3. Special considerations for TOE in the mechanically ventilated patient
In common with all invasive procedures, peri-operative or critical care TOE should only be performed if there is a favourable risk: benefit ratio. This analysis should be done not just for the patient but also for the echocardiographer and other members of the team (giving consideration to high risk groups such as those with cardiovascular disease, diabetes mellitus, chronic kidney disease, immunocompromised patients, BAME background and staff members living with at risk individuals). The incidence of asymptomatic or pre-symptomatic COVID-19 positive patients remains one of the unanswered questions about the pandemic. This uncertainty is further complicated by false-negative test results and the recognised presence of viable virus in asymptomatic individuals. It is therefore acknowledged that the evidence base on which to base decisions is extremely sparse whilst also being confounded by an inability to separate the different procedures performed intraoperatively (i.e. endotracheal intubation, pre and post cardio-pulmonary bypass TOE or bronchoscopy).
If possible, a goal-directed, focused TOE is performed by a single operator who performs all aspects of the exam including probe insertion, manipulation, image acquisition, and probe removal. This could be the same physician who performs the endotracheal intubation thus limiting provider and staff exposure.
Since TOE is being performed in an anaesthetised, paralysed and intubated patient, the risk might be considered to be lower although this has not been quantified yet. However, contact and droplet transmission from oral secretions, close physical proximity of patient, blood and body fluid splash events can occur. Extra care must be taken to prevent contamination during trans-gastric views, removal of the “dirty” TOE probe from the oesophagus and accidental extubation of the endotracheal tube, and disconnection of the anaesthetic circuit.
Changing gloves, a transparent plastic cover (such as image intensifier covers) placed over the TOE machine controls, sterilisation of the probe and thorough wipe down of the echo machine should reduce the risk of spread.
Finally, it is difficult to make strong recommendations about PPE due to the lack of good evidence. This is likely to change as the evidence base evolves. A high index of suspicion of COVID-19 is encouraged and we recommend continued use of full PPE (FFP3 mask) throughout the perioperative phase at this stage.
However, in lower risk patients (i.e. COVID-19 test negative, asymptomatic and adequate, preoperative self- isolation), a pragmatic but hitherto untested approach would be to use full PPE for endotracheal intubation and pre-bypass TOE. A lower level of PPE may be worn later if the overall risk is deemed to be low for that particular situation based on a personal risk benefit analysis with an aim to avoid the discomfort of full PPE. This decision should take into account the probability of COVID-19 infection in the patient, the possibility of false negative tests and the individual risk factors of the operator and other individuals in the area.
4. Special considerations in the COVID-19 positive patient
If possible, TOE should be avoided in COVID-19 positive patients. Alternative imaging modalities should be considered to answer a clinical question if TTE images are deemed insufficient (e.g. CT scan to exclude aortic root abscess).
If TOE has to be performed in a COVID-19 patient, all of the above precautions are recommended and, in addition, we recommend performing the scan as a focussed study directed to answer the clinical question (i.e. the minimum number of images required to answer the clinical query).
5. Example standard operating procedure for TOE (from the University Hospital Southampton)
1. Purpose of this document
To set out and standardise a template for booking and undertaking transoesophageal echocardiograms within our echocardiography Department, University Hospital Southampton, as strict lockdown measures are eased in the midst of endemic COVID-19 infection.
2. Scope of this SOP
Applies to all University Hospital Southampton NHS Foundation Trust employed staff who may need to undertake a TOE as requested by a clinician and after approval by a senior member of the echocardiography staff (i.e. Dr D Rakhit or Dr B Shah).
3. Competencies required
The healthcare professional performing the TOE must:
- Be fully trained in both the practical and reporting aspects of echocardiography, and have current British Society of Echocardiography (BSE) TOE accreditation
Understand the current PPE guidance as appropriate to TOE and demonstrate competency in safe donning and doffing
- Hold a current competency in Immediate or advanced life support and be familiar with the location and layout of the Resuscitation Trolley and the updated resuscitation guidance given the current COVID-19 situation
- Demonstrate a high level of communication with the patient in explaining the procedure and putting the patient at ease
- Ensure the patient details are entered correctly including name, hospital number and date of birth
- Be aware of any contraindications to performing the test
- Clean the equipment and patient environment in line with current guidance to reduce the risk of contamination during the COVID-19 pandemic
4. Who Can Attend for an Outpatient TOE
This will be decided in line with the changes in Government restrictions and Trust initiatives but is likely to begin with more urgent referrals and patient groups that are not ‘shielding’ due to underlying health concerns where possible.
The senior echo team / imaging consultants will triage and select appropriate patients to be booked. If the patient has referrals for other tests these should be performed on the same day if at all possible to avoid repeat hospital attendances. In order to maintain social distancing, only the patient will be able to attend the appointment and wait in the waiting room – relatives and carers will be asked to wait in the car / outside the department.