Dose Of Lidocaine Research Articles

Relative Contributions of Intraoperative Low Dose Ketamine, Lidocaine and Ketamine-Lidocaine Combination in Addition to Intrathecal Morphine for Postoperative Analgesia in Open Liver Resection: A Prospective, Randomized, Four-Arm, Triple Blind, Placebo-Controlled Trial

Background and Aims: Open liver resection requiring an upper abdominal incision is associated with significant opioid use due to postoperative pain. We tested the hypothesis that the intraoperative combination of low dose lidocaine and ketamine would reduce opioid consumption when given in conjunction with intrathecal morphine for liver resection surgery. Methods: In this triple blind, parallel group four-arm placebo-controlled trial, we randomized 124 adult ASA 2 - 4 liver resection patients to receive intraoperative lidocaine 0.33 mg/kg/h (group L), ketamine 70 μg/kg/h (group K), combination of lidocaine 0.33 mg/kg/h and ketamine 70 μg/kg/h (group KL) and saline (group P). All patients received 300 μg intrathecal morphine prior to induction of anesthesia. All infusions were started immediately after intubation and continued until the end of surgery. Primary outcome measurements included opioid consumption at 24-hours. Secondary outcomes included pain scores, opioid consumption at 48 and 72-hours and side effects including nausea, vomiting, dizziness, hallucinations, headaches and signs of local anaesthetic toxicity. Patients were followed up for 12 weeks. Results: There was no difference in the primary outcome of opioid consumption within all 4 groups at rest or movement at 24-hours. Secondary outcome of 48-hour rest pain score was significantly higher in the L group (p = 0.03) but without any difference in opioid use. There was no difference in any other outcomes between the groups at any time points. Conclusions: Low dose lidocaine and its combination with ketamine did not add any analgesic/morphine sparing benefit in the presence of single dose intrathecal morphine in patients with major liver resection.

Intravenous Lidocaine for the Prevention of Cough: Systematic Review and Meta-analysis of Randomized Controlled Trials.

It remains unclear to what extent intravenous lidocaine prevents cough and whether there is dose-responsiveness and risk of harm. We searched electronic databases to January 1, 2017 for randomized trials comparing intravenous lidocaine with placebo for the prevention of cough in surgical patients. Primary outcome was the incidence of cough. Data were analyzed using a random-effects model and were expressed as risk ratio (RR) and number needed to treat (NNT) with 95% confidence interval. In 20 trials in adults (n = 3062) and 5 trials in children (n = 445), intravenous lidocaine 0.5-2 mg·kg was tested for the prevention of intubation-, extubation-, or opioid-induced cough. Twenty-two trials included only American Society of Anesthesiologists I or II patients; 3 trials (n = 99) also included American Society of Anesthesiologists III patients. Lidocaine was associated with a lower incidence of cough compared to placebo in adults and children, irrespective of dosage and cough etiology. Data from adults suggested dose-responsiveness; with 0.5 mg·kg, RR was 0.66 (0.50-0.88) and NNT was 8 (5.4-14.3); with 1 mg·kg, RR was 0.58 (0.49-0.69) and NNT was 7 (4.6-8.9); with 1.5 mg·kg, RR was 0.44 (0.33-0.58) and NNT was 5 (3.3-5.2); and with 2 mg·kg, RR was 0.39 (0.24-0.62) and NNT was 3 (2.0-3.4). Adverse effect reporting was sparse. Within a range of 0.5-2 mg·kg, intravenous lidocaine dose dependently prevents intubation-, extubation-, and opioid-induced cough in adults and children with NNTs ranging from 8 to 3. The risk of harm in high-risk patients remains unknown.

Nitroglycerin as Adjuvant to Two Different Doses of Lidocaine During IVRA for Hand Surgery

Nitroglycerin as Adjuvant to Two Different Doses of Lidocaine During IVRA for Hand Surgery

Repeated Intravenous Lidocaine Infusions for Patients with Fibromyalgia: Higher Doses of Lidocaine Have a Stronger and Longer-Lasting Effect on Pain Reduction.

