Effect of Lidocaine 2% on Bacterial Culture of Bronchial Fluid.

OBJECTIVE: To evaluate the action of 2% lidocaine on the culture results of bronchial fluid in patients suspected of having lower respiratory tract infections. STUDY DESIGN: Cross-sectional analytical study. PLACE AND DURATION OF STUDY: Shahid Sadoughi Hospital, Yazd, Iran, from November 2014 to November 2015. METHODOLOGY: Patients suspected of lower respiratory tract infections referred to bronchoscopy unit of the Hospital were included. Those with incomplete questionnaire and bronchoscopy contraindication were excluded. Bronchial fluid was aspirated before and after local application of 2% lidocaine and cultured, according to the suspected clinical diagnosis. Finally, statistical analysis was performed using SPSS software, version 17.0. For statistical comparisons, McNemar's test was used. Level of significance was kept at p <0.05. RESULTS: The mean age of the study population was 51.83 ±15.93 with a range of 25 - 80 years. Out of 130 patients, 60 patients had positive culture results. Nineteen (31.7%) cases had positive culture for tuberculosis and 41 (63.3%) cases had positive results for other bacteria before intervention that did not change after using 2% lidocaine (p=1). In 70 (53.84%) cases, results were negative before and after use of 2% lidocaine. CONCLUSION: No significant difference was found between culture results before and after the use of lidocaine. Therefore, lidocaine can be used during bronchoscopy to increase patient tolerance.

Estimated Maximal Safe Dosages of Tumescent Lidocaine.

BACKGROUND: Tumescent lidocaine anesthesia consists of subcutaneous injection of relatively large volumes (up to 4 L or more) of dilute lidocaine (≤1 g/L) and epinephrine (≤1 mg/L). Although tumescent lidocaine anesthesia is used for an increasing variety of surgical procedures, the maximum safe dosage is unknown. Our primary aim in this study was to measure serum lidocaine concentrations after subcutaneous administration of tumescent lidocaine with and without liposuction. Our hypotheses were that even with large doses (i.e., >30 mg/kg), serum lidocaine concentrations would be below levels associated with mild toxicity and that the concentration-time profile would be lower after liposuction than without liposuction. METHODS: Volunteers participated in 1 to 2 infiltration studies without liposuction and then one study with tumescent liposuction totally by local anesthesia. Serum lidocaine concentrations were measured at 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, and 24 hours after each tumescent lidocaine infiltration. Area under the curve (AUC∞) of the serum lidocaine concentration-time profiles and peak serum lidocaine concentrations (Cmax) were determined with and without liposuction. For any given milligram per kilogram dosage, the probability that Cmax >6 µg/mL, the threshold for mild lidocaine toxicity was estimated using tolerance interval analysis. RESULTS: In 41 tumescent infiltration procedures among 14 volunteer subjects, tumescent lidocaine dosages ranged from 19.2 to 52 mg/kg. Measured serum lidocaine concentrations were all <6 µg/mL over the 24-hour study period. AUC∞s with liposuction were significantly less than those without liposuction (P = 0.001). The estimated risk of lidocaine toxicity without liposuction at a dose of 28 mg/kg and with liposuction at a dose of 45 mg/kg was ≤1 per 2000. CONCLUSIONS: Preliminary estimates for maximum safe dosages of tumescent lidocaine are 28 mg/kg without liposuction and 45 mg/kg with liposuction. As a result of delayed systemic absorption, these dosages yield serum lidocaine concentrations below levels associated with mild toxicity and are a nonsignificant risk of harm to patients.

Intraperitoneal local anesthetics have predominant local analgesic effect: a randomized, double-blind study.

