Epidural and nerve block anaesthesia with sympocaine

MAx S. S~.DOVE 0 1 M 0 1 D. 0 1 ANTItONY] 0 1 . MELGRaVE 0 1 M.B. 0 1 B.S. 0 1 MYRON J. LEVIN 0 1 M.I). 0 1 Authority Moore Dodd 0 1 0 Can Anaes Soc J , vol 5, no 1, January, 1958 1 1Presented at the Annual Meeting, Canacllan Anaesthetists' Socmty , Saskatoon, Saskatchewan, June 24-26 , 1957. 2CoUege of Medicine, Dlvismn of Anesthesm, University of Illinois: , Chicago 12, Illinois , and Department of Anesthesia, Hines Veterans Admmtstration Hospital , Hines, Illinois No KNOWN LOCAL m'eaESTr~.~C AGENT can be said to be ideal, but we have at hand a number of reliable ageats which under average clinical conditions give adequate anaesthesia with a snflqcient degree of safety. The pharmaceutical houses continue to present us v0ith new substances in the hope that the nebulous ideal may be more nearly approached. A number of 2-alkoxy derivatives of procaine have been synthesized and investigated in animals. One of these is the 2-butoxy derivative first synthesized by Clinton and Salvador (1). Its structure t,. - ~/,---OCH~CH2CH2CH3 [ /C2H6 COOCH.~-CH~--N~ \C~H~ Maximum dose 80 ec. of 0.25% or 200 mg. 50 ee. of 0.1% or 50 mg. 800 ce. of 0.1% or 300 mg, 2 reg./lb, body wt, or 800 nag Nerve block Infiltration Body wt (lb) CANADIAN ANAESTHETISTS' SOCIETY JOURNAL In view of the suggested maximum dose of 15 rng., ~Le mitial concentration used was 0 1 per cent Th~s proved to be madequate and so the concentration was increased until, by trial and error, the minimum effective eoneentratmn of 0.5 per cent was &seovered Sympocame was then used without the additmn of epinephrine, which would mask the charaetenstms of the drug The patmnts were selected at random from the surgmal lists and the appropriate block performed with the new agent An earher report on the use of Sympocame m 100 caudal anaesthesias gave an average dose of 109 mg and an average duration of 2 hours (7). Body weight was plotted against duration of anaesthesia f ~ 30 brachlal blocks using 150 mg doses No relahonstnp could be defined Dose was plotted against durat-ton m 80 cases of caudal, sacral and epidural blocks m two age groups 25-40 and 55-70. No relataonship could be defined between dose and duration, nor could the age groups be separately defined. Age was plotted agamst durabon at 100 mg dose level for 32 males using caudal block. No relataonslnp could be defined COMPLICATIONS Duration (hr.,) SADOVE et al.. E P I D U R A L & NERVE BLOCK 3r (c) In the epidural group, one failure was probably due to poor technique and another was a partial failure Two further failures occurred after an adequate dose of the drug and were suggestive of drug failure. ( d ) There were two incomplete brachial blocks in which the cause for failure was uncertain. technique ( e ) One sciatic-femoral block faded and this was almost certainly due to poor (f) In the maseellaneous group, one sciatic block failed due to poor technique Possilale Evidence of Toxicity ( a ) In the caudal group, there was one case each of: (i) generalized pilomotor response, (fi) generalized flush for one mmute, (11i) drowsiness for ten minutes, T A B L E Id DE rAILED LIST OF HYPOTENSIONS Haemorrho Ld ~V P -- Vasopressor given with satisfactory results 198 Haemorrhou:l 120 Haemorrhold I H 161 Pdonldal cyst 116 G a s t r o s t o m y 150 Proctoscopy polyp removal EPIDURALS CAN~DL~N ~ a ' ~ m ' r m T s " socm-rY ][otrmo,r~ Hypotension occurred in 18 cases among the epidural-type blocks: 10 epidurals (25 per cent); 7 caudals (4 0 per cent); and I sacral (3.7 per cent). Hypotension did not appear in the other groups of blocks. From Table II it can be seen that the cause of hypotension in these groups was more ]J~kelyrelated to the form of block and consequent loss of sympathetic vasomotor control. Evidence of Irritation Transient stinging or burning on injection occurred in the groups of blocks other than the epidtu-al type; these latter had skin whea~[s of procaine. In the brachial block group, 37 out of 98 patients had these, a high incidence of about 38 per cent. No evidence has appeared suggestive of any more serious form of irritation in the skin or deeper tissues. The preservative in the solution contains among other things 1:600 phenol and this w i l l b e modified ff the drug is marketed, This technique was used largely for rectal and permeal surgery. The chief dose groups were 50-75 rag. (39 cases); 76--100 rag. (65 cases) and 101-125 mg. ( 31 cases ). The common doses were 15 cc. (75 rag. ) or 20 co. ( 100 mg. ). On occasion, even these doses may give a higher leve_ than de,~red, as can be seen from the examples in Table III T A B L E i i i EXAMPLES OF EXCESSIVE SPREAD Age Sex 47 Comment~ Altogether, twenty-two ( 12 5 per cent) of the levels were too high; five (3 per cent) of these were excessively tngh, but only two could be related to generosity in dosage It must be kept in mind that there is considerable variability in the anatomy of the region, in particular the volume, which can vary from 12 to 65 ee. (8). Test doses of 5 ec. were used routinely and these were then followed by the main dose of a size thought to be adequate. Despite the evidence of toxicity in animalS it seems fairly certmin that, when used for the variety of blocks already mentioned, a dose of 1 mg./Ib, is a safe dose of Sympocaine, and that th~ dose is not the maximal. The complications in the doses used appear to have been very few. The hypotensive episodes are almost certainly referable to the form of block (lumbar and caudal epidural), while evid4fice of systemic toxicity was chiefly seen as drowsiness in five patients (1.25 per cent). The only disturbing phenomenon was the high occurrence of irritation ~on intradermal injection, but this is very likely to be due to the phenol preservative contained in the solution. The onset of anaesthesia with the agent is fast (4-5 migutes), and this is most in evidence in direct nerve blocks, for example, of the braehial plexus. However, with epidural blocks adequate conditions for surgery may not be present until fifteen minutes after injection. The duration is ap 3roximately two hours, with a variation between one and a half and two and a haL"hours. Many more blocks than those discussed here have been performed. The group of cases mentioned are typical of the general impression which has been so good that Sympoeaine is now our routine agent for nerve blocks. In all 413 patients were anaesthetized with Sym-~ocaine 0.5 per cent without epinephrine. Most (175) of the blocks were cauda_ epidurals with a f t u ~ e r 28 sacral and 41 thoraco-lumbar epidural anaesthetics. Possible toxic reactions were observed in 10 patients (2.5 per cent). Hypotension was noted in epidural type anaesthesia and was almost certainly related to the form of bloc'k. Temporary irritation occurred on intradermaI injection in more than one-third of skin wheals, but thi~ is considered to occur because the experimental solution contains 1:600 (...truncated)