[Effects of pretreatment of electroacupuncture on bupivacaine poisoning in rats].

OBJECTIVE: To observe the effects of electroacupuncture (EA) pretreatment at different times for heart arrest induced by bupivacaine poisoning in rats. METHODS: With a randomized, blind, control study, 24 SD rats were divided into a control group, a EA for 60 min (EA 60) group and a EA for 30 min (EA 30) group, 8 cases in each one. Rats in the EA 60 group and EA 30 groups were treated with EA at bilateral "Neiguan" (PC 6), "Zusanli" (ST 36) and "Fenglong" (ST 40) for 60 min and 30 min respectively. While no treatment was given in the control group. Then rats were monitored by leadⅡelectrocardiograph; catheters were inserted into the femoral vein to open the vein access and into the carotis to monitor the arterial pressure. Three hours after EA, 10 mg/kg bupivacaine was injected through femoral vein. The mean arterial pressure (MAP) and heart rate (HR) were automatically recorded by PowerLab system. The time points when QRS widened by 20 percent and cardiac arrest and the survival rates were observed. RESULTS: After the injection of bupivacaine, five rats in the EA 60 group caught cardiac arrest,while all the rats in the other two groups caught it. The survival rates were not statistically significant among the three groups (P>0.05). The time of QRS widening by 20 percent in the EA 60 group was (87.4±14.8) s,which was longer than (63.6±14.2) s in the EA 30 group and (51.2±12.4) s in the control group (both P<0.05). From injection of bupivacaine to cardiac arrest, the time of (375.3±23.7) s in the EA 60 group and that of (328.3±47.7)s in the EA 30 group were more than (235.5±91.5) s in the control group (both P<0.05). After the injection, MAP and HR in the EA 60 group were higher than those in the EA 30 group and control group at most time points (all P<0.05). CONCLUSIONS: EA pretreatment apparently decreases the vulnerability of bupivacaine-induced heart arrest, with better protective effect of 60 min pretreatment than that of 30 min.

[Severe local anesthetic intoxication in an infant undergoing circumcision]. / Intoxication grave aux anesthésiques locaux lors d'une circoncision.

Local anesthetic intoxication is an uncommon complication of regional anesthesia. We report the case of a 4-month-old infant who presented with generalized tonic-clonic seizure complicated by cardiac arrest secondary to a severe intoxication to local anesthesia. These complications were observed after a bilateral dorsal penile nerve block with lidocaine for circumcision in a non-hospital setting. This report emphasizes the potential risk of local anesthetic systemic toxicity in such circumstances and describes its treatment.

Successful Resuscitation With Intralipid After Marcaine Overdose.

UNLABELLED: The authors present the case of a 32-year-old woman who underwent concomitant abdominoplasty and mastopexy. Before discharge from the recovery room, she experienced cardiac arrest and seizures resulting from an accidental overdose of Marcaine, caused by failure of an intramuscular pain pump. The anesthesiologist initiated a rescue protocol with an Intralipid 20% bolus (1.5 mg/kg), followed by continuous intravenous infusion of 0.25 mg/kg for 60 minutes. The Intralipid intervention resulted in a successful outcome. This case emphasizes the importance of ensuring the availability of Intralipid 20% infusion in the operating room. Plastic surgeons who place postoperative pain pumps must be aware of this method of resuscitation and its effectiveness in treating possible cases of local anesthetic overdose or toxicity. LEVEL OF EVIDENCE: 5.

Regional anaesthesia: back to basics.

Regional anaesthesia has become more popular in recent years with an emphasis on cost effectiveness, bed occupancy, and reduction in hospital acquired infections (HAls). Anaesthesia is a worrying time for any patient, but now the emphasis is to encourage patient empowerment by involving patients in their own care throughout their holistic journey. This article explores patient selection for regional anaesthesia, and the different types of central and peripheral blocks in line with national policies. The equipment required, pharmacology, toxicity of local anaesthetics, and their physiological effects on the cardiovascular, respiratory, and gastrointestinal systems of the body will also be discussed.

Preliminary results of the Australasian Regional Anaesthesia Collaboration: a prospective audit of more than 7000 peripheral nerve and plexus blocks for neurologic and other complications.