BACKGROUND: It remains unclear whether analgesia from intraperitoneal local anesthetics is via local or central mechanisms. This double-blind clinical trial tests the hypothesis that intraperitoneal local anesthetic is superior to continuous IV infusion for pain management. Primary outcome was morphine consumption during 0 to 24 h. METHODS: Informed consent was obtained from 60 patients, age 30 to 75 yr, American Society of Anesthesiologists physical status I to II, undergoing abdominal hysterectomy. A computer-generated program randomized patients in parallel arms to group IV: continuous infusion of lidocaine 50 mg/h (10 ml) IV and saline 10 ml/h intermittently intraperitoneal; group IP: injection of lidocaine 50 mg/h (10 ml) once every hour intraperitoneally and continuous infusion of saline 10 ml/h intravenously; and group P (placebo): saline 10 ml/h both intravenously and intermittent intraperitoneal injection. Postoperative morphine consumption, pain intensity, recovery, home discharge, and lidocaine concentrations were measured. RESULTS: Morphine consumption during 0 to 24 h was lower in group IP versus group IV, mean difference -22.6 mg (95% CI, 11.4 to 33.8; P < 0.01). No difference was seen between group IV and group P. The total mean plasma concentration of lidocaine in group IP was significantly lower than group IV, 0 to 4.5 h postoperatively (P = 0.03) with no evidence of systemic toxicity. Pain intensity and other recovery parameters were similar between the groups. CONCLUSION: The lower supplemental morphine consumption and plasma lidocaine concentration in group IP would confirm that the effects of local anesthetics are likely to be predominant via local intraperitoneal receptors or anti-inflammatory effects and not via central mechanisms alone.

Topical lidocaine enhanced by laser pretreatment: a safe and effective method of analgesia for facial rejuvenation.

BACKGROUND: Injectable forms of anesthesia for nonsurgical facial rejuvenation, although efficacious, are uncomfortable for the patient. Preclinical studies have demonstrated that laser pretreatment at low energies enhances absorption of topical lidocaine. OBJECTIVES: The authors assess the safety and efficacy of laser-assisted transdermal delivery of topical anesthetic. METHOD: Ten patients were split into 2 groups (A and B). All patients received 15 g of BLT (20% benzocaine, 6% lidocaine, and 4% tetracaine triple anesthetic cream) for 20 minutes with no occlusion. Then the cream was removed and the first blood draw taken. Group A patients were pretreated with the full ablative laser and group B patients with a fractional ablative laser to the full face. A further 15 g BLT was applied for another 20 minutes. Group A patients then underwent full ablative laser treatment, and group B received fractionated ablative laser treatment. Blood draws were taken at 60, 90, 120, 180, and 240 minutes after the initial topical anesthetic application, and the serum was analyzed for lidocaine and monoethylglycinexylidide (MEGX) levels. Patients were asked to rate the pain felt at intervals during the procedure. RESULTS: No patient required supplemental nerve blocks. Pain scores were equivalent at the end of the first pass for both groups (P = .436). Group A patients had significantly lower pain scores at the start of the second laser treatment (P = .045), but pain scores became equivalent by the end (P = .323). Combined serum lidocaine and MEGX levels were significantly higher in group A patients up to 90 minutes (peak average of 0.61 µg/mL for group A and 0.533 µg/mL for group B; P = .0253), which corresponded to greater initial analgesic effect. CONCLUSIONS: Data from this study demonstrate that topical anesthetic for facial rejuvenation can be enhanced with laser pretreatment while maintaining safe blood serum levels. Further studies should examine optimal application amount and time to allow safe multipass facial rejuvenation without the need for invasive nerve blocks.

Comparison of lidocaine metabolism for different anesthesia techniques in rabbits with liver disease.

OBJECTIVE: This study was designed to investigate the serum lidocaine concentrations (SLC) after local infiltration anesthesia (IA) and mandibular anesthesias (MA) in rabbits with carbon tetrachloride (CCl4)-induced chronic liver damage (CLD). STUDY DESIGN: Fourteen rabbits were administered CCl4 in group 1, MA (CLD-MA; n = 7); in group 2, IA (CLD-IA; n = 7); in group 3, MA (H-MA; n = 7); and in group 4, IA (H-IA; n = 6) was performed. SLC were measured. RESULTS: SLC showed difference over time. At the 10th minute, mean SLC in IA groups were higher than in MA groups. At the 120th minute, the highest mean concentration was found in the CLD-IA group. CONCLUSIONS: SLC increases in CLD, and serum lidocaine concentration after IA in the mandibular anterior region is higher than it is after MA.

Topical anaesthesia alleviates short-term pain of castration and tail docking in lambs.

