Discussion
With no established superiority of approach and location of tracheostomy procedures from the standpoint of infectious transmission, the choice is determined by balancing the risks to patients and staff, and considering local expertise and resources.
Performance of surgical tracheostomy in theatre requires availability of operating rooms, negative-pressure ventilation, staff and equipment, with the need for multiple disconnection and reconnection of the breathing circuit. Circuit disconnection could potentially lead to impaired oxygenation in the critically-ill patient due to loss of positive end-expiratory pressure (5), and additionally increase exposure risks to additional personnel during patient transfer. A systematic review evaluating the available international guidelines for tracheostomy in COVID-19(6) highlighted the role of bedside tracheostomy in the Intensive Care Unit (ICU) in negative-pressure rooms. However, it is generally recognised that the availability of negative pressure air flow setting both in operating room and ICU is in reality limited and not a usual part of the UK hospital infrastructure. As with many institutions that were severely affected with COVID-19, multiple operating theatre rooms were converted to accommodate the saturation of ITU beds. These logistical factors, together with scarce operating room resources, favoured open surgical tracheostomy to be performed by the bedside in ICU.
The specific challenges of bedside open approach include limited space, need of transfer of surgical equipment and instruments, and suboptimal lighting and positioning. This was made more challenging due to the enhanced PPE and associated impaired communication. We find that in order to overcome these challenges, bedside open tracheostomies in the ICU should be standardised and meticulously planned with participation of highly experienced surgeons, anaesthetist and scrub team
We followed key recommendations in minimising aerosol generation during open tracheostomy in COVID-19 patients including advancing the endotracheal tube distal to proposed site of tracheal window prior to entry, hyperinflation of endotracheal cuff, withholding ventilation at key points and covering operative site with gauze swabs when ventilation recommences (7).
A key approach in performing a safe and swift bedside tracheostomy is to ensure that major bleeding is avoided. Many of the critically ill tracheostomy candidates will be anticoagulated; making haemostasis even more crucial. Common source of bleeding is typically from the anterior jugular veins and from the encountered thyroid gland and its feeding vessels. A pre-operative ultrasound assessment can be considered in conjunction with palpation of the neck particularly in in obese patients or where anatomical landmarks are difficult to assess by palpation. It provides important anatomical information including distance from skin to trachea, identification of vulnerable structures, such as thyroid gland and blood vessels.
We acknowledge and follow the recommendations to limit the use of diathermy. The evidence surrounding risk of aerosolisation from surgical smoke plumes is still not fully understood (8), however transmission is theoretically plausible. Therefore, we opted for vascular clips and and surgical ties when possible and considered diathermy on case-by-case basis; balancing the potential risk of aerosolisation with the risk of intra-operative bleeding. To mitigate theoretical viral transmission from diathermy plumes, we ensured the use of an extractor suction. Our practice also includes the use of LigaSure sealing device in cases where thyroid isthmus division is required. This approach as opposed to traditional clamping, division and ligation with transfixion sutures; is considered a less time-consuming option.
Bedside open tracheostomy demonstrated a short mean procedural time of 9 minutes and with no tracheostomy-related complications. The higher in-hospital mortality and mean time to decannulation may be a reflection of the inherent selection bias in the bedside tracheostomy group as these patients are typically selected due to their comorbidities and higher risk of transfer. Further studies are needed to better understand this association.