Dose Of Lidocaine Research Articles

Greater Cephalad Extent of Thoracic Epidural Sensory Anesthesia After Lidocaine and Epinephrine Test Dose Correlates With Analgesic Consumption and Pain Burden After Uterine Fibroid Artery Embolization.

Ischemic pain after uterine fibroid artery embolization (UFAE) is often severe. We evaluated the sensory anesthesia extent from thoracic epidural catheter test injection of lidocaine 75 mg with epinephrine 25 μg as a predictor of analgesia effectiveness after UFAE. One hundred patients were studied. Pinprick and cold insensitivity were assessed from L3 to T4 at 5-minute intervals for 30 minutes after the test dose. Thoracic epidural management was standardized. Total epidural infusate and numeric rating of pain (0-10) scores were recorded. Pinprick or cold insensitivity at T9 to T10 dermatome was present in 94% of patients. Forty-six subjects (45%) achieved a sensory level at or above the T6 dermatome at 30 minutes. Median analgesic consumption in the first hour and at catheter discontinuation was greater in subjects with a sensory level above T6 compared with those below T6: first hour difference, 7 mL (95% confidence interval [95% CI], 0-12 mL; P = 0.02); difference at discontinuation, 21 mL (95% CI, 4-35 mL; P = 0.02). The area under the pain score by time curve for the first 24 hours was greater in patients with sensory levels above T6: difference 32 score · hour (95% CI, 12 score · h - 60 score · h; P = 0.001). Sensory anesthesia spread above the T6 dermatome 30 minutes after a test dose of 1.5% lidocaine was an independent predictor of the analgesic consumption after UFAE. Pain burden and oral opioid consumption were also increased in subjects who demonstrated a high sensory spread after the test dose.

Effects of topical and systemic administration of Eugenia caryophyllata buds essential oil on corneal anesthesia and analgesia.

Clinical studies suggest that essential oil of Eugenia caryophyllata (Clove) buds (EOEC) is efficacious in the treatment of dental pain. In the present study, we investigated the analgesic and local anesthetic effects of EOEC and its possible mechanisms of action in acute corneal pain in rats. EOEC was extracted by hydro-distillation in a Clevenger type apparatus from clove buds. The acute corneal pain was induced by applying a drop (40 µl) of 5 M NaCl solution on the corneal surface, and the numbers of eye wipes were counted during the first 30 s. The mechanical sensation of the cornea was evaluated by calibrated Von Frey filaments. Systemic administration of EOEC (100 and 200 mg/kg, SC) and morphine (2.5 and 5 mg/kg, IP) produced a significant antinociceptive effect in acute corneal pain. Pretreatment with naloxone or atropine prevented the EOEC-induced analgesia. However, L-arginine and methylene blue did not change the suppressive effect of EOEC on corneal pain response. Topical application of EOEC, eugenol and lidocaine significantly decreased corneal sensitivity. Combination treatments of eugenol (25 µg) with lidocaine (0.5%) and EOEC (50 µg) with lidocaine (0.5%) also significantly suppressed corneal sensitivity. Systemic administration of EOEC produced analgesia in the acute corneal pain through mechanisms that involved both opioidergic and cholinergic systems. In addition, topical instillation of EOEC, eugenol, and lidocaine produced local anesthesia in the rat cornea. Sub-anesthetic doses of EOEC or eugenol produced a significant local anesthetic effect when concurrently used with the sub-anesthetic dose of lidocaine.

Effect of a single dose of lidocaine and ketamine on intraoperative opioids requirements in patients undergoing elective gynecological laparotomies under general anesthesia. A randomized, placebo controlled pilot study

