The Teaching of Obstetric Extradural Analgesia: A Personal View*

Br.J. Anaesth. (1979), 51, 53S

THE TEACHING OF OBSTETRIC EXTRADURAL ANALGESIA* A Personal View A. DOUGHTY

On the other hand, the approval in 1970 by the Central Midwives Board of England and Wales for midwives to undertake the topping-up procedure has undoubtedly been the spur to the development of extradural services in many of our hospitals. Thus the medical skill of setting up the extradural block can be segregated from the responsible but lesser skill of maintaining analgesia by giving the supplementary injections through a cannula safely sited in the extraANDREW

DOUGHTY, M.B.,

F.F.A.R.C.S., Department

of

Anaesthetics, Kingston Hospital, Wolverton Avenue, Kingston Upon Thames, KT2 7QB. * This paper includes material presented in Dr Doughty's Presidential Address to the Section of Anaesthetists of the Royal Society of Medicine, November 4, 1977 (Doughty, 1978), and is published here by kind permission of the editor of the Journal of the Royal Society of Medicine. 0007-0912/79/130053-14 §01.00

dural space. It follows that, while one's teaching of doctors should cover the whole field of extradural analgesia, one must also assume responsibility for the training of midwives in the care of the patients enjoying its benefits. In fact the Central Midwives Board rules include the statement that the full responsibility for the extradural block must still rest with the doctor performing it, that the midwives must be properly instructed in the procedure and that the primary dose through the cannula must be given by the doctor. In 1971 the Board prescribed for midwives in training "participation in advanced analgesic techniques under the supervision of a registered medical practitioner". Thus, at least in England and Wales, the principle has been accepted that midwives enter into a partnership with the doctor in maintaining the continuity of analgesia. As with any innovation, the practice has advantages and disadvantages. The obvious advantage is that the analgesia can be maintained continuously, leaving the anaesthetist free to pursue other work away from the labour ward. A disadvantage is that the discretion of when to give the top-up is left in the hands of midwives whose experience of the method may be variable and whose enthusiasm for total analgesia may be unpredictable. We have then to determine: whom do we teach? How do we teach ? What do we teach ? Whom do we teach ? I would say that we teach any doctor, be he anaesthetist or obstetrician, who is willing to take the trouble to learn, and we have also to teach midwives to play their part in assisting the doctor and in caring for the patients. How do we teach ? The main plank of teaching in my own hospital is a locally produced booklet revised every year and issued to all who practise extradural analgesia. It is also issued to all midwives and to pupil midwives to whom a special section is addressed dealing with the © Macmillan Journals Ltd 1979

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The ability successfully and safely to manage an extradural block for the relief of pain in labour does not come as a natural instinct to anaesthetists; it is nevertheless a skill that can be readily and rapidly acquired if the teaching is concentrated and effective. The practice of continuous extradural analgesia has been slow in spreading in Europe. It is probably better developed in Britain than in any other European country and considerable progress has been made against the background of medical and lay prejudice and the shortage of anaesthetists with suitable experience in our National Health Service. A prerequisite for training is the existence of an obstetric department with a well-developed extradural service, and yet such training facilities vary throughout the country. A recent enquiry of the London Teaching Hospitals has shown that, in 1976, the percentage of all confinements in which extradural analgesia was given varied from 62% in one hospital down to 5% in another (Doughty, 1978). A low extradural rate in any teaching hospital must imply that anaesthetists emerge from their training presumably fully equipped for specialist status according to the regulations laid down by the Faculty of Anaesthetists, but quite untrained to become involved in an extradural service. This situation may well persist until the Faculty prescribes specific training in obstetric analgesia.

