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31. Crawford JS. Some matenal complications of epidural analgesia for labour. Anaesthesia 1985; 40: 1219-1225. 32. Brownridge P. A three-year survey of an obstetric epidural service with top-up doses administered by midwives. Anaesth Intens Care 1982; 10:298-308. 33. Bromage PR. In: Epidural Analgesia. WB Saunders, Philadelphia 1978:548. 34. Guidelines for the conduct of epidural analgesia in obstetrics. Faculty of Anaesthetists, Royal

Australasian College of Surgeons: P14-1987. 35. Jones MJT, Bogod DG, Rees GAD, Rosen M. Midwive's assessment of the upper sensory level after epidural blockade. Anaesthesia 1988; 43:557-559. 36. Steenberg VA. In: Epidural Analgesia in Obstetrics. Doughty A, ed. Lloyd-Luke, London 1980:34. 37. Brownridge P. Another misplaced epidural catheter. Anaesth Intens Care 1984; 12:369-371.

Monitoring Epidural Analgesia in the Parturient J. A. CROWHURST*, R. W. BURGESSt AND R. J. DERHAM* Department of Anaesthesia and Division of Obstetrics, Queen Victoria Hospital, Adelaide, South Australia SUMMARY Appropriate monitoring during obstetric epidural analgesia consists of 1. Indirect BP and pulse monitoring before epidural insertion, frequently after every dose, and intermittently thereafter. 2. The aspiration test before all injections. 3. Frequent clinical monitoring for signs of intravascular injection during administration of small intermittent doses (not more than 3-5 ml at a time). 4. Frequent clinical monitoringfor sympathetic, sensory and motor signs indicating upward extension ofthe block. ' 5. Frequent monitoring of the fetal heart rate (FHR) and other signs offetal welfare. In many instances continuous tocogram with fetal heart rate (CTG) monitoring is useful. We do not believe CTG use is mandatory for epidural analgesia in the uncomplicated pregnancy, but we do advocate that it (and other appropriate fetal monitoring techniques) be used when risk factors or complications, either fetal or maternal, are present or suspected. The anaesthetist should be familiar with fetal monitoring techniques, their use and interpretation. He or she should be prepared to recommend their use when it is considered appropriate to do so. Key Words: ANAESTHESIA, ANESTHESIA, OBSTETRIC: regional, epidural; MONITORING: haemodynamic, fetal heart rate, cardiotocography; OBSTETRICS: analgesia, labour

Since the late 1960s, continuous epidural blockade has radically altered the practice of modem obstetrics. In Australia, epidurals are almost always administered by anaesthetists. Despite the great efficacy of the technique, the risks to both mother and fetus, although low, are very significant. I•3 Maternal deaths from high spinal block or local anaesthetic toxicity and fetal morbidity and mortality from decreased placental blood flow do occur. "A.U.A. (Pharm.), D. (Obst) R.C.O.G., F.F.A.R.A.C.S., Director of Anaesthesia. tF.F.A.R.A.C.S., Senior Registrar - Anaesthesia. tB.A.O., M.R.C.O.G., FeUow in Feto-matemal Medicine. Address for Reprints: Dr. J. A. Crowhurst, Director of Anaesthesia, Queen Victoria Hospital, Rose Park, S.A. 5067, Australia. Accepted for publication April 23, 1990

To detect and avoid these potential disasters the most important factors are a safe epidural technique, sound nursing practices, appropriate clinical monitoring, and availability of skilled clinicians.4-6 This paper deals with monitoring the parturient receiving epidural analgesia with local anaesthestic drugs only. Although epidural opioids in labour are being investigated widely at present, their possible advantages have not been proved nor their use widely accepted. A discussion of this use of opioids or other drugs then, is beyond the scope of this paper. Likewise, specific monitoring requirements of parturients with severe hypertensive or other specific disease states are not discussed. Anaesthesia and Intensive Care, Vol. 18. No. 3, August, 1990

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Analgesia in labour may alter the physiology of the mother, her fetus, and the function of the uteroplacental unit. Oxygen delivery to maternal vital organs and the fetus should not be compromised. Before any analgesia is administered in labour, the anaesthetist must be aware of the condition of the mother, her fetus, the stage and progress of the labour, and the intended mode of delivery. After administration, monitoring should continue to focus on the mother, the fetus and utero-placental function. MATERNAL MONITORING