OBJECTIVE: To investigate the effect of a topical anaesthetic formulation on pain alleviation, wound healing and systemic levels of local anaesthetic actives in lambs undergoing castration and tail docking. DESIGN: Three placebo-controlled and/or randomised experiments were conducted using three groups of Merino lambs (n = 62, 68 and 19) undergoing routine castration and tail docking. PROCEDURE: Surgical castration, with either surgical or hot-iron tail docking, was performed with and without the application of topical anaesthetic (Tri-Solfen) or placebo. The effects of this procedure were compared with those of rubber ring castration and tail docking, and of the handled but unmarked controls. Wound pain was assessed using calibrated Von-Frey monofilaments over a 4-h period, pain-related behaviour was assessed over 5 h, wound healing was assessed at 14 and 28 days, and the plasma levels of lignocaine and bupivacaine were determined. RESULTS: Rapid and up to 4 h primary hyperalgesia developed following surgical castration and tail docking in the untreated and placebo-treated lambs. It was absent in the castration wounds, and significantly reduced in the tail-docking wounds, of the treated lambs. Hot-iron docking was associated with mild and transient secondary hyperalgesia, which was abolished by the topical anaesthesia. There was a significant reduction in pain-related behaviours in treated lambs, which were not significantly different in their behaviour to the sham-operation handled controls. Plasma lignocaine and bupivacaine levels were below the toxic thresholds in all tested lambs. CONCLUSION: Topical anaesthesia alleviates wound pain and significantly reduces pain-related behaviours in lambs undergoing surgical castration plus surgical or hot-iron tail docking, without a negative effect on wound healing or a risk of systemic toxicity.

Atomised lidocaine for airway topical anaesthesia in the morbidly obese: 1% compared with 2%.

Airway anaesthesia using atomised lidocaine for awake oral fibreoptic intubation in morbidly obese patients was evaluated using two doses of local anaesthetic. In this randomised, blinded prospective study, 40 ml of atomised 1% (n = 11) or 2% (n = 10) lidocaine was administered with high oxygen flow as carrier. Outcomes included time for intubation, patient tolerance to airway manipulation, haemodynamic parameters, the bronchoscopist's overall satisfaction, and serial serum lidocaine concentrations. Patients receiving lidocaine 1% had a longer mean (SD) time from the start of topicalisation to tracheal tube cuff inflation than those receiving lidocaine 2% (8.6 (0.9) min vs 6.9 (0.5) min, respectively; p < 0.05). Patients in the 1% cohort demonstrated increased responses to airway manipulation (p < 0.0001), reflecting lower bronchoscopist's satisfaction scores (p < 0.03). Haemodynamic responses to topicalisation and airway manipulation were similar in both groups. Peak plasma concentration was lower in the 1% group (mean (SD) 1.4 (0.3) and 3.8 (0.5) microg.ml(-1), respectively; p < 0.001). Airway anaesthesia using atomised lidocaine for awake oral fibreoptic intubation in the morbidly obese is efficacious, rapid and safe. Compared with lidocaine 1%, the 2% dose provides superior intubating conditions.

Plasma levels of lignocaine during tumescent local anaesthesia in children with burns.

The aim of the study was to assess the changes in plasma lignocaine concentrations over time when the tumescent solution is injected into subcutaneous tissue of children undergoing surgical treatment of burns. Sixteen consecutive children with burns were studied using a prospective study design. After induction of general anesthesia, tumescent lignocaine solution 0.1% with adrenaline in nine patients (adrenaline group) for the treatment of postburn sequelae, or without adrenaline in seven patients (no-adrenaline group) for the treatment of acute burns, was injected into the subcutaneous tissue of burned and donor areas. The maximum dose of lignocaine was 7 mg/kg. Blood samples were collected before the start of the injection as well as at 5, 10, 20, 30, 45, 60, 90 minutes and 2, 4, 8, 12, 24 hours after the infiltration was completed. The course of lignocaine plasma levels was chaotic in the adrenaline group and biphasic during the first hour in the no-adrenaline group. The maximum plasma concentration of lignocaine was 2.09 microg/ml in the adrenaline group and 1.98 microg/ml in the no-adrenaline group. No adverse reactions were noted. Tumescent injection in burned children resulted in lignocaine plasma concentrations that were always lower than the often quoted value of 5 microg/ml, considered to be the toxic plasma threshold in adults. These data lend support to the use of lignocaine using the tumescent technique in burned paediatric patients.