Background and goal of studythere is evidence that perioperative intravenous ketamine and lidocaine reduce postoperative pain, postoperative opioids consumption, shortens hospital stay and accelerates intestinal function recovery. However, it has not been studied the beneficial effects in the intraoperative period. The aim of this study was to evaluate the effect of a single dose of lidocaine and ketamine on intraoperative opioids requirements in patients undergoing elective gynecological laparotomies under general anesthesia. Materials and methodswe performed a single-centre, prospective, randomized, double-blinded, placebo-controlled study. We included 33 patients (11 in the ketamine group, 11 in the lidocaine group and 11 in the placebo group). Postoperative analgesia was accomplished by patient-controlled morphine. Patients were randomly assigned to receive either a 1.5 mg/kg of 2% lidocaine, 0.5 mg/kg of 5% ketamine or 0.9% saline bolus. The primary outcome was the opioids consumption during surgery. The secondary outcomes included: emergence time, pain scores, opioids consumption within 24 h after surgery and side effects. Resultsdecreased intraoperative opioids requirements were noted in the experimental groups (ketamine: 402.3 ± 106.3 and lidocaine: 397.7 ± 107.5, compared with saline: 561.4 ± 97.1); p = 0.001. We found a positive correlation between intraoperative opioids consumption and emergence time (r = 0.864, p < 0.001). There was no significant difference between the groups in VAS pain scores at rest within the first 24 postoperative hours. Total morphine consumption within 24 h after surgery did not differ significantly among the groups (placebo: 27.54 ± 11.75; ketamine: 30.95 ± 7.88; lidocaine 34.77 ± 10.25; p = 0.26). Postoperative nausea and vomiting were more common in placebo group (it was observed in 3 subjects in ketamine group, in 5 subjects in lidocaine group and in 9 subjects in placebo group; p = 0.027). Conclusionour results do not support the use of intraoperative single dose of lidocaine or ketamine to reduce postoperative pain and postoperative opioids consumption after open gynecological surgery. However, they seem to decrease intraoperative opioids requirements and shorten emergence time. Nevertheless, these findings should be validating in further studies with large sample size.

Convulsion tardive après instillation de lidocaïne pour bronchoscopie

Lidocaine toxicity usually appears rapidly and is directly correlated with plasma concentrations of the drug. We report a case of a late neurologic toxicity occurring after instillation of lidocaine during fibre-optic bronchoscopy. A patient with bronchiolitis obliterans underwent a diagnostic bronchoscopy. She received multiples instillations of Xylocaine(®) 2% (lidocaine). Three and a half hours later, she had a tonic-clonic seizure. Seven hours later, this recurred. Lidocaine plasma levels were in the toxic range at the time of the first seizure (18.32μg/mL) with a significant decrease in the concentration noted 24hours later. The slow absorption of lidocaine into the blood from the bronchial tree explains the delayed neurologic toxicity. Our observation is a reminder that complications can occur due to high doses of lidocaïne administrated by instillation. Thus, if the recommended dose of lidocaine is exceeded, it is essential to monitor patients closely for a prolonged period, especially those with fibrosing lung disease in order to avoid possible late toxicity.

Systemic exposure to monoethylglycinexylidide in extensive tumescent liposuction

Background Plastic surgery patients frequently request extensive liposuction on approximately 30 % of the total body surface area, which indicates that the total dose of lidocaine used might exceed the recommended level. Our previous study demonstrated that the risk of toxicity is low because the peak lidocaine level is below the toxic threshold (3 μg/mL). However, monoethylglycinexylidide (MEGX), the active metabolite of lidocaine, has not been measured in extensive liposuction operations.

Lidocaine-Induced Cardiac Arrest in the Emergency Department: Effectiveness of Lipid Therapy

BackgroundLocal anesthetics are commonly used in the emergency department (ED). Overdoses can lead to disastrous complications including cardiac toxicity and arrest. Recognition of local anesthetic systemic toxicity (LAST) is important; however, prevention is even more critical. Knowledge of proper lidocaine dosage can prevent LAST. LAST may be effectively treated with lipid emulsion therapy. Although the mechanism is not well understood, its use may have a profound impact on morbidity and mortality. Case ReportFifty milliliters of 2% lidocaine was infiltrated for local anesthesia in a 35-year-old woman during the incision and drainage of a labial abscess. Following the procedure, the patient complained of vomiting, with rapid progression to an altered mental state and seizure requiring endotracheal intubation for airway protection. Suspecting lidocaine toxicity, intralipids were ordered. While waiting for the intralipids, the patient decompensated and suffered pulseless electrical activity (PEA) cardiac arrest. A 100-mL bolus of 20% intralipids was administered 3 minutes into the resuscitation, after which return of spontaneous circulation occurred. The intralipid bolus was then followed by a continuous infusion of 0.25 mL/kg/minute, for an infusion dose of 930 mL. Despite a complicated hospital course, the patient was discharged home neurologically intact. Why Should an Emergency Physician Be Aware of This?We believe this patient's cardiovascular collapse was secondary to an iatrogenic overdose of lidocaine. This is one of the first cases to support the efficacy of intravenous lipids in the treatment of LAST in humans in the ED.