General The mother's conscious and emotional state, respiration, pulse rate and rhythm, central and peripheral perfusion and level of pain should be monitored frequently. Pregnant patients receiving epidural analgesia should not be permitted to lie in the supine position without some form of uterine displacement. Aorto-caval compression is a significant hazard beyond twenty weeks' gestation, especially if there is any degree of sympathetic blockade.? No parturient who has received an epidural should ever be left unattended. 8 Pulse and Blood Pressure These parameters are measured because it is easy to do so and because changes in their values are usually reasonable indicators of cardiac output. Many studies have demonstrated that hypotension is the most common complication of epidural blockade (Table 1). The incidence will not be high if adequate assessment of the patient has been carried out, appropriate intravenous volume expansion is undertaken prior to administering the block, aortocaval compression is avoided and the epidural block performed carefully and extended slowly with small intermittent doses of local anaesthetic while monitoring the parturient appropriately. Monitoring for early hypotension is necessary not only to detect an extended epidural block, but also to identify an inadvertent subdural (SD) or TABLE

I

Complications of epidural analgesia in labour Complications

Percent of Epidurals

Hypotension* Failure Dural puncture IV placement IV injection Total spinal (subarachnoid) block

10 4 2 2 I 0.1

*(Systolic BP < 90 torr; or > 20% fall) (After Redick LF. Clinics in Perinatology 1982; 9: I :65.) Anaesthesia and Intensive Care, Vol. 18, No. 3, August, 1990

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subarachnoid (SA) block, early signs of which are changes in pulse rate and blood pressure (BP). There are few data available at present on the use of automated oscillometric sphygmomanometers in pregnancy in general, or in labour in particular, but they are used widely. It is known however, that these monitors may be inaccurate when BP is low or high.9 Diastolic BP assessment in obstetrics is common, and these monitors have some limitations with respect to diastolic BP measurement. Incorrect cuff size too is an important source of error in BP measurement. 9 Monitoring BP and pulse rate should be done between uterine contractions. During strong contractions systolic BP may increase by up to 25 mmHg and diastolic BP by up to 15 mmHg. to 'Significant hypotension' is an empirical term with no absolute numerical value, particularly as far as the fetus is concerned. 11 Hypotension must be regarded as 'significant' whenever signs of decreased perfusion of the placenta or maternal organs are seen. Such signs can be detected only by careful observation of the mother and her fetus. Intravascular injection Methods which may be used to detect impending local anaesthetic toxicity, due to intravascular injection of local anaesthetics are: 1. The aspiration test. 2. Injection of a test dose of local anaesthetic and monitoring for changes in conscious state, dysphasia, circumoral numbness or tingling, tinnitus, apprehension, drowsiness, increased uterine contraction pain and twitching. 3. Injection of a test dose of a 'marker', such as adrenaline (up to 15 micrograms), and then monitoring the mother for palpitations, anxiety, visual disturbances, increased pulse rate and/or BP or ECG changes. However, there are shortcomings with each of these tests, and the whole issue of monitoring for intravascular injection is highly controversial. 12•1? The use of adrenaline has been shown to be a good marker of intravascular placement in premedicated surgical patients when monitored with an ECG,18 and in the non beta-blocked patient, 15 micrograms (3 ml of 1 in 200,000 solution), will increase the heart rate by 30 bpm in about 30 seconds and will last for about one minute. In labour, however, a mother in pain, already with increased circulating catecholamines and a tachycardia, is unlikely to exhibit such a predictable response. 12 The response to intravenous adrenaline may be so transient that it requires a continuous monitor to detect it, and even then, the many false positives make interpretation difficult.