To determine the effect of escalating doses of lidocaine infusion with or without added magnesium on pain levels and the duration of pain relief in patients with fibromyalgia (FM). A retrospective chart review of 74 patients diagnosed with FM who underwent at least three escalating doses of intravenous (IV) lidocaine infusions (5 mg/kg of body weight, 7.5 mg/kg, and 7.5 mg/kg of lidocaine + 2.5 g of magnesium sulfate) was conducted. Each patient's subjective impression of change in pain intensity and duration of pain relief after each treatment was recorded, along with an 11-point numeric rating scale (NRS) for pain intensity, immediately before and after each infusion. Short-term lidocaine analgesia was evaluated by the reduction in NRS pain score according to the patients reported pre- (immediately before treatment) and post-treatment (immediately after treatment) values. There was a statistical difference in the NRS score reduction between doses 5 mg/kg and 7.5 mg/kg of lidocaine (P = 0.009). Long-term analgesia was evaluated at follow-up visits by the patient's subjective impression of change in pain intensity and duration of pain relief. There was a statistical difference in the percentage of pain relief and the mean duration of pain relief between the treatments with 5 mg/kg and 7.5 mg/kg of lidocaine (P = 0.007 and P = 0.003). Although there was a trend of greater response to magnesium sulfate as a beneficial adjunct to the lidocaine infusion, we were unable to find a statistically significant difference for any of the variables studied. This study demonstrated that escalating doses of IV lidocaine to 7.5 mg/kg safely and effectively reduced the pain with prolonged effect in a significant number of patients diagnosed with fibromyalgia. Larger, prospective clinical studies are required to confirm this finding.

Ca2+-dependent recruitment of voltage-gated sodium channels underlies bilirubin-induced overexcitation and neurotoxicity

Neonatal jaundice is prevalent among newborns and can lead to severe neurological deficits, particularly sensorimotor dysfunction. Previous studies have shown that bilirubin (BIL) enhances the intrinsic excitability of central neurons and this can potentially contribute to their overexcitation, Ca2+ overload, and neurotoxicity. However, the cellular mechanisms underlying elevated neuronal excitability remain unknown. By performing patch-clamp recordings from neonatal neurons in the rat medial vestibular nucleus (MVN), a crucial relay station for locomotor and balance control, we found that BIL (3 μM) drastically increases the spontaneous firing rates by upregulating the current-mediated voltage-gated sodium channels (VGSCs), while shifting their voltage-dependent activation toward more hyperpolarized potentials. Immunofluorescence labeling and western immunoblotting with an anti-NaV1.1 antibody, revealed that BIL elevates the expression of VGSCs by promoting their recruitment to the membrane. Furthermore, we found that this VGSC-trafficking process is Ca2+ dependent because preloading MVN neurons with the Ca2+ buffer BAPTA-AM, or exocytosis inhibitor TAT-NSF700, prevents the effects of BIL, indicating the upregulated activity and density of functional VGSCs as the core mechanism accountable for the BIL-induced overexcitation of neonatal neurons. Most importantly, rectification of such overexcitation with a low dose of VGSC blocker lidocaine significantly attenuates BIL-induced cell death. We suggest that this enhancement of VGSC currents directly contributes to the vulnerability of neonatal brain to hyperbilirubinemia, implicating the activity and trafficking of NaV1.1 channels as a potential target for neuroprotection in cases of severe jaundice.

The Cricothyroid versus Spray-As-You-Go Method for Topical Anesthesia during Flexible Bronchoscopy: The CRISP Randomized Clinical Trial

Background: Comparative characteristics of the cricothyroid injection and spray-as-you-go methods for lidocaine administration during diagnostic flexible bronchoscopy are not clear. Objectives: Co-primary outcomes were comparison of cough count from bronchoscope introduction until reaching carina and operator-rated overall procedure satisfaction on a Visual Analogue Scale (VAS) between groups. Secondary outcomes were cumulative lidocaine dose, procedure duration, assistant-rated cough, willingness to return for repeat procedure, and procedural complications between groups. Methods: Consecutive subjects were randomized (1:1) to either the cricothyroid or the spray-as-you-go method for topical anesthesia to the vocal cords and trachea. All received nasal 2% lidocaine gel and pharyngeal 10% lidocaine spray. Results: A total of 500 subjects were randomized, and 495 subjects were analyzed (248 cricothyroid and 247 spray-as-you-go). Cough count until reaching carina (median [range]) was significantly lower (cricothyroid, 1 [0–10], and spray-as-you-go, 4 [0–30], p < 0.0001) and operator-rated overall procedure satisfaction, VAS (mean ± standard deviation) (cricothyroid, 7.86 ± 1.39 and spray-as-you-go, 6.86 ± 1.59, p < 0.0001) significantly greater in the cricothyroid group. Patient willingness to return for repeat procedure was greater (87.1 vs. 70.5%, p < 0.001)) and cumulative lidocaine dose significantly lower (305.08 ± 13.40 vs. 322.18 ± 10.67 mg, p < 0.001) in the cricothyroid group. Minor complications occurred in 6 patients in the cricothyroid group and 9 patients in the spray-as-you-go group. Conclusion: Cricothyroid lidocaine administration is associated with less cough and superior operator-rated procedure satisfaction during bronchoscopy at a lower cumulative lidocaine dose.