Reduction in Lidocaine Dose Administration for Flexible Bronchoscopy Following Order Set Implementation

Reduction in Lidocaine Dose Administration for Flexible Bronchoscopy Following Order Set Implementation

Rate-dependent activation failure in isolated cardiac cells and tissue due to Na+ channel block.

While it is well established that class-I antiarrhythmics block cardiac sodium channels, the mechanism of action of therapeutic levels of these drugs is not well understood. Using a combination of mathematical modeling and in vitro experiments, we studied the failure of activation of action potentials in single ventricular cells and in tissue caused by Na(+) channel block. Our computations of block and unblock of sodium channels by a theoretical class-Ib antiarrhythmic agent predict differences in the concentrations required to cause activation failure in single cells as opposed to multicellular preparations. We tested and confirmed these in silico predictions with in vitro experiments on isolated guinea-pig ventricular cells and papillary muscles stimulated at various rates (2-6.67 Hz) and exposed to various concentrations (5 × 10(-6) to 500 × 10(-6) mol/l) of lidocaine. The most salient result was that whereas large doses (5 × 10(-4) mol/l or higher) of lidocaine were required to inhibit action potentials temporarily in single cells, much lower doses (5 × 10(-6) mol/l), i.e., therapeutic levels, were sufficient to have the same effect in papillary muscles: a hundredfold difference. Our experimental results and mathematical analysis indicate that the syncytial nature of cardiac tissue explains the effects of clinically relevant doses of Na(+) channel blockers.

Comparing the Duration of Spinal Anesthesia Induced With Bupivacaine and a Bupivacaince-Lidocaine Combination in Trans-Urethral Resection of the Prostate (TURP).

Background:Spinal anesthesia is a safe anesthetic mode for transurethral prostate resection (TUPR). There are several studies assessing the effect of bupivacaine, lonely or accompanied by other drugs, on short duration operations. However, there is controversy regarding the exact combination.Objectives:The aim of the study was to compare the effects of spinal anesthesia with bupivacaine and low dose lidocaine with bupivacaine alone on postoperative pain in those undergoing transurethral resection of prostate (TURP).Materials and Methods:This was a randomized clinical trial performed in Shiraz university of medical sciences during one year. Eighty men scheduled for TURP were randomly assigned to receive spinal anesthesia with 1.5 mL bupivacaine 0.6% and 0.6 mL Lidocaine 1% or spinal anesthesia with 1.5 mL bupivacaine 0.5% in combination with 0.6 mL normal saline. The primary endpoint was the time lag between induction of spinal anesthesia and reaching the highest spinal block level. We also recorded the duration of spinal block declining to L1 level, operation duration and the admission duration.Results:Both study groups were comparable regarding the baseline characteristics. We did not find any difference between the two study groups regarding the duration of anesthetic block reaching the maximum level (P = 0.433) and duration of decreasing it to L1 (P = 0.189). The course of postoperative recovery and duration of hospital admission were also comparable between the groups (P = 0.661).Conclusions:Lidocaine does not have additive effects on duration and quality of spinal anesthesia with bupivacaine in those undergoing TURP.

