Spirometry is a test of lung function which confirms or refutes a respiratory diagnosis. It gives a pattern of airflow from numerical interpretation, which alongside clinical history gives a diagnosis. With this objective test comes responsibility; as with any diagnosis, there are implications for the person receiving it.
COVID-19 bought a halt to lung function testing and the advice from various professional bodies meant that spirometry was ceased as it was deemed to be an aerosol generating procedure (AGP). It was the potential for cough during the procedure that caused it to be high risk and it was therefore added to the list of procedures that should not be undertaken (European Respiratory Society, 2021). The latest statement to restart spirometry originates from a larger Task and Finish Group and replaced the original ARTP statement (Association for Respiratory Technology and Physiology (ARTP) and British Thoracic Society (BTS), 2020). NHS England and Improvement guidance specifically provides advice on the safety of performing spirometry, during the COVID-19 ‘endemic phase’. The statement is applicable to spirometry performed in both primary and secondary care settings and is underpinned by further COVID-19 information, developed by the ARTP, BTS and other international organisations.
This can be found at the BTS website: https://www.brit-thoracic.org.uk/covid-19/covid-19-resumption-and-continuation-of-respiratory-services/.
The recent advice has been met with concern and confusion, as the group who created it had to be mindful that advice would need to be locally, and perhaps individually, interpreted, as one size would not fit all. A literature review of evidence (Crimi et al, 2020) could not find consensus among international guideline groups and therefore local guidance must be considered for employers and their staff.
My current role in primary care, establishing a diagnostic hub for a primary care network (PCN), is dependent on diagnostic procedures such as spirometry and fraction of inhaled nitric oxide (FeNO), which were both considered to be a risk for the population under the umbrella of AGPs. In the process of establishing the service, it was recognised there was more potential harm by not performing spirometry as we entered the endemic phase of COVID-19 infections. This was borne out by findings in the first few tests undertaken, as several cases of restriction have been identified. Also, by bringing these patients in and seeing them face to face there have been clinical signs identified, such as finger clubbing, alongside previously undiagnosed hypoxia on exertion which would have not been detected by remote consultations even with video links. This article will look at how my service has restarted spirometry.
Risk assessment
As the diagnostic element of the hub is currently only myself undertaking testing, the risk assessment that is recommended has been based on my personal safety and that of my patients. It also considers those using the room after, but this is generally the next day. The surgery in which I am based has established processes in place to minimise risk, ie text to pre-warn attending patients and an intercom to admit patients to the surgery, as well as one way systems and hand sanitising stations. This has not currently changed despite the recent removal of lockdown restrictions.
Pre-test triage
As patients are triaged by me prior to invitation to attend the appointment, the risk can be determined in the way a pre-test questionnaire would. While I would not refuse to test a non-vaccinated patient if there were clinical need, most of the patients tested have been dual vaccinated, as have I and all members of our primary care team. Regardless of vaccine status, the spirometry would only be performed if there is likely to be a changed outcome. For example, if the patient would still need to be referred to respiratory or for CT, then there is little benefit in undertaking spirometry beforehand.
The environment
The clinical rooms in the practice have low level windows that open onto a walkway behind the building which is little used. The window is open throughout the clinic and the patient sits blowing towards the window with me stood behind them (Figure 1).
Figure 1. When performing the test, the patient sits blowing towards the window with the nurse stood behind them
The area around them is cleaned before and after the session and bacterial viral filters are used which are deemed to be 99.9% effective against airborne virus (Crimi et al, 2020). It is essential that any testing should utilise the extra protection of these filters and not be reliant on previous one-way valve cardboard mouthpieces (Figure 2).
Figure 2. Bacterial viral filters are used which are deemed to be 99.9% effective against airborne virus
The test (pre-advice)
The guidance suggests ‘cough management and advice’, which has been interpreted as supporting the patient to cough into the machine (via the BV filter) or replace their mask and cough into that. In my experience very few are able to cough into the filter and many opt to cough into their mask or a tissue given for the purpose. Hand hygiene in all these instances is key and the availability of hand sanitiser is fundamental to infection prevention. The clinical bin is placed near the patient, and they are asked to remove the filter and place into the bin on completion of the test. They are given hand sanitiser and asked to clean their hands after disposal, and an alcohol wipe (eg Clinell) is used to wipe the immediate surrounding areas and equipment while they are doing this.
They are asked to turn the chair and the consultation continues with results and next steps explained. When they leave, the area is again cleaned, including the chair and all areas such as the window ledge etc.
There are no methods of air changes in our primary care setting and the room is not left fallow as the clinic is all day. However, of eight patients seen in a day, spirometry is undertaken approximately three times in any one session. If it is possible not to do it then it is noted it should be undertaken in the future and a further ‘waiting list’ created. This is regularly reviewed against further presenting symptoms. The current rise in risk with the delta variant has meant that need is revisited at each appointment.
The test
The document suggests that relaxed blows are less likely to cause cough (relaxed vital capacity [VC] or slow VC) and that these can be undertaken followed by one second forced blows (forced vital capacity [FVC] not blown until empty) to enable the measurement of forced expiratory volume in one second (FEV1). This is because the evidence suggests that it is the end of the forced manoeuvre when cough is most likely.
The FEV1 can then be divided into the VC to obtain a ratio (FEV1/VC), which could indicate the presence of obstruction. The FEV1 percent predicted can be read from the short, forced blows to grade the severity of the obstruction if present.
Current experience
As this is essentially diagnostic spirometry, I have tried to undertake the best quality assured spirometry at each test dependant on the individual risk, ie amount of coughing/health of the patient. If two VCs have given reproducible results (less than 100 mls between them) I have accepted them and moved onto FVC. Although the guidelines suggest only undertaking short blows, I have attempted to undertake FVC and at least two attempts (three if possible and reduced cough). As with any test, I try to obtain the best reproducibility (less than 100 mls) to ensure the validity of this diagnostic process.
When the trace is printed from the machine, I explain the results to the patient and then write on the trace the limitations of the test, eg ‘COVID restrictions in place, only two blows attempted’. These are then scanned to the notes. It is also important to ensure in any template entry in the patient consultation/notes that the limitations of the test are documented for future reference or diagnostic discussion.
Reflection
While this is an imperfect process, it is a pragmatic interpretation of the guidance based on personal risk assessment and individual patient risk assessment of a very experienced respiratory nurse, who is dual vaccinated with no underlying risk factors, and full support of the team. There are also one hour appointment slots to enable full history taking, testing and cleaning. It is important that staff are supported and enabled to undertake testing if they wish, but more importantly the right to refuse if they feel unsafe should be respected.
Local discussion at both PCN and strategic level is varied as to the benefit/safety of testing. The common belief is that it should be performed in a diagnostic hub or general practice, but as most hubs will be in primary care there is discussion and agreement needed for this to be further rolled out. It is impossible and impractical for all lung function testing to be completed in secondary care, even if this is limited to diagnostic testing. Therefore a solution must be agreed as we move towards the ‘new normal’.