Epinephrine and local anesthesia revisited

Effect of a Preoperative Subacromial Epinephrine Injection on Visualization During Shoulder Arthroscopic Surgery: A Randomized Controlled Trial

Background

The addition of epinephrine to arthroscopic irrigation fluid has been shown to improve surgeon-rated visual clarity during shoulder arthroscopic surgery. Subacromial injections of epinephrine are also used for this purpose.

Purpose/Hypothesis

To assess the influence of a preoperative subacromial epinephrine injection on surgeon visualization during subacromial shoulder arthroscopic surgery. It was hypothesized that the epinephrine injection would improve surgeon-rated visual clarity.

Study Design

Randomized controlled trial; Level of evidence, 1.

Methods

A double-blind randomized controlled trial including adult patients undergoing shoulder arthroscopic surgery in the beach-chair position requiring visualization of the subacromial space was performed. Patients in the epinephrine group (n = 30) received a preoperative subacromial injection of bupivacaine and epinephrine, and those in the control group (n = 30) received a preoperative subacromial injection of bupivacaine. Epinephrine was added to the first 10 L of arthroscopic irrigation fluid in all patients. The primary outcome was surgeon-rated visual clarity throughout the procedure that was recorded at the end of the procedure using a visual analog scale (VAS) scored from 0 (worst) to 10 (best). Secondary outcomes included an increase in pump pressure during the procedure, total operative time, and the intraoperative use of blood pressure-modulating medications.

Results

Rotator cuff repair was performed in 88.3% of patients (25/30 epinephrine; 28/30 control), with multiple procedures performed in 85.0% of patients (23/30 epinephrine; 27/30 control). The VAS score for visual clarity was slightly better in the epinephrine group compared with the control group, although the difference was neither statistically nor clinically significant (8.3 ± 1.4 vs 7.5 ± 1.8, respectively; P = .09). There was no difference between the epinephrine and control groups in the need for an increase in pump pressure to improve visualization (8/30 [26.7%] vs 7/30 [23.3%], respectively; P > .99), total operative time (62.0 ± 19.4 vs 64.0 ± 30.1 minutes, respectively; P = .90), or the intraoperative use of blood pressure-modulating medications (20/30 [66.7%] vs 17/30 [56.7%], respectively; P = .60). There were no perioperative adverse events in either group.

Conclusion

The addition of a subacromial epinephrine injection before shoulder arthroscopic surgery resulted in a small improvement in visual clarity that was neither statistically nor clinically significant, with no adverse effects reported in this study.

Registration

NCT05244525 (ClinicalTrials.gov).

Cardiovascular and Vector-Cardiographic Effects of Articaine Anesthesia with Epinephrine

The aim was to investigate the vector-cardiographic effects in patients submitted to dental extraction under local anesthesia. Twenty-one patients aged 36.6 ± 12.4 years with a clinical and radiographic indication of mandibular or maxillary tooth extraction were enrolled. The intervention was a local or mandibular nerve block anesthesia with 4% articaine hydrochloride containing epinephrine (1 : 100,000; 40 mg/ml + 10 μg/ml). Blood pressure (BP), heart rate (HR), pulse wave transit time, and vector-cardiography data were recorded throughout 3 min before and 5 min after injection. QRS- and T-wave area under the curve (QRS AUC/T AUC) were calculated from the X/Y/Z QRS-vector or T-vector. T-wave amplitude (T AM), T AUC values, and diastolic BP decreased, and HR significantly increased 4 min after injection. A transient moderate HR drop and a corresponding small increase in T AM and T AUC immediately after the injection procedure may be explained by a decreased sympathetic tone due to psychological relief. In dental anesthesia, the systemic epinephrine effects are represented by a decrease in T AUC. These effects are most pronounced in the X- and Y-leads. The 3D determination of vector planes or amplitudes is a simple method to register the sympathetic tone in local anesthesia independently of possible effects on T-wave characteristics in single leads. In conclusion, T-wave determination may help to detect even small increases in systemic adrenaline concentration in case of accidental intravascular injection. At the same time, full rhythm and spatial ischemia control is provided.

Intrathecal dopamine and serotonin enhance motor and nociceptive blockades of lidocaine in rats

The study examined the effect of intrathecal injection of dopamine (serotonin) and/or lidocaine. Intrathecal injections of dopamine (serotonin or epinephrine), lidocaine, or their combination were carried out in male Sprague Dawley rats. Neurobehavioral examinations (motor and nociceptive reactions) were performed before and after spinal injection. Intrathecal serotonin (1.5 μmol), dopamine (2.5 μmol), epinephrine (1:40000), and lidocaine (0.75 μmol) produced 29%, 33%, 29%, and 54% nociceptive blockade, whereas serotonin (1.5 μmol), dopamine (2.5 μmol), or epinephrine (1:40000) produced a longer duration of nociceptive blockade than lidocaine (0.75 μmol) (P < 0.05). Serotonin (1.5 μmol), dopamine (1.25 and 2.5 μmol), or epinephrine (1:40000 and 1:80000) prolonged the duration and increased the potency of spinal motor and nociceptive blockades of lidocaine (50% effective dose, ED50) (P < 0.05). The motor and nociceptive blockades caused by lidocaine (ED50) plus dopamine (2.5 μmol) or lidocaine (ED50) plus epinephrine (1:40000) were more outstanding than lidocaine (ED50) plus serotonin (0.75 μmol) (P < 0.05). Our study provides evidence that intrathecal dopamine or serotonin produces spinal nociceptive blockade dose-dependently. Dopamine and serotonin are less potent than lidocaine in inducing spinal nociceptive blockade. When mixed with lidocaine solution, dopamine or serotonin improves spinal motor and nociceptive blockades. The motor and nociceptive blockade caused by lidocaine (ED50) plus dopamine (2.5 μmol) is similar to that caused by lidocaine (ED50) plus epinephrine (1:40000).

