Disclaimer: The information contained within the Grand Rounds Archive is intended for use by doctors and other health care professionals. These documents were prepared by resident physicians for presentation and discussion at a conference held at Baylor College of Medicine in Houston, Texas. No guarantees are made with respect to accuracy or timeliness of this material. This material should not be used as a basis for treatment decisions, and is not a substitute for professional consultation and/or peer-reviewed medical literature. Local and Regional Anesthesia in the Head and Neck Cocaine, derived from the Erythroxylum coca leaf, was probably the first widely used anesthetic agent. It was extensively used by the Indians of Inca and Peru to alleviate hunger and fatigue and to anesthetize battle wounds. Freud (1884) experimented with cocaine in an effort to cure a friend's morphine addiction. In that same year Koller is credited with its first use in modern times in topical anesthesia (for ophthalmologic procedures). Halsted, also in 1884, was the first to use cocaine in a regional block. 1905 brought the development of procaine (Novacaine) and ushered in a new era of anesthetic practice. Löfgren (1948) developed lidocaine, now considered the standard in local anesthetic agents because of its low toxicity, potency, stability, and good tissue penetration without addiction. Why Local Anesthesia? Local anesthesia in the right setting can benefit the patient. Airway and respiration are maintained by the patient, making the procedure safer. There is usually a smoother recovery from local anesthesia, less physiologic stress, earlier discharge from the recovery room, reduced costs, reduced bleeding when a concurrent vasoconstrictor is used and, finally, the patient may assist with maneuvers or responses to questions. Why Not ? Apprehension and anxiety can be significant problems and good patient rapport and a thorough explanation of the procedure and expectations is required. Also, placement of regional blocks and administration of adequate anesthesia is a learned technique requiring experience and skill. One must also consider the various toxicities of the agents, their delay to onset, the risk of nerve damage and the reduced effectiveness in the presence of infection. Physiology and Pharmacology Nerve impulses depend on the flow of ion currents through channels in the cell's membrane. Nerve cell's are negatively polarized at rest and this is maintained by active Na+/K+ exchange. When a cell is stimulated it becomes depolarized and an action potential occurs. Local anesthetics work by stabilizing the cell membrane and preventing depolarization. Factors which affect a nerve's exposure to the anesthetic agent or the ability of the agent to optimally function thus directly affect the efficacy of anesthetic blockade. This includes the acidity and pH of the local environment and the competition between diffusion of agent to a nerve and its clearance by systemic absorption or metabolism by plasma pseudocholinesterase. Toxicity The most common and serious toxicities of local anesthetic are CNS and cardiac, starting with excitement and confusion and ultimately causing seizures, myocardial depression and cardiac arrest with prolonged toxic doses. Other less common toxicities include allergy, fetal toxicity, methemaglobonemia, local complications such as nerve injury, syncope, and aspiration. The maximum recommended doses of all drugs used for a given procedure should be known and not exceeded. Monitoring should include frequent BP monitoring and continuous pulse oximetry, in combination with an IV +/ IVF and possibly supplemental oxygen. Emergency preparedness includes airway management equipment and skills, ACLS drugs and skills and antiseizure medications. A Word About Conscious Sedation Conscious sedation refers to "a medically controlled state of depressed consciousness that allows the maintenance of protective reflexes and retains a patient's ability to independently maintain a patent airway." Great care should be exercised when sedating patients in conjunction with local anesthesia. Guidelines for