CAUDAL ANAESTHESIA WITH BUPIVACAINE (MARCAINE FOR ANAL SURGERY: A CLINICAL TRIAL*

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1 CAUDAL ANAESTHESIA WITH BUPIVACAINE (MARCAINE FOR ANAL SURGERY: A CLINICAL TRIAL* EmKA ROCHOWANSKI, M.D., ROBERT D. KREISER, M.D., AND LUCIEN E. Moams, ]~$.D. THE RECENTLY INTRODUCED LOCAL ANAESTHETIC bupivacaine (Marcaine 1-nbutyl-DL-piperidine-2-earboxylie acid-2,6 dimethylanilide hydrochloride) is the first long-acting drug in which duration is not aecompanied by a closely proportional increase in toxicity. Chemieally related to mepivaeaine (Carboeaine bupivaeaine is about four times as toxic per mgm as mepivaeaine, but is used in one-fourth the concentration. Its potency/toxicity ratio is the same, but bupivacaine has a considerably longer action and lower cumulative and infusion toxicity, relatively to mepivacaine, and absolutely to tetracaine. 1-3 MATERIALS AND METHODS In a clinical trial bupivacaine was employed for caudal anaesthesia in anorectal surgical procedures (Table I) which are known to cause extreme discomfort during the first post-operative hours. The study was conducted in sequential groups of 83 patients (60 male, 23 female), the youngest being 18 years of age, the oldest 84 years (Table II). The average weight of the males was 78.4 kg (range kg), and of the females 57.2 kg (range kg). Thirteen of these patients had coincidental diagnoses suflqcient to warrant classification as physical state 3; six of these were serious cardiovascular problems. The first 30 patients - all male - were premedicated with various combinations of atropine, barbiturate, pethidine, and antihistamine. In this group minimal amounts of thiopentone were administered in 12 instances for intraoperative sedation at the patient's request to be asleep. The other group of 53 patients (30 males, 23 females) were premedicated with scopolamine and promethazine (Phenergan Intraoperatively 42 of these were further sedated with intravenous pentazocine, mgm (Talwin and/or thiopentone in amounts only sufficient to make the patient conversationally dull. The agent was employed in two concentrations without the use of any vasoconstrictor. The practice of adding a vasoconstrictor, although it lessens absorption, appears to increase the incidence of cardiovascular changes. 4 The increased acidity of solutions with epinephrine (ph 3.5) may contribute to some delay in onset of the block effect. *This study was supported in part by Winthrop Laboratories. tanesthesia Research Laboratories, Providence Hospital, Seattle, Washington, U.S.A. and Department of Anaesthesia, University of Toronto, St. Michael's Hospital Unit, Toronto, Canada. Canad. Anaesth. Soc. J., vol. 18, no. 1, January

2 ROCHOWANSKI et al.: CAUDAL ANAESTHESIA WITH BUPIVACAINE 19 The caudal block was performed with the patient in prone position, using a 9.1- or 22-gauge needle (1.5 inches long). Then the patient remained either prone, or was turned into lithotomy position, according to surgical preference. Procedures TABLE I No. of cases Haemorrhoidectomies 49 Anorectoplasties 19 Other 15 Total 83 TABLE II AGE DISTRIBUTION Age Males Females Total TABLE III VOLUME AND CONCENTRATION OF BUPIVACAINE Bupivacaine No. of Average Range (per cent) patients dose in ml in ml Evaluation of the effectiveness of anaesthesia First onset of anaesthesia. The time at which contraction of the anal sphincter was no longer reflexly produced following stroking of the perianal skin with a needle. Fully effective anaesthesia. This stage was considered reached when there was no complaint of pain in the surgical area. Regression of anaesthesia. Was taken as subjective information when the patient felt a decrease in numbness. Recurrence oj complete sensation. Time at which spontaneous discomfort was felt, numbness was absent, and/or total skin sensation had returned. Investigations carried out Vital signs were observed continuously throughout the operation and then at intervals during recovery. The first 30 patients were investigated for possible consequential changes in

3 20 CANADIAN ANAESTHETISTS' SOCIETY JOURNAL the complete blood count, prothrombin time, urinalysis, and for occurrence of methaemoglobin. For this purpose blood and urine specimens were taken before surgery and 24 hours postoperatively. The relative freedom from post-operative discomfort noted in the first group of patients prompted further evaluation. Analgesic medication requirements within the first 24 hours postoperatively was, therefore, recorded in 47 patients, Time of the first spontaneous mieturition and incidence of catheterization were noted. RESULTS AND DISCUSSION Caudal anaesthesia was produced to a level of x-10, usually T-12 to L-1. In most instances there was a decrease in muscle power for about 1-9. hours. The evaluation of the quality of block produced is listed in Table IV. Unsatisfactory results were uniformly caused by anatomical difficulty of landmarks poorly defined or obscured. There was one complete failure. In one case there was spotty analgesia in the anal region, despite good muscle relaxation. The other three instances showed a markedly delayed onset of anaesthesia. Anaesthesia was considered satisfactory when analgesia was present, and the procedure could be performed with minimal intravenous sedation (patient still talking). Results from the two concentrations of bupivacaine are listed in Table V according to duration of effect in the 78 patients with excellent or satisfactory block. TABLE IV QUALITY OF BLOCK Males Females Total Excellent Satisfactory Unsatisfactory TABLE V LATENCY AND DURATION OF BUPIVACAINE BLOCKS IN 78 PATIENTS WITH EXCELLENT OR SATISFACTORY BLOCK Bupivacaine 0.25 per cent 0.50 per cent Time n mean SD n mean SD First onset (minutes) Full effect (minutes) Regression (hours) Complete sensation (hours) n = number of patients so = standard deviation of the mean