Hemodynamic protective effects of epinephrine containing saline irrigation in biportal endoscopic lumbar surgery

During endoscopic orthopedic surgery, epinephrine mixed with irrigation saline is frequently used to improve visualization. By monitoring hemodynamic parameters throughout the procedure, we intended to discover the hemodynamic effect of epinephrine between the normal saline irrigation fluid without epinephrine group (NS) and normal saline irrigation fluid with epinephrine group (EPI). Patients who underwent 1-level lumbar decompression or discectomy surgery without fusion between August 2019 and July 2020 were reviewed retrospectively. The hemodynamic parameters were compared between the NS group and EPI group. As a second endpoint, the incidence of hypotension and hypertension events, expected blood loss, postoperative nausea and vomiting and postoperative epidural hematoma were compared between the 2 groups. The 2 groups were homogeneous in terms of age, sex, weight, height, body mass index (BMI), ASA physical status (ASA PS), and diagnosis. The incidence of hypotension events (67.2 % in the NS group, 45.7 % in the EPI group, P =.015) and severe hypotension events (51.7 % in the NS group, 28.6 % in the EPI group, P = .015) were less frequent in the EPI group. Only epinephrine had a significant protective effect through a multivariable analysis (P = .027, OR = 2.361) and in severe hypotension events, only epinephrine had a significant protective effect through a multivariable analysis (P = .011, OR = 2.818), and EBL was the risk factor through a multivariable analysis (P = .016, OR = 1.002) We believe that the addition of epinephrine to irrigation saline has hemodynamic protective effects in patients who underwent endoscopic lumbar surgery.

Pharmacokinetics of adrenaline autoinjectors

Anaphylaxis is a medical emergency with adrenaline acknowledged as the first-line therapy. It is therefore important that patients have access to self-injectable adrenaline in the community. Manufacturers have been requested by European Medicine Regulators to generate pharmacokinetic data for these autoinjector devices. For the first time, these data provide an insight into how individual devices work in different populations, and how they compare. We undertook a thorough literature search and also accessed grey literature, using searches of medicine regulators' websites and freedom of information requests. The data demonstrate that it takes at least 5-10 min to achieve early peak plasma concentration for most devices. The specific autoinjector device seems to be the most important determinant of pharmacokinetics, with different devices giving rise to different plasma adrenaline profiles. Needle length does not seem to be the most important factor; rather, the force and speed of injection (which varies from one device to another) is likely to be of greater importance. In general, peak plasma adrenaline concentration is lower and time-to-peak concentration longer with increased skin-to-muscle depth. However, it is difficult to draw conclusions with the current available data, due to a lack of head-to-head comparisons, small numbers of study participants and the failure to acknowledge the biphasic nature of intramuscular adrenaline absorption for analysis purposes.

Comparison of the Effects of Articaine and Lidocaine Anesthetics on Blood Pressure after Maxillary Infiltration Technique: A Triple-Blind Randomized Clinical Trial

Background

Many dental procedures begin with local anesthesia. Subsequent increase in blood pressure in healthy individuals commonly occurs and may be affected by several factors such as mental and physical stress, painful stimuli, and action of catecholamines present in local anesthetic solutions. The aim of the present study is to compare the effects of 4% articaine with 1 : 100000 epinephrine and 2% lidocaine with 1 : 80000 epinephrine on blood pressure after maxillary infiltration technique.

Materials and Methods

In this randomized clinical trial, 102 patients were randomly assigned into two groups. One group received 4% articaine with 1 : 100000 epinephrine and the other group received 2% lidocaine with 1 : 80000 epinephrine for local maxillary infiltration. Systolic and diastolic blood pressure of both groups was determined twice: once before anesthetic injection and once 10 minutes after injection. The data were statistically analyzed using descriptive statistics, Shapiro–Wilks test, Levene test, chi-square test, independent t-test, and paired t-test.

Results

The mean systolic blood pressure after anesthetic injection in the articaine and lidocaine groups was 125.00 ± 5.67 and 123.16 ± 6.417 mmHg, respectively, showing no statistically significant difference (p=0.127). The mean diastolic blood pressure after injection was 85.02 ± 7.331 in the articaine group and 81.35 ± 12.815 mmHg in the lidocaine group. These values show no statistically significant difference (p=0.080). In both groups, the mean systolic and diastolic blood pressures have increased significantly (p < 0.001).

Conclusion

Articaine can be regarded as a suitable alternative for lidocaine for maxillary local infiltration, as no significant difference was observed between the effects of the two anesthetic solutions on blood pressure.

Local anaesthetics combined with vasoconstrictors in patients with cardiovascular disease undergoing dental procedures: systematic review and meta-analysis

OBJECTIVES

There is a lack of evidence about the use of local anaesthetics (LAs) in patients with cardiovascular diseases (CVD) in dental procedures. Thus, this study evaluated the safety of using LA with vasoconstrictor to determine the risk of cardiovascular events in patients with CVD.

DESIGN

Systematic review and meta-analysis.

METHODS

We have searched in Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (via Ovid), EMBASE (via Ovid), Healthstar (via Ovid), CINAHL, Web of Science and ClinicalTrials.gov for randomised controlled trials (RCTs) up to January 2020. We have included RCTs involving adults with CVD within two groups: intervention group with LA with vasoconstrictor and control group with LA without vasoconstrictor. The primary outcomes assessed were death, mortality by a specific cause, stroke, acute myocardial infarction, hospitalisation, pain, bleeding and arrhythmias. The secondary outcomes were ST segment depression, anxiety, adverse effects and changes in haemodynamic parameters. The data were pooled using random effects meta-analyses and the confidence in the estimates was verified using the Grading of Recommendations Assessment, Development and Evaluation (GRADE).

RESULTS

Ten RCTs (n=478 participants) were included. Most of them had a high risk of bias. There were more cases of pain and bleeding in groups without vasoconstrictor. Meta-analysis demonstrated a decrease in the systolic blood pressure with the use of LA with vasoconstrictor (standard mean difference -0.95, 95% CI -1.35 to -0.55) after procedure. Overall, for the other outcomes assessed there was no statistical difference. The quality of evidence was considered low according to the GRADE profile.

CONCLUSIONS

The results suggest that the use of LA with vasoconstrictors (epinephrine in low doses) is safe in patients with some types of CVD. However, the low quality of evidence demonstrated that literature needs further studies in order to confirm these results.

PROTOCOL REGISTRATION

PROSPERO (CRD42016045421).

Sympathetic Nerve Activity During Tooth Extraction in Women Is Related to Dental Anxiety Immediately After Surgery

PURPOSE

This study assessed the relationship between changes in autonomic nervous system activity during impacted mandibular third molar extraction and a patient's postoperative psychological status, with the overarching aim of informing the development of interventions to reduce dental phobia and anxiety. We hypothesized that changes in autonomic nervous system activity during tooth extraction are related to postoperative psychology.

