Anesthesia for dermatologic surgery

Bupivacaine as an Adjunct to Lidocaine in Mohs Micrographic Surgery: A Prospective Randomized Controlled Trial

BACKGROUND

In Mohs micrographic surgery (MMS), the standard local anesthetic agent used is lignocaine with adrenaline. However, MMS can be prolonged; thus reinjections of local anesthetics are often required.

OBJECTIVE

Is 0.5% bupivacaine with 1:200,000 epinephrine a useful adjunctive treatment when compared with the use of 1% lidocaine with 1:100,000 epinephrine in MMS for the nose?

METHODS

Participants undergoing MMS received 2.5 mL of 1% lidocaine with 1:100,000 epinephrine before commencement of Stage 1. At the end of Stage 1, participants were randomized sequentially to either 2.5 mL 0.5% bupivacaine with 1:200,000 epinephrine (Group A) or 2.5 mL of 1% lidocaine with 1:100,000 epinephrine (Group B). Effectiveness of anesthesia was assessed using 30 G needle to 5 points of the wound before further stage or repair.

RESULTS

Fifty-one patients were randomized, 26 to Group A, and 25 to Group B. No differences between the 2 groups in size of defect and time lapse between time of injection and time of testing were observed. Seven of 25 were tested positive in Group B. Zero of 26 tested positive in Group A (p = .003, 95% confidence interval: 10%-46%).

CONCLUSION

Adjunctive use of 0.5% bupivacaine with 1:200,000 epinephrine is effective in prolonging anesthesia in MMS.

Hypersensitivity to local anaesthetics--update and proposal of evaluation algorithm

Local anaesthetics (LA) are widely used drugs. Adverse reactions are rare but may be caused by delayed-type hypersensitivity reactions and probably also immediate-type reactions. As it is not always easy to clinically differ between these subtypes, allergy skin testing should be considered. Although numerous test protocols have been published, how patients with hypersensitivity reactions to LA are ideally evaluated remains a topic of discussion. This review attempts to generate a comprehensive update on allergic reactions to LA and to present an algorithm that can be used for the evaluation of patients suspected with immediate- and delayed-type immune reactions. Literature was examined using PubMed-Medline, EMBASE, Biosis and Science Citation Index. Based on the literature, the proposed algorithm may safely and rapidly distinguish between immediate-type and delayed-type allergic immune reactions.

Use of preservative-free lidocaine for cataract surgery in a patient allergic to “caines”

Although many patients have been labeled allergic to local anesthetics (LAs), true allergic reactions to LAs are rare. An 81-year-old woman with a history of procaine (Novocaine) allergy presented for cataract surgery. Skin testing showed sensitivity to amide and ester LAs. Further testing with preservative-free lidocaine was negative, suggesting the patient was allergic to ester LAs and preservatives found in amide anesthetic preparations. Cataract extraction was subsequently and uneventfully performed in both eyes with topical anesthesia using preservative-free lidocaine.

Dermatologic surgery in the demented patient

BACKGROUND

Dementia is an organic mental disorder that is characterized by a general loss of intellectual abilities involving impairment of memory, judgment, and abstract thinking as well as changes in personality. Demented patients are a growing subgroup within the practice of dermatologic surgery and especially in Mohs surgery. These patients often have other medical and social concerns in addition to their dementia.

OBJECTIVE

Demented patients require specific knowledge of their problems to care for them properly, especially in cases in which prolonged procedures are required such as Mohs surgery.

METHODS

A review the literature is given regarding this subgroup of patients and how to best prepare and care for them before, during, and after dermatologic surgery.

RESULTS

Demented patients often have other medical concerns and therefore have associated medications, medical ailments, postsurgical care, and social and mental challenges.

CONCLUSION

The dermatologic surgeon needs to be aware of the special concerns of demented patients, especially in prolonged and potentially complicated surgeries. Not only do they have mental challenges, but they often have other medical and social challenges that need to be specifically accounted for before, during, and after dermatologic surgery.

Preoperative assessment of the elderly patient

Preoperative assessment of the elderly patient for surgery is vital to the success of the surgical procedure. A thorough evaluation must first begin with an understanding of the physiologic and pathophysiologic changes unique to the elderly patient and the aging skin. A complete preoperative assessment entails assessing the patient and dermatologic problem, preparing the patient and caregivers for the surgery and its expected outcomes, and highlighting issues and problems that need to be managed prior to the procedure. With the continued growth of the geriatric population, all dermatologic surgeons should be aware of the special issues related to their geriatric patients. With heightened awareness of and screening for potential pitfalls in the elderly surgical patient, adverse outcomes can be avoided.