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What do we teach ? One cannot cover the whole field in a short period of training, but one can at least launch a fairly competent performer into practice by close attention to four fundamental points: (1) Skill, speed, safety and finesse of technique (2) Ensuring the reliability of the block (3) Reduction of side-effects (4) Avoidance of complications The early training concentrates on the first two points. The ability to set up an extradural block speedily and skilfully depends not only on effective teaching, but also on establishing a standard routine in the labour ward to be practised by the anaesthetist and by the midwife who is helping him. Standard instructions are placed in each labour ward and these are framed so that any midwife who has never previously seen an extradural block given can give effective help to the anaesthetist without his even speaking a word to her. The standard routine for the doctor is prescribed not only for the preparation and testing of the equipment but also for the orderly, safe and considerate performance of the insertion of the Tuohy needle and extradural cannula. Stress is placed on the initial correct siting and alignment of the needle so that the extradural space is penetrated at the first attempt. Bad technical habits are eliminated before they become established. In particular, the attitude that inadvertent dural puncture is acceptable during training is discouraged by the teaching of a safe technique based on the belief that such an event is an avoidable accident. Nonetheless, unnecessary delay is not tolerated. There is no reason why the anaesthetist's stock-intrade of organized efficiency in the anaesthetic room

should be abandoned when setting up an extradural block in the labour ward. After all, the relief of severe pain is a matter of some urgency to the sufferer, and a quick, efficiently-given extradural block can be fitted into a busy timetable when a tedious time-consuming ritual cannot. The second important principle in teaching is to instil a sense of obligation to ensure that, once an extradural block is undertaken, every effort must be made to provide continuous and perfect pain relief for the mother until delivery. In order to maintain high standards of supervision by the midwives it is essential that every patient who has received extradural analgesia should be followed up so that the quality of the analgesia achieved can be assessed, as it is only by identifying the source of unsatisfactory analgesia that improvements can be made in the service. Unhappily, a somewhat passive attitude towards the management of an extradural block is prevalent and this is epitomized by the conventional classification of the assessment of extradural efficacy by which each is graded as "fully satisfied", "helped" or "no benefit" (Crawford, 1972). Now, as I believe that the category "helped" implies some degree of dissatisfaction, I prefer the more active policy implied by the alternative grading of "satisfactory", "satisfactory after adjustment" or "unsatisfactory" (Doughty, 1975). In figure 1 the two attitudes are compared and,

Conventional System (Passive) Proposed System (Active)

1

Fully Satisfied! j 80 Satisfactory

80

!i

Helped

No benefit

14

Satisfactory

I I Unsatisfactory aitcr i l(a)Management Failure! Adjustment I | ( b ) M e t n o d F a j | u r e 14

H

FIG. 1. Assessment of efficacy of extradural analgesia.

although the figures given with both classifications may appear at first sight to be similar, the more active striving after perfection in the second classification would suggest a higher standard of efficacy in that more patients are ultimately satisfied. No extradural should deserve to be categorized as "no benefit", unless the labour has proceeded so rapidly that time did not allow for setting up the block again. I believe, too, that one should examine more closely the reasons why some extradural blocks are unsatisfactory. Many cases can be traced to a human failure, a failure of management, but the remainder, and these should be

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topping-up procedures and the detailed nursing care of the patients. Special emphasis is given to the avoidance and treatment of the effects of aorto-caval occlusion. I believe that teaching of doctors is most effective if it is intensive, continuous, individual and extends over a period of 2 weeks under graduated supervision. Further, it is most important that the active practice of the technique should be continued in the parent hospital immediately following the intensive course. The demonstrations and practical work in the labour wards are supplemented by tutorials with film and still projections and by the provision of a compendium of reprints of relevant publications on all aspects of the subject.

BRITISH JOURNAL OF ANAESTHESIA

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TEACHING OBSTETRIC EXTRADURAL ANALGESIA very few, may be attributed to the intrinsic fallibility of the method. A breakdown of my personal results (table I) collected from more than 2500 patients shows that approximately three-quarters of them were classified TABLE I. Efficacy of extradural analgesia in 2532 patients, 1968-78

Satisfactory Satisfactory after adjustment Unsatisfactory Management failure Method failure

1920 (75.8%) 430 (17.0%) 104(4.1%) 78 (3.1 %)

100%-

1971-72

1973-74

TABLE I I . Failure of management of extradural analysis of 104 patients

Top-ups not given correctly Anaesthetist not present to make a necessary adjustment Labour progressed too rapidly for the extradural block to become effective

analgesia:

76 21 7

or in the correct position appropriate to the site of the mother's pain. Occasionally, the anaesthetist was not called to make the necessary adjustment: the extradural block had been established satisfactorily and yet the subsequent doses given by the midwife did not give adequate relief. Satisfactory analgesia was not restored on 21 occasions, either because the anaesthetist was unavoidably occupied elsewhere or, more frequently, because his help had not been sought by 1975-76

1977-78

FIG. 2. Change of assessment of efficacy of extradural analgesia with passage of time.

