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.