Anästhesiol Intensivmed Notfallmed Schmerzther 2002; 37(10): 637-640
DOI: 10.1055/s-2002-34525
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© Georg Thieme Verlag Stuttgart · New York

“Chair Dentals”:
Outpatient Dental Anaesthesia in the UK

„Chair Dentals”: Ambulante zahnärztliche Anästhesie in den UKS.  Bricker1
  • 1Consultant Anaesthetist, The Countess of Chester Hospital, Chester, UK
Further Information

Publication History

Publication Date:
07 October 2002 (online)

The severity of the pain of acute toothache is matched only by the simplicity of its cure. Swift dental extraction provides almost immediate relief, and so it is not surprising that it is for this procedure that the earliest recorded general anaesthetics were given. In Rochester, New York State in 1842 a Dr Elijah Pope used ether to anaesthetise a Miss Hobbs for dental extraction, and in 1846, in London, a Dr Francis Boott used the same technique in the first general anaesthetic authenticated in England. Precise details of these anaesthetic and surgical techniques are not known, but it is likely that anaesthesia would have been induced in the sitting position in a dental chair, that the patient’s mouth would have been held open with some form of gag or prop, and that the teeth would have been extracted in a matter of seconds. Dental practitioners of that era were accustomed to removing teeth without the benefit of anaesthetic, under which circumstances speed would have been essential. From these humble beginnings anaesthesia evolved rapidly and it would be almost 150 years before the subject once again excited much interest. Yet in the meantime huge numbers of what are known colloquially in the UK as ‘chair dental’ anaesthetics were administered, so that in England and Wales in the 1950 s, which is the first decade for which data are available, no fewer than 3.5 million such anaesthetics were performed annually. This would suggest that the numbers of anaesthetics for dental extraction by far exceed those administered for any other single surgical procedure. Given that dental caries is the developed world’s most prevalent disease this should perhaps come as no great surprise: what is more curious is that extraction under general anaesthesia in the dental chair appears to be a technique that is confined largely to the UK. Why then should it have persisted? Dental phobia is common and appears to be embedded in human culture throughout the world, being suffered by all classes irrespective of wealth or education. But true though this may be, it still does not explain why the practice should continue in the UK as compared, say, with mainland Europe. There is little evidence from the literature about how children with advanced dental caries are managed Europe-wide, but at least one small survey suggests that referral to hospital for treatment is much more common than in England. Davies and Nind surveyed European practice in a number of different countries via a questionnaire relating to the management of sample clinical situations. Their worst-case scenario was a child requiring extraction of 4 deciduous molars plus three other teeth, which in some European countries mandates hospital anaesthesia with tracheal intubation [1]. Most UK dental anaesthetists would consider that technique to be unnecessarily invasive. In respect of UK outpatient practice some dental anaesthetists have used the justification that they provide a social service to a deprived group of patients at the point of need. It is equally probable, however, that their continued provision of the service was driven mainly by financial imperatives. In Liverpool, in the 1900 s, for example, teeth could be extracted without anaesthetic free of charge but at the cost of 2 shillings per tooth under general anaesthetic (current equivalent ∼ 10 euro). These charges seem high, and the creation of the National Health Service in 1948 decreased the costs to the patient. It decreased also, however, the effective remuneration to dental anaesthetists who were paid on an item-for-service basis. In the late 1990 s an individual providing dental anaesthetic services in general dental practice would receive payment on a sliding scale which ranged from £ 18.75 (∼ 30 euro) for 1 - 4 teeth to £ 31.60 (∼ 49 euro) for more than 17 teeth. The dentist was paid the same. These government fees contained obvious anomalies: anaesthetist and dentist could struggle with 8 adult molars and receive less than £ 3 (∼ 4.5 euro) more than if the patient was a child with a single deciduous incisor. Be that as it may, it is very obvious that fees were low in comparison with the private sector, which meant that there was a clear financial incentive to maximize numbers. Just how great these numbers were is illustrated by an unpublished pilot survey of 50 UK anaesthetists who were particularly experienced in this field. (SRW Bricker, personal data) In reply to the question about their total lifetime experience of chair dental anaesthetics, over half of the overall total of 1,047,000 cases was accounted for by 8 individuals. Between them they claimed to have administered in the region of 655,000 outpatient dental anaesthetics. Even were these doctors to have exaggerated by 100 % their caseload, this represents nonetheless a vast body of experience quite unmatched in any other area of anaesthesia. Anaesthesiologists who are not familiar with the practice will wonder doubtless just how any individual can anaesthetise well over 120 000 patients, as two of the respondents claimed to do. It is not as improbable as it may sound. A typical chair dental anaesthetic is very brief. In a personal series of over 12,000 cases using both inhalational and intravenous anaesthesia, the mean time from the start of induction until eye opening on command was 251 seconds in children and 307 seconds in adults. (SRW Bricker, personal data) With each episode averaging less than 5 minutes it is not difficult to see, therefore, that a well-organised clinic or dental surgery could process 10 or more cases per hour. Such rapid turnover may seem alarming but speed, paradoxically, is one of the strengths of the technique, because it is probable that the very brevity of the anaesthetic contributes to its safety. Despite a widespread perception that chair dental anaesthesia is somehow uniquely perilous, mortality statistics suggest, on the contrary, that there is no safer form of anaesthesia. Dental anaesthetic deaths have been investigated by a number of authors, amongst whom was Tomlin, who in 1974 calculated a mortality of 1 in 274,000 administrations [2]. This contrasts with the figures published for all hospital anaesthetics in the first report of the Confidential Enquiry into Peri-operative Deaths (CEPOD) in 1987, which quoted a substantially higher