Cardiovascular tolerance of intravenous lidocaine in broiler chickens (Gallus gallus domesticus) anesthetized with isoflurane

ObjectiveTo determine the cardiovascular effects of lidocaine infused intravenously (IV) in broiler chickens. Study designTwo phase study: Phase 1, randomized up-and-down study to determine effective dose 50 (ED50) for lidocaine; Phase 2, prospective randomized study to determine the cardiovascular effects of lidocaine. AnimalsSeventeen Ross-708 broiler chickens (Gallus gallus domesticus) [11 chickens (Phase 1) and 6 chickens (Phase 2)], weighing 2.6–4.3 kg. MethodsAfter induction of anesthesia with isoflurane and placement of monitoring equipment including invasive blood pressure, chickens were administered lidocaine IV. During Phase 1, using an up-and-down design, each animal received a variable dose selected based on the response of the previous animal. During Phase 2, each animal was administered 6 mg kg−1 of lidocaine IV over 2 minutes. Clinically irrelevant cardiovascular effects were defined as a relative decrease of heart rate (HR) and mean blood pressure (MAP) <30% subsequent to IV lidocaine administration. The ED50 was defined as the dose rate that would cause clinically irrelevant cardiovascular depression in 50% of the population. ResultsDuring Phase 1, using an up-and-down study design (n = 11), the ED50 of lidocaine was determined to be 6.30 mg kg−1 and 6.22 mg kg−1 (95% confidence interval, 5.30–7.13 mg kg−1), when calculated by Dixon's up-and-down method, and logistic regression, respectively. During Phase 2, following infusion of lidocaine (6 mg kg−1), no clinically relevant effects on HR or MAP were detected in any animal. Conclusions and clinical relevancePrevious reports state that the dose of lidocaine used in birds should be =4 mg kg−1. In this study, 6 mg kg−1 of lidocaine injected IV was not associated with adverse cardiovascular effects. These results suggest that the dose of 4 mg kg−1 can be exceeded, at least in chickens, and opens the possibility of other therapeutic uses for lidocaine in birds.

Consequences of temporary inhibition of the medial amygdala on social recognition memory performance in mice.

Different lines of investigation suggest that the medial amygdala is causally involved in the processing of information linked to social behavior in rodents. Here we investigated the consequences of temporary inhibition of the medial amygdala by bilateral injections of lidocaine on long-term social recognition memory as tested in the social discrimination task. Lidocaine or control NaCl solution was infused immediately before learning or before retrieval. Our data show that lidocaine infusion immediately before learning did not affect long-term memory retrieval. However, intra-amygdalar lidocaine infusions immediately before choice interfered with correct memory retrieval. Analysis of the aggressive behavior measured simultaneously during all sessions in the social recognition memory task support the impression that the lidocaine dosage used here was effective as it—at least partially—reduced the aggressive behavior shown by the experimental subjects toward the juveniles. Surprisingly, also infusions of NaCl solution blocked recognition memory at both injection time points. The results are interpreted in the context of the importance of the medial amygdala for the processing of non-volatile odors as a major contributor to the olfactory signature for social recognition memory.

EN3427: a novel cationic aminoindane with long-acting local anesthetic properties.

