Post COVID-19 guidance | Stress echo

During the initial phase of the COVID-19 pandemic, most stress echo departments in the UK ceased activity.

Now that we are over the first peak, restoration of cardiac activity has been recognised as one of the priorities for the NHS, being mindful of the need to find operating procedures that minimise transmission whilst protecting staff. For most of us, this ‘new normal’ will feel very different but it is vital to start serving our patients who need these tests. The main message would be to start slow and get used to things before up-scaling services, equally recognising that a second peak could necessitate further interruption to activity. 

The British Society of Echocardiography recognises that local considerations will be paramount in the restoration of a stress echocardiography service, ensuring that re-introduction of this test is undertaken in tandem with all of the other parts of a well-functioning Cardiology service. With this in mind the purpose of this guidance is to provide examples of how this goal can be achieved, with a particular focus on infection prevention and control during exercise stress echo. It is divided into four sections covering the following areas:

1. Screening and triaging patients
2. Undertaking dobutamine stress echocardiography
3. Special considerations for exercise stress echocardiography
4. Example SOP for DSE (written by Kate Coldwell, Manchester Foundation Trust)

1. Screening and triaging patients for stress echo

As with all service restoration, booking patients for stress echo should take into account the urgency of the referral and the risk to the patient attending for the test. Booking should start with urgent patients and patients who are not ‘shielding’ as per NHS advice. A list of shielding criteria is shown in Appendix 1. A senior member of the clinical team should be involved in triage and selection. As with TTE, the booking call should screen the patient for COVID symptoms with a questionnaire and for exercise echo we would also advise a negative swab (please see section 3). The screening questionnaire for COVID symptoms will be repeated with the patient on arrival for the test. Some hospitals will also screen with a temperature check at the door.

2. Undertaking a Dobutamine Stress Echocardiogram

Dobutamine stress echo should be undertaken in the same way as pre-COVID except for the following additional considerations

1. PPE - Minimise the number of personnel in the room to essential staff, which has to be a minimum of two trained members of the DSE team. Standard PPE should be worn throughout the procedure (apron, glove, fluid resistant surgical mask and visor). However, due to the small risk of a cardiac arrest, every member of the team should have a fit-tested FFP3 mask available in the room. Some staff (e.g. BAME or with health issues) may feel more protected wearing enhanced PPE throughout. Governance arrangements should be the same as pre-COVID and PPE should be immediately available if any additional personnel have to enter the room during the test.
2. Whenever possible and practical, staff within the room should stay six feet away from the patient. This should be feasible intermittently throughout the test.
3. In the rare event of a cardiac arrest, a nominated person has to commence defibrillation as appropriate while the resuscitation call is activated. The other team members need to don enhanced PPE (long-sleeved gown, FFP3 mask, gloves, visor). The resuscitation council do not regard CPR as an aerosol generator but tracheal intubation, if required is still regarded as an AGP.
4. Longer appointment times will be required as the patient should be fully recovered within the room rather than sit in a holding area after the test. The experience from departments who have started the service suggests 75mins appointment times are sufficient.

3. Special considerations for Exercise Stress Echocardiogram

There is a paucity of data with regard to the aerosol generating potential of an exercise-based stress echo (treadmill or cycling) but the consensus opinion amongst stress echo experts in the UK is that it may be. This makes it important to put some thought into the local infrastructure before starting. The infection prevention considerations can be divided into three groups and local solutions found for each department after discussion with their own estates and infection prevention teams.