mortality solely associated with anaesthesia at 1 in 185.000 administrations [3]. Coplans and Curson, meanwhile, in two separate studies, examined deaths associated solely with dental anaesthesia over a 20-year period from 1970 until 1989, which identified 54 deaths in the first decade, and 18 in the second [4] [5]. There were 119 fatalities overall, 60 % of which occurred in premises outside hospital. Children comprised 29 % of the cases. In the first decade denominator data allowed these authors to establish a mortality rate of 1 in 230,000. Total general anaesthetic numbers were not available for the second decade, but best estimates suggest that the mortality rate was equally low. More recent data issued by The Department of Health (DOH) issued figures that included the decade of the 1990 s which showed that over the past 30 years in the UK there have been 147 deaths, twice as many in adults as in children [6]. An anaesthetist, Bourne, previously had proposed the hypothesis that a major cause of mortality was fainting and consequent cerebral hypoperfusion which went unrecognised in patients who were anaesthetised in the sitting position. His study was based on a retrospective questionnaire sent to 386 dentists, and on a collation of newspaper reports of 14 deaths over 2œ years; a methodology that by current standards seems laughable [7]. In spite of this Bourne gained supporters and the issue continued to divide dental anaesthetists, even though there is ample research evidence to demonstrate that arterial blood pressure does not show any significant fall. Several studies compared arterial blood pressure in patients undergoing dental anaesthesia in different positions, including sitting and fully supine, and concluded that there was no evidence to support the use of the supine position for outpatient dental anaesthesia [8] [9]. Coplans and Curson also concluded that there was no consistent relationship between mortality and position, while identifying more respiratory problems in patients who were supine [5]. An editorial in the British Journal of Anaesthesia in 1998 tacitly ignored Bourne’s theory and speculated instead that some of the deaths may have been due to cardiac arrhythmias associated with the administration of halothane [10]; a hypothesis that was given credibility by a subsequent study which demonstrated persistent and potentially malignant rhythms in almost 50 % of patients who received halothane as part of the anaesthetic technique for dental extraction [11]. Although this paper has helped consign halothane to history in the UK it would be unjust to blame the agent exclusively for dental anaesthetic deaths. Tomlin’s study included a description of a technique destined to cause serious problems: “Anaesthesia was induced with 100 % N20 which was gradually reduced to 90 % and then to 80 % while unknown concentrations of halothane and trichloroethylene were administered” [2]. This adult suffered a fatal cardiac arrest, which is hardly surprising, yet it is definitely possible that such techniques were widespread. What almost certainly protected most patients from disaster is, once again, its brevity, which may have contributed to safety statistics by allowing some anaesthetists to use unacceptable techniques without causing the carnage that might otherwise ensue were procedures to be prolonged. It is also probable that because most children are inherently fit and healthy mortality remained low. The Chairman of the Royal College of Anaesthetists’ Standing Committee on Dental Anaesthesia has argued that even if mortality is low, ‘there was, almost certainly, much morbidity associated with the practice’ [12]. There is no evidence either to support or refute this contention: in the survey of experienced anaesthetists referred to above, the incidence of critical incidents such as laryngospasm and bradycardia was 1 in 75,000. This low immediate morbidity is plausible given the very short duration of these anaesthetics. About longer-term morbidity we have no information. The transience of chair dental anaesthetics, however, is its weakness as well as strength; because there is no doubt that many thousands of chair dental anaesthetics have been administered by individuals who have lacked the skills necessary to perform the technique safely or to resuscitate patients effectively in the event of collapse. That individual who was administering nitrous oxide anaesthesia for two shillings a tooth in a Liverpool dental practice in the 1900 s had not only received no formal training either in medicine or in anaesthesia: but had received no education at all. This may have not been that unusual and although the situation improved over succeeding decades, chair dental anaesthetics continued to be given by a disparate assortment of practitioners. As late as the 1980 s in at least one teaching hospital in England, dental students were still being ‘taught’ to administer anaesthetics for extractions in preparation for general dental practice. There were still then some dental surgeries, after all, in which a daily walk-in general anaesthetic service continued to be offered. Many of these dentists, moreover, became skilled in using a technique that was probably broadly similar to that used by the very first dental anaesthetists, who did at least have the benefit of being medically qualified. So a century and more later the individuals who were maintaining their tradition ranged from dentists and family doctors to paediatric anaesthetists from tertiary specialist centres. These latter, however, were not usually giving chair dental anaesthetics within their own establishments but were peripatetic, often travelling between premises which included dental surgeries and community clinics. It was concern about the disparate nature of these facilities as well as anxieties about safety that stimulated the publication of the Poswillo Report in 1990, which in effect was the first serious attempt to improve standards of what in the USA would be called ‘office’ anaesthesia [13]. The report made a series of recommendations pertaining to minimum standards of monitoring and resuscitation, insisting, for example, that a defibrillator should be readily available in every site where anaesthesia was given. It now seems remarkable, twelve years on, that so many anaesthetists were prepared to administer literally thousands of anaesthetics without access to cardiac defibrillation and without the use of minimal monitoring, and this only serves to emphasise the low technology culture that pervaded the whole enterprise. Many UK anaesthetists believed that the Poswillo report was designed specifically to ensure that chair dental anaesthesia ceased, but obsequies were premature because 5 years later in a follow up report, the Clinical Standards Advisory