Attenuation of Pneumoperitoneum-Induced Hypertension by Intraoperative Lidocaine Infusion in Laparoscopic Cholecystectomy

Background: Laparoscopy has now become the standard technique and is considered gold standard for cholecystectomy but the intraoperative requirements of laparoscopic surgery produce significant physiological changes, which pose many challenges for the anesthesiologist. Objective: The aim of this work was to evaluate the effect of intraoperative IV lidocaine infusion for attenuation of pneumoperitoneum-induced hypertension. Patients and Methods: After approval of the Medical Ethical Committee at Al-Azhar University Hospitals, Department of Anesthesia, and after patient written consent, 90 patients of American Society of Anesthesiologists (ASA) physical status I or II, scheduled for laparoscopic cholecystectomy were enrolled in this randomized, controlled, prospective, double-blind, clinical trial study. Results: Regarding the intraoperative and postoperative hemodynamics, in the present study it was observed that patients who received intravenous lidocaine (1.5 mg/kg bolus before skin incision and abdominal inflation followed by 1 mg/kg/h or 2 mg/kg/h and stopped immediately after abdominal deflation) were associated with a reduction in intraoperative BP and HR without any associated hemodynamic instability in comparison to patients who did not received lidocaine with no statistically significant difference between the two doses of lidocaine. Conclusion: This study showed that the intraoperative infusion of lidocaine of two different doses in patients undergoing laparoscopic cholecystectomy was associated with attenuation of blood pressure, heart rate, decreases the intensity of postoperative pain, and early recovery of bowel function without causing significant adverse effects, with more satisfaction for both patients and surgeons.

Attenuation of Pneumoperitoneum-Induced Hypertension by Intraoperative Lidocaine Infusion in Laparoscopic Cholecystectomy

Background: Laparoscopy has now become the standard technique and is considered gold standard for cholecystectomy but the intraoperative requirements of laparoscopic surgery produce significant physiological changes, which pose many challenges for the anesthesiologist. Objective: The aim of this work was to evaluate the effect of intraoperative IV lidocaine infusion for attenuation of pneumoperitoneum-induced hypertension. Patients and Methods: After approval of the Medical Ethical Committee at Al-Azhar University Hospitals, Department of Anesthesia, and after patient written consent, 90 patients of American Society of Anesthesiologists (ASA) physical status I or II, scheduled for laparoscopic cholecystectomy were enrolled in this randomized, controlled, prospective, double-blind, clinical trial study. Results: Regarding the intraoperative and postoperative hemodynamics, in the present study it was observed that patients who received intravenous lidocaine (1.5 mg/kg bolus before skin incision and abdominal inflation followed by 1 mg/kg/h or 2 mg/kg/h and stopped immediately after abdominal deflation) were associated with a reduction in intraoperative BP and HR without any associated hemodynamic instability in comparison to patients who did not received lidocaine with no statistically significant difference between the two doses of lidocaine. Conclusion: This study showed that the intraoperative infusion of lidocaine of two different doses in patients undergoing laparoscopic cholecystectomy was associated with attenuation of blood pressure, heart rate, decreases the intensity of postoperative pain, and early recovery of bowel function without causing significant adverse effects, with more satisfaction for both patients and surgeons.