Currently approved local anesthetic drugs provide relatively brief local anesthesia that is appropriate and even desirable in some settings, but an extended duration of action beyond their capabilities would be a distinct benefit in other clinical situations. We implemented a drug discovery program that sought to identify novel local anesthetic molecules that specifically demonstrated a long-acting, preferential action on nociceptor sensory afferents that expressed transient receptor potential (TRP) channels. The hypothesis we tested was whether relatively membrane-impermeant local anesthetic molecules could confer long-lasting anesthesia if neuronal access was facilitated by TRP channel activation. The current work describes in vivo studies on a lead molecule that emerged from the discovery program, EN3427, in several rodent pain models. Studies were performed on male Sprague-Dawley rats using 2 models of acute mechanical paw-pinch-evoked and pinprick-evoked nociceptive pain. Behavioral responses to noxious stimuli were assessed at baseline, that is, before any pharmacologic intervention, and at various timepoints after a single perisciatic or subcutaneous administration of either EN3427 alone or in combination with lidocaine. Paw withdrawal thresholds or cutaneous trunci reflexes were quantified, and pre-post drug values were compared statistically with analysis of variance followed by post hoc Dunnett multiple range test. A single perisciatic injection of lidocaine (2%) produced relief of paw-pinch-evoked pain that was significantly different from baseline through to the 1-hour timepoint (Dunnett multiplicity-adjusted P = 0.0081), as assessed using paw withdrawal or vocalization end points. EN3427 (0.2%), in the same model, produced a long-lasting block, with pain thresholds being significantly above baseline through to the 18-hour timepoint (Dunnett multiplicity-adjusted P = 0.0002); the combination of EN3427 (0.2%) plus lidocaine (2%) produced even longer lasting analgesia, with pain thresholds being significantly above baseline through to the 24-hour timepoint (Dunnett multiplicity-adjusted P = 0.0073). Similar results were obtained with use of the pinprick approach. A single subcutaneous injection of lidocaine (2%) produced complete loss of sensation to cutaneous pinprick through 0.5 hours, but sensitivity thresholds were no different to baseline by the 1-hour timepoint, a similar injection of EN3427 alone (0.2%) produced a loss of sensation that was significantly different from baseline through the 8-hour timepoint (Dunnett multiplicity-adjusted P = 0.0045), and the combination of lidocaine (2%) plus EN3427 (0.2%) appeared to further enhance duration of analgesia, although this was significantly different from baseline only through the 10-hour timepoint (Dunnett multiplicity-adjusted P = 0.0048). Analgesic efficacy was dose related; using the combined injection approach, we found that increases in the dose of EN3427 with a fixed 2% lidocaine led to substantially extended analgesia and increasing doses of lidocaine combined with a fixed dose of EN3427 (0.2%) led to only modestly increased duration of action. The present studies demonstrate that a new molecular entity, EN3427, produces effective and long-lasting analgesia in 2 rodent pain models. The analgesic effects of EN3427 are significantly longer-lasting than lidocaine and are further extended when EN3427 is combined with lidocaine. The results are discussed with respect to a possible lidocaine-mediated TRP channel activation and facilitated neuronal access of EN3427, with subsequent entrapment conferring extended-duration efficacy.

Association of CYP450 single nucleotide polymorphisms with the efficacy of epidural ropivacaine during mastectomy.

Ropivacaine is frequently used for local anesthesia in the clinic and is metabolized by cytochrome P450 (CYP450) in the liver. CYP450 polymorphisms may alter the therapeutic efficacy of drugs in patients. In this study, we selected six CYP450 polymorphisms from the dbSNP and HapMap databases, using a combination of functional analysis and Tag SNP strategies and examined these polymorphisms for association with the efficacy of epidural ropivacaine in patients during mastectomy. A total of 256 patients with breast cancer received thoracic epidural anesthesia with ropivacaine for elective mastectomy with axillary lymph node clearance. Blood samples from patients were genotyped using the SNaPshot method. We found that patients with rs11636419 AG and GG genotypes required lower doses of epidural ropivacaine than patients with the AA genotype (corrected P = 0.024 and P < 0.001, respectively). Similarly, patients with rs17861162 CG and GG genotypes required lower doses of epidural ropivacaine than those with the CC genotype (corrected P = 0.018 and P < 0.001, respectively). There was no statistically significant association between the other four single nucleotide polymorphisms (SNPs) and total or mean ropivacaine dose, the onset of ropivacaine, or the initial dose of lidocaine. Our present data demonstrate that CYP1A2 SNPs rs11636419 and rs17861162 alter the sensitivity of epidural ropivacaine in patients undergoing breast cancer surgery. As such, detection of these two CYP1A2 SNPs may aid in the development of effective personalized treatments for breast cancer patients.

Potential advantages of an additional forearm rubber tourniquet in intravenous regional anesthesia: a randomized clinical trial.