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The safety of adrenaline use must also be examined, even though it has been reported that epidural adrenaline maintains intervillous blood flow. 17 If injected intravenously, intervillous blood flow will decrease. 19 In sheep, this reduction in flow has been equated to that seen during strong uterine contractions. 20 Adrenaline also affects uterine contractility21 especially in large doses 22 ; this is considered significant in some circumstances. 13 It is not our practice to use adrenaline test doses routinely in labour. They are used however for anaesthesia blocks with maternal ECG, pulse and BP monitoring. Lignocaine 2% with adrenaline (1 in 200,000) is used in more than 95% epidural blocks for caesarean section in our unit, where such anaesthesia is always administered incrementally in the theatre with full maternal and frequent fetal heart monitoring. We believe that acute local anaesthetic toxicity reactions can be avoided by the fractional or incremental injection technique which was advocated by Covino and others long before the Albright report was published. 24 Each small dose should be regarded as a 'test' dose and clinically monitored accordingly. Aspiration should be performed. The use of up to 5 ml increments ofless concentrated solutions, e.g. bupivacaine 0.25%, may virtually eliminate acute toxic reactions. 12. 14 Subarachnoid (or Subdural) Injection Monitoring for inadvertent SA or SD block may be achieved by: 1. The aspiration test, whereby aspiration of the catheter or needle is performed looking for the presence of CSF, which is confirmed by glucose oxidase stick ('Dextrostix'@ or other) testing; 2. Injection of a test dose while monitoring for rapid sympathetic, sensory or motor block. The test dose technique has similar shortcomings to its use as a test for intravascular placement. Interpretation of the aspiration test may be difficult if liquid (saline or local anaesthetic solution) has been injected down the needle prior to catheter placement. To the experienced operator this is not a problem, but if doubt exists about the composition of the fluid returning, it should be tested for glucose, even though false positives and negatives may occur. Failure to detect subarachnoid placement also occurs. 1,25,26 The main limitation of the test dose is the variation in spread and onset time of some local anaesthetics, particularly isobaric bupivacaine. 27-31 For the initial test dose, 2-chloroprocaine (not available in Australia) is favoured by some American anaesthesiologists, while lignocaine

1.5%-2.0% with adrenaline is recommended by others. 28 Hyperbaric solutions of lignocaine probably have a more rapid onset of action than bupivacaine and more predictable spread, and have thus been recommended for test dosing in this contextp-31 Weak solutions, if used for the initial or test dose, are less likely to reliably detect SA or SD placement. This is most important when a subsequent larger dose is administered (e.g. for anaesthesia for operative delivery), which may result in the rapid onset of a high spinal block. 25 It has been argued however, that weak solutions are suitable as 'test' doses. 32 The test is positive for misplacement (e.g. intravascular, extravertebral) when analgesia does not develop, or develops weakly in only one or two segments. SD placement of needle or catheter is not detected by aspiration,24 nor by a lignocaine test dose. 33 The clinical signs of SD block - extensive sensory block, 'moderate' hypotension (SBP down to about 80 mmHg) and frequent Homer's syndrome - are gradual in onset and relatively rapid in recovery. Only ongoing vigilant clinical assessment and monitoring will detect SD placement. It should be remembered that the 'test dose controversy' is just that - a controversy. EVERY dose should be regarded as a test dose.",32, As top-up doses are sometimes given by midwives, proper training of staff and availability of resuscitation equipment and skilled personnel are of paramount importance.4-6 After some tragic deaths, the lack of ready availability of these resources has lead to the withdrawal of epidural services from some small British hospitals. 4 (A comprehensive discussion of this controversy by Chestnut32 was published last year and is strongly recommended.) Pulse oximetry There are insufficient data on the use of maternal pulse oximetry to recommend its general use in labour, whether or not an epidural is in use, but it is useful in specific cases and when systemic opioidl nitrous oxide analgesia is used. 34 FETAL MONITORING

The subject of fetal monitoring is well reported in recent obstetric anaesthesia texts l7 ,21 and in specific review papers. 35 ,36 The purpose of such monitoring is to detect fetal compromise at an early stage so as to allow corrective action to be taken so preventing death and morbidity. The most common types of monitoring in clinical use include:1. Recording of the fetal heart rate (FHR) by scalp clip ECG, external Doppler ultrasonography, or direct auscultation. Anaesthesia and IntensiYe Care, Vol. 18, No. 3, August, 1990

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2.

Assessment of fetal scalp blood acidlbase and Po 2 • 3. Noting the presence and extent of meconium in the liquor amnii. Other less common (experimental) techniques include: 1. Electroencephalography. 2. Continuous acidlbase, P02 and Peo2 analysis using fetal scalp electrodes. 3. Oxyhaemoglobin saturation (scalp pulse oximetry). The anaesthetist administering and supervising epidurals needs to be aware of the benefits and pitfalls of FHR monitoring. The role of continuous electronic FHR monitoring in the low-risk obstetric population is controversiaP6,37 and its exact place in monitoring parturients receiving epidurals has not been evaluated fully. Traditional interpretation of the FHR tracing has been based largely on specific patterns of bradycardia and tachycardia. Currently, increasingly greater emphasis is being placed on the presence or absence of FHR variability (FHR V) as a marker of fetal well-being. Scalp electrocardiography reflects FHRV best, as it measures the R-R interval between successive ECG complexes. Doppler ultrasound on the other hand measures cardiac pulse wave intervals and so is oversensitive to interference, especially where atrial and ventricular contraction is asynchronous. Modern monitors use auto-correlation to average out this asynchronism, but in doing so lose sensitivity in determining true FHRV.38 FHRY can also be influenced by a number of factors, including drugs (Table 2). Even uncomplicated epidural analgesics will alter FHRY. Lignocaine can decrease FHRy39 whereas 2-chloroprocaine does not. 40 The effects of bupivacaine are variable. 40 It remains to be proved whether FHR changes are more sensitive end-points for epidural monitoring than the maternal monitoring methods discussed in this paper. However, hypoxic (and other) FHR changes observed in humans have been recreated in sheep by reducing uteroplacental TABLE 2 Causes of decreased fetal heart rate variability*

1.