conscious sedation have been formally recognized by the pediatric community (see references.) The following drugs are commonly utilized in conscious sedation: major tranquilizers droperidol, compazine; narcotics morphine, fentanyl, meperidine; and benzodiazepines diazepam, midazolam. Specific Techniques Specific techniques of local anesthesia include topical application, local infiltration, field blocks, and regional blocks. Topical anesthesia is useful for anesthetizing the skin, tympanic membrane (TM), nose, oral cavity and larynx. Topical anesthesia refers to traditional topical applications of agents, as well as newer techniques, such as iontophoresis, EMLA and TAC. Local anesthetics can be applied by syringe, spray or pledgets. They are commonly used with neosynephrine or other vasoconstricting agent. Cocaine is the only local anesthetic which also has vasoconstrictive properties. Iontophoresis utilizes a DC current to "drive" anesthetic molecules across the tympanic membrane, it does not however provide any anesthesia of the EAC. EMLA, a "Eutectic Mixture of Local Anesthetics" is an oil in water emulsion (cream) of 2.5% lidocaine and 2.5% prilocaine (achieving 80 % drug in active form.) It has been shown to be equal or better than iontophoresis for anesthesia of the TM. It has also been used for topical anesthesia (such as IV in pediatric population. TAC (mixture of Tetracaine, Adrenaline and Cocaine) has been used for topical application (such as laceration repair). It has been shown to be 95% effective for head and neck anesthesia. However, it is not approved by the FDA and must be prepared by the administering physician or local pharmacy. Local infiltration and field blocks can be utilized for limited procedures in the head and neck, especially those involving the face, ear, nose and neck. Anesthetic agent is infiltrated in a ring or "field" around the area of consideration. Procedures such as laceration repairs, excisional biopsies, most nasal procedures, and tracheotomies are particularly amenable to this technique. Regional blocks provide larger areas of anesthesia by anesthetizing peripheral nerves more proximally at known, consistent anatomic locations, eg. nerve exit sites from the various cranial foramen. These blocks are numerous and very useful. Some of the commonly used ones in the head and neck are supratrochlear and supraorbital, infraorbital, mental, mandibular, superior laryngeal, and cervical. Pain control On a final note, more and more, local anesthetics are being infiltrated locally to provide postoperative pain relief during the initial period after emergence from general anesthesia. Case Presentation A 19-year-old Hispanic woman was involved in a motor vehicle accident. She was an unrestrained front seat passenger and sustained a blunt trauma injury to her nose and face. On physical examination there was an open nasal-septal fracture and another laceration at her brow. She was also noted to have a septal dislocation with a large septal perforation. The facial series was unremarkable except for a nasal bone fracture. P> She was seen in the Ben Taub General Hospital ENT Clinic where she underwent reduction of the septal dislocation, repair of the septal perforation and irrigation, debridement and closure of the open nasal and facial lacerations. These procedures were performed under local and regional anesthetic blocks and she did not require sedation. She tolerated the procedure well and will be seen for follow-up this week in clinic. Bibliography Academy of Pediatrics. Committee on Drugs. Guidelines for monitoring and management of pediatric patients during and after sedation for diagnostic and therapeutic procedures. Pediatrics 1992;89:29-34. Adriani J. Labat's Regional Anesthesia: Techniques and clinical Applications, fourth ed. St. Louis: Warren H. Green, 1985. Appling WD, Wright WK. Nerve block anesthesia for cosmetic facial surgery. Am J Cosmetic Surg 1985;2:39-43. Baker JD III, Blackmon BB Jr. Local anesthesia. Clin Past Surg 1985;12:25-31. Berk WA, Welch RD, Bock BF. Controversial issues in clinical management of the simple wound. Ann Emerg Med 1992;21:95-103.
