Effect of body locale and addition of epinephrine on the duration of action of a local anesthetic agent

Effects of vasoconstrictor use on digital nerve block: systematic review with meta-analysis

Conventionally, the association of local anesthetics with vasoconstrictors is avoided at extremities due to the risk of ischemia. However, recent studies suggest that there is safety in the use of vasoconstrictors at extremities. Thus, we sought to evaluate the effectiveness and safety of vasoconstrictor use combined with local anesthetics in digital nerve block compared to the use of anesthetics without vasoconstrictors, through a systematic review with meta-analysis of randomized clinical trials. Until May 2019 we searched MEDLINE, LILACS, SciELO, ScienceDirect, Scopus, ClinicalTrials.gov, and gray literature databases, without date or language restrictions. The keywords were the following: digital block, vasoconstrictor, and ischemia. We included randomized clinical trials in which there was the use of local anesthetics with associated or not with vasoconstrictors in digital blocks. In the primary variables, the occurrence of ischemic complications and the duration of anesthesia were analysed; in the secondary variables, the need for anesthetic reapplication, bleeding control, and latency were observed. Ten studies were included in this review. The occurrence of ischemia was not observed, regardless of the use of vasoconstrictors or not. The use of vasoconstrictors at a concentration of 1:100,000 or less was associated with longer anesthesia duration (P<0.00001), lower need for anesthetic reapplication (P=0.02), lower need for bleeding control (P=0.00006), and lower latency (P<0.00001). We could conclude that the use of vasoconstrictors associated with local anesthetics in digital block proved to be a safe and effective technique.

Wide Awake Hand Surgery

Background: “Wide awake hand surgery”, where surgery is performed in local anaesthesia with adrenaline, without sedation or a tourniquet, has become widespread in some countries. It has a number of potential advantages and we wished to evaluate it among our patients.

Methods: All 122 patients treated by this method during one year were evaluated by the surgeons and the patients on a numerical scale from 0 (best/least) to 10 (worst/most). Theatre time was compared to that recorded for a year when regional or general anaesthesia had been used.

Results: The patients’ mean score for the general care they had received was 0.1 (SD 0.6), for pain during lidocaine injection 2.4 (SD 2.2), for pain during surgery 0.9 (SD 1.5), and for other discomfort during surgery 0.5 (SD 1.4). Eight reported that they would want general anaesthesia if they were to be operated again. The surgeons’ mean evaluation of bleeding during surgery was 1.6 (SD 1.8), oedema during surgery 0.4 (SD 1.1), general disadvantages with the method 1.0 (SD 1.6) and general advantages 6.5 (SD 4.3). The estimation of advantages was 9.9 (DS 0.5) for tendon suture. 28 patients needed intra-operative additional anaesthesia. The proportion was lower among trained hand surgeons and fell significantly during the study period. Non-surgical theatre time was 46 (SD 15) minutes during the study period and 55 (SD 22) minutes during the regional/general period (p < 0.001). This gain was cancelled out by a longer surgery time during the wide awake period.

Conclusions: Wide awake surgery is fully acceptable to most patients. It has a number of advantages over general or regional anaesthesia, but we feel it is unlikely to improve the efficiency of the operating theatre.

[Necrosis in fingers and toes following local anaesthesia with adrenaline--an urban legend?]

BACKGROUND

It is often maintained that a local anaesthetic (usually lidocaine) with adrenaline must not be used in fingers and toes because it may cause necrosis due to vascular spasm in end arteries. This review article is an attempt to find evidence to support this warning.

METHOD

Relevant literature was found by means of searches in PubMed limited downwards to 1946 and in EMBASE from 1980 to 2012, and in reference lists.

RESULTS

Five review articles on finger necrosis following local anaesthesia concluded that lidocaine with adrenaline does not entail a risk of ischaemic injury. One article found 48 reported cases of finger necrosis in the period 1880 to 2000. Most were from the first half of the 1900s, and none involved lidocaine. Gangrene of part of the finger tip has subsequently been described in one patient with Raynaud's syndrome. No cases of necrosis have been described in a large number of reported accidents in which EpiPen injections contained the same quantity of adrenaline as is found in 60 ml lidocaine with adrenaline. Over a quarter of a million reports have been made of operations on feet, hands, fingers and toes anaesthetised with lidocaine with adrenaline without resulting necrosis.

INTERPRETATION

There are no grounds for the warning against using lidocaine with adrenaline in fingers and toes. This anaesthetic offers considerable practical advantages. Care should be taken with infected fingers or fingers with poor circulation.