METHODS

In our prospective cohort study, heart rate variability, heart rate (HR), and systolic blood pressure (SBP) were recorded during impacted mandibular third molar extraction. Heart rate variability values were dichotomized as either low frequency (LF 0.04-0.15 Hz) or high frequency (HF >0.15 Hz). The relative ratios (intraoperative vs baseline) of LF/HF, HF, HR, and SBP were divided into high and low groups based on their median values; the State Anxiety Inventory (STAI-S) results were compared between the groups with high and low relative ratios.

RESULTS

Data of 34 female patients (age, 28.23 ± 1.05 years) were analyzed. Postoperative STAI-S values were significantly lower than preoperative values. Patients in the high LF/HF group had a significantly lower change in STAI-S values than those in the low LF/HF group (P < .05). There were no significant differences in the change in STAI-S values between the groups with high and low HF, HR, or SBP.

CONCLUSIONS

Patients with low sympathetic nervous system activity had lower anxiety; the LF/HF index was the most sensitive indicator for changes in stress. Additional studies are required to develop optimal interventions for reducing sympathetic nerve activity in patients with dental phobia.

The effect of epinephrine on the perfusion index during ultrasound-guided supraclavicular brachial plexus block: a randomized controlled trial

The perfusion index (PI) is an objective tool used to assess a successful nerve block. Epinephrine is a widely used adjuvant to local anesthetics, and it may affect PI values because of the vasoconstrictive property. The aim of this study was to investigate the influence of epinephrine on PI as an indicator of a successful block in ultrasound-guided supraclavicular brachial plexus block (SCBPB). In this randomized controlled trial, 82 adult patients underwent upper limb surgery under SCBPB were recruited between July 2018 and March 2019 in a single tertiary care center. Participants were randomly assigned to one of two groups: non-epinephrine group (n = 41) or epinephrine group (5 mcg ml⁻¹, n = 41). The primary outcome was the comparison of the “PI ratio 10,” which was defined as the ratio of the PI 10 to the baseline. Receiver operating characteristic (ROC) curves were constructed to determine the accuracy of the PI in predicting the block success at each time interval. The PI ratio 10 was 2.7 (1.9–4.0) in non-epinephrine group and 3.3 (2.2–4.4) in epinephrine group (median difference: 0.4; 95% confidence interval [CI] − 1.1 to 0.2; P = 0.207). The ROC curves compared without group identification were not significantly different over time. The cut-off value for the PI and PI ratio at 5 min (PI ratio 5) were 7.7 (area under the ROC [AUROC]: 0.89, 95% CI 0.83–0.94) and 1.6 (AUROC: 0.94, 95% CI 0.90–0.98), respectively. The perineural epinephrine did not affect the PI following a SCBPB. The PI ratio 5 > 1.6 might be considered as a relatively accurate predictor of a successful SCBPB.

Trial registration: This study was registered at the Clinical Trial Registry of Korea (https://cris.nih.go.kr. CriS No. KCT0003006).

Hydroxychloroquine and the treatment of Sjogren syndrome, chronic ulcerative stomatitis, and oral lichen planus in the age of COVID-19

The Food and Drug Administration has recently approved the off-label use of hydroxychloroquine (HCQ) for the treatment of coronavirus disease 2019 (COVID-19) infections. However, a recent study not only failed to demonstrate HCQ efficacy but also documented a serious side effect of COVID-19 therapy with HCQ: QT prolongation and secondary arrhythmia. HCQ has been used as an off-label drug and deemed safe and effective for the treatment of oral lesions, such as Sjogren syndrome (SS), chronic ulcerative stomatitis (CUS), and oral lichen planus (OLP). Because HCQ may be appropriately used for the off-label treatment of SS, CUS, and OLP, relevant safety concerns regarding HCQ therapy with regard to dosage, drug-to-drug interactions, and QT prolongation and secondary arrhythmia are discussed here. Because of the possibility of decreased pharmacy supplies of HCQ, replacement drugs with respect to patients with SS, CUS, and OLP being successfully treated with HCQ are also discussed.

Junctional rhythm with severe hypotension following infiltration of lidocaine containing epinephrine during dental surgery

We experienced an unusual case of accelerated junctional rhythm with severe hypotension after infiltration of lidocaine containing epinephrine during dental surgery under general anesthesia. The patient's electrocardiogram exhibited retrograde P-waves following the QRS complex, which could be misinterpreted as ST-segment depression. As a temporary measure, administration of ephedrine restored the patient's blood pressure to normal levels. The importance of this case lies in its demonstration of an unexpected and serious side effect of commonly used epinephrine infiltration. This case also highlights the need for accurate interpretation of the electrocardiogram and comprehensive understanding of best practices for patient management.

Passive Cigarette Smoking Impact on Blood Pressure Response to Epinephrine and Felypressin in 1K1C Hypertensive Rats Treated or not with Atenolol

Background

Cigarette smoking is usually associated with hypertension and may modify vasoconstrictor response.

Objective

The present study aimed to analyze and compare the interaction of passive cigarette smoking and hypertension on epinephrine and felypressin blood pressure effects after intravascular injection.

Method

45-day male Wistar rats had the main left renal artery partially constricted and the right kidney removed (1K1C model). Rats were placed in the chamber for exposition to passive cigarette smoking (10 cigarettes) during 10 min (6 days a week). Hypertensive rats received atenolol (90 mg/kg/day) by gavage for two weeks. Hypotensive and hypertensive response, response duration and heart rate were recorded from direct blood pressure values. The significance level was 5%.

Results

Passive cigarette smoking increased maximal hypertensive response to epinephrine in normotensive and 1K1C-atenolol treated rats and to felypressin only in 1K1C-atenolol treated rats; it also reduced epinephrine hypotensive response. Epinephrine increased heart rate in normotensive and hypertensive passive smokers or non-smoker rats. Comparing the two vasoconstrictors, epinephrine showed greater hypertensive response in normotensive smokers, 1K1C-atenolol treated smokers and non-smokers. However, in normotensive-nonsmoker rats, felypressin showed a greater and longer hypertensive effect.

Conclusions

Our results suggest that passive cigarette smoking may reduce epinephrine vasodilation and increase hypertensive response when compared to felypressin. Therefore, felypressin may be safe for hypertensive patients to avoid tachycardia and atenolol interaction, but for normotensive and non-smoker patients, epinephrine may be safer than felypressin.