Bingham B, Hawthorne M. The use of anaesthetic EMLA cream in minor otological surgery. J Laryngol Otol 1988;102:517. Bonadio WA, Wagner V. Efficacy of TAC topical anesthetic for repair of pediatric lacerations. Am J Dis Child 1988;142:203-205. Bonadio WA, Wagner V. Efficacy of tetracaine-adrenaline-cocaine topical anesthetic without tetracaine for facial laceration repair in children. Pediatrics 1990;86:856-857. Carrasco VN, Prazma T, Biggers WP. A safe, effective anesthetic technique for outpatient myringotomy tube placement. Laryngoscope 1993;103:92-93. Collins JF. Methemoglobinemia as a complication of 20% benzocaine spray for endoscopy. Gastroenterology 1990;98:211-213. Dembo JB. The use of intravenous anesthesia and sedation techniques in oral and maxillofacial surgery. J Oral Maxillofac Surg 1993;51:346-351. Deramo EM. Morbidity and mortality with outpatient aesthesia: the Massachusetts experience. J Oral Maxillofac Surg 1992;50:700-704. Ehlert TK, Arnold DE. Local anesthesia for soft-tissue surgery. Otolaryngol Clin North AM 1990;23:831-844. Ellis DA, Gage CE. Evaluation of conscious sedation in facial plastic surgery. J Otolaryngol 1992;20:267-273. Eriksson E, editor. Illustrated Handbook in Local Anaesthesia, second edition. Philadelphia: WB Saunders, 1980. Hickey SA, Buckley JG, O'Connor AF. Ventilation tube insertion under local anesthesia. Am J Otol 1992;12:142-143. Kays CR. Local infiltration versus regional anesthesia of the face: case report and review. J S C Med Assoc 1988;84:494-496. Lancer JM, Fisch U. Local anaesthesia for middle ear surgery. Clin Otolaryngol 1988;13:267-274. Mahieu HF, Dikkers FG. Indirect microlaryngostroboscopic surgery. Arch Otolaryngol Head Neck Surg 1992;118:21-24. Metzinger SE, Bailey DJ, Boyce RG, Lyons GD. Local anesthesia in rhinoplasty: a new twist? Ear Nose Throat J 1992;71:405-406. Minasian A, Yagiela JA. The use of amide local anesthetics in patients susceptible to malignant hyperthermia. Oral Surg Oral Med Oral Pathol 1988;66:405-415. Ovassapian A, Krejcie TC, Yelich SJ, Dykes MH. Awake fibreoptic intubation in the patient at high risk of aspiration. Br J Anaesth 1989;62:13-16. Pere P, Iizuka T, Rosenberg PH, Lindqvist C. Topical application of 5% eutectic mixture of lignocaine and prilocaine (EMLA) before removal of arch bars. Br J Oral Maxillofac Surg 1992;30:153-156. Pfleiderer AG, Brockbank M. Cocaine and adrenaline: a safe or necessary combination in the nose? A study to determine the effect of adrenaline on the absorption and adverse side effects of cocaine. Clin Otolaryngol 1988;13:421-426. Raj PP, editor. Clinical Practice of Regional Anesthesia. New York: Churchill Livingstone, 1991. Randle HW, Salassa JR, Roenigk RK. Know your anatomy. Local anesthesia for cutaneous lesions of the head and neck - practical applications of peripheral nerve blocks. J Dermatol Surg Oncol 1992;18:231-235. Reese BR. External rhinoplasty approach to unusual rhinologic procedures. Ear Nose Throat J 1991;70:431-437. Schoem SR, Watkins GL, Kuhn JJ, Alburger JF, Kim KZ, Thompson DH. Control of early postoperative pain with bupivacaine in adult local tonsillectomy. Arch Otolaryngol Head Neck Surg 1993; 119:292-293. Sirimanna KS, Madden GJ, Miles S. Anaesthesia of the tympanic membrane: comparison of EMLA cream and iontophoresis. J Laryngol Otol 1990;104:195-196. Smith SM, Barry RC. A comparison of three formulations of TAC (tetracaine, adrenalin, cocaine) for anesthesia of minor lacerations in children. Pediatr Emerg Car 1990;6:266-270. Stromberg BV. Regional anesthesia in head and neck surgery. Clin Past Surg 1985;12:123-136. Summerfield MJ, White PS. Ventilation tube insertion using topical anaesthesia in children. J Laryngol Otol 1992;106:427-428. Uminski ML. Anesthesia care in the outpatient setting. Clin Plast Surg 1992;19:537-544. Grand Rounds Archive | Department Home page BCM Public | BCM Intranet | Privacy Notices | Contact BCM | BCM Site Map | ©2001-2006 Baylor College of Medicine
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