The use of single-use devices in anaesthesia: balancing the risks to patient safety^*

Summary

Single-use devices are designed, manufactured and sold to be used once and then discarded. This paper addresses growing concerns about the quality of some devices. Single-use devices, manufactured at a lower cost to justify their disposal, are perceived to have a lesser efficacy, which may threaten patient safety through iatrogenic harm. There is, in addition, growing scepticism about the actual risk of contracting variant Creutzfeldt-Jakob disease and other blood-borne diseases from reused surgical instruments. Interview data suggests that when choosing to use a single-use device, clinicians balance concerns about the risk of infection against those about the risk of injury. However, despite reservations about induced harm and the unknown risk of an iatrogenic disease, most clinicians would want single-use devices used on themselves and their family if they were patients.

Single-use devices are designed, manufactured and sold to be used once and then discarded. It is known that these devices are reused, although individuals doing this may incur clinical risks for themselves and their patients. By reusing a single-use device, practitioners also assume the complex legal obligations for safety and effectiveness that usually rest with the original manufacturer [1]. However, there is growing concern about the quality and efficacy of some single-use devices, which has led a number of clinicians to question the safety of using these devices at all, let alone contemplating their reuse.

The use of single-use devices has increased as a result of a heightened awareness that sterilisation and decontamination processes are ineffective in removing all microbial and proteinaceous materials from surgical and anaesthetic instruments [2–8]. Evidence of iatrogenic transmission of Creutzfeldt-Jacob disease (CJD) first emerged in the 1950s [9], and then again in the 1970s when a case of iatrogenic CJD infection stemming from the use of cadaveric corneas during transplantation was reported [10]. The risk of iatrogenic transmission of new variant CJD (vCJD) is relatively small. Those cases that have been reported have mostly been associated with the use of human-derived pituitary growth hormone or dura mater grafts [11]. However, cases of iatrogenic infection linked to cross-contamination of a medical device, whilst rare, have been acknowledged [11]. Will [10] reported that of the 312 cases of iatrogenic transmission of CJD, just six were linked to the use of a contaminated medical device.

In 2001, the UK Department of Health, following advice from the Spongiform Encephalopathy Advisory Committee [12], published a circular requiring the exclusive use of single-use instrumentation for tonsillectomy procedures [13]. The Association of Anaesthetists of Great Britain and Ireland subsequently recommended that anaesthetists should use only single-use laryngoscope blades because of the proximity of the blade to the tonsils [14]. Although the Department of Health guidance was subsequently withdrawn after an increase in adverse incidents and at least one patient death [15], the guidance to anaesthetists remains in force. However, there is concern that the rapid deployment of single-use devices because of the hyperbole surrounding vCJD and cross-infection arose despite the devices being potentially unfit for purpose [16–19].

This paper presents results from a 2-year study investigating the use and reuse of single-use devices in the English National Health System (NHS). It focuses particularly on the need to balance patient safety, in terms of the quality and efficacy of single-use devices, with the risk of infection and contamination linked to the use of reusable equipment.

Methods

A multimethod study was carried out between June 2004 and March 2006 using survey, focus group and interview methodologies. This paper draws solely on data from the interview phase. A theoretical or purposive sample of eight English NHS Trusts covering 12 hospital sites was selected. This type of sampling is commonly used in the social sciences where the objective is to map the range of variation or uniformity in a population rather than to measure the incidence or prevalence of a phenomenon of interest. By establishing what answers may occur, subsequent survey questionnaires administered to a randomised sample can be better designed (although in this case NHS research governance regulations meant that it was impossible to carry out the commissioned survey). It was hypothesised that size of hospital and performance rating might have an influence on responses. By sampling from different regions, it would be possible to look for any influences that reflected catchments or whether it was likely that responses would be uniform across the country. Sample hospitals were selected to include different strategic health authorities, Healthcare Commission star ratings (for 2004/5) and number of beds. In each hospital, the clinical director of anaesthesia, the theatre manager and at least one operating department practitioner (ODP) were invited to participate in a qualitative interview. Ethical approval was received from the Trent Multi-centre Research Ethics Committee (MREC), and research governance approval was gained from each participating NHS Trust. All respondents gave their written, informed consent. As a condition of this approval, all data have been anonymised. Where direct quotations from respondents are used, they are identified by the individual's occupational role.