Development and evaluation of a technique for spinal anaesthesia in broiler chickens

ABSTRACTAimsTo develop a technique for the injection of local anaesthetic into the spinal canal of broiler chickens by first determining the ideal location for needle placement based on anatomy and histology, and then using the developed technique to assess the onset and duration of action of three doses of lidocaine.MethodsTwo-month-old Ross broiler chickens (n = 30) were used in this study. Computed tomography imaging followed by anatomical examination of fresh cadavers (n = 6) were used to identify a suitable intervertebral space for injection of local anaesthetic, and landmarks to locate this space. Histological evaluation of the microanatomy of the caudal vertebral column in another six birds was used to examine the position of the spinal cord within the canal. Spinal anaesthesia was attempted using injection of lidocaine at 0.5 mg/kg (n = 6), 1 mg/kg (n = 6), and 2 mg/kg (n = 6) via the selected intervertebral space. Analgesia was tested by pinching the skin of the pericloacal area with thumb forceps to determine the onset and duration of analgesia. Respiratory rate, and cloacal temperature were measured at 0 minutes and every 10 minutes after injection until sensation returned.ResultsThe space between synsacrum and first free coccygeal vertebra (synsacrococcygeal space) was selected as the most suitable site for spinal injection. In this region, the dura mater adhered to the internal wall of the spinal canal, and the subarachnoid space was large indicating that injection would be into the subarachnoid rather than the epidural space. The interval to onset of analgesia was similar for all doses of lidocaine (1.5 (SD 0.7), 2 (SD 1) and 1.3 (SD 0.5) minutes for 0.5, 1 and 2 mg/kg, respectively; p = 0.604). Duration of analgesia was longer following injection with 2 than 0.5 or 1 mg/kg lidocaine (21.3 (SD 2.5) vs. 4.5 (SD 3.5) vs. 11.3 (SD 2) minutes, respectively; p = 0.002). Mean cloacal temperature decreased between 0 and 20 minutes after injection with all doses of lidocaine (p = 0.021).Conclusions and clinical relevanceSpinal anaesthesia in chickens is feasible and is a practical, inexpensive and simple technique for regional anaesthesia of the pericloacal area.

Effects of lidocaine on equine ejaculated sperm and epididymal sperm post-castration

In equids, it is common to inject lidocaine into the testicles at the time of routine castration to provide analgesia. The effects of lidocaine on equine sperm have not been evaluated in vitro or on epididymal sperm collected following castration. The aims of this study were to determine effects of clinically relevant doses of lidocaine on equine spermatozoa in vitro using freshly collected semen and to compare the characteristics of epididymal spermatozoa after routine castration with or without intra-testicular lidocaine administration. We hypothesized that increasing concentrations of lidocaine would decrease total motility (TM), progressive motility (PM), velocity of the average path (VAP), velocity of the curved line (VCL), linearity (LIN), normal morphology (M) and membrane integrity (MI). We also hypothesized that injection of intra-testicular lidocaine would decrease TM, PM, VAP, VCL, LIN, M, and MI following routine castration, epididymal flushing and cryopreservation. In experiment 1, sperm was collected from four stallions and mixed with lidocaine at concentrations of 1 μg/ml, 10 μg/ml, 100 μg/ml, 1,000 μg/ml and 10,000 μg/ml. M and MI were compared to the control sample at 0 and 48 h. Motility parameters were analyzed at 0, 2, 4, 6, 24, and 48 h. In experiment 2, 12 stallions were castrated under general anesthesia. One testicle was removed without the use of intra-testicular lidocaine and the other testicle was removed 10 min after injection of 10 ml of 2% lidocaine. Results: In experiment 1, fresh sperm showed no significant difference (p < 0.05) compared to control at either 1 μg/ml or 10 μg/ml concentrations of lidocaine. There were significant decreases in PM, VAP, VCL, and LIN at concentrations of 100μg/ml-10,000 μg/ml and for TM at lidocaine concentrations of 1,000–10,000 μg/ml compared to control. Morphology did not change at any lidocaine concentration. Membrane integrity decreased significantly at 10,000 μg/ml lidocaine. In the second experiment 1.03 ± 0.42 μg/ml lidocaine was detected in the epididymal flush of stallions treated with lidocaine. There were no significant differences in any measured parameters between the control and the lidocaine treated testicles. Intra-testicular lidocaine injection at the time of castration did not affect any measured parameters after epididymal flush. Lidocaine concentrations higher than 100 μg/ml in-vitro resulted in decreased motility parameters of the spermatozoa independent of exposure time.