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as "satisfactory". These were patients in whom the extradural block was set up and gave complete satisfaction against the background of standard management instructions to the midwives and therefore required no further intervention by the anaesthetist. A further 17% were in the category "satisfactory after adjustment"—in other words, they were salvaged from being unsatisfactory by some further positive action by the anaesthetist, from giving a small extra dose with the patient tilted to one side, to re-siting the cannula in another lumbar interspace. The remaining 7% were unsatisfactory, this impression being gained by observation during labour, at the time of delivery,

or by interviewing the patient on the day following delivery. Let us accept that in perhaps 3 % of cases some dissatisfaction can be attributed to the essential fallibility of the method, although most observers would have described these cases as having been "helped". The failures that are preventable are those of management (table II), the commonest reason for which was the failure of the midwife to give the top-up punctually

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BRITISH JOURNAL OF ANAESTHESIA in their education is still needed to reduce the chance of mismanagement. Romine, Clark and Brown (1970) of Arkansas have shown how the efficacy of extradural blocks varies according to the experience of the operator (fig. 3). The senior staff appear to obtain results similar to those that I have just presented. Those obtained by more junior staff underline the importance of very close attention to training and supervision when the service is in the hands of less experienced performers. The senior staff's standards are those which should be maintained and it is therefore the senior staff who should be doing the teaching. In Britain, all too often novices receive their teaching from those with relatively modest competence and short experience. There exists a prevalent belief that a senior anaesthetist's training obligations are discharged by teaching extradural blocks in the operating theatre against the background of general surgery. This is of limited value, as it must be evident that obstetric extradural analgesia can only be learned in the delivery suite and in harmony with the total obstetric management of the woman in labour. CONCLUSION

I believe that anaesthetists have a serious responsibility to ensure that extradural blocks are given effectively and safely. Where training and supervision

j f f i l i SENIOR STAFF \

| HOUSE STAFF STUDENTS

ENTRY SUCCESS

INITIAL ANAESTHESIA SATISFACTORY

FINAL ANAESTHESIA SATISFACTORY

FIG. 3. Success of entry into the extradural space, and initial and final satisfactory quality of anaesthesia by experience of operator (after Romine, Clark and Brown, 1970).

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the midwives. On seven occasions the labour progressed too rapidly to give time for the extradural block to become effective. In other words, the anaesthetist was called too late. Although an extradural block should not be attempted when the baby's head is crowning, one should have the confidence to try to give the mother a painless delivery with a single-dose injection even though labour has advanced to the second stage. In these circumstances the ability to be quick and safe is at a premium. From thesefiguresit will be seen that more than onehalf of the failures could have been salvaged by more effective management. These 104 cases, 4% of the total, may be regarded as the casualties of the system in which the anaesthetist is not constantly present in the labour ward. It might be asked whether the results have improved with continuing experience and advances in technique over the passing years: figure 2 shows that between 1971 and 1976 unsatisfactory analgesia has continued at the rate of 7-8% of all extradural blocks and that these were evenly divided between method and management failure. In 1977-78 a marked reduction in the frequency of failure of the block is shown and a gradual trend can be discerned towards a higher frequency of immediate and sustained success of the analgesia in recent years. While more blocks can now be left in the hands of the midwives without the need for the anaesthetist's intervention, persistent effort

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TEACHING OBSTETRIC EXTRADURAL ANALGESIA

unskilled practice of the method does not attract justifiable criticism. REFERENCES

Central Midwives Board (1970-71). Annual Report, p. 16. Central Midwives Board (1971-72). Annual Report, p. 13. Crawford, J. S. (1972). Lumbar epidural block in labour: a clinical analysis. Br. J. Anaesth., 44, 66. Doughty, A. (1975). Lumbar epidural analgesia—the pursuit of perfection. Anaesthesia, 30, 741. (1978). Epidural analgesia in labour—the past, the present and the future. J. R. Soc. Med., 71, 879. Romine, J. C , Clark, R. B., and Brown, W. E. (1970). Lumbar epidural anaesthesia in labour and delivery: one year's experience. J. Obstet. Gynaecol. Br. Commonw., 77, 722.