BACKGROUND AND OBJECTIVES: Peripheral nerve blockade is associated with excellent patient outcomes after surgery; however, neurologic and other complications can be devastating for the patient. This article reports the development and preliminary results of a multicenter audit describing the quality and safety of peripheral nerve blockade. METHODS: From January 2006 to May 2008, patients who received peripheral nerve blockade had data relating to efficacy and complications entered into databases. All patients who received nerve blocks performed by all anesthetists during each hospital's contributing period were included. Patients were followed up by phone to detect potential neurologic complications. The timing of follow-up was either at 7 to 10 days or 6 weeks postoperatively, depending on practice location and time period. Late neurologic deficits were defined as a new onset of sensory and/or motor deficit consistent with a nerve/plexus distribution without other identifiable cause, and one of the following: electrophysiologic evidence of nerve damage, new neurologic signs, new onset of neuropathic pain in a nerve distribution area, paresthesia in relevant nerve/plexus distribution area. RESULTS: A total of 6950 patients received 8189 peripheral nerve or plexus blocks. Of the 6950 patients, 6069 patients were successfully followed up. In these 6069 patients, there were a total of 7156 blocks forming the denominator for late neurologic complications. Thirty patients (0.5%) had clinical features requiring referral for neurologic assessment. Three of the 30 patients had a block-related nerve injury, giving an incidence of 0.4 per 1000 blocks (95% confidence interval, 0.08-1.1:1000). The incidence of systemic local anesthetic toxicity was 0.98 per 1000 blocks (95% confidence interval, 0.42-1.9:1000). CONCLUSIONS: These results indicate that the incidence of serious complications after peripheral nerve blockade is uncommon and that the origin of neurologic symptoms/signs in the postoperative period is most likely to be unrelated to nerve blockade.

Complications associated with eye blocks and peripheral nerve blocks: an american society of anesthesiologists closed claims analysis.

BACKGROUND AND OBJECTIVES: Concern for block-related injury and liability has dissuaded many anesthesiologists from using regional anesthesia for eye and extremity surgery, despite many studies demonstrating the benefits of regional over general anesthesia. To determine injury patterns and liability associated with eye and peripheral nerve blocks, we re-examined the American Society of Anesthesiologists Closed Claims Database as part of the American Society of Regional Anesthesia and Pain Medicine's Practice Advisory on Neurologic Complications of Regional Anesthesia and Pain Medicine. METHODS: Claims with eye or peripheral nerve blocks performed perioperatively from 1980 through 2000 were analyzed. The liability profile of anesthesiologists who provided both the eye block and sedation for eye surgery was compared with the profile of anesthesiologists who provided sedation only. The injury patterns associated with peripheral nerve blocks and payment factors were analyzed. RESULTS: Anesthesiologists who provided both the eye block and sedation for eye surgery (n = 59) had more injuries associated with block placement (P < .001), a higher proportion of claims with permanent injury (P < .05), and a higher proportion of claims with plaintiff payment (P < .05), compared with anesthesiologists who provided sedation only (n = 38). Peripheral nerve blocks (n = 159) were primarily associated with temporary injuries (56%). Local anesthetic toxicity was associated with 7 of 19 claims with death or brain damage. CONCLUSIONS: Performance of eye blocks by anesthesiologists significantly alters their liability profile, primarily related to permanent eye damage from block needle trauma. Though most peripheral nerve block claims are associated with temporary injuries, local anesthetic toxicity is a major cause of death or brain damage in these claims.

Lignocaine toxicity; a complication of local anaesthesia administered in the community.

Local anaesthetic agents are among the most commonly used drugs in the emergency department. A case is reported of a complication arising from systemic toxicity after the injection of lignocaine (lidocaine). Emergency practitioners should maintain a high level of vigilance for the symptoms of toxicity after local anaesthetic administration. Particular care should be taken when calculating the maximum safe dose for young children.

Adverse drug reactions to local anesthesia.

A dentist's ability to safely administer regional anesthesia is essential for dental practice. Local anesthetic solutions used in the United States for dental anesthesia are formulated with several components. The contents of a standard local anesthetic cartridge may include an amide or ester local anesthetic drug, an adrenergic vasoconstrictor, and an antioxidant. In susceptible patients, any of these components may induce systemic, dose-dependent adverse reactions. Although extremely rare, allergic reactions may also occur. Signs and symptoms of the various adverse reactions associated with local anesthetics are quite distinctive, permitting rapid diagnosis and treatment. Serious reactions are extremely infrequent and, when treated properly, unlikely to result in significant morbidity or mortality.

When patients become cyanotic: acquired methemoglobinemia.

BACKGROUND: The authors conducted literature review to create a heightened awareness of the potential for developing toxic methemoglobinemia from local anesthetics. Methemoglobin normally is present in the blood at levels less than 1 percent. Levels may become toxic as hemoglobin is oxidized to methemoglobin after local anesthetics such as benzocaine and prilocaine are administered. TYPES OF STUDIES REVIEWED: The authors searched the medical and pharmaceutical industry literature. They found and reviewed case studies of incidences of methemoglobinemia that resulted from local anesthetic overdoses. RESULTS: Cases of local anesthetic-induced methemoglobinemia in dental practice are under-recognized and rare. Reported cases of prilocaine-induced methemoglobinemia have resulted in recent changes in some prilocaine literature. These changes include maximum recommended doses for patients of various weights. CLINICAL IMPLICATIONS: Dentists should identify patients who are at increased risk of developing methemoglobinemia before administering local anesthetics. They also should follow new recommended dosing guidelines for prilocaine and be aware of symptoms of this adverse reaction.