1. Patient Screening
   The degree of screening recommendation is very variable. The lowest level of screening for an exercise echo attendee would be with the COVID symptom questionnaire (as for DSE and TTE) and the highest level would be with the patient being asked to self-isolate for two weeks followed by a negative swab 72/48hrs before attendance. The intensity of screening undertaken may be adjusted according to the current local prevalence of COVID positive cases (e.g. a sustained low prevalence in the local community may allow a down-grading of the screening process).
2. How much PPE?
   Because of the aerosol generating potential and the closeness needed for image acquisition during the test, especially for a bicycle test, it is reasonable for the person scanning to use FFP3 masks if one is readily available; otherwise surgical masks are deemed adequate. It should be remembered that these patients are highly unlikely to be COVID positive if they clear the screening criteria. Other personnel would not require FFP3 if they can stand away from the patient for the most part of the test. This will depend partly on the room size and the number of personnel required for the test. Again, only essential personnel should be in the room. It may also be advisable for the patient to wear a surgical mask if they can manage to exercise with one.
3. How much air contamination?
   Aerosols from an exercising patient are potentially small enough to defy gravity and stay suspended in the air. Room decontamination following an exercise stress echo is therefore important before the next patient if brought into the room. Departments will need to engage with their local infection prevention teams to calculate this time within their own estates. Table 1 illustrates the time it takes to reduce the aerosols in a typical hospital room with four air changes per hour. Table 2 shows how the time reduces as the air change rates increase. 5 air exchanges reduces the air contamination to <1% but the time starts from the when the patient stops the exercise.

A turnaround time of 75mins is obviously too long to run an efficient, sustainable service longer term. However, it has to be remembered that these are patients who have passed their screening criteria and the average community prevalence in the UK is currently at a very low level (0.25% at the time of writing). This procedure is also not regarded as aerosol generating by public health. All things considered, following the general PHE turnaround guidance of 30mins would seem appropriate, which can be reviewed if we see a second peak in prevalence.

 

Table 1: Air change rate 4 per hour - a typical hospital room
Adapted from: T.M Cook, Personal Protective equipment during the Covid-19 pandemic- a narrative review. Anaesthesia. https://www.esahq.org/uploads/2020/04/anae-15071.pdf

Table 2- Increasing air change rates clears virus load quicker
Ref- CDC guideline for preventing the transmission of Mycobacterium Tuberculosis in health-care settings 2005

In summary, to restart a stress echo service, the BSE would recommend you

• Engage with your local estates and infection control teams
• Invite urgent patients and non-shielding elective patients
• For exercise echo consider high-intensity pre-procedure screening (e.g. swab patients 72-48hrs pre-attendance)
• For exercise echo wear FFP3 mask if readily available otherwise surgical mask is adequate. For Dobutamine stress echo wear standard PPE
• Allow a minimum of 75min for both tests
• Start slow and build up when team is comfortable
• Be alert to changes in NHS/PHE/WHO guidance
• Be alert to disease prevalence in local community

4. Example SOP for Dobutamine Stress Echo- Author Kate Coldwell, Expert Physiologist, Manchester Foundation Trust

1. Purpose of this document:

To set out and standardise the procedure for appointing and undertaking Stress Echocardiograms within the Echo Department, North West Heart Centre, Wythenshawe Hospital as the COVID-19 crisis resolves and lockdown measures are gradually removed.

2. Scope of this SOP:

Applies to all Manchester University NHS Foundation Trust employed staff (Wythenshawe Site), who may need to undertake a stress echocardiogram (SE) as requested by a medical clinician, as part of a diagnostic or treatment management regime.

3. Competencies required:
   The healthcare professional must:
   
   • Be fully trained in both the practical and reporting aspects of echocardiography, and have current British Society of Echocardiography (BSE) accreditation;
   • Have or is currently working towards gaining the new BSE Stress Echocardiography accreditation;
   • Have been practically assessed by and signed off by an appropriately trained healthcare scientist/imaging consultant in Stress echo;
   • Understand the current PPE guidance as appropriate to OP Stress Echo and demonstrate competency in safe donning and doffing;
   • Hold a current competency in Immediate 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 able to select the appropriate stress protocol to allow for most optimum assessment;
   • Be aware of any contraindications to performing the test; and
   • Clean the equipment and patient environment in line with current guidance to reduce the risk of contamination during the Covid-19 crisis.
      
4. Who Can Attend for an Outpatient Stress Echo:
   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 younger patient groups where possible.
   
   A list of conditions which have been identified as a “higher risk for Covid-19” can be found in Appendix One.
   
   The senior echo team/ imaging consultants will triage and select appropriate patients to be booked. If the patient has referrals for multiple tests these should be performed on the same day to avoid repeat attendances.
   
   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.