2. 3. 4. 5.

Maternal drugs (e.g. local anaesthetics, opioids, hypnotics). Fetal CNS lesions (e.g. anencephaly). Asphyxia (e.g. reduced uterine blood flow and P02)·

Fetal cardiac conduction defects. Vagal blockade (e.g. atropine, hyoscine).

*Modified from P. Boylan35 • Anaesthesia and Intensive Care, Vol. 18, No. 3, August, 1990

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blood flow - the most important factor in fetal oxygen delivery.41 Despite some doubts about the limitations of sensitivity and specificity of current FHR monitoring technology, many Level III obstetric units (including our own unit) use cardiotocographic (CTG) monitoring for all epidural patients. Most perinatologists, obstetricians and obstetric anaesthetists, at least in the U .S.A., use CTG monitoring when known risk factors are present. 32 In at-risk cases it is preferable for the status of the fetus to be determined before an epidural is commenced. Continuous CTG monitoring will frequently provide this information, supplemented where necessary, by a fetal scalp pH and/or P0 2 measurement. Ideally then, in at-risk cases, and perhaps in all cases, the CTG should be reviewed before the epidural is administered, and any doubts discussed with the obstetrician. 42 If CTG facilities are unavailable, the fetal heart rate should be checked by other means. Auscultation every five minutes, either with a Pinard or Doppler stethoscope, for twenty minutes after each dose of local anaesthetic, and thereafter every fifteen minutes during labour is a reasonable routine. 42 On a more positive note, placental blood flow may improve after an epidural. This may be seen on the CTG and confirmed by Doppler ultrasonography.43,44 UTERINE MONITORING (ToeOGRAPHY)

As the fetal heart and nervous system are usually more sensitive to the effects of drugs or to subtle changes in maternal cardiorespiratory physiology, the uterine monitor is of less value to the anaesthetist than the FHR record, but in some instances it may detect unwanted drug or other effects. Changes in tone after intravenous local anaesthetic, adrenaline or other drug administration can be detected. 21,22 Alterations in uteroplacental blood flow secondary to aorto-caval compression or sympathetic blockade may alter uterine activity. Tocographic monitoring is most commonly performed by the use of an external pressure transducer. This of course gives no information about the intrauterine pressure, but provides comparative quantitative information about the frequency, amplitude and duration of contractions. As the tocogram is recorded continuously with the FHR (the CTG), the two recordings are considered together, so increasing the usefulness of the FHR tracing.

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Some units use intrauterine catheters (connected to a pressure transducer) to measure intrauterine pressure directly. Pressures > 2500 kilopascals/15 minutes can be tolerated by an uncompromised term fetus. 45 ACKNOWLEDGEMENT

The authors gratefully acknowledge the assistance of our Departmental Secretary, Mrs. P. L. Thorn. REFERENCES