Forced degradation studies of norepinephrine and epinephrine from dental anesthetics: Development of stability-indicating HPLC method and in silico toxicity evaluation

Injectable solutions containing epinephrine (EPI) and norepinephrine (NE) are not stable, and their degradation is favored mainly by the oxidation of catechol moiety. As studies of these drugs under forced degradation conditions are scarce, herein, we report the identification of their degradation products (DP) in anesthetic formulations by the development of stability-indicating HPLC method. Finally, the risk assessment of the major degradation products was evaluated using in silico toxicity approach. HPLC method was developed to obtain a higher selectivity allowing adequate elution for both drugs and their DPs. The optimized conditions were developed using a C18 HPLC column, sodium 1-octanesulfonate, and methanol (80:20, v/v) as mobile phase, with a flow rate of 1.5 mL/min, UV detection at 199 nm. The analysis of standard solutions with these modifications resulted in greater retention time for EPI and NE, which allow the separation of these drugs from their respective DPs. Then, five DPs were identified and analyzed by in silico studies. Most of the DPs showed important alerts as hepatotoxicity and mutagenicity. To the best of our acknowledgment, this is the first report of a stability-indicating HPLC method that can be used with formulations containing catecholamines.

Difference in the Effects of Lidocaine With Epinephrine and Prilocaine With Felypressin on the Autonomic Nervous System During Extraction of the Impacted Mandibular Third Molar: A Randomized Controlled Trial

PURPOSE

Complications during local anesthesia include increased blood pressure and vasovagal reflex, which are caused by changes in the autonomic nervous system. The commonly used local anesthetic preparations are lidocaine to which the vasoconstrictor epinephrine is added (lidocaine-epinephrine) and prilocaine to which the vasoconstrictor felypressin is added (prilocaine-felypressin); however, their effects during dental treatment are unclear. We examined the effects of these 2 different local anesthetic preparations on the autonomic nervous system and circulation during extraction of the impacted mandibular third molar.

MATERIALS AND METHODS

In this randomized controlled trial, 40 female patients scheduled for extraction of an impacted mandibular third molar were randomized to the lidocaine-epinephrine group or prilocaine-felypressin group. Heart rate variability, heart rate, and systolic blood pressure were recorded during the experiment. Descriptive and bivariate statistics were computed, and the P value was set at .05.

RESULTS

The low frequency-high frequency ratio was significantly increased in the prilocaine-felypressin group during extraction compared with that in the lidocaine-epinephrine group (P < .05). In the lidocaine-epinephrine group, a significant decrease in the high-frequency component was observed during bone removal and extraction compared with that at rest (P < .05). In both groups, a significant increase in systolic blood pressure was observed during local anesthesia, incision and reflection of the flap, bone removal, separation of the tooth crown, extraction, and suturing compared with that at rest (P < .01).

CONCLUSIONS

This study is the first to investigate the differences in the influence of 2 different local anesthetic preparations on the autonomic nervous system during extraction of the mandibular third molar. Changes in circulatory dynamics during tooth extraction with the 2 different local anesthetic preparations were the result of a decrease in parasympathetic nervous activity with lidocaine-epinephrine and an increase in sympathetic nervous activity with prilocaine-felypressin.

Optimal Epinephrine Concentration and Time Delay to Minimize Perfusion in Eyelid Surgery: Measured by Laser-Based Methods and a Novel Form of Extended-Wavelength Diffuse Reflectance Spectroscopy

OBJECTIVE

This study investigates the hypoperfusion effects of epinephrine in local anesthesia in eyelid surgery. A novel form of extended-wavelength diffuse reflectance spectroscopy was evaluated.

METHODS

Blood perfusion in porcine eyelid flaps was measured using laser Doppler velocimetry and laser speckle contrast imaging, whereas the tissue response was measured using diffuse reflectance spectroscopy with a broad spectrum (450-1550 nm). Epinephrine was either injected cumulatively, 0.1 (1:10,000,000), 1.0 (1:1,000,000), 10 (1:100 000), and 100 μg/ml (1:10 000), to determine the dose-response relation, or given as a single dose (10 μg/ml). Control experiments were performed with saline or lidocaine.

RESULTS

Increasing concentrations of epinephrine resulted in a gradual decrease in tissue perfusion, measured by laser Doppler velocimetry and laser speckle contrast imaging, approaching a minimum after the injection of 10 μg/ml. Similar tissue response was observed with diffuse reflectance spectroscopy. The time from the injection of epinephrine (10 μg/ml) to the stabilization of hypoperfusion was 75 seconds. After administration of 10 μg/ml epinephrine, about 20% of the blood perfusion remained, supporting the use of epinephrine in eyelid flaps with a narrow pedicle.

CONCLUSIONS

10 μg/ml epinephrine appears to be adequate for vasoconstriction before oculoplastic surgery. Incisions need only be delayed for about 1 minute. Extended-wavelength diffuse reflectance spectroscopy appears to be a promising technique for monitoring the tissue response following changes in blood perfusion in plastic surgery reconstructions. However, more rigorous validation of the technique is required before it can be implemented in clinical practice.

Anesthetic Considerations for Patients on Antidepressant Therapy-Part I

Millions of patients take antidepressant medications in the United States for the treatment of depression or anxiety disorders. Some antidepressants are prescribed off-label to treat problems such as chronic pain, low energy, and menstrual symptoms. Antidepressants are a broad and expansive group of medications, but the more common drug classes include tricyclic antidepressants, selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, and monoamine oxidase inhibitors. A miscellaneous or "atypical" category covers other agents. Some herbal supplements that claim to have antidepressant activity will also be discussed. In Part I of this review, antidepressant pharmacology, adverse effects, and drug interactions with adrenergic agonists will be discussed. In part II, drug interactions with sedation and general anesthetics will be reviewed. Bleeding effects and serotonin syndrome implications in anesthetic practice will also be highlighted.

Epinephrine Vasoconstriction Effect Time in the Scalp Differs According to Injection Site and Concentration

BACKGROUND

There have been few studies of the action of epinephrine injected into scalp tissue, or whether the action of epinephrine differs according to vascular anatomy within the same surgical field. Effective perioperative control of bleeding is critical during hair transplantation due to its time-consuming nature.

OBJECTIVE

To identify the vasoconstriction time of epinephrine by concentration and injection site in the scalp tissue.