Booking procedure

A member of the admin team will contact the patient by telephone to discuss attendance for the appointment. They must ask the following:

Question 1: Have you or anyone you live with had a letter from the NHS informing you that you are at higher risk of COVID-19 and should not leave your home?

If the patient answers Yes, they should not attend the hospital at this time. Patients who are shielding should be advised to ring the department on 01612 914642 when they are able to leave the house and come for the appointment. The patient should be reassured that they will not be taken off the waiting list. If the patient has still not attended for the appointment after 6 months from the referral date, the request will be sent back to the referrer for review.

If the patient answers No, proceed to question 2.

Question 2: Have you or anyone you live with had a high temperature, new or continuous cough, loss or change to your sense of smell or taste? (i.e. symptoms of COVID 19 as outlined by the NHS)

If the patient answers Yes, until they and the other occupants of their home have been symptom-free for 14 days – they will need to contact us with an update before we will proceed to an appointment. They should use the online 111 service or GP for further advice.

If the patient answers No, proceed to question 3,

Question 3: Are they able to get themselves to the hospital for an appointment? i.e. ensure they do not need transport or catch 4 different buses.

If the patient answers No, We may have to wait until further relaxation of lockdown measures to proceed with their appointment.

If the patient answers Yes, Offer them the next available appointment and inform them that only they will be able to attend the department.

Advise the patient:

To stop any of the medications from the list in appendix 2 prior to the test (unless specified differently on the request form).

Furthermore if a certain medication is required during the test (Atropine) the patient will not be permitted to drive for 2 hours after the test and therefore recommend where possible a member of their household drive them to their appointment and wait in the car/outside for them. Ensure the patient is aware the test will take approximately 75 minutes.

On the day of the appointment the patient should enter the hospital at Entrance 6, where a staff member will meet them and take their temperature.

Before ending the call inform them that if they or a person they live with develop symptoms between now and the appointment time they must phone the department to re-schedule.

Ensure the outcomes of all calls are documented, if patients were called but the patients were self-isolating/shielding or repeatedly not answering this needs to be logged on EPR and Prism.

6. Appointment schedule

Stress echo appointments should be scheduled with a 75 minute appointment slot as below, this allows us to perform the test, recover the patient fully and report the test all in the same room, whilst also having sufficient time to clean all equipment and surfaces appropriately after each patient.

7. Arrival at Entrance 6

The main front door should be segregated with the barrier to ensure one route in and one out, the café area must be cordoned off. There will need to be a supply of alcohol gel for patient use on the incoming side and a clinical waste bin and a supply of alcohol gel on the outgoing side.

The patient will be met at the door by a member of our team who will be wearing a mask, gloves, apron and visor. They will determine that the patient is attending for an appointment – either with us, cardiac MRI/CT or cardiology outpatient clinic – no one should be using the route as a thoroughfare and should, if necessary, be directed to another relevant entrance.

The patient's temperature should be recorded:

If it is greater than 37.8°C:

They should be advised to return home and consult NHS 111 if concerned - they must not enter the department.

If it is less than 37.8°C:

The patient should be asked “Have you or anyone you live with had a persistent cough, temperature or tested positive for COVID-19 within the last 14 days?”

If the patient answers Yes, they should be advised to return home, self-isolate as per guidelines and consult NHS 111 if concerned - they must not enter the department.

If the patient answers No, Ask them to alcohol gel their hands and take a seat in the cafe waiting area.

The seats in the waiting area will be set out 2 metres apart to maintain social distancing and should be cleaned down with Clinell wipes when the patient is called in for their appointment.

8. The stress echo appointment

The SE team should all wear the following PPE - apron, gloves, fluid resistant surgical mask and visor, which should be donned and doffed appropriately. This PPE should be worn to collect the patient from the cafe waiting area. Follow the one way system in the department to bring the patient to the clinic room.

On the way through the sub-wait, invite the patient to gel their hands.

Once in the room, the nurse will gain consent from the patient for the test to be performed, following discussion and explanation of the procedure, including reference to the amended SOP for cardiac arrest during Covid-19. Record the patient’s height and weight. The patient should be given a gown and mask to wear.

