ANESTHESIA (1) (Lidocaine allergy) Diphenhydramine substitution (2) EMLA (3) Should epinephrine be used in acral anesthesia? ------------------------------------------------------ ---------------------------- DIPHENHYDRAMINE SUBSTITUTION ---------------------------- For a patient with a history of allergy to local anesthetics, I would like to do a biopsy and D&C under local anesthesia with Benadryl, but have forgotten the proper concentration. I will dilute the Benadryl IV solution, which comes 50 mg/ml, with water. Please advise how much to dilute it. Neither the patient nor I want to go through allergy testing with lidocaine or to do the procedure with cryoanesthesia or hypnosis! Yelva Lynfield, MD ------------------ There was a great review on local anesthetics in the June 1996 issue of Dermatologic Surgery. Most studies have used 1% diphenhydramine. Diphenhydramine is supplied as a 5%(50mg/ml) solution and can be diluted with bacteriostatic saline. I have used it full strength a few times without complications although there have been reported cases of tissue necrosis using 5% strength. Robert Bader ------------ I find that most patients who say they are allergic really are not. They may have a history of sensitivity to epinephrine or they may have experienced a vasovagal reaction to the stress of a past procedure. We commonly do a simple scratch test to the local anesthetic and sometimes a little intradermal. We have never had a problem. I would only be cautious if there was a documented history of an anaphylactic reaction or urticarial reaction in the past. Robert M. Peppercorn, M.D. -------------------------- One can also inject sterile saline to raise a bleb with good anaesthesia for superficial surgery. By the way has anyone documented true allergy to xylocaine? Gary Salenger ------------- I have used the Benadryl Steri-Vials (10 mgm/cc) and injected the lesion with 1/2 cc or so intradermally. There seems to be a "pressure effect" and subcutaneous injection doesn't seem to work. Philip Hughes, M.D. ------------------- If you are going to use normal saline for local anesthesia- make sure it is PRESERVED Saline- i.e. that it contains benzyl alcohol 0.9%. If you use "preservative free" normal saline you will not get an anesthetic effect. Another advantage to saline is that when it is injected in the skin it is completely PAINLESS (except for the needle stick). I use saline alot- I have used it for shaves and superficial D&Cs. You cannot rely on it, however, when you get down to fat- so it's not good for punches and excisions- unless you're using it to decrease the pain of a lidocaine injection. Mark D. Kaufmann, M.D. ---------------------- I agree completely. This is what I prefer for children...they appreciate it much more than lidocaine, even with added bicarbonate. The benzyl alcohol has anesthetic properties (in addition to pressure effect, of course) and is available in topical form as an over the counter product for bug bites (Rhuli-Gel, which incidentally works well on chicken pox because it stops the itch and is non-occlusive). Edward Zabawski, Do, R.Ph. -------------------------- ---- EMLA ---- EMLA is potentially another alternative, either by itself or preceding another agent. According to an article in the September JAAD (1), EMLA alone, applied 2 to 3 hours prior to either excisional surgery or D & C's, was effective in 87% of patients, although supplemental anesthesia was sometimes needed. For shave biopsies, EMLA alone is usually effective. In my limited experience, EMLA is sometimes effective for deeper biopsies, even for those that require sutures. I would speculate that EMLA plus intradermal saline might be additionally efficacious. 1. Gupta AK and Sibbald RG. Eutectic lidocaine/prilocaine 5% cream and patch may provide satisfactory analgesia for excisional biopsy or curettage with electrosurgery of cutaneous lesions. A randomized, controlled, parallel group study. J Am Acad Dermatol 1996; 35:419-23. Stephen L. Comite, MD --------------------- From what I have observed, the Tegaderm mushes the emla peripherally. so the area you wanted covered quickly becomes uncovered by the cream, with only the tegaderm remaining. There are new patches out now or soon which will hopefully make the mound history. Where it is glopped now you can certainly see the vasoconstriction (or the erythema when someone is sensitive to it!). Diane Thaler ------------ In my experience the neatest and best way to use EMLA is: 1. scrub the skin to get off oils, etc 2. THIS IS IMPORTANT: Soak some gauze with EMLA and apply THAT to the area to be treated. The gauze keeps the EMLA where you want it, and keeps it evenly distributed. 3. Cover the gauze / EMLA with Tegaderm or whatever. No muss, no fuss! In a coule of hours the treated area is FROZEN. Kevin C. Smith MD FRCPC ----------------------- I think part of the thickness issue has to do with its melting point. It tends to melt at body temp into a liquid that does not stay on as well or perhaps loses some of its efficacy. Bill Liss I know it doesn't make sense, but a thick layer (several millimeters thick) occluded with Saran wrap is necessary for it to work. Patients never put it on thick enough. During pulsed dye laser surgery, if the patient complains, I will wipe the area with 70% isopropyl alcohol, apply a thick layer of EMLA, cover with Saran wrap and always get good analgesia, sometimes after 10 minutes (the alcohol cleansing enhances penetration). You can tell if it's working by the pallor it produces. Philip Hughes, M.D. ------------------- I think a thick layer of EMLA is