Although the usefulness of an additional forearm tourniquet to conventional intravenous regional anesthesia (IVRA) has been reported, the forearm cuff may disturb the surgical field to some degree, especially in wrist surgery. In the present study, we assessed the clinical efficacy of a temporary additional forearm rubber tourniquet to the conventional upper arm tourniquet on the quality of IVRA. The study included 32 ASA physical status I and II adult patients undergoing elective hand surgery who were randomly allocated to either an additional forearm tourniquet group (Group F) or to a conventional upper arm tourniquet group (Group C). Upper arm tourniquet IVRA was established using 40mL of 0.5% lidocaine in Group C. Hypothetically enhanced forearm tourniquet IVRA was established using 10mL of 0.5% lidocaine with an additional forearm rubber tourniquet and then administering 30mL of 0.25% lidocaine after removing the forearm tourniquet in Group F. The sensory and motor block onset and recovery times, onset time of tourniquet pain, intraoperative fentanyl consumption, and incidence of local anesthetic toxicity were recorded. The numerical rating score (NRS) of perioperative and postoperative pain and quality of anesthesia were also assessed. Although the total dose of lidocaine in Group F was less and the sensory and motor block onset times were significantly shorter in Group F than those in Group C (P<0.05), there was no difference regarding sensory and motor block recovery times, onset time of tourniquet pain, intraoperative fentanyl consumption, NRS of perioperative and postoperative pain, and the quality of anesthesia in the two groups (P>0.05). Compared with Group C, the incidence of local anesthetic toxicity (i.e., dizziness, 43.8 vs 6.2%, P=0.02) was significantly decreased in Group F. The combination of the additional forearm and upper arm tourniquets with a smaller amount of local anesthetic achieved more rapid onset of sensory and motor block, a similar quality of anesthesia and a lower incidence of local anesthetic toxicity compared with the conventional technique.

Efficacy of paraspinal anesthetic block in patients with chronic pelvic pain refractory to drug therapy: a randomized clinical trial.

To determine whether paraspinal block reduces pain scores compared to placebo in women with chronic pelvic pain refractory to drug therapy. Subjects with chronic pelvic pain due to benign conditions and refractory to drug therapy were invited to participate in a randomized, double blind, superiority trial at a tertiary reference center. Subjects were randomly allocated to receive paraspinal anesthetic block with 1% lidocaine without epinephrine or placebo (control). Lidocaine was injected along the spinal process of the painful segment in the supra- and interspinal ligaments using a 25G X 2" needle. Placebo consisted of introduction of the needle in the same segment without injecting any substance. The main outcome measured was the pain score based on a visual analog scale at T0 (baseline), T1 (within 15 min after the procedure) and T2 (one week after the procedure). Data were statistically analyzed by ANOVA and the 95% confidence interval (95%CI). Mean age was similar for both groups, i.e., 51.2 (paraspinal anesthetic block) and 51.8 years (control). A blind examiner measured the degree of pain according to the visual analog scale from 0 (no pain) to 10 (worst pain imaginable). Based on the visual analog scale, the mean pain scores of the paraspinal anesthetic block group at T0, T1 and T2 were 5.50 (SD=2.92; 95%CI 3.84-7.15), 2.72 (SD=2.10; 95%CI 1.53-3.90), and 4.36 (SD=2.37; 95%CI 1.89-6.82), respectively. The difference between T0 and T1 was statistically significant, with p=0.03. Paraspinal anesthetic block had a small effect on visual analog scale pain score immediately after the injections, but no sustained benefit after one week. Further studies are needed to determine the efficacy of paraspinal anesthetic block with different lidocaine doses for the treatment of visceral pain of other causes.

Safe Extensive Tumescent Liposuction With Segmental Infiltration of Lower Concentration Lidocaine Under Monitored Anesthesia Care

