
7 days after intubation, so as to prevent excessive prolonged intubation
when the chance of weaning off the ventilator is low. Hence, while the
general consensus remains that tracheotomy among COVID-19 positive
patients should be delayed beyond 10 days (table 3), a reasonable
approach is to consider a tracheotomy within 10 days when these patients
show no signs of improvement such as decrease in oxygen requirement or
PEEP. We are also cognizant of the fact that despite clinical
indications guiding us, other overarching considerations such as the
variability of ICU bed availability between different countries and
institutions may play a greater role in influencing a clinician’s
decision to do an early tracheotomy if there is a shortage of these beds
during a surge of COVID-19 cases.
New recommendations have also been made to potentially help reduce the
risk of aerosol generation in tracheotomy. One paper suggested pushing
the endotracheal tube beyond the site chosen for the tracheal stoma at
the beginning of the procedure during ST. (14) Three papers proposed the
use of a transparent surgical shield. (15) One new PDT technique was to
place the bronchoscope alongside the endotracheal tube and not inside
it, while another study offered sealing the bronchoscope with an in-line
suction sheath. (16) Another modified PDT technique described the use of
a smaller ETT cuffed at the carina. A fibre-optic bronchoscope was also
inserted between the tube and the inner surface of the trachea. With
this method, the authors reported improved airway management,
respiratory function, patient comfort, and reduced risk of transmission
to staff. (17) Another paper also presented the use of a novel
negative-pressure aerosol reduction cover. (18) However, these new
techniques presented have only been performed on a small number of
patients, and more evidence needs to be presented before adopting these
techniques into our “new normal” workflow. It is also important to
note that despite the advantages of PDT, complications such as
post-procedural hemorrhage may still have to be emergently sent to the
OT for hemostasis. This may not give adequate time to optimise infection
control considerations enroute to OT, such as ensuring a transport route
clear of hospital staff and patients, leading to higher virus
transmission risks as compared to an elective ST.
Currently, testing for COVID-19 positivity is performed using a
Reverse-Transcriptase Polymerase Chain Reaction (RT-PCR) based
pharyngeal swab for SARS-CoV-2 virus. Based on reports, this RT-PCR
based test has a high specificity and sensitivity in SARS-CoV-2
detection, making it the gold standard. Additionally, performing this
RT-PCR based test using bronchoalveolar lavage fluid (BALF) samples has
the highest sensitivity when compared to sputum (88.9% in severe cases
and 82.2% in mild cases), nasopharyngeal (73.3% in severe cases and
72.1% in mild cases) and oropharyngeal samples (60.0% in severe cases
and 61.3% in mild cases). (19) Despite this added sensitivity,
obtaining BALF samples is invasive and is associated with higher
transmission risks. (19) Preoperative negative swabs have the advantage
of allaying fears of the airway team during airway procedures such as
tracheotomy; although a full PPE with PAPR donning are still required as
per contact with any suspect COVID-19 patients. As there remains a small
chance of a false negative result from a pharyngeal swab (17-28%) test,
healthcare personnel should not be complacent when performing
tracheotomy in a previously COVID-19 positive patient as the risk of
exposure to any remaining virus in the lower airway is still possible.
As COVID-19 is highly infectious and likely to persist globally for an
extended period of time, modifications to the existing tracheotomy
workflow are necessary. Combining the assimilated findings from our
review, we propose a new workflow incorporating a series of
recommendations aimed at minimising the risk of transmission to HCWs.
(Figure 2)
Limitations of this review include the lack of high quality articles
investigating our study parameters, with most of the available articles
included in our systematic review being level 4 to 5 evidence studies.
This is likely due to the novel nature of COVID-19, and more prospective
studies validating the “new normal” workflow are warranted.
Furthermore, many of the included studies primarily look at the
immediate management of COVID-19 positive patients requiring
tracheotomy, and longer term outcomes of these patients are required in
order to refine this “new normal” workflow.