Serum Lidocaine Levels Research Articles

Lidocaine as Topical Anesthesia for Bladder Mappings and Cold-Cup Biopsies

We describe the use of lidocaine as a topical anesthetic for 35 patients undergoing random bladder biopsies (bladder mappings) and cold-cup resection of small bladder lesions. Serum lidocaine levels were measured 7 to 10minutes after instillation of the anesthetic using fluorescent polarization immunoassay. Adequate pain control was noted in 33 of 35 patients (94%), with negligible serum lidocaine levels noted in all 35. One patient had a 2cm. tumor on the anterior wall of the bladder making resection with topical anesthesia suboptimal and 1 patient required 1mg. supplemental intravenous midazolam hydrochloride to complete the procedure. We conclude that topical lidocaine is a safe, inexpensive and effective mode of anesthesia for bladder mappings and cold-cup biopsies of small bladder lesions. However, it may be inadequate for lesions large enough to require resection rather than cold-cup biopsy and those at poorly accessible regions of the bladder.

Cardiopulmonary Resuscitation-Reply

In Reply. —We know that endotracheal drug administration is inferior to intravenous administration and should only be used when personnel cannot obtain intravenous access. However, when endotracheal drug administration is the only possibility, should we inject the agents through the proximal port of the endotracheal tube or through a catheter threaded down the endotracheal tube? Administration through a catheter is more cumbersome and time-consuming. Does catheter administration produce better drug levels in the circulation? Researchers have not observed consistent results regarding which technique produces superior drug delivery. The study quoted by Dr Muniz observed no differences in the serum lidocaine levels when lidocaine diluted in saline was administered at four different locations in the lungs: upper end of the endotracheal tube, proximal carina, right main stem bronchus, or right lower lobe bronchus. 1 This study was limited by the fact that these were well-perfused patients with normal cardiac outputs. Absorption

Local anesthesia in reduction mastoplasty for out-patient surgery.

To perform a breast reduction under local anesthesia we need a large amount of anesthetic with lasting effects. For this I use a solution of 25 cc of lidocaine, 25 cc of bupivacaine, and 1 cc of epinephrine in 350 cc of saline solution. The bupivacaine allows a 4-6-hour operation. Once the breast is infiltrated, a great amount of anesthetic is lost in the incision, in the dissection, and in the resected tissue. Thus, a low dose remains subcutaneously to be metabolized by the liver. The serum lidocaine levels are low during these operations, as demonstrated by fluorescence polarization immunoassay. Under analgesic sedation the submammary sulcus and the retroglandular space are infiltrated, blocking the perforants of the intercostal nerves, under the areola, beneath the skin where the incision is made and where the areola is placed. This procedure has been applied to many techniques of breast reduction by modifying the infiltration under the incision lines. For hypertrophy up to 1000 g, 200-300 cc of anesthetic solution is used for both breasts at one stage, while for gigantomastia, about 400 cc of anesthetic is used, infiltrating and reducing one after the other. As the blood loss is minimal and the recovery very fast, with an appropriate adhesive bandage and a "soutien," the patient could be discharged in the afternoon. Our experience includes 94 reduction mastoplasties with local anesthesia, and also 74 other mastoplasties with equally good results. There were no patient complaints and, in general, they felt very comfortable, awakening without pain or side effects.

Lidocaine blood levels following aerosolization and intravenous administration

Study Objective: To determine whether, following aerosolization of lidocaine for topical airway anesthesia, intravenous (IV) lidocaine produces toxic Lidocaine blood concentrations. Design: Randomized, double-blind study. Setting: University-affiliated hospital. Patients: Forty healthy patients scheduled for outpatient surgery. Interventions: The patients received in a randomized, double-blind manner aerosolized lidocaine or placebo followed 10 minutes later by IV lidocaine or placebo. Measurements and Main Results: After completion of lidocaine or placebo aerosolization and 2 minutes following IV administration of either lidocaine or the placebo, venous blood samples were obtained. Lidocaine concentration was measured using a homogenous enzyme assay. The group receiving both aerosolized and IV placebo and the group receiving aerosolized Lidocaine and an IV placebo had undetectable (<0.05 μg/ml serum Lidocaine levels. The groups that received either an aerosolized placebo or aerosolized lidocaine and IV lidocaine had similar serum lidocaine concentrations [3.34 ± 0.46 vs. 3.24 ± 0.55 μg/ml (mean ± SEM); p > 0.05 by Mann-Whitney U test]. Conclusion: IV lidocaine can be safely administered following aerosolization of lidocaine in spontaneously breathing patients without producing toxic blood lidocaine concentrations.