Tumescent anesthesia makes it feasible to perform liposuction in an office setting. There are often patients who desire extensive liposuction on approximately 30% of total body surface area, which means the lidocaine total dose might be over the dosing recommendation. So the segmental infiltration is applied, although the concentration of lidocaine in tumescent fluid is gradually reduced to 0.0252%. Moreover, supplemental intravenous (IV) sedation using monitored anesthesia care is usually applied concurrently to help alleviate discomfort and pain of the patients during tumescent anesthetic infusion and fat extraction which in turn increases the risks of potential lidocaine toxicity due to possible drug interactions. This study was to demonstrate the safety of segmental infiltration of tumescent fluid with lower lidocaine concentration combined with IV sedation in extensive liposuction and determine whether the risk of lidocaine toxicity is increased in this protocol. Ten female patients who requested the extensive liposuction participated in the study. The targeted areas were divided into 2 segments and treated in turn in 1 session. Lidocaine (1600 mg) was infiltrated into the first segment, and approximately 928 mg lidocaine was subsequently infiltrated after accomplishment of the first segment operation. Serum levels of lidocaine were taken every 4 hours during the first 24 hours after the second infiltration. The average time of the procedure is 222 (33) minutes. The dose and total amount of lidocaine injected are 40.7 (5.8) mg/kg and 2528.2 (155.2) mg, respectively. The total volume of the infusates and aspirates are 9918.1 (494) and 6325 (1461.6) mL, respectively, the ratio of total infusates to total aspirates is 1.66 (0.45). The total aspirated fat and fluids are 3280 (1051.8) and 3045 (824.1) mL, respectively. The peak lidocaine levels [2.18 (0.63) μg/mL] occurred after 12 to 20 hours [16.4 (2.27) hours]. No significant correlation between dose per kilogram body weight or total dose of lidocaine infiltrated and its peak levels or time existed. The extensive liposuction covering the 30% total body surface areas was well tolerated by the patients under tumescent anesthesia in combination with the supplemental IV sedation. Our previous study on the fluid management has demonstrated the risk of hypovolemia or fluid overload is very low with this technique, although the patients who received only maintenance fluid (500 mL) in the operating room and could discharge and resume oral intake after 6 hours of recovery room stay. The adequate anesthesia support is available in our office-based setting with adequate recovery facilities in place. It has a high margin of safety, without increasing of lidocaine toxicity or adverse cardiopulmonary sequelae while using a segmental tumescent infiltration with lower concentration of lidocaine.

Comparison of the Concentrations of Lidocaine in Different Body Fluids/Tissues after Subarachnoid Space and Intravenous Administration of a Lethal Dose of Lidocaine

The objective of the study was to compare the concentration of lidocaine in different body fluids/tissues after subarachnoid space and intravenous administrations of a lethal dose of lidocaine. Totally 18 dogs were used in the experiment. Six dogs were given subarachnoid anesthesia, another were given an intravenous injection of a dose of 75 mg/kg weight of lidocaine hydrochloride in 5 min and the last 6 dogs were used as the blank control dogs and given a subarachnoid space injection or a femoral artery injection of the same volume of sodium chloride. As soon as its vital signs disappeared, each dog was dissected and the specimen, such as brain, cerebrospinal fluid (CSF) in lateral ventricle, CSF in subarachnoid space, spinal cord (cervical spinal cord, thoracic spinal cord, lumbar spinal cord, and waist spinal cord), heart, lung, liver, spleen, kidney, bile, urine, heart blood, peripheral blood, muscle in injection location, and muscle in no injection location, were collected for analysis of lidocaine immediately. Analysis was performed with gas chromatography-mass spectrometry (GC-MS). From the maximum to the minimum, the order of lidocaine concentration detected in the subarachnoid space-administered dogs was as follows: CSF in subarachnoid space, waist spinal cord, thoracic spinal cord, CSF in lateral ventricle, lumbar spinal cord, cervical spinal cord, lung, kidney, muscle in injection location, heart, brain, spleen, heart blood, liver, peripheral blood, bile, muscle in no injection location, and urine. The order of lidocaine concentration detected in the intravenously administered dogs was as followed: Kidney, heart, lung, spleen, brain, liver, peripheral blood, bile, heart blood, cervical spinal cord, thoracic spinal cord, muscle in injection location, lumbar spinal cord, muscle in no injection location, CSF in subarachnoid space, urine, and CSF in lateral ventricle. The maximum concentration of lidocaine was detected in the subarachnoid space CSF of subarachnoid space-administered dead dogs, while in intravenously injected dead dogs, the maximum concentration of lidocaine was detected in the kidney. Our study provides some useful data for the forensic identification of epidural anesthesia accidents to decide the way the lidocaine enters the body.