METHODS

Twenty-five volunteers were injected with epinephrine at concentrations of 1:400,000, 1:200,000, 1:100,000, and 1:50,000 in the path of the supraorbital artery on the anterior hairline in the midfrontal area (Point A) and at the frontotemporal junction of the frontal hairline (Point B). Laser Doppler was used to measure scalp blood flow, and vasoconstriction time at Points A and B with each concentration of epinephrine was recorded.

RESULTS

The duration of action of epinephrine increased in direct proportion with the concentration of epinephrine. The duration of vasoconstriction was shorter at Point A than at Point B, but this difference was only statistically significant at an epinephrine concentration of 1:50,000.

CONCLUSION

The vasoconstriction time of epinephrine in the scalp correlated positively with concentration, and the duration of vasoconstriction was longer at Point B than at Point A.

Synergistic Effects of Serotonin or Dopamine Combined With Lidocaine at Producing Nociceptive Block in Rats

BACKGROUND

The purpose of this experiment was to investigate the interactions of the local anesthetic lidocaine combined with an agent (serotonin or dopamine) as infiltrative anesthetics.

METHODS

Cutaneous analgesia was characterized by the blockade of the cutaneous trunci muscle reflex following 6 skin pinpricks on the rat back. Serotonin or dopamine at producing cutaneous analgesia in a dosage-dependent fashion was compared with lidocaine. Drug-drug interactions were calculated using the isobolographic analysis.

RESULTS

We revealed that serotonin, dopamine, and lidocaine provoked dose-related cutaneous analgesic effects. On the 50% effective dose basis, the rank of drugs' potency was found to be serotonin (1.70 [1.56-1.85] μmol) > lidocaine (5.18 [4.67-5.75] μmol) > dopamine (43.0 [40.9-45.2] μmol) (P < 0.01). At doses equivalent to their 25%, 50%, and 75% effective doses, serotonin or dopamine elicited a longer duration of action than lidocaine (P < 0.01) on producing cutaneous analgesia. Coadministration of serotonin or dopamine with lidocaine produced a synergistic effect.

CONCLUSIONS

The preclinical data showed that serotonin and dopamine produce dose-related cutaneous analgesic effects as an infiltrative anesthetic. Serotonin has a better potency with a much longer duration of action compared with lidocaine at provoking cutaneous analgesia. Serotonin or dopamine as an adjuvant increases the quality of lidocaine in cutaneous analgesia.

Hypoperfusion in response to epinephrine in local anaesthetics: Investigation of dependence on epinephrine concentration, spread of hypoperfusion and time to maximal cutaneous vasoconstriction

OBJECTIVES

The present study aimed to examine hypoperfusion in response to epinephrine following the administration of a local anaesthetic. The concentration of epinephrine that causes maximal hypoperfusion, the spread of hypoperfusion in the tissue and the time to the stabilization of hypoperfusion were investigated.

METHODS

Blood perfusion was monitored using laser Doppler velocimetry and laser speckle contrast imaging of random-pattern advancement flaps (1 × 4 cm) or intact skin on the pig flank. Epinephrine was either injected cumulatively (0.1, 1.0, 10 or 100 μg/ml) after injecting 20 mg/ml lidocaine, to determine the concentration response, or given as a single dose (12.5 μg/ml epinephrine+20 mg/ml lidocaine). Control experiments were performed with saline or lidocaine (without epinephrine).

RESULTS

Increasing concentrations of epinephrine resulted in a gradual decrease in skin perfusion, approaching a minimum after injecting 10 μg/ml. The area of hypoperfusion was 12 mm in radius, and the time from the injection to the stabilization of hypoperfusion was approximately 120 s. After the administration of 10 μg/ml epinephrine in flaps with small pedicle, 25% blood perfusion still remained.

CONCLUSIONS

Local anaesthetic with an epinephrine concentration of approximately 10 μg/ml appears to be adequate for vasoconstriction before surgery. Incisions were required to be delayed only for 2 min following local anaesthetic with epinephrine in pigs. The remaining 25% blood perfusion observed after the administration of epinephrine supports the use of epinephrine in flaps with a small pedicle. Obviously, these experimental findings must be clinically assessed before being considered for infiltration anaesthesia during plastic surgery procedures.

Evaluation of Anxiety Induced Cardiovascular Response in known Hypertensive Patients Undergoing Exodontia - A Prospective Study

INTRODUCTION

Anxiety towards exodontic procedures is a common occurrence in dental practice. In hypertensive patients this anxiety induced stress may have an effect on cardiovascular system which may be clinically significant.

AIM

To evaluate the cardiovascular changes in hypertensive patients that may manifest following anxiety induced stress in patients undergoing exodontic procedures under local anaesthesia.

MATERIALS AND METHODS

Eighty known hypertensive patients under medication reporting to Department of Oral and Maxillofacial surgery, Dayananda Sagar College of Dental Sciences Bangalore, Karnataka, India for extraction of teeth were taken up for the study. Anxiety was measured before local anaesthetic delivery using Amsterdam Pre-operative Anxiety and Information Scale (APAIS). Cardiovascular response data including blood pressure, heart rate, pulse rate, oxygen saturation and electrocardiographic changes were measured pre-operatively, immediately after local anaesthesia administration and Post-operatively at five, ten and fifteen minutes interval. Kruskal-Wallis test was used to compare continuous variables before and after the injection of local anaesthesia including heart rate, pulse rate, oxygen saturation, and blood pressure. Repeated-measures analysis of variance (ANOVA) was used to analyse the significance of changes in heart rate, pulse rate, blood pressure, and oxygen saturation over time between groups.Chi-square test was used to analyse the significance of electrocardiographic changes.

RESULTS

The results revealed that the mean anxiety score before administration of local anaesthetic was 9.91(S.D ±2.9) with a range 4-20. Severe preoperative anxiety (<12) was associated with significantly increased heart rate, pulse rate, systolic blood pressure. At the pre-injection phase the mean values were systolic blood pressure (130.72±9.2), diastolic blood pressure (81.6±7.7), heart rate (72.7±11.9) and oxygen saturation (95.2±1.9). These values were increased immediately after local anaesthetic delivery and this relation was statistically significant for all parameters except oxygen saturation. Electrocardiographic abnormalities were found before and after injection of local anaesthetic (p>0.001). One patient showed right bundle branch block pattern.