Serum lidocaine and bupivacaine levels in local technique knee arthroscopy

We investigated serum levels of lidocaine and bupivacaine following their intraarticular and subcutaneous injection for anesthetic effect in local technique knee arthroscopy. Fifteen patients scheduled for knee arthroscopy, but who were otherwise healthy, were studied. Following preparation of the knee, 25 cc of 1% lidocaine with epinephrine (1:100,000) and 25 cc of 0.25% bupivacaine were instilled into the knee joint. An additional 40 cc of the combined solution was used to anesthetize four arthroscopic portal sites from the skin into the joint capsule. The arthroscopic procedure was then performed. We took blood samples 5, 15, 30, 60, and 120 minutes after intraarticular injection. High-performance liquid chromatography was used to determine serum values of the agents. Levels of the anesthetic agents in all of the patients at all time intervals were well within the ranges considered safe. Patient surveys of these and 49 other patients indicated a high degree of satisfaction with the technique. No complications from the anesthetic agents were noted at our hospital in over 500 similar cases. We conclude that local anesthesia as described here is a safe and effective alternative to conventional anesthetic techniques. Additionally, it can save time in the operating room and reduce patient costs.

Lidocaine as a Topical Anesthetic for Bladder Biopsies

The views of the authors do not purport to reflect the position of the Army or the Department of Defense.The use of lidocaine as a topical anesthetic in bladder biopsies is described. Lidocaine was used in 7 patients undergoing random bladder biopsies and serum lidocaine levels were measured 7 to 10 minutes after instillation. Adequate pain control was noted in each patient with negligible serum lidocaine levels even in the face of denuded bladder mucosa.

Lidocaine toxicity after subcutaneous infiltration in children undergoing cardiac catheterization

The administration of subcutaneous lidocaine as a local anesthetic is readily observed in dental, orthopedic, and minor surgical procedures as well as for the insertion of monitoring catheters. The use of any local anesthetic presents significant risk to the patient, and extreme caution should be exercised in its administration 1. Significant complications resulting from lidocaine toxicity have been reported. 2–5 However, it is not well recognized that an elevated serum lidocaine level may result from the subcutaneous infiltration of lidocaine. Although the guidelines for the subcutaneous infiltration of lidocaine are established for children, these recommendations are often exceeded. In our study of 10 sequential patients, we describe 2 cases of lidocaine toxicity that occurred in children undergoing cardiac catheterization. This study was designed to determine if elevated serum lidocaine levels could occur after subcutaneous infiltration in children.

Effets de la lidocaïne sur la circulation artérielle et veineuse des membres chez l'homme