Group noted with some dismay that the numbers of outpatient general anaesthetics had actually increased [14]. This was due largely to the emergence of a group of dental clinics that were set up to provide services to general dental practitioners. It can be argued that these clinics were simply identifying a need which the NHS had left unmet, and in 1996 no fewer than 80,000 patients were treated on an item-for-service basis. These centres took referrals from dentists and then claimed the fee for work done from the Dental Estimates Board (a government body). Fees were relatively low and once 50 % of that fee had been used to pay the operator and the anaesthetist, the remainder could meet the capital and revenue costs of the clinics only if numbers were very high. The incentive, therefore, was to treat as many patients as possible, and so these clinics ended up by offering a service to the dental phobic public in which almost every dental need could be treated under general anaesthesia. There were misgivings about standards in these as well as other clinics and dental surgeries, and it was, finally, a cluster of fatalities in children in the late 1990 s that precipitated a dramatic change in the regulations which governed the administration of dental anaesthetics in the UK. The first significant influence was exerted by the General Dental Council (GDC) which emphasised, in guidance published in 1998, the professional liability of dental practitioners were they to lapse from minimum standards or to work with anaesthetists who were not fully accredited (on the specialist register for anaesthesia). [15] These revised GDC regulations had a marked effect, and in the first quarter following the announcement, overall numbers of case in the UK fell by 80 % [6]. Figures released by the UK Department of Health confirmed, however, that there continued to be fatalities, most of which received substantial media attention, and it was in this context that the Chief Medical and Dental Officers of England and Wales produced a report on dental anaesthesia in primary care [6]. It is an unimpressive document which in response, it would seem, to media concern over the tragic deaths of a small number of children, created a standard for dental anaesthesia which far exceeds that for every other surgical specialty. The report imposes vicarious liability on the dentist, on whom is placed the responsibility for the clinical standards within the unit to which he or she may refer a patient: “Referring dentists have a responsibility to ascertain that the facilities at the premises to which they refer patients are adequate and that clinical staff are properly trained.” Were this extraordinary requirement to be applied equally to general medical practitioners it would, quite properly, be derided as unworkable and quite unfair. In respect of the issue of the venue in which outpatient dental anaesthesia should be administered the report stated that “… dental treatment under general anaesthesia should be provided in a hospital setting.” “Hospital setting” was defined carefully: as “…any institution for the reception and treatment of persons…requiring medical or dental treatment, …has critical care facilities on the same site…and includes clinics and outpatient departments maintained in connection with any such institution.” It was clear that this was defining in effect a typical acute hospital. As far as the term “critical care facilities” was concerned most UK anaesthetists assumed that this meant what it had always meant: namely an intensive care unit (ICU) or at the very least a high-dependency unit (HDU). Not so: in supplementary guidance issued by the DOH in May 2001 [16] it was stressed that critical care facilities should not be seen necessarily to comprise dedicated HDUs or ICUs but are areas rather in which the necessary resuscitative expertise can be marshalled pending expeditious transfer. Such expertise includes “additional skilled support”: presumably a cardiac arrest team. These poorly drafted regulations have meant, in effect that since January 1st 2002 a healthy child in the UK who requires the simplest of dental extractions under general anaesthesia has had to be treated in a hospital with ready access to intensive care. Adults with significant concomitant disease, however, continue to undergo any number of other major surgical procedures, such as total hip replacement or major gastrointestinal surgery, undertaken in medical facilities without such resources. That this anomalous situation has arisen at all provides an interesting example of how even individuals trained in scientific method can act on emotion rather than on evidence. What these recommendations also missed is the crucial fact that the various enquiry reports into the recent deaths of children undergoing dental anaesthesia confirmed that by far the most important contributory factor to these tragedies was not the venue but the incompetence of the anaesthetists who were involved [17] [18]; a truth that has applied probably since the early beginnings of anaesthesia itself. The ambiguity and lack of clarity in the report has made the implementation of the recommendations problematic. General Dental Practitioners no longer extract teeth under general anaesthesia in their surgeries, and Community Dental Services have struggled to find appropriate accommodation on hospital sites. Where the service has been able to continue there has been a change in referral patterns. It is now uncommon to deal with adults and with older children who require orthodontic extractions; instead the majority of cases are children between the ages of 3 and 7 years who require exodontia because of caries in multiple quadrants. The cases for which general anaesthesia was formerly a simple option are being treated; it would seem, by different methods of pain and anxiety management, including the use of various techniques of sedation. This is as it should be, with general anaesthesia being reserved for the core of cases for which there is no other option. But that core need does remain, and it is important that these patients, who are frequently from disadvantaged socio-economic groups, should continue to have ready access to a rapid and responsive service. It is also important, however, that they are not subjected to sedation techniques that are inappropriate. Given that a fee is still payable in dental practice for this service, it is vital that financial incentives are not allowed to put patients at risk in the same way as happened with general anaesthesia. An anaesthetist in the UK has already been convicted of manslaughter following the death of a patient in 2000 whom he failed to monitor adequately during sedation, and it is evident that sedo-analgesia has its own very real potential to cause harm.