4 ROCIIOWANSKI ei~ al.: CAUDAL ANAESTHESIA WITH BUPIVACAINE 2]. The durations are comparable to those found by other authors, 5-7 although in their studies vasoconstrictors were used with the local anaesthetic. Variation in premedieation did not influence the results. Analgesia remained longest in the perianal region. It was interesting to note the prolonged pain relief in the presence of full skin sensation, an observation made previously. ~.:' All laboratory determinations carried out before, during, and after anaesthesia were within normal limits. There were few side effects of note (Table VI). Blood pressure and pulse were stable except for two brief instances of hypotension, one requiring ephedrine, which occurred after the block had just been established. One ease of nausea, vomiting, and diarrhoea (starting 3 hours postoperatively and lasting about 3 hours, with nausea up to 15 hours) was believed to be unrelated to the anaesthetic. None of the other occurrences can be definitely attributed to the anaesthetic. Haemorrhoidectomy is notorious for requiring postoperative analgesia. In the patients studied the need for analgesics was limited. Some requested none at all (7 out of 47 patients); the rest were given pain medication after a mean time of 10.4 z 0.39 SO hours. It can be postulated that the duration of this local anaesthetic is suffcient to extend beyond the time at which muscle spasm frequently occurs, thus reducing the need for analgesics. Those patients who had had previous experience with surgery in the rectal area were uniformly surprised at the extended comfort of this block, and found it preferable to a general anaesthetic. TABLE VI SIDE EFFECTS SUBSEQUENT TO BUPIVACAINE CAUDAL BLOCKS Hypotension 2 Nausea 3 Vomiting 2 Headache :3 Chills 2 In S patients 12 With such a long-lasting anaesthetic effect, one wonders about urine retention. There appears to have been no greater difficulty following anaesthesia with this agent than is usual after operations in this area. Spontaneous micturition was usually possible without difficulty, and often occurred at a time of existing perianal anaesthesia. Catheterization was done in 7 patients, two of whom had bladder distension. Time of catheterization was between 11 and 22 hours after the local block had been produced, and at a point when the anaesthetic effect had fully disappeared. SUMMARY The local anaesthetic bupivacaine (Marcaine was investigated for its usefulness in caudal anaesthesia for anorectat surgery in 83 patients. Concentrations of 0.25 per cent bupivacaine (average 23.7 ml) were effective for

5 22 CANADIAN" ANAESTHETISTS' SOCIETY ~OURNAL hours; concentrations of 0.5 per cent (average 21.6 ml) were effective for hours. Postoperative analgesics were given only after 10 hours. There were no major side effects. Therefore, bupivacaine appears to be a useful anaesthetic for caudal block in cases where long-lasting analgesic may be advantageous. R~SUM~ On a 6tudi6 l'aneth~sique local bupivacaine quant ~t son utilit6 en anesth6sie caudale pour la chirurgie anorectale chez 83 malades. Des concentrations de 0.25 pour cent de bupivacaine (rnoyenne 23.7 co) ont 6t6 efl]caces durant heures; des concentrations de 0.5 pour cent (moyerme 21.6 co) ont 6t6 efl~caces durant heures. En p~riode post-op~ratoires on n'a administr6 des analg6siques que dix heures apr~s l'op6ration. I1 n'y a pas eu d'effets seeondaires importants. Par cons6quent, la bupivacaine semble &re un anesth6sique utile pour bloc caudal lorsqu'une analgesic prolong6e peut 8tre avantageuse. REFERENCES l. HENN, F & BRATTSAND, R. Some Pharmacological and Toxicological Properties of a New Long-Acting Local Analgesic, LAC-43 (Marcaine@), in Comparison with Mepivacaine and Tetracaine. Acta Anaesth. Scandinav., Supp. xxl, 9-30 (1966). 2. E*r~LOM, L. & WIDMAN, B. A Comparison of the Properties of LAC-43, Prilocaine and Mepivaeaine and Extradural Anaesthesia. Acta Anaesth. Scandinav., Supp. xxi, (1966). 3. JOBFELDT, L.; LOFSTROM, B.; PERNOW, B.; PERSSON, B.; WAHBEN, J.; WmMAN, B. The Effect of Local Anaesthetics on the Central Circulation and Respiration in Man and Dog. Acta Anaesth. Scandinav., 12: (1968). 4. NORUQVlST, P. & DHUN~R, K.G. Influence of Local Anaesthetics with Vasoconstrictors upon Circulation and Metabolism. Acta Anaesth. Scandinav. 5:63-71 (1961). 5. HEXaBnINC, B. G. A Comparative Study of LAC-43, Mepivacaine, and Tetracaine in Caudal Anaesthesia. Acta Anaesth. Scandinav. Supp. xxi, (1966). 6. DHUN~.n, K. G. Clinical Experience with Marcaine (LAC-43), A New Local Anaesthetic. Acta Anaesth. Scandinav. Supp. xxm, (1966). 7. KvAH, K. B. & YATES, M.J. Bupivacaine Caudal Analgesia in Labour. A Clinical Trial. ]. Obstet. Gynaec. Brit. Cwlth., 75: (1968). 8. B~oMncE, R. A Comparison of Bupivacaine and Tetracaine in Epldural Analgesia for Surgery. Can. Anaesth. Soc. J. 16:37-45 (1969). 9. STEEL, G. C. & MASSEY DAWKINS, C. J. Extradural Lumbar Block with Bupivaeaine (Marcaine: LAe-43). A Clinical Trial in Lower Abdominal and Perineal Surgery. Anaesthesia, 23:14-19 ( 1968 ).