The effects of intravenous lidocaine on limb arteries and veins were investigated in a placebo-controlled study. Seven young healthy volunteers, 23 to 28 — years — old, were included. Electrocardiogram, arterial pressure and arm and leg blood flows were recorded continuously. Systolic and diastolic blood pressures were measured in the left arm by finger photoplethysmography. Limb blood flow and the limb venous system were studied by venous occlusive plethysmography. The venous parameters studied were venous tone, lowest closing pressure, venous volume at 30 mmHg, and venous distensibility. After an initial bolus of 1.5 mg · kg −1 lidocaine had been given, 30, and then 60, μg · kg −1 · min −1 were given for one hour each. Plasma noradrenaline and serum lidocaine titres were measured before giving the lidocaine, and at the end of each one hour period. Placebo consisted in a two hour infusion of 0.25 ml · min −1 normal saline. Lidocaine titres were 1.64 ± 0.40 μg · ml −1 after one hour, and 2.55 ± 0.69 μg · ml −1 after two hours. Lidocaine increased vascular resistances in both the forearm (+ 81 % to + 93 %) and the calf (+ 38 % to + 57 %). There was a concomitant increase in mean arterial blood pressure (+ 21 % to + 28 %) without any change in heart rate. There was a significant dose-dependent increase in plasma noradrenaline levels during the second period of the lidocaine infusion with respect to the preinfusion period and the same period during the placebo infusion. Venous capacitance measured before any infusion had been started was greater in the leg than in the arm. Lidocaine induced a progressive increase in forearm venous tone, which became significant during the period of higher infusion rate. There wasn't any change in calf venous tone. It would therefore seem that the arterial and venous effects of lidocaine which have been reported may be due to an increase in adrenergic tone. The vascular effects of therapeutic serum levels of lidocaine may contribute to the good cardiovascular tolerance of this drug, both as local anaesthetic agent, and as antiarrhythmic drug.

Lidocaine hydrochloride versus lidocaine bicarbonate for epidural anesthesia in outpatients undergoing arthroscopic surgery

In a randomized, double-blind .study, 24 patients undergoing outpatient arthroscopic knee surgery were divided into two groups. Group 1 received 2% lidocaine hydrochloride; group 2 received pH-adjusted 1.73% lidocaine made by adding 1 ml of NaHCO 3 44.6 meg/L to 10 ml of 2% lidocaine hydrochloride. Epidural anesthesia was administered in the sitting position. Group 1 consisted of 12 males; group 2 consisted o J 6 males and 6 females ( p < 0.01). Statistical analysis using the unpaired Student's t-test and the Mann-Whitney test found no significant differences between the two groups regarding time o J onset o J analgesia, degree of spread of analgesia, time to maximum motor blockade, degree of motor blockade, length of surgical procedure, total anesthesia time, regression of anesthesia, dosage of lidocaine used, and serum lidocaine levels. Intraoperative conditions were satisfactory in all cases. Postoperatively, all patients reported having experienced a satisfactory anesthetic without any complications. The authors conclude that epidural anesthesia is a satisfactory technique for outpatient arthroscopic surgery. There appears to be no advantage to adding bicarbonate to lidocaine anesthetic solutions for use in epidural anesthesia.

Free and total lidocaine levels in cardiac surgical patients

A lidocaine bolus of 2 mg/kg has been shown to decrease the incidence of ventricular fibrillation in cardiac surgical patients during reperfusion following aortic cross-clamp release (CCR). In an effort to extend this effect into the immediate postoperative period, many centers routinely administer a prophylactic lidocaine infusion for the first 12 to 24 hours after surgery. Sequential total serum lidocaine levels were measured over 6 hours in 28 adult cardiac surgical patients without liver, kidney, or respiratory disease, and free serum lidocaine levels were measured in 15 of these patients. In addition, pharmacokinetic data were collected and analyzed in 8 of these patients. Each patient received a lidocaine bolus of 1.5 mg/kg and an infusion at 2 mg/min immediately before CCR. Serum levels were determined just before CCR, and at 10, 20, 30, 60, 120, 240, and 480 minutes after CCR. More than 50% of patients had subtherapeutic total serum lidocaine levels from 20 to 120 minutes after CCR, but free lidocaine levels remained within the therapeutic range. No patient showed malignant ventricular dysrhythmias during the study. The results suggest that (1) it may be misleading to estimate free lidocaine concentration based on total lidocaine levels; and (2) free drug is the moiety-responsible for lidocaine's antiarrhythmic effect.