Morbidity, mortality and local anaesthesia.

Two cases of local anaesthetic overdose and death are described. The patients, a four-year-old child and a 68-year old female, received local anaesthetic doses greatly in excess of those recommended. Their overdose reactions are described as well as subsequent management. The paper reviews the causes of local anaesthetic overdose, its signs and symptoms, and the recommended management of these reactions. Specific discussion as to the cause of death of these two patients and of the means to prevent such occurrences in the future concludes the paper.

How to avoid local anaesthetic toxicity.

Local anaesthetic overdose is not common in dental practice but can occur. In rare cases it can be fatal. Normally the use of good technique employing small amounts of solution limits toxicity. In addition, thorough medical history taking should forewarn the dentist of any patient who has experienced problems in the past and will also alert the operator to those few patients who exhibit idiosyncratic reactions. This article aims to offer practical advice to help avoid local anaesthetic toxicity.

Local anesthesia.

In summary, many surgical procedures may be safely and comfortably performed utilizing regional anesthesia if only a few guidelines are followed as to choice and usage of local anesthetics. The success of a regional block will always be dependent upon correct needle placement by an experienced physician with good technical skills. However, the safety of the patient is not solely a function of experience. Modern local anesthetic preparations are reliable enough and simple enough to use that all physicians should be capable of achieving optimal patient safety at all times. If placed in a position which seems to require unfamiliar knowledge or expertise, the practitioner need only seek a consultant anesthesiologist for assistance. Plastic surgery is recognized as a specialty that frequently utilizes local anesthetics for office and outpatient procedures. The manner in which these drugs are used or abused determines their clinical reputation as well as that of the physician. It is important to promote a correct understanding of local anesthetic compounds, not only among ourselves as physicians, but also among our patients, who are becoming ever more knowledgeable of medical practice as time goes on.

Diagnosis and treatment of complications associated with local anaesthesia.

The safety record of local anaesthetic agents is high but complications do occur. These may be systemic reactions to the local anaesthetic itself or to the vasoconstrictor. The former may be allergic or toxic in nature. Psychomotor reactions, often attributed erroneously to the vasoconstrictor, are more common. Regional complications, usually due to faulty technique, may be immediate or delayed. Among the former are pain, haematoma formation, tissue blanching, facial paralysis, amaurosis, diplopia and needle breakage. The delayed regional complications include pain, prolonged anaesthesia or paraesthesia, trismus, infection, sloughing and ulceration. The management of these complications is described.

Local anesthesia in otolaryngology. A re-evaluation.

Almost a half century following attempts to ban its use, cocaine remains at the pinnacle of topical anesthesia in otolaryngology. To understand how nonaddicting synthetic substitutes such as procaine, dibucaine, tetracaine and lidocaine have not totally supplanted cocaine, requires an in-depth analysis of its unique pharmological properties, untoward effects and potential substitutes. Almost all of the reported cocaine deaths occurred after subcutaneous injection; when used topically, cocaine's toxicity has been confined to an occasional reaction. Certain variables under physician control may be manipulated to reduce the chance of reaction to a minimum. For example, intermittent application of a particular dosage results in lower blood levels, and allowing sufficient time between doses reduces the amount necessary to obtain the desired anesthesia. If total dosage is kept below 200 mg there are few reactions. A singular advantage of cocaine over other topical anesthetics is its inherent ability to cause vasoconstriction, thus retarding its own absorption. The addition of a topical vasoconstrictor such as epinephrine is thus redundant, and may actually be harmful as cocaine sensitizes the patient to exogenous epinephrine. Finally, the usual preoperative dosages of barbiturates are entirely inadequate to prevent or treat cocaine reactions. Why, then, have synthetic local anesthetics not replaced cocaine? Inherent differences in topical effectiveness, duration of anesthesia and toxicity provide the answer. Of other local anesthetics possessing topical effectiveness tetracaine is about six times more toxic than cocaine. Dibucaine is as toxic as tetracaine, and lidocaine, while relatively nontoxic, provides only a 15 minute duration of topical anesthesia. A review of cocaine and its potential substitutes thus leads to the conclusion that cocaine is still a vital and necessary instrument in the otolaryngologist's armamentarium, singularly providing excellent topical anesthesia of usable duration, vasoconstriction, and shrinkage of mucous membranes, all with a quite acceptable margin of safety.