Comparing perioperative magnesium sulphate, lidocaine, and their combination in preventing ventricular arrhythmia in off-pump coronary artery bypass grafting

BackgroundTechniques of coronary artery bypass grafting (CABG) have developed rapidly over the last decades. However, dysrhythmia is a common feature during off pump CABG. The aim of this work was to study effect of perioperative magnesium sulphate infusion on the incidence of cardiac arrhythmia in off-pump CABG: and comparing such effects to lidocaine alone or combined to magnesium.MethodologyNinety patients undergoing elective coronary artery bypass grafting surgery were randomly divided into three equal groups: magnesium group received magnesium over 12 h prior to off-pump surgery and over 30 min intraoperatively; lidocaine group were given an intravenous bolus injection of lidocaine followed by a continuous infusion; and combination group received half the doses of magnesium and lidocaine prescribed for the other two groups. The patients’ perioperative hemodynamic data (heart rate and mean arterial pressure) and the occurrence of intraoperative and postoperative arrhythmia were recorded.ResultsThere was statistically significant difference between study groups as regards mean intraoperative heart rate and intraoperative mean arterial pressure. In addition, the need for intraoperative beta-blockers was significantly higher in lidocaine group; there was no need for intraoperative beta-blockers for combination group. Also, the need for perioperative aortic balloon pump was significantly higher in lidocaine group (20.0%), followed by 6.7% in magnesium group, and none in combination group. The percentage of ventricular tachycardia was significantly higher in lidocaine group (16.7%), followed by magnesium group (3.3%) and none in combination group.ConclusionResults of the present study revealed that combination of both perioperative magnesium and lidocaine when compared to each of both drugs separately has a better effect in controlling hemodynamics (heart rate and mean arterial blood pressure intraoperatively), less ventricular tachycardia, and reduction in the need for beta blockers and aortic balloon pump perioperatively. In addition, magnesium was superior to lidocaine, although both are effective.

ANALGESIA FOR AGED AND GERIATRIC PATIENTS DURING CARDIAC SURGERY WITH CARDIOPULMONARY BYPASS

Balanced perioperative multimodal analgesia using multiple synergistic agents minimizes side effects that can be caused by high doses of only one aesthetic agent. The aim of the work was to determine the efficacy of perioperative multimodal low-opioid analgesia as anesthetic assurance techniques in aged and geriatric patients during cardiac surgery with cardiopulmonary bypass.Materials and methods. The study included 18 patients (11 (61.1%) men and 7 (38.9%) women) aged from 63 to 76 years old (mean age 69.5±6.2 years), who underwent coronary artery bypass grafting with cardiopulmonary bypass support. The average body weight was 89.6±13.9 kg (75 to 115 kg). The anaesthesia consisted of intravenous (iv) administration of propofol in a dose of 1.52±0.05 mg/kg and fentanyl in a dose of 1 μg/kg. Muscle relaxation was achieved by injecting pipecuronium bromide in a dose of 0.1 mg/kg. Sevoflurane inhalation was used to maintain anesthesia. Before making incision, the subnarcotic dose of ketamine (0.5 mg / kg) and lidocaine 1 mg/kg bolus were added with simultaneous administration of the continuous infusion of the latter in a dose of 1.5-2 mg/kg per hour. For postoperative analgesia ketorolac tromethamine was used. The intensity of the pain syndrome was assessed using a 10-point visual-analog scale of pain. The level of endocrine-metabolic response was determined by measuring the dynamics of lactate and cortisol.Results. The average dose of fentanyl, which was used for the patient during the whole time of anaesthesia, was 1.09±0.03 μg / kg per hour (on average 358.3±27.1 μg for all time of surgery). During the extracorporeal circulation and in the early postoperative period, the blood circulation parameters in all patients examined corresponded to the hemodynamic profile of the operated pathology. Positive verbal contact with patients was recorded in 18.6±3.4 minutes after the end of anaesthesia. The level of cortisol in the early postoperative period was 479.3±26.4 nmol/l. The average values of the intraoperative level of lactate were 1.61±0.2 mmol/l. The mean pain level in the first postoperative day in the examined patients was 4.6 ± 1.2 (3-6) scores by VAS, one day after the operation – 2.6±1.1 (1.5-4) scores by the VAS.Conclusions. Multimodal low-opioid analgesia provides an adequate analgesic effect in aged and geriatric patients that is confirmed by the absence of hemodynamic and endocrine-metabolic disorders. The use of ketorolac as a component of multimodal low-opioid analgesia is an effective method for achieving adequate postoperative analgesia and contributes to reducing the side effects associated with the use of narcotic analgesics.