Prolonged peripheral nerve blockade in patients using lithium carbonate

Peripheral nerve blocks with local anaesthesia are routinely utilized in oral surgical procedures to achieve anaesthesia at the operative site. A number of local tissue factors as well as systemic conditions and medications may alter the onset, depth and duration of peripheral nerve blocks. This article describes two cases of extremely prolonged anaesthesia in patients treated with chronic oral lithium carbonate who had been administered inferior alveolar, lingual, long buccal, greater palatine and posterior superior alveolar nerve blocks with lidocaine with adrenaline for surgical removal of an upper and a lower third molar tooth. A possible relation with systemic lithium therapy and its probable mode of action are explored.

Onset, duration and efficacy of four methods of local anesthesia of the horn bud in calves

OBJECTIVE

To determine the onset, duration and efficacy of four local anesthetic methods for the horn bud in calves.

STUDY DESIGN

Crossover study.

ANIMALS

Eight, 2 month-old Holstein Friesian bull calves.

METHODS

Calves were subjected to one of the four following treatments: 1) cornual nerve block (C), 2) ring block (R), 3) cornual nerve block using a percutaneous jet delivery technique (JET) all using 2% lidocaine with epinephrine (0.01 mg mL(-1)), and 4) topical eutectic mixture of local anesthetics (EMLA) cream. A peripheral nerve stimulator was used to assess cutaneous sensation over the horn bud using a graded response. Onset, duration and efficacy of anesthesia were determined.

RESULTS

The efficacy of the blocks was as follows: C 87.5%, R 100%, JET 37.5%, EMLA 0%. The median onset time and duration of anesthesia for C and R were: 2 (range 0.5-5) and 304 (range 107-512), and 3.25 (range 1-9) and 147 (range 62-299) minutes, respectively. Three of eight JET injections had a median onset and duration of 8 (range 0.5-9) and 132 (range 101-155) minutes, respectively. The duration of the C block was significantly longer than the R block (p = 0.047).

CONCLUSIONS AND CLINICAL RELEVANCE

The relatively rapid onset and long duration of anesthesia with C or R blocks using 2% lidocaine with epinephrine validates their practical use in dehorning calves while jet injection and EMLA cream provided insufficient analgesia to be clinically useful. The efficacy of the C block requires further study.

Local anesthesia in hair transplantation

BACKGROUND

Safe and effective use of local anesthesia is essential in hair transplantation.

OBJECTIVE

To review the agents and techniques of local anesthesia as applied to hair transplantation.

METHODS

Information was retrieved from texts, journal articles found by MEDLINE searches, and related references.

RESULTS

Agents, vasoconstrictors, maximum dosages, toxicity, and techniques are discussed.

CONCLUSION

Effective local anesthesia can be maintained throughout hair transplantation. Care must be exercised to minimize discomfort through proper technique and to minimize toxicity through judicious use of vasoconstrictors and nerve blocks and by monitoring total dosage. Constant monitoring for toxicity is required, as is early intervention in the unlikely event that warning signs should appear.

Local anesthetics for facial plastic procedures

The use of local anesthetic in facial plastic surgical procedures is well established as an effective and safe mode of anesthesia delivery. Local infiltration of anesthesia may be used alone for minor surgical procedures, or it may be used with general anesthesia or intravenous sedation and analgesia for more complex, lengthy procedures. When considered independently, the use of local anesthetic agents has undeniable limitations. Local anesthetics can cause toxicity and side effects. Injection of local anesthetics for subcutaneous infiltration frequently is painful until sensory anesthesia occurs. Local anesthetics have limited efficacy with respect to the intensity and duration of sensory blockade that can be achieved. In some situations, use of local anesthesia with the maintenance of an awake patient also may be undesirable for the surgeon and impractical for the patient. Despite these shortcomings, local anesthetics are fundamentally ideal for use in facial plastic surgery.

A rational approach to the outpatient management of lacerations in pediatric patients

Lacerations are a frequent reason for pediatric health care visits. Many are referred to EDs or to surgical specialists but may be treated by the pediatrician who has the time and interest in maintaining wound care skills. Although skin closure is often viewed as the primary event in wound care, local anesthesia and wound toilet are equally important aspects in which expertise is often undervalued. On occasion, patient anxiety and resistance complicates wound care, and a variety of sedative techniques facilitates completion of procedures that otherwise would require general anesthesia. Adherence to basic principles and the occasional use of innovations in wound care enable the clinician to bring about optimal outcomes.

Wound care

Soft-tissue injuries remain one of the most common problems encountered in the emergency department. This article discusses techniques to minimize pain during the evaluation and repair process, methods to decrease healing complications, and repair considerations.