CONCLUSION

Dental anxiety impacts the effects of delivery of local anaesthesia on blood pressure, heart rate, pulse rate and electrocardiograph and is significantly associated with the increase in systolic blood pressure, heart rate, pulse rate and changes in electrocardiograph. Thus, present study supported that increased anxiety in hypertensive patients who underwent extraction is associated with cardiovascular changes.

B. K, Kannan R, Rajaram K, Rajendra Sharma A. 'Plain lignocaine' vs 'Lignocaine with vasoconstrictor'-Comparative evaluation of pain during administration and post-extraction wound healing by a double blinded randomized controlled clinical trial

OBJECTIVES

The aim of this double blinded randomized controlled clinical trial was to evaluate the efficacy of two local anaesthetic solutions, 'Plain lignocaine' and 'Lignocaine with vasoconstrictor', on pain during administration and post-extraction wound healing in patients undergoing therapeutic extractions.

MATERIALS AND METHODS

Fifty patients indicated for therapeutic extraction of upper and lower premolars for orthodontic purpose were recruited for the study. Using a split-mouth study design, anaesthesia was achieved using lignocaine with adrenaline on the control side and plain lignocaine on the study side. Pain perception was measured by modified visual analogue scale and wound healing was assessed by Landry's Wound Healing Index. Sample allocation was done by simple randomization. The outcome parameters compared were (1) pain during administration of LA and (2) post-operative healing after extraction. Data analysis involved Chi-square test to compare proportions between treatment groups and independent sample t-test to compare mean values between treatment groups. SPSS version 22.0 was used to analyse the data.

RESULTS

The study group demonstrated a statistically significant wound healing on day1 and day 3 between the study and control group with p < 0.001. In the control group 68% had severe pain, whereas only 2% had severe pain in the study group. The proportions between the two groups were statistically significant (p < 0.001).

CONCLUSION

The patients who received Plain Lignocaine perceived less pain during injection of local anaesthetic solution when compared to patients who received lignocaine with vasoconstrictor. The early post-operative wound healing was better in patients anaesthetized by Plain Lignocaine.

[Dermatosurgery in the elderly]

In recent decades, the portion of elderly has increased substantially due to demographic changes in developed countries. Dermatological surgery is particularly affected by this development, because a large proportion of the elderly suffer from skin tumors, which are primarily treated surgically. Physiological changes of age and multimorbidity, often associated with polypharmacy, present the treating physician with enormous challenges. What aspects of care are important? What must be considered? What are possible complications and how can they be prevented? These important questions are answered. Finally, selected surgical approaches for the care of very old patients are also described.

Propranolol combined with dopamine has a synergistic action in intensifying and prolonging cutaneous analgesia in rats

BACKGROUND

The purpose of the experiment was to assess interactions of dopamine with propranolol as an infiltrative anesthetic.

METHODS

After injecting the rats with four doses of drugs subcutaneously, the cutaneous analgesic effect of propranolol was compared with dopamine through the blockade of cutaneous trunci muscle reflex (CTMR) in response to local skin pinprick. Drug-drug interactions were examined via an isobolographic analysis.

RESULTS

We demonstrated that the action of propranolol and dopamine was dose dependent to skin infiltrative analgesia. On the ED(50) (50% effective dose) basis, the rank of drug potency was propranolol (11.3 [10.6-12.2]μmol) > dopamine (195 [188-205]μmol) (p < 0.001). At the equi-anesthetic doses (ED(25), ED(50), ED(75)), the block duration caused by dopamine was equal to that caused by propranolol. Coadministration of dopamine and propranolol exhibited a synergistic effect on infiltrative cutaneous analgesia.

CONCLUSIONS

The preclinical data showed that dopamine produced a lesser potency but a comparable duration of cutaneous analgesia compared to propranolol. Adding dopamine to propranolol potentiated and prolonged propranolol's cutaneous analgesic effect.

Hemodynamic changes following injection of local anesthetics with different concentrations of epinephrine during simple tooth extraction: A prospective randomized clinical trial

Background

Presence of epinephrine in local anesthetic cartridge increases the duration of local anesthesia (LA), decreases the risk of toxicity, and provides hemostasis. However, the unfavorable effects are increasing heart rate (HR) and raising blood pressure (BP). The aim was to evaluate hemodynamic changes in the BP, HR, and oxygen saturation (SpO2) of normal patients undergoing tooth extraction using LA with various epinephrine concentrations.

Material and Methods

A prospective randomized clinical trial was conducted on 120 patients who were divided randomly into 3 parallel groups according to the LA received. Group 1: lidocaine 2% with epinephrine 1:80,000 (L80). Group 2: articaine 4% with epinephrine 1:100,000 (A100). Group 3: articaine 4% with epinephrine 1:200,000 (A200). Inclusion criteria: normal patients whose BP < 140/90. Exclusion criteria: hypertension, cardiovascular disease, hyperthyroidism, pregnancy, and allergy to LA. BP, HR, and (SpO2) were evaluated in 3 different time points: 3 minutes before LA, 3 minutes after LA, and 3 minutes after extraction.

Results

Systolic blood pressure (SBP) significantly increased after injection of L80 and continued after extraction to be significant than pre-injection. SBP significantly increased after injection of A100 then decreased after extraction. In the group of A200, SBP insignificantly decreased after injection then increased after extraction. The increasing of SBP between time point 1and 2 was significantly higher in G1 than G3 (p=0.014). Diastolic blood pressure decreased after LA in the 3 groups; however it was significant only with L80, then increased after extraction for all.

Conclusions

The changings of DBP, HR and SpO2 after anesthesia and extraction showed no significant difference among the three groups. However, A200 had significant lesser effect on SBP than L80 and the least effect on other parameters. Therefore, A200 is considered safer than L80 and A100 and is recommended for LA before teeth extraction in normal patient.

Key words:Local anesthesia, lidocaine, epinephrine 1:80,000, articaine, epinephrine 1:100,000, epinephrine 1:200,000, tooth extraction.