Comparison of the Effect of Intraoperative 1 mg/kg/h and 2 mg/kg/h IV Lidocaine Infusion on Postoperative Pain and Nausea-Vomiting in Laparoscopic Gastric Bypass Surgery

Objective: To relieve postoperative pain and nausea and vomiting, various drugs and methods, including intraoperative IV lidocaine infusion in different surgeries. However, the exact dose has not yet been determined. The purpose of this study was to evaluate and compare the effect of intraoperative 1 mg/kg/h and 2 mg/kg/h IV lidocaine infusion on postoperative pain and nausea-vomiting in laparoscopic gastric bypass surgery.&#x0D; Methods: This clinical trial study was performed on patients undergoing laparoscopic gastric bypass surgery in Rasoul-e-Akram Hospital, Iran. Patients were randomly assigned into two groups (1 mg/kg/h lidocaine) and (2 mg/kg/h lidocaine). Postoperative pain and nausea and vomiting were evaluated at times 0, 30 min, 1 h, 6 h, 12 h and 24 h after surgery. Data was analysed using statistical tests and SPSS 22.&#x0D; Results: There was no significant difference in the effect of intraoperative 1 mg/kg/h and 2 mg/kg/h IV lidocaine infusion on static and dynamic pain and nausea-vomiting, agitation, systolic BP, diastolic BP, pulse rate and postoperative administration of pethidine in laparoscopic gastric bypass (P&gt;0.05).&#x0D; Conclusion: Based on results of this study, administration of low dose lidocaine (1 mg/kg/h) can be considered as an appropriate dose of IV lidocaine infusion in order to control postoperative pain and nausea and vomiting in laparoscopic gastric bypass surgery.

Evaluation of Neosaxitoxin as a local anesthetic during piglet castration: A potential alternative for Lidocaine

ObjetiveTo evaluate Neosaxitoxin (NeoSTX) as a local anesthetic drug, for pain control during and after piglet castration. Study designProspective, randomized and double-blind study. Animals24 commercial hybrids, males, 23-day-old piglets. MethodsThe piglets were randomized into two groups: a Lidocaine group and a NeoSTX group. One minute before castration, they were injected intra-scrotally with a single dose of Lidocaine (20 mg, in 1 mL) and NeoSTX (0.1 μg, in 1 mL), respectively. ResultsNeoSTX does not generate vasoconstriction or scrotal contraction, unlike Lidocaine, where a decrease in temperature and scrotal size is observed within 5 min after the procedure. After 24 h, wound inflammation, as measured by scrotal size, was lower in the NeoSTX group. No significant difference could be shown between the vocalizations and facial expressions of pain of both groups during the castration procedure. ConclusionsA single dose of NeoSTX is safe and effective for pain management during and after piglet castration. NeoSTX treated piglets were less affected by castration than those in the Lidocaine group, thus reducing piglet stress and enhancing the quality of piglet convalescence.

Lidocaine safety after saphenous vein tumescent anesthesia.

Objectives For endovenous thermal ablation of the saphenous veins, tumescent lidocaine anesthesia is often used. Unfortunately, information is sparse on the pharmacokinetics of lidocaine absorption and its maximum safe dose. The aim of this study was to evaluate plasma concentration of lidocaine on 12 lead electrocardiograms (ECGs) and symptoms over time after the administration of tumescent lidocaine during endovenous thermal ablation procedures in healthy volunteers. Methods An observational study of symptoms, 12 lead ECGs, and serum lidocaine levels were obtained following the administration of either 15 mg/kg lidocaine or 35 mg/kg lidocaine in the perivenous saphenous space under ultrasound guidance. Blood was drawn at regular intervals in heparinized tubes and spun at 3000 r/min for 10 min. The plasma lidocaine levels were plotted vs. time for statistical comparisons. Results With the 35 mg/kg dose, four of 11 participants developed symptoms of lidocaine toxicity at 40 min, which resolved by 180 min. The 35 mg/kg dose resulted in a mean serum lidocaine peak of 2.55 µg/ml at 60 min. The 15 mg/kg dose did not result in any symptoms of lidocaine toxicity, and it resulted in a serum lidocaine plateau of 0.85 µg/ml at 180 min. No significant changes were seen on the 12-lead ECG after the administration of lidocaine at either dose. Conclusions The 15 mg/kg total lidocaine dose did not cause symptoms and appears to be a safe lidocaine dosage for tumescent anesthesia for saphenous endovenous thermal ablations. The 35 mg/kg lidocaine dose is associated with lidocaine toxicity. More study on the maximal safe dose of lidocaine for endovenous thermal ablations is needed.