Continuous Intercostal Blockade With Lidocaine After Thoracic Surgery

The efficacy and the side effects of a continuous infusion of lidocaine in the fifth intercostal space for the management of postoperative pain after lateral thoracotomy were evaluated in 20 adults. An indwelling catheter was inserted in the appropriate intercostal space before thoracotomy closure. After recovery from general anesthesia, a loading dose of 3 mg/kg of 1.5% lidocaine with epinephrine 1:160,000 was injected through the catheter, followed by a continuous infusion of 1% lidocaine without epinephrine at a rate of 1 mg.kg-1.h-1 for 54 h. In seven patients pharmacokinetic data were obtained. Pain, assessed by visual continuous analog scale, decreased from a median score of 8 (range, 7-10) to a score of 5 (range, 2-7) 20 min after the loading dose of lidocaine and continued to decrease until the end of the study (P = 0.0001). Complete cutaneous analgesia, assessed by pinprick test, was seen in a median of three thoracic spinal segments (range, 0-6) with partial cutaneous analgesia in seven segments (range, 6-9) 40 min after the loading dose, and levels that remained unchanged for 54 h (P = 0.0001). Peak lidocaine serum concentrations, 1.9 +/- 0.7 micrograms/mL, were present 9 +/- 3 min after injection of the loading dose. Serum concentrations of lidocaine under steady state conditions averaged 4.8 +/- 0.9 micrograms/mL (range, 3.5-5.8 micrograms/mL). This level under steady state conditions, though below the toxic level, suggests that additional bolus injection of lidocaine during the course of infusion might result in potentially toxic serum levels of lidocaine.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma Lidocaine Levels During Augmentation Mammaplasty and Suction-Assisted Lipectomy

Many plastic surgical procedures are dependent on or aided by the use of local anesthetics. Drug toxicity, although uncommon, is the most feared complication of this technique. There are multiple factors that lead to varying drug levels. These include drug concentration, speed of injection, rate of degradation, total dosage, site of injection or application, rate of administration, and the adjunctive use of vasoconstrictors. This study evaluates the use of subcutaneously injected lidocaine in patients undergoing suction-assisted lipectomy and augmentation mammaplasty. Lidocaine in the concentration of 0.5% containing either 1:100,000 or 1:200,000 epinephrine was used in doses up to 500 mg. Serial lidocaine levels were then obtained up to 1 1/2 hours after injection utilizing two different assay techniques. Our findings demonstrate consistently nondectable serum lidocaine levels despite the use of doses in excess of recommended "safe" amounts. This suggests that under specific circumstances and with certain operative procedures, lidocaine dosing can be liberalized.

Therapeutic serum lidocaine and metabolite concentrations in patients undergoing electrophysiologic study after discontinuation of intravenous lidocaine infusion

Serum concentrations of lidocaine and its metabolites monoethylglycinexylidide (MEGX) and glycinexylidide (GX) were measured in seven patients after discontinuation of intravenous lidocaine necessary for control of spontaneous arrhythmias prior to electrophysiologic study. Standard loading doses of lidocaine were given intravenously followed by 2 mg/min infusions for 79.5 ± 6.5 hours. Electrophysiologic studies all started more than 5 half-lives or 7.5 hours after discontinuation of intravenous lidocaine. Local anesthesia with subcutaneous lidocaine (mean 162 ± 96 mg) was administered in six patients. Plasma concentrations of lidocaine and its metabolites were determined at the termination of the infusion, 2 and 4 hours afterwards, at the start of the electrophysiologic study prior to local anesthesia, and at the end of the study. Levels were also determined at 12 and 24 hours after discontinuation of the infusion. Mean plasma concentrations of lidocaine, MEGX, and GX at the start of the study were 1.02, 0.86, and 0.62 μg/ml, respectively. These had increased to 2.78, 0.92, and 0.68 by the end of the electrophysiologic study. One patient with coronary artery disease and prior out-of-hospital ventricular fibrillation had a therapeutic lidocaine level and no inducible arrhythmia at the time of the initial study. At a subsequent electrophysiologic study, no lidocaine or metabolites were detected in the serum and ventricular fibrillation was induced. Thus using the reported half-life of 90 minutes and discontinuing lidocaine 5 half-lives prior to electrophysiologic evaluation does not ensure lack of electrophysiologic effects of the parent compound or its metabolites. Lidocaine given for local anesthesia further increases lidocaine and metabolite levels. To avoid significant electrophysiologic sequelae, intravenous lidocaine should be discontinued for as long as possible prior to programmed stimulation. Local anesthesia with lidocaine should also be minimized or an alternate anesthetic agent should be used. Serum levels of lidocaine and its metabolites should be determined if electrophysiologic effects are suspected at the time of the study.