Optimization of lidocaine application in tumescent local anesthesia.

Tumescent local anesthesia is based upon the infusion of large volumes of neutralized anesthetic solutions, mainly lidocaine, at very low concentrations. This results in the paralysis of sensory nerve endings and minute nerve twigs, leading to a reduction in pain. The aim of this study was to assess the safety of lidocaine application in tumescent local anesthesia on different regions of patient's bodies. Measures of safety included the analysis of lidocaine concentrations and its pharmacokinetic parameters. In total, 48 patients were infused with tumescent anesthesia in the hypogastrium, buttocks and thighs, axillae, breasts, trunk, and face and neck areas. Lidocaine was infused in doses ranging from 5.2-40 mg/kg b.w., and in concentrations of 0.05% (hypogastrium, buttocks, thighs) or 0.1-0.15% (axillae, breasts, trunk, face, neck), using a total amount of 300-3200 mg. As the peak lidocaine concentration did not exceed 5 microg/ml (commonly known as the toxic threshold), the results of our study indicate that the doses used (not exceeding 40 mg/kg b.w.) are completely safe for patients undergoing tumescent anesthesia in different body areas. The observation of statistically significant correlations between both the dose and the total amount of lidocaine administered and its peak plasma concentration, together with the lack of correlations between the dose and the amount and the time taken to reach peak concentration, allows the safety of each anesthetic dose to be predicted. An analysis of the heterogeneous dynamics of lidocaine plasma concentration changes in tumescent anesthesia in different body areas indicates that both the rates and the degrees of absorption and elimination depend on the area of infiltration; this is in turn related to the vascularization of any given area. The study of lidocaine concentration and pharmacokinetic parameters also showed that there may potentially be a higher risk of a large anesthetic concentration developing within a short period of time during anesthesia of the upper parts of the body. During tumescent anesthesia, significantly higher plasma concentrations of lidocaine were observed in the face and neck than in the hypogastrium, buttocks and thighs, axillae, breast and trunk 0.5 to 4 h after its infusion. This indicates the need for carefully conducted patient observations immediately after infiltration into the aforementioned areas.

Efficacy of lidocaine for pain control in subcutaneous infiltration during liposuction.

BACKGROUND: Liposuction remains the most commonly performed aesthetic surgical procedure in the United States. Preoperative infiltration of the subcutaneous tissues with a wetting solution has become standard. These solutions typically contain some amount of lidocaine for pain control. High doses of lidocaine have been demonstrated to be safe, but large amounts of this cardioactive agent during elective cosmetic procedures may be unnecessary. OBJECTIVE: A study was designed to examine the effects of wetting solutions with lower concentrations of lidocaine on perioperative pain. METHODS: Seventeen patients were prospectively randomized to subcutaneous infiltration with one of 3 different lidocaine concentrations: 10 mg/kg, 20 mg/kg, or 30 mg/kg. Intra- and postoperative lidocaine and monoethylglycinexylidide (MEGX) plasma concentrations were measured and the total intraoperative inhalation gas requirements and minimum alveolar concentrations were recorded. Postoperative pain medication requirements were recorded and morphine equivalents were calculated. Patient pain level was subjectively assessed by using a visual analog pain scale. RESULTS: There was no difference in the intraoperative lidocaine or MEGX concentrations between any of the 3 groups. There was also no statistical difference between the 3 groups when comparing intraoperative inhalational gas requirement, postoperative morphine equivalence requirements, or subjective pain using the visual analog scale. CONCLUSIONS: Decreasing concentrations of lidocaine in infiltrative wetting solutions did not significantly affect intraoperative anesthesia requirements or postoperative pain with liposuction. Lower concentrations of lidocaine can effectively be used, use of any lidocaine may be unnecessary. Future investigations may examine whether total elimination of lidocaine yields similar results in terms of anesthesia requirements and postoperative pain.

Study on the pharmacokinetics drug-drug interaction potential of Glycyrrhiza uralensis, a traditional Chinese medicine, with lidocaine in rats.