Effect of Neosaxitoxin on Epidural Anesthesia in Cats: a Promising Alternative to Conventional Anesthetics

Neosaxitoxin (NeoSTX) is a specific high-affinity inhibitor of voltage-dependent sodium channels, which has shown excellent results as a local anesthetic in various pathologies and post-operative protocols, since it effect is long-lasting and have virtually no side effects.The aim of this study was to analyze the effect of NeoSTX as an epidural anesthetic in female cats, undergoing ovariohysterectomy, compared to Lidocaine in a randomized and double-blind study. Two groups of 11 female cats were randomly in the NeoSTX group and the lidocaine group. They were administered, respectively, a single dose of NeoSTX (0.5 μg / kg) or lidocaine (4 mg / kg, 2%) by epidural via. Using the UNESP-Botucatu pain assessment scale, which considers multiple behavioral and physiological factors, the epidural anesthetic effect of NeoSTX and lidocaine was evaluated, up to 240 min after the ovariohysterectomy procedure. NeoSTX no altered the peripheral blood pressure during the cut of uterine cervix, and generated lower values on the pain scale as compared to the lidocaine treatment. None of the cats anesthetized with NeoSTX required an extra dose of pain-relieving drugs (2 mg / kg of tramadol) during the first 150 min after surgery, whereas nine cats from the lidocaine group did need an extra dose of analgesic. NeoSTX is a powerful pain blocker, with a long-lasting anesthetic effect when administered by an epidural procedure. Therefore, NeoSTX emerges as a promising alternative to conventional anesthetics for the treatment of postoperative pain.

Design and Development of Lidocaine Microemulsions for Transdermal Delivery.

Topical administration is a preferable choice for local anesthetic delivery. Microemulsions have shown great effectiveness for transdermal transport of lidocaine. However, fabrication of microemulsions containing highly concentrated lidocaine (10%) to provide an extended local anesthetic effect is still a challenge. This study investigated the feasibility of using microemulsions for transdermal delivery of a high dosage of lidocaine (10%). At first, eutectic mixtures by kneading lidocaine with thymol were tailored to form a lipophilic solution, then the mixtures were readily incorporated into the oil phase of microemulsions after addition of proper surfactants and cosurfactants. The physicochemical properties, the skin permeation, local anesthetic efficacy, and the irritation experiment of the developed microemulsions were evaluated. The optimum composition was as follows: 12% of ethyl oleate as oil phase, 28% of the mixed surfactant, and cosurfactant (polyoxyl 15 hydroxystearate and ethanol) and 60% of the aqueous phase. The average particle size was about 13nm. The transmission electron microscope (TEM) studies revealed almost homogeneous spherical globules without aggregation. The Fourier-transform infrared spectroscopy (FTIR) results highlighted the drugs homogeneously dispersed in the microemulsions. In vitro skin permeation and in vivo anesthesia effect evaluation indicated that microemulsions can enhance and extend the anesthetic effect of lidocaine. The irritable results indicated that the microemulsions had the better biocompatibility and the negligible influence on the dermal. Therefore, incorporating the eutectic mixtures into microemulsions could be proposed as an attractive choice and a promising transdermal delivery strategy for the future topical anesthetic therapy.

A Comparative Study between Dexmedetomidine Alone versus Combined Low Dose of Dexmedetomidine and Lidocaine for the Hemodynamic Response to Endotracheal Extubation in Patient Undergoing Abdominal Surgery—A Prospective Randomized Controlled Study