The use of high-dose lidocaine in wetting solutions for lipoplasty.

The use of lidocaine as a local anesthetic has been limited to 7 mg/kg. The authors question whether amounts of lidocaine greater than the recommended dosage may be safely used in the patient undergoing lipoplasty of the torso and knees. Six patients were used as a sample and a wetting solution of 750 mg or 1,000 mg of a .25% lidocaine solution containing 1:400,000 epinephrine was injected into the surgical site. The ratios of milligrams of lidocaine to kilograms of body weight varied from 9.1 to 13.8. Serum lidocaine levels were measured at frequent intervals. Because of many factors, including poor vascularity of subcutaneous fat, vasoconstrictive effect of epinephrine, and aspiration of a portion of the lidocaine, blood levels of lidocaine in the patients never exceeded 1.0 microgram%. We conclude that lidocaine, 9 to 14 mg/kg, results in peak serum lidocaine levels of only 0.5 to 0.8 microgram%.

Clinical pharmacokinetics of carbonated local anesthetics. III: Interscalene brachial block model.

To compare serum levels of lidocaine resulting from 1.1% lidocaine carbonate and 1.0% lidocaine hydrochloride, the two salts were administered to ten healthy adult patients undergoing upper extremity surgery under interscalene brachial plexus block. Epinephrine (1:200,000) was added to both the solutions just prior to injection, and, following performance of the blocks, venous blood samples were drawn at 3, 5, 10, 15, 20, 30, 60 and 120 minutes. The concentration of lidocaine tended to rise more rapidly and to achieve higher levels in the first 10 minutes following injection of the carbonated lidocaine. However, no significant differences were found in the parameters of Cmax, Tmax or AUC for the two salts, and the serum levels in both groups at all times were well below the levels known to produce systemic toxicity. Therefore, while previous studies appear to indicate that the carbonate salt enhances diffusion, penetration, and uptake of neural tissues as compared with the hydrochloride salt, the present study indicates that vascular uptake is not similarly affected.

Serum Lidocaine Levels During Arthroscopy Using Continuous Irrigation with Lidocaine

Forty patients with symptoms of internal derangement of the knee were examined arthroscopically under local anesthesia using a continuous irrigation solution of 0.2% lidocaine. Serum levels were measured during and following the procedure to determine peak levels obtained and to assure that toxic levels were not exceeded. The procedure was well tolerated by all patients and found to be adequate by the surgeon. No procedure was terminated because of discomfort. Lidocaine levels ranged from undetectable to 2.5 micrograms/ml with an average of 0.6 microgram/ml. No complications of lidocaine toxicity were noted by the anesthesiologist or the operating surgeon. This technique provides a safe and efficient method of meeting the demands for diagnostic and therapeutic arthroscopy in ambulatory patients.

Optimum Anesthesia with Intrapleural Lidocaine during Chemical Pleurodesis with Tetracycline

Chemical pleurodesis with tetracycline is frequently complicated by pleuritic chest pain. The most promising approach to control pain is to optimize the use of intrapleural lidocaine. While administering amounts of intrapleural lidocaine larger than commonly reported, we attempted to determine a safe and more effective dose, by using a subjective and objective assessment of pain, by measuring serum concentrations of lidocaine, and by observing patients for possible toxic effects of lidocaine. Chemical pleurodesis with tetracycline was performed on ten patients receiving an intrapleural dose of 200 mg of lidocaine (group 1) and on ten patients receiving a 250-mg dose (group 2). A significantly greater number of patients in group 2 were free of pain following pleurodesis (7/10 vs 1/10; p = 0.006). Of the 80 serum lidocaine levels obtained, only one value (6.1 micrograms/ml), in an asymptomatic patient in group 1, exceeded the therapeutic range (1.5 micrograms/ml to 5.5 micrograms/ml). One patient in group 2 experienced transient numbness of the right hand, a possible side effect of lidocaine. We conclude that to achieve optimum anesthesia during chemical pleurodesis with tetracycline, it is necessary to use doses of intrapleural lidocaine large than previously reported. Until the feasibility of a further escalation is demonstrated, 250 mg should be considered the standard dose.