Addition of dexmedetomidine to a safe intravenous dose of lidocaine for intravenous regional anesthesia

Background Intravenous regional anesthesia (IVRA) is a simple and reliable type of regional anesthesia. However, it has some limitations such as tourniquet pain, lack of postoperative analgesia, and local anesthetic toxicity in case of tourniquet malfunction. Various additives to local anesthetics, such as opioids, NSAID, ketamine, and clonidine, are used. Aim The aim of this study was to evaluate the addition of dexmedetomidine to a safe intravenous dose of lidocaine for IVRA. Patients and methods a total of 50 patients undergoing elective superficial hand surgery were assigned into two groups: the L group and the LD group. In the L group, IVRA was achieved using 2 mg/kg lidocaine 2% alone, diluted with saline to a volume of 25 ml. In the LD group, IVRA was achieved using 2 mg/kg lidocaine 2% along with 0.5 mg/kg dexmedetomidine diluted with saline to a volume of 25 ml. The motor and sensory block onset and recovery times were assessed. Tourniquet pain and sedation score were assessed intraoperatively and postoperatively. The quality of anesthesia and the duration of analgesia were also recorded. Results Sensory and motor block onset times were shorter and recovery times were prolonged in the LD group. The quality of anesthesia was better in the LD group, and the fentanyl dose required intraoperatively was also lower in the LD group. The duration of postoperative analgesia was longer and the doses of lornoxicam required were lower in the LD group. Conclusion A safe intravenous dose of lidocaine can be used for IVRA for superficial hand surgery, and the addition of 0.5 mg/kg dexmedetomidine shortened the onset times for both sensory and motor blockade and improved the quality of anesthesia, with prolonged postoperative analgesia time.

Comparative evaluation of adding different opiates (morphine, meperidine, buprenorphine, or fentanyl) to lidocaine in duration and quality of axillary brachial plexus block.

Background:There is no agreement about the effect of adding opioids to local anesthetics in peripheral nerve blocks. The aim of this study was to investigate the effect of adding different opioids with equipotent doses of lidocaine in axillary brachial plexus block using ultrasonography and nerve locator guidance.Materials and Methods:In a prospective, randomized, double-blind clinical trial study, 72 adult patients aged 18–65 years old scheduled for orthopedic surgery of the forearm and hand with axillary brachial plexus block were selected and randomly allocated to four groups. Meperidine (pethidine), buprenorphine, morphine, and fentanyl with equipotent doses were added in 40cc of 1% lidocaine in P, B, M, and F groups, respectively. The onset and duration of sensory and motor blocks, severity of patients’ pain, duration of analgesia, hemodynamic and respiratory parameters, and adverse events (such as nausea and pruritus) during perioperative period were recorded.Results:The onset time for the sensory block was similar in the four groups. The onset time for the motor block was significantly faster in morphine and pethidine groups (P = 0.006). The duration of sensory and motor blocks was not statistically different among the four groups. The quality of motor blockade was complete in 100% of patients receiving pethidine or morphine and 77.8% of patients receiving buprenorphine or fentanyl (P = 0.021).Conclusion:In the upper extremity surgeries performed under axillary brachial plexus block addition of morphine or pethidine to lidocaine may be superior to other opioids (i.e. fentanyl and buprenorphine) due to better quality and quantity of motor blockade and faster onset of the block.

Electroencephalographic changes associated with antinociceptive actions of lidocaine, ketamine, meloxicam, and morphine administration in minimally anaesthetized dogs.

Effects of ketamine and lidocaine on electroencephalographic (EEG) changes were evaluated in minimally anaesthetized dogs, subjected to electric stimulus. Six dogs were subjected to six treatments in a crossover design with a washout period of one week. Dogs were subjected to intravenous boluses of lidocaine 2 mg/kg, ketamine 3 mg/kg, meloxicam 0.2 mg/kg, morphine 0.2 mg/kg and loading doses of lidocaine 2 mg/kg followed by continuous rate infusion (CRI) of 50 and 100 mcg/kg/min, and ketamine 3 mg/kg followed by CRI of 10 and 50 mcg/kg/min. Electroencephalogram was recorded during electrical stimulation prior to any drug treatment (before treatment) and during electrical stimulation following treatment with the drugs (after treatment) under anaesthesia. Anaesthesia was induced with propofol and maintained with halothane at a stable concentration between 0.85 and 0.95%. Pretreatment median frequency was evidently increased (P < 0.05) for all treatment groups. Lidocaine, ketamine, and morphine depressed the median frequency resulting from the posttreatment stimulation. The depression of median frequency suggested evident antinociceptive effects of these treatments in dogs. It is therefore concluded that lidocaine and ketamine can be used in the analgesic protocol for the postoperative pain management in dogs.