This then, has been a brief history of what has been described as not only a practice peculiar to the UK, but also a very peculiar practice. For a century and a half isolated practitioners of doubtful competence were able to make an income alongside those who were experienced and skilled. At the very end of this long period during which regulation was minimal, there was a flurry of official activity that has over regulated the activity almost out of existence. What will almost certainly ensure its final demise, however, is not regulation but the gradual disappearance of anaesthetists who have the necessary skills. For the newer generations of anaesthetists in the UK, chair dental anaesthesia remains a curiosity to which they have little exposure, and very few have the inclination to develop any further interest. Its loss will be unfortunate, because it is a safe and expeditious means of facilitating simple dental extraction in amongst others, the very fearful and the very young, and it exemplifies the challenges of the shared airway. Some of its skills are generic; the experience of 4.000 or 5.000 inhalational inductions means, for instance, that paediatric airway problems in the non-dental setting hold many fewer terrors than otherwise they might. It is not yet entirely clear what will take the place of chair dental anaesthesia, but it is likely to involve more complex anaesthesia conducted on a formal day case basis. It would have been more satisfactory were this transition to have occurred on the basis of evidence; on a proper comparison between the traditional and modern methods of dental anaesthesia, because there are no data to show that one is necessarily better or safer than the other. This will now not happen. What is likely to be lost is the provision of a responsive anaesthetic service delivered at the point of need, as well as some important anaesthetic skills born of the specific experience of large numbers of dental cases. What is likely to be gained is at least the perception of increased safety, which will satisfy the public, the politicians and the profession. What may be gained at best is the reality of safer practice and an end to the spectre of tragic fatalities in otherwise healthy children. It is inevitable, however, that there will continue to be a small number of tragic deaths until the eradication of dental caries renders the need for anaesthesia redundant. That utopian task, however, is for those who work in dental public health and is not one, fortunately, for European anaesthesiologists.

References

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  • 15 General Dental Council.  Maintaining Standards, Guidance to Dentists on Professional and Personal Conduct. London; General Dental Council 1998
  • 16 Department of Health Guidance Letter.  General anaesthesia for dental treatment in a hospital setting with critical care facilities. 2001
  • 17 Southern Derbyshire Health Authority. Report of the internal inquiry into the death of Katie Dougal. 1996
  • 18 Fatal Accident Inquiry. Sheriffdom of Lothian and Borders at Edinburgh Inquiry into the circumstances of the death of Darren Denholm. 2000

Dr. S. R. W. BrickerMA, MB, ChB, FRCA 

Consultant Anaesthetist, Dept. of Anaesthesia


The Countess of Chester Hospital, Liverpool Road, Chester CH 2, 1 UL, United Kingdom

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