Twenty-three interviews were completed. The final sample consisted of one sterilisation manager (whose participation was recommended by the theatre manager at that Trust), eight ODPs, nine theatre managers and five clinical directors of anaesthesia. All interviews were semistructured and presented comparable questions to all participants. The interview schedule contained nine questions that asked about rationales for the reuse (or avoidance of reuse), cost differences between single-use and equivalent reusable devices, and procedures employed for decontamination and their associated costs (where reuse was reported). Table 1 lists the questions. The semistructured format of the interview schedule allowed the interviewer to adapt questions and elicit further responses from participants in the light of local circumstances. All interviews bar one were audio recorded. Data were transcribed verbatim and stored in accordance with research governance and data protection requirements.

Table 1. Interview questions.

What is the department's or hospital's policy relating to the use and reuse of single-use devices?

How many single-use devices are used in the department each year?

How many single-use devices are purchased by your department each year?

What are the cost differences between similar single-use and reprocessable devices? For example, a laryngeal mask is available in both a single-use and reusable form. Please provide examples of devices and their costs.

What are the cost differences between reusing single-use devices and purchasing new equipment? Please include all costs associated with the device lifecycle.

What procedures are undertaken to return a single-use device to a state where it can be reused?

What are the costs involved in these procedures?

What is the time delay involved in these procedures?

What are the indemnity costs involved regarding the use and reuse of single-use devices?

Are the lifecycle and indemnity costs associated with reusing single-use devices included within your department's calculations or budgeting decisions? For example, are these lifecycle costs factored into the decision to use single-use devices verses reprocessable devices, or to purchase new single-use devices verses reusing single-use devices? If they are not, which department picks up the cost of the reprocessing?

How is the balance of likely adverse effect against cost and performance pressures assessed and what is the response?

Results

Respondents were clear about the role that risk of infection and contamination had played in the introduction of single-use devices:

‘With vCJD coming to the fore and the risk of transmission through tonsil tissue and any tube that’s going to pass them, hence that was mainly the main spur for us moving to single-use bougies and laryngoscope blades' (theatre manager).

Moreover, given the emphasis that has been placed on the threat of iatrogenic transmission of vCJD and other transmissible spongiform encephalopathies, clinicians generally agreed that their awareness of risk was now greater than previously. However, there was disagreement about the actual significance of the threat from iatrogenic vCJD or any other disease. Whereas one anaesthetist considered that ‘clearly there’s a risk of transmission of diseases we know about and I'm sure some we don't yet know about, so single-use would appear to be the way to go', others questioned whether the magnitude of the actual risk had been exaggerated.

Employing single-use devices direct from their packaging allows clinicians to have a consistent expectation about the product they are using. Unlike reusable devices, which can experience fatigue, general wear and tear, and damage during reprocessing, single-use devices should always be fit for use. Participants confirmed this expectation:

‘You know if you’re going to open a disposable one it's going to be pukka' (ODP).

However, others were adamant that ‘workable’ equipment was not necessarily perceived as high quality:

‘Sometimes they may say that this is a single-use device and it’s comparable to a reusable one but obviously a lot cheaper and the actual quality of the device is not always exactly the same and straight away on usability and appropriateness it's not used' (theatre manager).

While this is not a condemnation of all single-use devices, it does present a problem for both the health service and the device industry. Clinicians perceive that devices designed to meet the lower costs demanded by the single-use status of the equipment can be compromised in terms of quality and efficacy. For example:

‘Sometimes I think you might worry about the strength of things, as things are often cheaper’ (ODP).

‘Some of the single-use items obviously because they’re single-use, they're cheap and they're not quite as good a quality as other things' (ODP).

‘There is pressure on the stores manager to get things as cheap as he can. We’ve had one or two instances where he's brought something in and then everybody just turns round and says: “It's pants, I'm not going to use it, it's rubbish, get the old ones back” and he doesn't have a choice' (ODP).

A particular concern for anaesthetists was the perceived under-engineering of plastic laryngoscope blades. Following concerns about the possible spread of transmissible spongiform encephalopathies and prions from the tonsils, single-use laryngoscopes were introduced [20–22]. However, whilst satisfying the objective of minimising the risk of cross infection, the quality and suitability for purpose of the disposable blades has been criticised [22–24]. One anaesthetist commented:

‘Plastic laryngoscopes are in fact under-engineered. They’re actually not up to the job' (anaesthetist).

Others also picked up the notion of unsuitability, and expressed their dissatisfaction with the quality of the blades:

‘The original laryngoscope blades that came out, they were quite cheap…and the plastic blades were just bloody dangerous, because they just contorted. If you got a difficult airway and you lifted it, it just bent across’ (anaesthetist).