1. Crawford JS. Some maternal complications of epidural analgesia for labour. Anaesthesia 1985; 40:1219-1225. 2. Hellman K. Epidural anaesthesia in obstetrics. A second look at 26,127 cases. Can Anaes Soc J 1965; 12,4:398. 3. Ontario Perinatal Mortality Study Committee, Canadian Dept of Health Second Report 1967; Tables 108-124. 4. Anaesthetic Services for Obstetrics - A plan for the future. Report of a working party of the Obstetric Anaesthetists' Association and the Association of Anaesthetists of Great Britain, October 1987. (Published by the Association, London.) 5. Joint Statement on the Optimal Goals for Anesthesia Care in Obstetrics - by the American College of Obstetricians and Gynecologists and the American Society of Anesthesiologists. ACOG Newsletter; September 1988; 9-11. 6. Report on Confidential Enquiries into Maternal Deaths in England and Wales 1982-84. HMSO, London 1989: 136. 7. Bassell GM, Marx GF. Anesthesia-Related Mortality. In: Shnider SM and Levinson G: Anesthesia for Obstetrics, 2nd Ed. Williams and Wilkins, Baltimore 1987, p. 330. 8. Naulty JS, Ostheimer GW. Monitoring in obstetric anaesthesia. In: Blitt CD ed. Monitoring in Anaesthesia and Critical Care Medicine, Churchill Livingstone 1985: Ch 26. 9. Rutten AL, Ilsley AH, Skowronski GA, Runciman WB. An evaluation of mean arterial blood pressure by automatic oscillometers, arterial cannulation and auscultation. A comparative study. Anaesth Intens Care 1986; 14:58-65. 10. Bonica JJ. Obstetric Analgesia and Anesthesia. World Federation of the the Societies of Anaesthesiologists, Amsterdam 1980; p 7. 11. Crowhurst JA. Comment - Obstetric Anesthesia Digest 1990; 9, 4:208. 12. Abouleish E, Bourke D. Concerning the use and abuse of test doses for epidural anesthesia. Anesthesiology 1984; 61 :344. 13. Marx GF. Cardiotoxicity of local anesthetics, the plot thickens. Anesthesiology 1984; 60: 1, 3-5. 14. Ostheimer GW. Manual of Obstetric Anesthesia. Churchill Livingstone 1984; 6: 184. 15. Moir DD. Local anaesthetic techniques in obstetrics. Br J Anaesth 1986; 58:747-759.

16. Moore DC. Local anesthetic toxicity IV-Management. In: Ostheimer GW ed. Clinics in Anaesthesiology, WB Saunders 1986; 4:1. 17. Albright GA. Anesthesia in Obstetrics. 2nd ed. Butterworths 1986; 297. 18. Moore DC, Batra MS: The components of an effective test dose prior to epidural block. Anesthesiology 1981; 55:693-696. 19. Albright GA, Jouppila R, Hollmen AL, Jouppila P, Vierola H, Kiorula A. Epinephrine and human intervillous blood flow during epidural anesthesia. Anesthesiology 1981; 54:131-135. 20. Hood DD, Dewan DM, Rose JC, James FM Ill. Maternal and fetal effects of intravenous epinephrine containing solutions in gravid ewes. Anesthesiology 1983; 59, A393. 21. Levinson G, Shnider SM. Anesthesia for Obstetrics 2nd Ed. Williams and Wilkins, Baltimore 1987; 76. 22. Matadial L, Cibils LA. The effect of epidural anesthesia on uterine activity and blood pressure. Am J Obstet Gynecol 1976; 125:846-854. 23. Gunther RE, Bauman J. Obstetrical caudal anaesthesia 11. A randomized study comparing 1% mepivacaine plus epinephrine. Anesthesiology 1972; 37:288-298. 24. Albright GA. Clinical aspects of bupivacaine toxicity. Report to the Anesthetic and Life Support Drugs Advisory Committee, U.S. Dept of Health and Human Services 1983 - as reported in: Anesthesia for Obstetrics. Albright GA ed, 2nd Ed. Butterworths 1986. 25. Brownridge P. Another misplaced catheter. Anaesth Intens Care 1984; 12:369-371. 26. Carr MF, Hehre FW. Complications of continuous lumbar epidural anesthesia: Inadvertent lumbar puncture. Anesth Analg 1962; 41:349-353. 27. Stonham J, Moss P. The optimal test dose for epidural anaesthesia. Anesthesiology 1983; 58:389-390. 28. Casey WF. Epidural test doses in obstetrics. Anaesthesia 1985; 40:597. 29. Mallaiah S. Epidural test dose. Anaesthesia 1986; 41:334. 30. Russell IF. Inadvertent total spinal for caesarean section. Anaesthesia 1985; 40: 199. 31. Abraham RA, Hams AP, Maxwell LG, Kaplow S. The efficacy of 1.5% lidocaine with 7.5% dextrose and epinephrine as an epidural test dose for obstetrics. Anesthesiology 1986; 64:116-119. 32. Chestnut DH. Obstetric Anesthesia - The state of the art. Audiodigest Anesthesiology 1989; 31: 12. 33. Crosby ET and Halpern S. Failure of a Lidocaine Test Dose to identify Subdural Placement of an Epidural Catheter. Can Anaes Soc J 1989; 36:445-447. 34. Zelcer J, Owers H, Paull JD. A controlled oximetric evaluation of inhalational, opioid and epidural analgesia in labour. Anaesth Intens Care 1989; 17:418-421. 35. Boylan P. Intrapartum Fetal Monitoring. Clin Obstet Gynaecol 1987; 1:73-95. 36. Grant A. Monitoring the fetus during labour. In: Effective Care in Pregnancy and Childbirth. Anaesthesia and Intensive Care, Vol. 18, No. 3, August, 1990