Hemodynamic changes by drug interaction of adrenaline with chlorpromazine

Adrenaline (epinephrine) is included in dental local anesthesia for the purpose of vasoconstriction. In Japan, adrenaline is contraindicated for use in patients receiving antipsychotic therapy, because the combination of adrenaline and an antipsychotic is considered to cause severe hypotension; however, there is insufficient evidence supporting this claim. The purpose of the present study was to clarify the changes in hemodynamics caused by drug interaction between adrenaline and an antipsychotic and to evaluate the safety of the combined use of adrenaline and an antipsychotic in an animal study. Male Sprague-Dawley rats were anesthetized with sodium pentobarbital. A catheter was inserted into the femoral artery to measure blood pressure and pulse rate. Rats were pretreated by intraperitoneal injection of chlorpromazine or chlorpromazine and propranolol, and after 20 minutes, saline or 1 of 3 different doses of adrenaline was administered by intraperitoneal injection. Changes in the ratio of mean arterial blood pressure and pulse rate were measured after the injection of adrenaline. Significant hypotension and tachycardia were observed after the injection of adrenaline in the chlorpromazine-pretreated rats. These effects were in a dose-dependent manner, and 100 μg/kg adrenaline induced significant hemodynamic changes. Furthermore, in the chlorpromazine and propranolol-pretreated rats, modest hypertension was induced by adrenaline, but hypotension and tachycardia were not significantly shown. Hypotension was caused by a drug interaction between adrenaline and chlorpromazine through the activation of the β-adrenergic receptor and showed a dose-dependent effect. Low-dose adrenaline similar to what might be used in human dental treatment did not result in a significant homodynamic change.

A prospective randomized clinical trial compared the effect of various types of local anesthetics cartridges on hypertensive patients during dental extraction

Objectives: To evaluate hemodynamic changes of blood pressure and heart rate on hypertensive patients undergoing tooth extraction using various types of local anesthesia (LA). Study Design: A prospective randomized clinical trial was conducted on 45 hypertensive patients who were divided equally into 3 parallel groups according to LA received. Group 1: Lidociane 2% with epinephrine 1: 80,000. Group 2: Prilocaine 3% with Felypressin 0.03 IU/ml. Group 3: Mepivacaine 3% plain. Inclusion criteria: hypertensive patients, under medical management with blood pressure ≤ 159/99. Exclusion criteria: Blood pressure ≥160 /100 and patients receiving β blockers. Negative aspiration was mandatory before the injection of 2 cartridges of LA. Blood pressure and heart rate were evaluated by Electronic Sphygmomanometer and Pulse Oximeters in 3 different time-points; 3 minutes before LA, three minutes after LA and three minutes after extraction. Results: The mean of systolic blood pressure (SBP) had increased after LA injection, and then decreased after extraction in the 3 groups of patients. Increase of SBP after extraction with (Mepivacaine plain) was higher than (Lidociane with Epinephrine) and the difference was statistically significant using ANOVA (p=0.037). The differences in the mean heart rates and mean diastolic blood pressures in the 3 groups were not significant. Conclusions: The increase of blood pressure with Epinephrine and Felypressin is negligible. Therefore, it is safe to use 2 cartridges of Lidociane 2% with Epinephrine 1:80,000 or Prilocaine 3% with Felypressin 0.03 IU/ml for hypertensive patients whose blood pressure ≤ 159/99 provided negative aspiration is verified before injection.

Key words:Local anesthesia, tooth extraction, hypertensive patients, vasoconstrictors, epinephrine, Felypressin.

Takayasu's arteritis--report of a case with masquerading jaw pain

Takayasu's arteritis (TA) often referred to as pulseless disease, is a chronic inflammatory disorder affecting the aorta and its main branches. While the first reported case was documented in Japan in 1908, it does occur worldwide, but is more prevalent in young oriental females from China and Southeast Asia. The main complications of the disease are due to occlusion of major branches of the aorta. During the initial stages, one of the presenting symptoms may be jaw pain. This may prove to be a diagnostic challenge for the dentist, since many diseases cause orofacial pain and the diagnosis must be established before final treatment. A literature review of TA is presented along with clinical presentation and treatment modalities. A case report is also presented.

Local anesthetics for skin grafting and local flaps

In plastic surgery, there are many procedures that can be performed using local instead of general anesthesia. Not only can this help mitigate health care costs, but precious operating-room resources can also be directed to areas of greater need. Common procedures that can be performed under local anesthetics include skin grafts and local flaps. However, as not all patients are suitable for local anesthesia, careful patient selection is necessary to maintain the standard of care. This article describes the detailed surgical approach to using local anesthetics for skin grafts and local flaps.

Antidepressants relevant to oral and maxillofacial surgical practice

Background:

Depression is commonly associated with a high-carbohydrate diet, lack of interest in proper oral hygiene and xerostomia connected to the use of antidepressants. Patients often consult their dentists as a result of changes affecting the hard dental substance and the soft-tissues.

Aim:

The aim of this study was to identify adverse drug interactions between the antidepressants and medications commonly administered in dentistry in order to give practicing dentists an overview of the scientific literature.

Objective:

The objective is to identify the adverse drug interactions between antidepressants and medication commonly administered in dentistry.

Study Design:

The literature search was performed using PubMed, Cochrane and the specific search items. The review (1984-2009) focused on medicines used in dental practice (vasoconstrictors, non-opioid analgesics, non-steroidal anti-inflammatory drugs, antibiotics, antifungals and benzodiazepines).

Results:

There are various drug interactions between antidepressants and medicines used in dentistry. When two or more drugs are co-administered, a drug interaction must always be anticipated though many of the interactions are potential problems, but do not seem to be real clinical issues.

Conclusion:

The probability of a drug interaction can be minimized by careful history-taking, skillful dose adjustment and safe administration of the therapeutic agent.

Critical ENT skills and procedures in the emergency department

Injuries and illness to the ears, nose, and throat are frequently seen in the emergency department. The emergency medicine physician must be proficient in recognizing these injuries and their associated complications and be able to provide appropriate management. This article discusses the most common otorrhinolaringologic procedures in which emergency physicians must be proficient for rapid intervention to preserve function and avoid complications. A description of each procedure is discussed, as well as the indications, contraindications, equipment, technique and potential complications.

Comparative evaluation of oxygen saturation levels using pulse oxymeter during nonsurgical and surgical periodontal therapy in chronic periodontitis patients

BACKGROUND AND AIM

Monitoring is the global method of observation and data recording in relation to body organ and system function that afford constant information to ensure continuous evalutation of the patient's physical condition. Basic monitoring provides essential information for assessing the vital signs, both circulatory and respiratory, and fundamentally comprises the control of blood pressure (BP) and heart rate (HR) and rhythm. Pulse oxymetry is used to record HR and oxygen saturation. The objective of the study was to assess and compare hemodynamic changes by monitoring oxygen saturation level changes during periodontal surgical and nonsurgical therapy.