However, similar criticisms were also voiced about disposable metal blades. One theatre manager described how discontent with single-use blades had influenced their decision to return to reusable metal blades despite the risk of cross infection from proteinaceous residue:

‘Laryngoscope blades, because of the scare with CJD, we were told we had to use disposable single-use laryngoscope blades. So we ordered a load of them, even though they were made of metal, they were rubbish because they were flexible… so in that instance, the single-use wasn’t as good as the autoclavable version, so we've stuck with the autoclavable' (theatre manager).

For these clinicians, disposable laryngoscope blades were perceived as providing a greater threat to patient safety from iatrogenic injury than the risk of cross-infection from reusable blades. If the blades were to slip, contort or flex unexpectedly, the patient's larynx could be damaged. Concerns about differences in the efficacy of single-use and reusable laryngoscopes were also influenced by the perceived difficulty of the intubation:

‘It’s okay if it's an easy intubation but then you know that's not really the issue, the problem is the one that's actually a bit more tricky, requires a bit more force and sometimes, but not always, but sometimes it's a life… you're in a life critical situation and you can't have your equipment not being up to the job, you don't know which of the patients that will happen in so you have to have an instrument that's going to be able to do it for every patient unfortunately' (anaesthetist).

A distinction is made between equipment that is acceptable for use with an easily managed patient, and equipment that is incompatible with use for difficult cases. However, when managing difficult cases, participants felt that there was no time to source alternative equipment. They wanted to be able to rely on the devices to hand, and so often turned to reusable kit, despite its infection risk:

‘It’s nice to know that you've got the back up of the emergency reusables, handy for safety reasons. Because every individual can do very strange things suddenly in an anaesthetic, so I think it would be very foolish to go over. It would be very foolish to get rid of all the reusable laryngeal masks' (ODP).

These comments reinforce Twigg et al.'s [16] warning about the need for equipment to be fit for purpose. One anaesthetist commented:

‘Sometimes I think: “I’m using this single-use laryngoscope blade and I don't think it's as good as the one I would like or it isn't shaped in exactly the way that I'm used to” and therefore my practice is probably inferior to what it would be if I'd got a re-sterilised laryngoscope' (anaesthetist).

Criticism was not restricted to the single-use blades' flexibility or strength. Disposable blades were also considered to have an inadequate light source:

‘There have been some queries about the quality of some single-use equipment. The laryngoscope blades aren’t quite good enough to offer you as excellent a view as you might wish in difficult patients' (anaesthetist).

‘Single-use laryngoscope blades have led to a higher risk of failed intubation, as plastic blades are more flexible and have a poorer light source. However, the use of disposable blades is in the patient’s best interest in terms of risk transmission' (anaesthetist).

Rassam et al.'s evaluation of 20 Macintosh-type laryngoscope blades included 19 single-use blades sourced from different manufacturers [25]. Anaesthetists were asked about the quality of illumination given by each blade, their satisfaction with the resulting view and their perception of its clinical appropriateness. Two single-use plastic blades had a poorer illumination score than the others, and one of these blades was also found to result in an inferior view and was therefore considered to impair clinical practice. The illumination quality of laryngoscopes is clearly important, as a difficult view of the larynx is associated with increased morbidity [26, 27].

Many of the respondents criticised single-use devices in terms of the potentially fatal outcomes from the use of inadequate equipment. The strongest criticism was about single-use bougies, which were described as substandard, dangerous and awful.

‘With regards to the bougies, I know there are new bougies which cost a fiver compared to the £85 gum elastic ones, which look similar, but I have to say, they don’t function similarly at all: they've got flat ends as opposed to the parabolic ends, and they don't have the nice characteristics of bendy and then gradually take the shape of things, so if you bend it, it manages to get into position and smoothly glides in, but this one flatly doesn't want to go in, and in slightly straightens as you put the tracheal tube over it, so the older one did function significantly better. The new ones could potentially present at problem' (anaesthetist).

The main area of concern, as implied in the last quotation, was the inability of the single-use bougie to retain its shape. This has been acknowledged elsewhere, with one particular example deemed inappropriate for use as an intubation aid [28]. Wilkes et al. found that single-use bougies tended to be stiffer than their reusable equivalents [29]. Annamaneni et al. compared the ability of single-use and multiple-use bougies to retain their shape, and found multiple-use bougies to be superior [30].