DISCUSSION DR ROSEN : Could I take issue with Dr Doughty about who should be allowed to administer extradural blocks. I do not believe that we should train anyone in this technique unless he is fully competent to resuscitate the patient, should a total spinal or cardiac arrest occur. The operator must therefore know the general principles of artificial ventilation, how to intubate the trachea, etc. Dr Doughty emphasized the need to make the technique effective. I would rather stress the question of safety. Patients do not die because of ineffective analgesia, so that the technique must be absolutely safe. Deaths resulting from extradural blockade associated with non-anaesthetists are now due to appear in the next confidential report on maternal deaths in the United Kingdom. DR DOUGHTY : I did say at the beginning of my talk that I intended concentrating on the teaching of the technique and on ensuring the efficacy of the block. You may be assured that the teaching of safety, the reduction of side-effects and. the avoidance of complications is well emphasized during our training course. CHAIRMAN: I would like to call two speakers to tell us about the percutaneous administration of ketocaine for analgesia in labour. Dr Holmberg, in collaboration with Dr H. Edstrom, has the results of a preliminary clinical study. Dr Akerman and Dr Berlin-Wahlen will then tell us something of the pharmacology. DR N.-G. HOLMBERG (SUNDSVALL): Like most painful sensations from the viscera, the pain of uterine contraction is referred pain, felt in the abdomen, groins and low back region (Bonica, 1975). The possibility of obtaining analgesia by interfering with this viscero-sensory reflex might therefore constitute an alternative form of analgesia. Rose (1929), using an intradermal infiltration of procaine during the first stage of labour, managed to achieve analgesia and good results were reported by others (Theobald, 1946; Abrams, 1950). Local infiltration of the skin of the dermatomes involved is time-consuming for the doctor and unpleasant for the

patient. A new preparation (Ane-Pad*) containing a local anaesthetic, ketocaine (fig. 1), in a special vehicle, produces percutaneous local anaesthesia. Dr Edstrom and I have carried out a preliminary study to determine if significant relief of pain could be obtained using these pads.

-N [CH (CH 3 FIG. 1. Ketocaine. Sixty patients in established labour were studied. Thirty received ketocaine Ane-Pads and 30 were controls, according to a randomized list. The patients were not studied in consecutive order, the majority being patients admitted to the labour ward at periods of relative quiet. Patients who had previous obstetric complications or known allergies were excluded. The pads are available in air-tight envelopes of plasticcoated aluminium foil and each contain ketocaine 840 mg. When the patient complained of pain, usually at cervical dilatation 3-4 cm, the pads were applied to the skin over the low back, covered by thin plastic foil (to prevent evaporation of the solution) and fastened by surgical tape. The application period was 1 h. We attempted also to apply the pads to the abdomen and groins, but found this impractical. There was a high proportion of primiparous women in the ketocaine group, but no other important differences between the groups (tables I and II). During labour a careful record was kept by the midwife, of contractions, cervical dilatation and effacement, fetal heart rate and maternal arterial pressure. Every 30 min an assessment of the pain in the abdomen, groins and back was made by the patient according to a 0-3 pain score. * Ketocaine (base) 0.10 g ml" 1 , isopropanol 0.45 g ml" 1 , glycerol 0.12 g ml" 1 , water 0.25 g ml" 1 , acetic acid 0.001 g ml" 1 .

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are haphazard, the results can only bring discredit on the method itself. Ineffective extradural blocks, accompanied by a high frequency of complications, deserve adverse criticism. Unfortunately, the attainment of consultant rank in anaesthesia does not necessarily guarantee the ability of the individual to practise or to teach the technique. There is an overwhelming need for the establishment of advertised instruction courses for those whose hospital appointments do not include opportunities for this experience. Irrational prejudice against obstetric extradural block can only be countered by the eloquence of consistently superb results speaking for themselves, but training must ensure that the