MATERIALS AND METHODS

A cross-sectional observational study was conducted in 30 chronic periodontitis patients. Patients were divided into two groups; Group A consisted of 15 patients undergoing surgical periodontal therapy, Group B consisted of 15 patients undergoing nonsurgical periodontal therapy. The hemodynamic changes were evaluated by monitoring HR and oxygen saturation level using pulse oxymeter (SaO₂). HR and SaO₂ were monitored continuously and registered pre-operatively, i.e. 10 minutes before the procedure, intra-operatively and postoperatively, i.e. 10 minutes after the procedure. One-way analysis of variance test (ANOVA) was performed for data analysis.

RESULTS

Both the groups showed a slight fall in oxygen saturation levels intraoperatively, but within the normal range. More decrease in oxygen saturation levels was observed in nonsurgical periodontal therapy as compared to surgical periodontal therapy at intraoperative levels. The differences in the values were statistically significant. There was no statistical difference seen in the postoperative and preoperative values.

CONCLUSION

Most of the hemodynamic changes induced during the periodontal therapy were within normal limits, taking into consideration the anxiety and stress produced by the surgical intervention. The hemodynamic change was more in nonsurgical as compared to surgical periodontal therapy.

Clinical study of hemodynamic changes comparing 4% articaine hydrochloride with 1:100,000 and 1:200,000 epinephrine

OBJECTIVE

To evaluate hemodynamic changes with the use of 4% articaine and 2 different concentrations of epinephrine (1:100,000 and 1:200,000) in the surgical removal of symmetrically positioned lower third molars.

STUDY DESIGN

A prospective, randomized, double-blind clinical trial was carried out involving 42 patients each undergoing 2 surgeries on separate occasions under local anesthesia with 4% articaine and either epinephrine 1:100,000 or 1:200,000. The following parameters were assessed at 4 different moments: systolic, diastolic, and mean blood pressure; heart rate; oxygen saturation; rate pressure product (RPP); and pressure rate quotient (PRQ).

RESULTS

The concentration of epinephrine did not affect diastolic blood pressure or oxygen saturation during the surgeries. Significant differences between were detected for heart rate, RPP, and PRQ (P < .05).

CONCLUSIONS

The epinephrine concentration (1:100,000 or 1:200,000) in a 4% articaine solution influences hemodynamic parameters without perceptible clinical changes in healthy patients undergoing lower third molar removal.

Efficacy of anesthetic agents to delay pain onset after periodontal surgery

The aim of this study was to evaluate the influence of 2 anesthetic agents on patients' postoperative pain perception after periodontal surgery. For this parallel-group, double-blinded, randomized clinical trial, 36 open flap debridement surgeries were performed on patients who presented with periodontal disease with clinical signs of inflammation after nonsurgical treatment on at least 1 quadrant. Patients were allocated to 1 of the following groups: group 1, 2% lidocaine with 1 ∶ 100,000 epinephrine; group 2, 2% mepivacaine with 1 ∶ 100,000 norepinephrine. Pain intensity was assessed using the visual analog scale during the first 8 hours after surgery. All patients received 750-mg acetaminophen tablets, which they were instructed to take as a rescue medication if necessary. The results demonstrated that postoperative pain intensity was statistically lower in group 2 than in group 1 at the 1-, 2-, and 3-hour periods after surgery, although the pain intensity for all groups could be considered mild. In conclusion, patients in both groups reported similar mild pain after periodontal surgery.

Does low-level laser therapy have an antianesthetic effect? A review

Because local anesthetics are vasodilators, they tend to be absorbed into the bloodstream from the operative field as a result of the vasodilation of peripheral arterioles. To counteract this vasodilation, vasoconstrictive agents are often included in local anesthetic solutions to provide a longer duration of anesthesia. Low-level laser therapy (LLLT) has the same benefits, such as microcirculation activation and more-efficient tissue metabolism, analgesic effects, and vasodilatation. If LLLT is used to prevent pain postoperatively, improvements in local circulation and increased vasodilatation may increase the absorption of a local anesthetic agent. This may reduce the duration of the anesthesia, thereby allowing postoperative pain management to begin sooner. The maximal intensity of pain occurs during the first hours after surgery, when the local anesthetic has worn off. Theoretically, postoperative pain control can be increased with the use of a local anesthetic with a more-prolonged action. If a treatment method has both analgesic and antianesthetic effects, then the method may block its own effects. We review whether LLLT applied postoperatively to operated-on areas has an antianesthetic effect, that is, whether pain in the first hours after surgery was greater for patients who received LLLT than for control patients. Not too much evidence supports the antianesthetic effects of LLLT. However, additional experimental and clinical studies must be performed to investigate the effects of LLLT on the duration of anesthesia.

Glucose levels and hemodynamic changes in patients submitted to routine dental treatment with and without local anesthesia

OBJECTIVE

The aim of this study was to (1) observe the extent to which hemodynamic and glucose measurements change in patients submitted to a dental procedure with and without a local anesthetic and a vasoconstrictor (LAVA; 2% mepivacaine with adrenaline 1100,000) and (2) correlate those parameters with the patients' anxiety levels.

METHOD

This was an unblinded, random, prospective, and observational study with paired groups. Patients were evaluated during two different consultations during which they either did or did not receive a local anesthetic/vasoconstrictor.

RESULTS

Thirty-seven patients ranging in age from 18 to 45 years (mean 30.4 ± 5.5 years) were evaluated. Hemodynamic parameters, including systolic blood pressure, diastolic blood pressure, heart rate, and glucose levels, did not change significantly in healthy patients, regardless of whether a LAVA was administered during the dental treatment.

CONCLUSION

The patients' anxiety statuses neither varied significantly nor showed any correlation with the studied hemodynamic parameters and glucose levels, regardless of whether local anesthetics were used.

Local anesthetics: uses and toxicities

Surgeons are asked to do more and larger procedures as outpatient procedures as the economics of medicine evolve. Indeed, we all carry out procedures on an outpatient basis that only a short time ago we would consider only on an inpatient basis. Further, procedures that had previously been performed under a general anesthetic are now being performed under local anesthesia. A good working knowledge of local anesthetics (LAs) will better enable the surgeon to meet those demands and to do so in a way that will enhance the patient's safety, experience, and comfort. Although the focus of this issue of Clinics is minor surgery, any meaningful discussion of LAs has to go a little further than a 3-mL syringe and a small amount of lidocaine.