needed so you can maintain a high partition coefficient (remember that from pre-med?) between the skin and the cream. If you only put on a thin layer there won't be enough of a concentration gradient to drive an adequate amount of the stuff into the skin faster than it gets washed away by the microcirculation. Once again, I'll point out that soaking EMLA into some gauze before applying it makes it a lot neater and easier to maintain a large quantity of EMLA in the desired location. Kevin C. Smith MD FRCPC ----------------------- It really seems to be needed. The only explanation I can figure is that the EMLA must have such a quick flux through the skin that a BIG reservoir is needed. Guy Webster ---------------- ----------------------------------------------- SHOULD EPINEPHRINE BE USED IN ACRAL ANESTHESIA? ----------------------------------------------- I am wondering what is the incidence of epinephrine induced digital ischemic necrosis from local anesthetic? I remember being taught to use plain Lidocaine on acral skin for this very reason, but does anyone know the number of cases of necrosis per 100,000 uses of Lidocaine with epinephrine on digits? In the absense of risk factors such as history of autoimmune diseases, atherosclerotic disease, Raynaud's, etc. what percent of dermatologists use only plain Lidocaine on acral sites? I will be brave enough to admit that I do use Lidocaine with epinephrine in otherwise young and healthy individuals with none of the above risk factors and I have never seen any problems. Anyone else? The friend of a friend would like you to comment. By the way, everyone might not know that this problem can be reversed using 0.5% phentolamine locally injected (Arch Fam Med 1994 Feb;3(2):193-5 Phentolamine reversal of epinephrine-induced digital vasospasm). Walter H. Wood, M.D. -------------------- Walter - thanks for reminding us about phentolamine for vasospasm after epinephrine injection. I hardly ever use plain lidoocaine, unless the patient is very old, had Raynaynaud's, or terrible circulation. I use it so seldom the bottle now in my office may have expired. I'll have to look and see. Kevin C. Smith MD FRCPC -------------------- Did we have a discussion here some months ago about this? And that epi was ok acrally? If it wasn't here, then I had the discussion with some EM folks. In that case, the ok is in the literature somewhere-possible in Emergency Medicine. I'll report back. Diane Thaler -------------------- I hate to admit this but I use lidocaine with epi all the time on fingers and toes as well as ears in spite of what I learned in training. I have never even had a close call with acral necrosis. I have done this since 1980! Maybe the lesson is that lawyers will use the information in the books against you even when all the evidence of experience goes counter to it. Pat Condry -------------- In 23 years I have used lidocaine with epinephrine in untold thousands of distal digits, noses and the penises with no problem whatsoever. I read an article somewhere many years ago that it is a myth about avoiding epinephrine in those sites. When I was a resident, I was told, in fact (I will ask the European members if this is true), that lidocaine was not even available in Scandinavian countries without epinephrine because of greater systemic toxicity without epinephrine. Philip Hughes, M.D. ------------------------- I believe that the incidence is very low and have been told (without a reference) that pressure from too large a volume used in a ring block is a bigger problem. Guy Webster ---------------- Scandinavia is a few miles further north, and here in Germany local anaesthetics are available without epinephrine. Furthermore, it is always taught NOT to use epinephrine in an acral localization, and I never will. Hans Juergen Kammler ---------------------------- In Denmark we have lidocaine with and without epinephrine. I takes a fairly large amount of lidocaine given iv to produce cardiac toxicity. On the other hand it only takes little epinephrine to initiate tachycardia. Mads Nielsen, MD ----------------------- Me, too. I use epi everywhere but ring blocks of the fingers and toes. Dan Mitchell, MD --------------------- I do not believe that Epinephrine(adrenalin) containing Lidocaine(lignocaine) should be used on digits or for digital blocks. When the digital arteries are exposed to the drug they shut down completely and the digit goes dead white. If this does not reverse in a reasonable amount of time necrosis will occur. If the patient sues you will have no defence whatsoever. What is the great advantage of using Epinephrine containing local on digits to justify the above risks? If bleeding is a problem a tourniquet can be used. Philip Bekhor ----------------- My husband says the article on epi being ok in digits etc was in Emergency Medicine News within the past four years. He also thinks podiatrists use epi around digits-I will check tomorrow as I work in the near vicinity of several podiatrists. I don't use epi near digits, and had a sleepless night when I used it on the distal nose once-but the patient still had a nose the next day. I faintly remember as a first year resident injecting lido-epi around a graft site during a Mohs procedure-the graft took-but I held my breath for weeks. Diane Thaler --------------- Re: Epi in lidocaine on digits: probably OK for local infiltration of small lesions or localized areas on digits, but I wouldn't use it for digital nerve blocks, where both digital arteries could be caused to vasoconstrict. Gene Sienkiewicz, M. D. ------------------------------