Drug-drug interaction potentials of an herbal medicine named Glycyrrhiza uralensis was investigated in rats via in vitro and in vivo pharmacokinetic studies. P(450) levels and the metabolic rate of lidocaine in the liver microsomes prepared from different treatment groups were measured. In a separate in vivo pharmacokinetic study, the pharmacokinetic parameters of lidocaine in plasma and urine were estimated. P(450) levels in the rats pretreated by Glycyrrhiza uralensis were significant higher than that in the non-treatment control. The increase in P(450) levels was dose-dependent. Glycyrrhiza uralensis (1 and 3 g/kg) increased P(450) levels by 62% and 91%, respectively, compared with the non-treatment control (0.695 nmol/mg protein). The metabolic rate of lidocaine in the liver microsomes was significantly higher in the herb pretreated rats. The pharmacokinetic profile of lidocaine was significantly modified in the rats with the herbal pretreatment. Elimination half-lives were shortened by 39%, and total clearances were increased by 59% with the pretreatment of Glycyrrhiza uralensis. In conclusion, Glycyrrhiza uralensis showed induction effect on P(450) isozymes. Efficacy and safety profiles of a drug may be affected when the herbal products or herbal prescriptions containing the plant medicine were concomitantly used.

Lidocaine, MK-801, and MAC.

BACKGROUND: Previous studies have found that the local anesthetic/sodium channel blocker lidocaine decreased MAC by maximum amounts approximately equal to the decreases produced by dizocilpine (MK-801), a N-methyl-d-aspartate (NMDA) receptor antagonist. Blockade of sodium channels by inhaled anesthetics has been suggested as a possible cause for impairment of transmission through NMDA receptors. We postulated that the net effect of lidocaine and MK-801 on MAC would be the same, albeit by affecting NMDA neurotransmission at different points. METHODS: We measured the effect of various lidocaine infusions on the MAC of cyclopropane, halothane, isoflurane, and o-difluorobenzene in rats. We also measured the effect of concurrent lidocaine-MK-801 infusion on the MAC of isoflurane and o-difluorobenzene. RESULTS: Our data contradicted our predictions. (a) We found no limit to the effect of lidocaine infusion, in some cases finding that lidocaine, alone, produced immobility; (b) lidocaine infusion did not decrease the MAC of o-difluorobenzene differently from the MAC of other inhaled anesthetics; and (c) the addition of MK-801 equally affected the decrease in MAC produced by lidocaine infusion for isoflurane versus o-difluorobenzene. CONCLUSION: Lidocaine does not primarily decrease MAC by decreasing the release of glutamate from nerve terminals.

[Tumescent anaesthesia for dermatological surgery. Plasma concentrations of lidocaine and prilocaine]. / Tumeszenzlokalanästhesie bei dermatologischen Eingriffen. Plasmakonzentrationen von Lidocain und Prilocain.

BACKGROUND: Tumescent anaesthesia is currently used for several dermatological procedures. The objective of this study was to determine the plasma concentrations of local anaesthetics under real operating conditions with this anaesthetic technique. METHODS: A total of 31 patients received 3 different anaesthetic solutions with prilocaine and lidocaine for several surgical procedures. The concentrations of local anaesthetics, methemoglobin, epinephrine as well as the occurrence of adverse reactions were determined 30 min, 1 h, 3 h, 6 h, 12 h and 24 h after administration RESULTS: Maximum plasma concentrations of prilocaine were measured predominantly after 3 and 6 h, for lidocaine after 6 h. In two patients maximum plasma levels occurred 24 h after infiltration. Although toxic concentrations were not exceeded, side-effects could be observed in four patients. CONCLUSIONS: Even if the measured concentrations of local anaesthetics appeared to be safe, slight and moderate side-effects could be observed in 12.9% of cases. Maximum plasma levels of local anaesthetics may still occur 24 h after administration.

Study of a combined percutaneous local anaesthetic and the TDS system for venepuncture.