Similar comparisons between the efficacy of other disposable and non-disposable devices were made. For example, the original laryngeal mask airway (LMA Classic^™, Intavent Orthofix, Berkshire, UK) was considered to be the gold standard, with respondents describing how ‘nothing is as good as the reusable to be quite honest’ (ODP). Compared to the original laryngeal mask airway, devices developed by other companies were reported to vary in design and material. These differences resulted in clinicians perceiving the masks to be bulkier, which led to soft tissue trauma and damaged teeth, as well as producing an inferior seal. However, anaesthetists were not solely concerned with the threat of soft tissue trauma or damage to the teeth. One was vehement in his assessment of single-use laryngeal masks:

‘Disposable laryngeal masks can be dangerous and can deform if the patient has a difficult airway’ (anaesthetist).

As these data have demonstrated, the safety offered by single-use devices in preventing infection and contamination is, to some extent, at odds with perceptions of their quality and efficacy. One ODP acknowledged:

‘Lots of things aren’t as good you know, you buy cheap and it looks cheap and it doesn't work properly, so you know, you have to weigh up the pros and cons: is it going to be safe for the patient or not?' (ODP).

Despite recognising the inconsistent quality and efficacy offered by some single-use devices, respondents were clear that their use was in the patient's interest, and typically referred to this as ‘best practice’. Moreover, respondents asserted that if they, or anyone close to them, were the patient, they would want single-use devices to be employed in their treatment, and felt that other patients should not be offered a lower standard:

‘I think the most important thing is that we as professionals need to make sure that what we use on the patient we would be happy to accept for use on ourselves or any member of our own family, and looking at the guidance and using that guidance thinking: “is this the best practice that we can give the patients”?’ (theatre manager).

‘I work on the principle that I’m the patient. You know, if this is being used on you, then I would want it to be used on me. I've had surgery here, as have my family, and I'm very happy with the standards here' (sterilisation manager).

These findings echo the results of a US survey in which 82% of all nurses and 71% of all surgeons questioned reported that they would feel wary if a reprocessed device were used on them [31]. Similarly, Walsh [32] carried out his own ‘straw-poll’ of UK theatre staff, and found that ‘almost all would prefer an unused laryngeal mask airway for their anaesthetic, because they see them contaminated with blood and secretions’.

Discussion

Single-use devices have been increasingly used following awareness that protein and bacteria remain on instruments after decontamination and sterilisation processes. This led to fears that patients may contract iatrogenic infections and diseases such as vCJD, HIV and hepatitis B or C. The use of single-use devices, which by definition should be used once and then discarded, removes this threat to the delivery of safe care to patients: new single-use devices are guaranteed to be clean and contaminant-free. Moreover, unlike reprocessable equipment, single-use devices are neither fatigued nor suffering from wear and tear. For the most part, the use of single-use devices appears to be in the patient's best interests. However, as this paper has demonstrated, concerns about the strength, flexibility and efficacy of certain single-use devices have arisen, and have led clinicians to question the use of such devices. The risks to patient safety in terms of infection and cross-infection have to be balanced against the risks linked to inferior quality single-use devices. A number of authors have argued that the extent of iatrogenic risk from contaminated devices has been overstated, and they cite the lack of any firm evidence that demonstrates the presence of a health hazard [33, 34]. Walsh [32] recently suggested that if the risk from airway devices such as breathing circuits and laryngeal masks had been significant, the consequences would already have been evident. The long-term safety and efficacy of reuse is still unknown because of the long incubation period of prion-related diseases [35, 36]. Given this, the use of single-use devices is seen by clinicians to be a sign of professionalism and adherence to good practice standards [37].

Nevertheless, dangers to patient safety are still present. This paper has added to a growing number of publications in which it is argued that single-use devices do not always function as well as clinicians would want [16–20]. Some may even endanger patients. For example, although the use of single-use laryngoscope blades was mandated because of the theoretical risk of cross contamination from prions, the unsatisfactory quality of some laryngoscope blades has resulted in actual risks to patients' health and safety. Hutton [26] described how:

‘New, inferior equipment has now claimed its first victims and the real danger of responding to theoretical risks in the face of practical experience has been exposed. The message is clear: hypoxia threatens life in minutes, haemorrhage in hours and tonsillar prions (maybe) in decades’.

It has been suggested that single-use devices were rushed into use as a result of Department of Health concerns about iatrogenic infection, and that new generations of these products will address the criticisms expressed by our informants. Until that day arrives, clinicians should be aware that patient safety is not threatened solely by the risk of contamination, and they should always question whether the devices they use are fit for purpose.

Acknowledgements

The contributions of other research team members at the University of Nottingham are acknowledged: Alan Aitkenhead, Graeme Currie, Beverley Norris, Sarah Sharples, David Whynes and John Wilson. The research was funded by the Department of Health's Patient Safety Research Portfolio (Ref PS022).