Local anesthetics

BACKGROUND

Dermatology is dependent upon the effects of local anesthetics for diagnostic and therapeutic interventions. A working knowledge of the drugs' actions and interactions is necessary for anyone aspiring to optimize the benefits derived from the use of local anesthetic agents.

OBJECTIVE

This article reviews nerve physiology, pharmacology, classification of local anesthetics, adverse reactions (toxic, drug, allergic), local anesthetic use in pregnancy, alternatives to the "-caine" anesthetics, methods for reducing the pain of infiltration, and new agents under development.

CONCLUSION

Local anesthetics are safe and effective. With the understanding of the actions and interactions of this class of drugs, maximum patient safety and satisfaction can be achieved.

Comparison trial of four injectable anesthetics for laceration repair

OBJECTIVES

To compare four injectable anesthetics (buffered 1% lidocaine, buffered 1% lidocaine with epinephrine, plain 1% lidocaine with epinephrine, and 0.5% diphenhydramine with epinephrine) for pain of infiltration and effectiveness of anesthesia during suturing of minor lacerations.

METHODS

A prospective, randomized, double-blind, comparison trial of the above agents was performed in an urban ED; adults with simple linear lacerations without vascular compromise were enrolled. Physicians and patients ranked the pain of injection and suturing according to a 10-cm visual analog scale (VAS). Fisher's exact and Kruskal-Wallis tests were used to compare demographic data, and Kruskal-Wallis and Newman-Keuls tests were used in analysis of VAS rankings. The power of the study was 0.8 to detect a 1.4-cm difference in VAS readings, and 0.9 to detect a 1.7-cm difference.

RESULTS

Seven of 200 enrolled patients were excluded due to improper data collection and 13 were removed from final statistical analysis due to need for additional anesthetic (treatment failures), leaving 180 subjects for final analysis. Demographic data were similar for the four groups (p > 0.05). Diphenhydramine with epinephrine was significantly more painful to inject than was buffered lidocaine or buffered lidocaine with epinephrine, according to both the patients (p = 0.0003) and the physicians (p = 0.0037). The two buffered compounds were slightly less painful to inject than was lidocaine with epinephrine, but statistical comparisons did not reach significance. For anesthesia effectiveness, lidocaine with epinephrine and buffered lidocaine with epinephrine were statistically better than buffered lidocaine or diphenhydramine with epinephrine (p = 0.0001 for the patients and the physicians).

CONCLUSIONS

Buffered lidocaine with epinephrine and lidocaine with epinephrine were more effective anesthetics during suturing, according to both the physicians and the patients. There was a tendency toward less pain with infiltration in buffered solutions, compared with plain lidocaine with epinephrine, but the comparisons did not reach statistical significance. Diphenhydramine with epinephrine was more painful to inject than were buffered lidocaine with epinephrine and lidocaine with epinephrine, and was less effective anesthetically than the other three solutions.

1% lidocaine versus 0.5% diphenhydramine for local anesthesia in minor laceration repair

STUDY OBJECTIVE

Our previous study demonstrated that 1% diphenhydramine is as effective as 1% lidocaine for anesthesia in minor laceration repair, but that it also is more painful to inject. The purpose of this study was to compare 0.5% diphenhydramine to 1% lidocaine for pain of injection and adequacy of local anesthesia.

STUDY DESIGN

Randomized, double-blinded, prospective study from December 1991 through June 1992.

SETTING

University-affiliated, urban, inner-city emergency department.

PARTICIPANTS

Ninety-eight adults with linear skin lacerations without end-organ involvement were included; 48 received lidocaine and 50 received diphenhydramine.

INTERVENTIONS

Wounds were anesthetized with either diphenhydramine or lidocaine according to a random table. Both patients and physicians rated the pain of injection and suturing according to a standard, previously tested, visual analog scale.

MEASUREMENTS AND MAIN RESULTS

Patient and physician ratings were ranked without regard to treatment group, and rank sum scores were calculated for each group. General linear models and multivariate analysis of variance were used to analyze the ranked sum scores. The power of the study to detect a ranked sum difference of 15 was 0.8 with P < .05 considered statistically significant. Lidocaine was found to be significantly more effective as a local anesthetic for facial lacerations according to both patients (P < .002) and physicians (P < .004). There was no statistically significant difference between 1% lidocaine and 0.5% diphenhydramine for pain of injection or suturing for all other locations according to both patients and physicians. Overall mean and median scores for injection and suturing with diphenhydramine corresponded to the mild pain category according to patients.

CONCLUSION

Although not a replacement for lidocaine, diphenhydramine is a viable alternative for anesthesia in the repair of minor lacerations.