Background: Tracheal extubation is related to many side effects of hemodynamic, especially for patients with comorbid states. The study compared the validity of dexmedetomidine 1 μg/kg and low combination dose of dexmedetomidine 0.5 μg/kg plus Lidocaine 1 mg/kg in softening hemodynamic stress response and estimated quality of extubation in study groups. Materials and Methods: The patients in our study, one hundred and fifty of both gender, ASA class I &II patients, aged 20 - 50 years old subject to elective abdominal operations under general anesthesia were allocated into three equal groups. Anesthetic technique was standardized. Before extubation by 10 minutes, the patients in Group N, D, and DL have given 0.9% normal Saline intravenous bolus infusion, dexmedetomidine 1 μg/kg and Dexmedetomidine 0.5 μg/kg, respectively within a 10-minute period. Before complete extubation by 90 seconds, in the three groups by syringe ten cc volumes and at time of extubation, Group N and D patients received 0.9% normal Saline intravenous bolus infusion, but in Group DL received Lidocaine 1 mg/kg then extubation completed. Heart rate (HR), Diastolic BP (DBP), Systolic BP (SBP), and Mean Arterial Pressure (MAP) were noted at baseline, at the reverse, extubation, 2, 4, 6, 8, 10 min and at the regular times after that for two hours. Extubation quality was assessed by extubation quality scale. Aldrete’s recovery score and Ramsay sedation score were also recorded and also any complications were noted and recorded. Results: All the hemodynamic parameters significantly elevated extubation and numerous periods of observation in the normal saline group than dexmedetomidine and dexmedetomidine plus Lidocaine group (p-value = 0.001). Response of tachycardia was seen in 41 (82%) in patients of N group, compared to 18 (36%) and 20 (40%) in D & DL group respectively (p = 0.001). Hypertensive response statistically significant noticed in 40 (80%) patients of N group, 9 (18%) of D group and 12 (24%) of DL group (p = 0.001). Tachycardia duration and the response of hypertension were significantly prolonged in the control group. As regards extubation quality, the three groups differed in D Groups (1.93 ± 0.57) and DL (1.51 ± 0.57) had decreased scores compared to group N (2.67 ± 0.48) modulating smoother extubation (p Conclusion: Low combined dose of (Dexmedetomidine 0.5 μg/kg plus Lidocaine 1 mg/kg) IV was useful as much as Dexmedetomidine 1 μg/kg IV in softening hemodynamic stress responses during emergence.

Adductor canal block with a suture-method catheter - A parallel or perpendicular approach?

We performed a randomised blinded pilot study in 16 healthy volunteers to assess whether placing a suture-method catheter in the adductor canal is feasible with two different insertion techniques. Each volunteer had a suture-method catheter placed approximately halfway between the superior anterior iliac spine and base of the patella in both legs. Catheters were placed using a parallel technique in one leg and a perpendicular technique in the other leg, according to randomisation. 15mL lidocaine 1% was injected in each catheter. Successful placement was defined as loss of cold sensation in the saphenous area 30min after injection. Volunteers were sent home and returned the following day and another dose of lidocaine (15mL, 1%) was injected through the catheters. Catheter displacement distance was assessed by ultrasound and cold sensation was assessed. In case of preserved cold sensation, we attempted to reposition the catheter with a subsequent injection of lidocaine and reassessment of cold sensation. All primary placements were successful using the perpendicular approach (100%; 95% CI 81%-100%) whereas one placement failed using the parallel approach (94%; 95% CI 72%-99%). Three catheters placed using the perpendicular approach were displaced on day 2, compared to one catheter placed with the parallel approach. Displacement distance was highly variable. All catheters, except one, could be repositioned. Three volunteers reported transient sensory deficits lasting approximately 6-8weeks. The suture-method catheter can be placed in the adductor canal with high success rates for initial placement with both techniques.

Extended pain relief achieved by analgesic-eluting biodegradable nanofibers in the Nuss procedure: in vitro and in vivo studies.

BackgroundThe most common complaint after the Nuss procedure is severe postoperative chest pain. The aim of this study was to evaluate the effectiveness of analgesic-eluting biodegradable nanofibers in pain relief after the Nuss procedure.Materials and methodsPoly(d,l)-lactide-co-glycolide, lidocaine, and ketorolac were dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol. This solution was electrospun into a nanofibrous membrane. The elution method and high-performance chromatography were used to characterize the in vitro drug release. Stainless steel bars with and without coating of the analgesic-eluting nanofibrous membrane were implanted underneath the sternums of New Zealand white rabbits. The in vivo characteristics were further investigated.ResultsThe in vitro study showed that the biodegradable nanofibers released high doses of lidocaine and ketorolac within 10 days. The in vivo study demonstrated high local and systemic concentrations of lidocaine and ketorolac. The serum creatinine level was unaffected. Animals that received implants of the analgesic-eluting nanofiber-coated stainless steel bar exhibited significantly greater food and water ingestion and physical activity than the control group did, indicating effective pain relief.ConclusionThe proposed analgesic-eluting biodegradable nanofibers contribute to the achievement of extended pain relief after the Nuss procedure, without obvious adverse effects, in an animal model.