Connect ECG and blood pressure monitoring equipment (if possible put the BP cuff over the gown). This should be monitored continuously throughout the test. Record a resting BP reading and document this. If resting BP is greater than 220/120mmHg then wait a few minutes and recheck. If the BP remains at > 220/120mmHg the test must be aborted.

Perform peripheral venous cannulation and ensure patency.

Ascertain the target heart rate that is to be achieved, if required (HR table is displayed on the wall in all stress rooms).

Obtain baseline echo images and make an assessment of resting LV function, any valvular disease. Exclude severe aortic stenosis.

Determine the need for contrast whilst obtaining baseline data. Contrast should be administered at each image acquisition stage if 2 or more segments of the left ventricle can not be clearly visualised on the non contrast images.

ICP checklist discussion immediately pre-procedure to clarify protocol;

1. Dobutamine Stress Echo Protocol - Ischemia Study

Select the stress protocol on the machine, turn on the contrast setting if required. Acquire baseline protocol images and begin dobutamine infusion starting at 5mcg/kg/min followed by 10, 20, 30mcg/kg/min (40mcg/kg/min in rare circumstances) at three minute intervals until target heart rate is achieved (see diagram below);

End points/termination of the test are achievement of target heart rate (85% of the age predicted maximum heart rate), new or worsening wall motion abnormalities of moderate degree, significant arrhythmias, hypotension, severe hypertension and intolerable symptoms.

2. Dobutamine Stress Echo Protocol - Viability Study

Select the stress protocol on the machine, turn on the contrast setting if required. Acquire baseline protocol images and begin dobutamine infusion starting at 5mcg/kg/min followed by 10mcg/kg/min at five minute intervals. Stop after low dose imaging (10mcg/kg/min).

If however ischemia assessment is required and significant LV contractile reserve is demonstrated proceed to high dose ischemia protocol and target heart rate (see diagram below). Please note a higher level of caution should be used during COVID-19 when proceeding to high dose Dobutamine protocols after viability studies, if in doubt do NOT proceed.

In the event of a contrast reaction the test must be immediately terminated and the allergy protocol/anaphylaxsis protocol must be followed (these are on the wall in the stress room).

If a cardiac arrest is confirmed at any point during the test, pull the emergency buzzer and follow the SOP for cardiac Arrest in Patients in the Cardiac Diagnostic Centre During the Covid-19 Pandemic and the Resuscitation Council ALS Algorithm for Covid-19 Patients.

Please note, once cardiac arrest is confirmed the physiologist should remain with the patient and apply the defibrillator pads and deliver up to three stacked shocks, if required, as per the cardiac arrest guidelines, while the rest of the team don full PPE (gloves, long sleeved gown, FFP3 (FIT tested) mask & visor).

Once the team has donned full PPE, the physiologist can then step out of the room and don full PPE. Do not commence CPR (chest compressions and ventilations) unless ALL staff members in the room are all wearing gloves, long-sleeved gown, FFP3 mask and visor.

Following completion of either the ischemia or viability DSE protocol, allow the patient a period of recovery until baseline state is achieved and 30 minutes has elapsed since contrast was administered (to ensure no late contrast reactions). Contact the imaging consultant via phone to review images remotely and complete the report where possible in the clinic room.

If required, to avoid any potential delays in transport causing patients to wait around outside the building for their lift, allow the patient to ring their driver ~15 minutes before leaving the clinic room. If the patient has driven to the appointment by themselves however and has had Atropine they are not permitted to drive for 2 hours and so must wait in their car/outside until they are safe to drive - they are not permitted to wander around the hospital.

When the patient is ready, invite them to gel their hands and direct them out of the echo department via the door beside Echo Room 5, and point them in the direction of the exit (there are arrows on the wall).

Explain to them that before exiting the building they should re-apply alcohol hand gel.

You must then clean down the remainder of the room – examination couch, patient chair, scanning chair, etc.

Remove your PPE as per protocol, clean the visor, wash your hands and leave in the room.

Associated Trust documents

• Standard Operating Procedure for Cardiac Arrest in Patients in the Cardiac Diagnostic Centre During the Covid-19 Pandemic
• Resuscitation Council ALS Algorithm for Covid-19 Patients.
• MFT Infection & Prevention Policy
• British Society of Echocardiography guidelines