Transdermal Delivery System (TDS) is a liquid formulation which can be applied to the skin via a metered pump spray to deliver drug across skin. This placebo controlled, double blind trial compared anaesthetic properties of two TDS systems (TDS alpha and TDS beta) with placebo. The active and placebo treatments were applied to the dorsum of the hands, bilaterally and simultaneously for 5 min on 100 healthy volunteers. Following cannulation, pain perception was measured using the verbal rating score (VRS) and visual analogue score (VAS). Lidocaine plasma levels were assessed at 0 and 2 h. The VRS and VAS results show that TDS beta significantly decreased pain score compared to placebo (p < 0.02). Blood lidocaine at 2 h post application was also higher for TDS beta than for TDS alpha, suggesting that a 5 min application of TDS beta was effective in delivering local anaesthetic and accelerating the onset of skin anaesthesia prior to venous cannulation in adults.

[Research on the effect of atenolol on lidocaine pharmacokinetics in rats]. / Studiul influentei atenololului asupra unor parametri farmacocinetici ai lidocainei la sobolani.

UNLABELLED: The aim was to determine the influence of atenolol on lidocaine pharmacokinetics in rats for one hour interval of time (average of a dental intervention). The study was carried out on 2 groups of Wistar rats treated with saline solution (0.5 ml/kg), respectively with atenolol (1.5 mg/kg), administered orally 24 hours and 3 hours before intraperitoneal administration of lidocaine (1.5 mg/kg). Blood samples were collected before and 5, 10, 20, 30, 60 minutes after lidocaine administration. Lidocaine plasma concentrations were determined by HPLC. Some pharmacokinetic parameters of lidocaine were statistically significant higher (p < 0.05, ANOVA) for the rats treated with atenolol compared with control group: Cmax (196.97 +/- 2.15 ng/ml vs. 125.29 +/- 2.90 ng/ml), AUD (7734.07 +/- 129.06 ng/ ml x min vs. 4478.57 +/- 296.61 ng/ml x min), AUC1 after 5 minutes (314.23 +/- 6.59 ng/ml x min vs. 190.71 +/- 19.75 ng/ml x min). Tmax was 20 minutes, similar for both groups. CONCLUSION: local anesthesia with lidocaine might be enhanced in the presence of atenolol compared to controls.

Plasma lidocaine levels and risks after liposuction with tumescent anaesthesia.

BACKGROUND: It is common today to use tumescent anaesthesia with large doses of lidocaine for liposuction. The purpose of the present study was to evaluate lidocaine plasma levels and objective and subjective symptoms during 20 h after tumescent anaesthesia with approximately 35 mg per kg bodyweight of lidocaine for abdominal liposuction. METHODS: Three litres of buffered solution of 0.08% lidocaine with epinephrine was infiltrated subcutaneously over the abdomen in eight female patients during monitored intravenous (i.v.) light sedation. Plasma levels of lidocaine and signs of subjective and objective symptoms were recorded every 3 h for 20 h after liposuction. RESULTS: Lidocaine 33.2 +/- 1.8 mg/kg was given at a rate of 116 +/- 11 ml/min. Peak plasma levels (2.3 +/- 0.63 microg/ml) of lidocaine occurred after 5-17 h. No correlation was found between peak levels and dose per kg bodyweight or total amount of lidocaine infiltrated. One patient experienced tinnitus after 14 h when a plasma level of 3.3 microg/ml was recorded. CONCLUSION: Doses of lidocaine up to 35 mg/kg were sufficient for abdominal liposuction using the tumescent technique and gave no fluid overload or toxic symptoms in eight patients, but with this dose there is still a risk of subjective symptoms in association with the peak level of lidocaine that may appear after discharge.

Effects of lidocaine with and without epinephrine on plasma epinephrine and lidocaine concentrations and hemodynamic values during third molar surgery.

Lidocaine with epinephrine is currently the most common local anesthetic agent used for impacted third molar surgery. The purpose of the present study was to define the adverse hemodynamic effects and plasma concentrations of lidocaine and epinephrine on 17 healthy patients during the impacted teeth operations. Arterial blood pressure (systolic blood pressure, diastolic blood pressure), heart rate, peripheral oxygen saturation range, and electrocardiography were measured by an automatic noninvasive pressure device and monitor. High-performance liquid chromatography was used to measure the changes of plasma concentrations of epinephrine and lidocaine from blood samples taken 5 different times during the operation. We concluded that lidocaine-epinephrine is effective local anesthetic and had no important adverse events in healthy patients during the third molar surgery.