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Chalmers I, Enkin M, Keirse MJNC eds; Oxford University Press 1989; 11:846-882. Editorial. Cerebral palsy, Intrapartum care and a shot in the foot. Lancet 1989; ii:125l-l252. Spencer JAD. Fetal Heart Rate Variability. In: Progress in Obstetrics and Gynaecology. Studd J. Churchill Livingstone, London 1989; 7: I 03-122. Boehm FH, WoodruffLF, Growdan JH. The effect of lumbar epidural anaesthesia on fetal heart rate baseline variability. Anesth and Analg 1975; 54:779-782. Lavin JP, Samuels SV, Miodovnik M et al. The effects of bupivacaine and chloroprocaine as local anaesthetics for epidural anesthesia on fetal heart rate monitoring parameters. Am J Obstet Gynecol 1981; 141:717-722. Itskovitz J, Goetzman BW, Rudloph AM. The mechanisms of late decelaration of the fetal heart

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rate and its relationship to oxygenation in normoxic and chronically hypoxic fetal lambs. Am J Obstet Gynecol 1982; 141:66-73. Guidelines for Perinatal Care. American Academy ofPediatrics and American College of Obstetricians and Gynecologists 2nd Ed, 1988; 63-68. Joupilla P et al. Lumbar epidural analgesia to improve intervillous blood flow during labor in severe preeciampsia. Obstet Gynecol1982; 59: 158. Giles WB, Lah FX, Trudinger BJ. The effect of epidural anaesthesia for C-section on maternal uterine and fetal umbilical artery blood flow velocity waveforms. Br J Obstet Gynaecol 1987; 94:55-59. Gibb DMF, Arulkumaran S. Uterine contractions and the fetus. In: Progress in Obstetrics and Gynaecology. Studd J, ed. Churchill Livingstone, London 1987; 7:133-153.

The Place of Caudal Anaesthesia in Obstetrics J. D. PAULL* Department of Anaesthesia, The Royal Women's Hospital, l'..felbourne, Victoria SUMMARY

Present day trainee anaesthetists could be forgiven if they finished their anaesthetic training believing that caudal anaesthesia in obstetrics is not only unnecessary, but dangerous and a relic of the past. Many anaesthetic texts teach applications and techniques which are little or no advance on the teachings of Hingson and Edwards in 1942 and reflect nothing of the true value and application of this valuable block. This paper presents a critical review ofthese texts and ofthe results ofthe use ofthe block in a busy obstetric unit.

Key Words: ANAESTHETIC, ANESTHETIC TECHNIQUES; caudal, epidural, blockade, obstetrics, pain relief; COMPLICATIONS; caudal, epidural anaesthesia.

A review of seven anaesthetic textbooks dealing principally with obstetric anaesthesia or with regional blockade reveals a range of advice about caudal anaesthesia. At one extreme is Shnider and Levinson's book, 'Anesthesia for Obstetrics', which has four entries for caudal anaesthesia in its index of over 3100 entries, viz 'Caudal anesthesia: complications, contraindications, for toxaemic patients, techniques.!' By contrast, 'Neural Blockade in Clinical Anesthesia and Management of Pain', by Cousins and Bridenbaugh contains 27 references to caudal anaesthesia in its index. 2 *F.F.A.R.A.C.S., Dip.Ed., Director of Anaesthesia. Address for Reprints: Dr. John D. Paull, Department of Anaesthetics, The Royal Women's Hospital, 132 GrattaD Street, Carlton, Victoria, 3053, Australia Accepted for publication January 12, 1990 Anaesthesia and Intensive Care. Vo/. 18. No. 3. August. 1990

While it may seem trite to assess a book by the number of entries for a topic in its index, in practice this parameter does give an indication of the coverage of the topic. In turn this gives a clear message to the reader about the author's opinion of the importance of the subject. Shnider and Levinson clearly do not see as much value in caudal blockade as do Cousins and Bridenbaugh. A review of the anaesthetic literature of the past decade reveals only two articles and a brief flurry of letters about caudal anaesthesia in obstetrics. 3-5 These deal with potential complications of the technique. CuRRENT BELIEFS Information derived from a number of anaesthetic trainees passing through a rotational training program suggests that caudal anaesthesia