The Tumescent Technique for Lipo-Suction Surgery

The tumescent technique of lipo-suction is a modification of the wet technique. A large volume of very dilute epinephrine is infiltrated into a targeted fat compartment prior to lipo-suction, producing a swelling and firmness. This tumescence of fat permits an increased accuracy in lipo-suction and minimizes postsurgical irregularities or rippling of the skin. Epinephrine-induced vasoconstriction minimizes blood loss, bruising, and postoperative soreness. Safe, rapid infiltration of large volumes of solution is achieved using a closed sterile system featuring a newly designed blunt-tipped, 30-cm-long, 4.7-mm-diameter needle having a hollow handle that accommodates a 60-cc syringe. Attached to a liter bottle of anesthetic solution by an intravenous line, the needle is inserted via the same incision and deposits the solution along the same path as that intended for the lipo-suction cannula. Thus, the solution is infiltrated exactly where it is needed for hemostasis or local anesthesia. Used in conjunction with general anesthesia, the tumescent technique saves time in achieving maximal vasoconstriction of the targeted fat compartment. If dilute lidocaine (0.1%) is added to the solution, the technique permits lipo-suction of more than 2 liters of fat totally by local anesthesia. Twenty-six patients, having received a mean lidocaine dose of 1250 mg (18.4 mg/kg or 8.5 mg/kg/hr) infiltrated into subcutaneous fat, had a mean serum lidocaine level of less than 0.36 μg/ml 1 hour after completion of the infiltration.

Influence of Age on Vascular Absorption of Lidocaine from the Epidural Space

The purposes of this study were to evaluate the effect of age on the vascular absorption of local anesthetics during epidural anesthesia and to corroborate the clinical observations of other investigators with respect to age. Using the arbitrary definition of significance (P less than 0.05), the maximum serum levels of lidocaine (Csmax) did not differ significantly with age, however, P values were equal to 0.06. Furthermore, the time to Csmax was significantly faster in elderly patients (P less than 0.00001). In conclusion, the mass of local anesthetic solution should be reduced in elderly patients undergoing epidural anesthesia because there is a greater segmental spread, and serum levels of local anesthetics are increased.

Effect on the seizure threshold in dogs of tocainide/lidocaine administration

Oral lidocaine analogues, such as tocainide, recently have been introduced to treat cardiac arrhythmias. The side effects of tocainide are similar to those of lidocaine, but possible interactions with lidocaine have not been examined thoroughly. With the increased use of these agents, emergency physicians must decide the safety of concurrent administration of lidocaine for local anesthesia or arrhythmia management. Twelve dogs were assigned randomly to either a lidocaine (L) or a tocainide/lidocaine (TL) group. The L group received lidocaine at a dosage of 0.5 mg/kg/min until the animals seized. The TL group received both loading and maintenance doses of tocainide to obtain therapeutic steady-state tocainide levels prior to receiving lidocaine at a dosage of 0.5 mg/kg/min. Venous blood samples to measure drug levels were obtained at 20-minute intervals and at the time of seizures. The average duration of lidocaine administration required to induce seizures in the L group was 70.0 +/- 7.5 minutes, and in the TL group 29.0 +/- 7.0 minutes (P less than .05). In addition, the average serum lidocaine level at the time of seizures was 11.2 +/- 1.0 micrograms/mL in the L group and 6.2 +/- 1.7 micrograms/mL in the TL group (P less than .05). Our results show that in animals the presence of a therapeutic serum level of tocainide lowers the seizure threshold following the administration of lidocaine. These findings may have important implications for clinical care because they suggest that lidocaine should be used cautiously and in reduced dosage in patients already taking tocainide.