Medical issues and emergencies in the dermatology office

We review the medical issues and emergencies potentially encountered in the practice of general or surgical dermatology. Traditional guidelines have largely consisted of dated extrapolations from the nondermatologic literature concerning procedures that are primarily irrelevant to dermatology. This article outlines a rational approach to organizing an office emergency plan for anaphylaxis, stroke, status epilepticus, myocardial infarction, and hypertensive crisis. We discuss the literature that has influenced current office behavior regarding endocarditis prophylaxis, the use of electrosurgery with pacemakers, arrhythmogenic drug interactions, vasovagal syncope, lidocaine "allergy," and bleeding complications from oral anticoagulants. Recommendations for managing these issues in a dermatologic context are provided.

Drug management in skin surgery

Lidocaine (lignocaine) 1% with epinephrine (adrenaline) 1:200,000 (maximum dose 40mL) is the agent of choice in skin surgery. It can be used at all sites except the fingers, toes and penis, where epinephrine should be avoided. Epinephrine-induced vasoconstriction delays local anaesthetic clearance, thus prolonging its effect and, by reducing peak blood lidocaine concentrations, enables a higher maximum dose to be used. Adding epinephrine, however, introduces the possibility of a drug interaction with tricyclic antidepressants and nonselective beta-blockers. Also, injection pain is greater because of the acidic sodium metabisulphite that has to be added to prevent epinephrine oxidation. Injection pain can be reduced by buffering the solution using sodium bicarbonate. There are no drug interactions that prevent the use of plain lidocaine: injection pain is least with 0.5% solutions. Injection of large volumes of very dilute lidocaine solutions (tumescent anaesthesia) enables higher maximum doses of lidocaine to be tolerated and large areas to be anaesthetised by infiltration. Amethocaine gel is a faster acting and more effective topical anaesthetic compared with eutectic lidocaine-prilocaine cream, but is a topical sensitiser. In high risk patients, prophylactic antibiotics should be given to prevent bacterial endocarditis when operating on infected lesions and on potentially colonised crusted lesions in high-risk patients (i.e. those with prosthetic heart valves). Wound infections following surgery on infected skin lesions can be prevented by the prophylactic use of mupirocin ointment. Aspirin-induced inhibition of platelet adhesion results in bleeding complications in approximately 15% of skin surgery patients receiving aspirin. Patients whose bleeding time is > 8 minutes are particularly at risk, and aspirin should be stopped at least 7 days prior to surgery in these patients. Aspirin can be continued in other patients without serious bleeding complications.

Understanding allergic reactions to local anesthetics

OBJECTIVE

To review the pharmacology and mechanisms by which local anesthetics cause allergic reactions. Recommendations concerning appropriate use of local anesthetics and alternative therapies in patients with documented local anesthetic allergies are given.

DATA SOURCE

A MEDLINE search of English-language literature identified pertinent clinical studies, case reports, and reviews. The periods of review were Med1, 1990-present, and Med2, 1985-1989, using the MeSH terms drug hypersensitivity and anesthetics. References from the selected studies, case reports, and reviews were reviewed.

STUDY SELECTION

Controlled and uncontrolled prospective studies and case reports pertaining to local anaesthetic allergies were reviewed. The selection focused on information pertaining to the etiology and diagnosis of allergic reactions to local anesthetics and alternative therapies for patients with local anesthetic allergies.

DATA SYNTHESIS

Local anesthetics are classified as either ester or amide compounds. Esters are associated with a higher incidence of allergic reactions, due to a p-aminobenzoic acid (PABA) metabolite. Amide agents do not undergo such metabolism. However, preservative compounds (methylparaben) used in the preparation of amide-type agents are metabolized to PABA. Patients who are allergic to ester local anesthetics should be treated with a preservative-free amide local anesthetic. If the patient is not allergic to ester local anesthetics, these agents may be used in amide-sensitive patients. In the rare instance that hypersensitivity to both ester and amide local anesthetics occurs, or if skin testing cannot be performed, than alternative therapies including diphenhydramine, opioids, general analgesia, or hypnosis can be used.

CONCLUSIONS

A true immunologic reaction to a local anesthetic is rare. Intradermal skin testing of local anesthetic compounds, methylparaben, and metabisulfite should be performed in patients when a thorough history does not rule out a possible allergic reaction to local anesthetics and future local anesthesia is necessary. Skin testing enables the clinician to identify autonomic responses to minor surgical procedures and toxic reactions to anesthetics so that patients are not incorrectly labeled as "caine" allergic. Diphenhydramine can be used as an alternative to ester and amide local anesthetics in minor procedures of short duration.

Drug interactions in dermatologic surgery

Intravenous sedation is a popular method of anesthesia in outpatient cosmetic surgery. To ensure a successful surgical outcome, awareness of potential interactions between intravenous agents and patient medications is essential. The more commonly used intravenous drugs are reviewed, with particular emphasis on their side-effects and potential for drug interactions.

Know your anatomy. Local anesthesia for cutaneous lesions of the head and neck--practical applications of peripheral nerve blocks

Peripheral nerve blocks can be used routinely in an outpatient setting. The innervation of the face and the technique we use to perform nerve blocks are reviewed. We present four cases of skin cancer and one of rhinophyma in which nerve blocks were used to minimize the discomfort associated with local anesthesia.

The ice-saline-Xylocaine technique. A simple method for minimizing pain in obtaining local anesthesia

Prior to skin surgery, localized cryoanesthesia is initially obtained utilizing Cryogel packs before local anesthesia injection, minimizing or abolishing pain from the piercing of the skin by the injection needle. The surgical field is then infiltrated with benzyl alcohol-containing normal saline, a painless solution producing moderate local anesthesia. Subsequently, a stronger anesthetic containing a vasoconstrictor or other desired additives can be infiltrated without significant patient discomfort. This simple three-step method has resulted in excellent patient acceptance, and is potentially useful for a wide range of surgical procedures and medical specialties.

Taking the 'sting' out of local anaesthetics

In order to investigate factors influencing the discomfort caused by the injection of different lignocaine preparations, a randomized, double-blind comparison of paired injections was performed in 32 patients. In all subjects 2% plain lignocaine was found to be more painful than 0.5% plain lignocaine. Lignocaine with adrenaline 1:200,000 was found to be significantly more painful than plain lignocaine. The presence of sodium metabisulphite (the antioxidant in commercial adrenalized lignocaine) significantly increased the discomfort. Neutralization of acidic 0.5% lignocaine (pH 4.7) reduced the discomfort caused in 44% of patients, but this was not statistically significant.

Prolongation of anesthesia in Mohs micrographic surgery with 2% lidocaine jelly

The authors performed a prospective, randomized trial of topical 2% lidocaine jelly in patients with basal cell or squamous cell carcinomas to test the effectiveness of the jelly in prolonging the time of anesthesia between the multiple stages of Mohs micrographic surgery. There was a 48% increase in the duration of anesthesia achieved by the use of 2% lidocaine jelly in patients given 1% lidocaine with epinephrine. In patients given 1% lidocaine without epinephrine, there was approximately a 2.5 times greater duration of anesthesia achieved by using topical 2% lidocaine jelly.

Neutralized lidocaine with epinephrine for local anesthesia

The pain of infiltrating lidocaine with epinephrine into skin is reduced by the addition of sodium bicarbonate. The effect of varied concentrations of sodium bicarbonate on pain of infiltration of 1% lidocaine with epinephrine 1:100,000 was measured. Sodium bicarbonate at 40 and 100 meq/L of anesthetic solution caused significantly less pain than did 0 or 10 meq/L. The stability of epinephrine in a solution at pH 7.3 was also determined. Epinephrine concentration declined approximately 25% per week in anesthetic solution containing 100 meq/L sodium bicarbonate.

An approach to patient assessment and preparation in cutaneous oncology

An outline of the many phases of preoperative evaluation of the dermatologic surgery patient is presented. Special emphasis is given to patient assessment and to patient preparation. The purpose of this review is not to create a compendium of steps that one must slavishly perform before each surgical procedure. Instead, it represents an effort to emphasize the importance of adequate preoperative evaluation and to discuss some of the subtleties that may be overlooked by the dermatologic surgeon.