A study on reducing the absorption of lidocaine from the airway in cats.

PURPOSE:: To determine if the combination of lidocaine with epinephrine or gamma globulin would decrease the rate or reduce the amount of local absorption of lidocaine through the airway. METHODS:: Twenty adult male cats were randomly and evenly distributed into four groups: 1) Group LG: lidocaine administered with gamma globulin; 2) Group LS: lidocaine administered with physiological saline); 3) Group LE: lidocaine administered with epinephrine; 4) Group C: control group. Invasive blood pressure, heart rate, and concentration of lidocaine were recorded before and after administration. RESULTS:: The peak of plasma concentrations appeared difference (Group LG: 1.39 ± 0.23 mg/L; Group LS: 1.47 ± 0.29 mg/L and Group LE: 0.99 ± 0.08 mg/L). Compared to Group C, there were significant differences in the average heart rate of Groups LG, LS, and LE (P < 0.05). The average systolic blood pressures were significantly different when each group was compared to Group C (P < 0.05). The biological half-life, AUC0-120, peak time, and half-life of absorption among the three groups have not presented statistically significant differences (P > 0.05). CONCLUSION:: Administering lidocaine in combination with gamma globulin through airway causes significant decrease the rate and reduce the amount of local absorption of lidocaine in cats.

A study on reducing the absorption of lidocaine from the airway in cats

Abstract Purpose: To determine if the combination of lidocaine with epinephrine or gamma globulin would decrease the rate or reduce the amount of local absorption of lidocaine through the airway. Methods: Twenty adult male cats were randomly and evenly distributed into four groups: 1) Group LG: lidocaine administered with gamma globulin; 2) Group LS: lidocaine administered with physiological saline); 3) Group LE: lidocaine administered with epinephrine; 4) Group C: control group. Invasive blood pressure, heart rate, and concentration of lidocaine were recorded before and after administration. Results: The peak of plasma concentrations appeared difference (Group LG: 1.39 ± 0.23 mg/L; Group LS: 1.47 ± 0.29 mg/L and Group LE: 0.99 ± 0.08 mg/L). Compared to Group C, there were significant differences in the average heart rate of Groups LG, LS, and LE (P < 0.05). The average systolic blood pressures were significantly different when each group was compared to Group C (P < 0.05). The biological half-life, AUC0-120, peak time, and half-life of absorption among the three groups have not presented statistically significant differences (P > 0.05). Conclusion: Administering lidocaine in combination with gamma globulin through airway causes significant decrease the rate and reduce the amount of local absorption of lidocaine in cats.

Transplacental Distribution of Lidocaine and Its Metabolite in Peridural Anesthesia Administered to Patients With Gestational Diabetes Mellitus.

BACKGROUND: Neonatal effects of drugs administered to mothers before delivery depend on the quantity that crosses the placental barrier, which is determined by the pharmacokinetics of the drug in the mother, fetus, and placenta. Diabetes mellitus can alter the kinetic disposition and the metabolism of drugs. This study investigated the placental transfer of lidocaine and its metabolite monoethylglycinexylidide (MEGX) in pregnant women with gestational diabetes mellitus (GDM) submitted to peridural anesthesia. PATIENTS AND METHODS: A total of 10 normal pregnant women (group 1) and 6 pregnant women with GDM (group 2) were studied, all at term. The patients received 200 mg 2% lidocaine hydrochloride by the peridural locoregional route. Maternal blood samples were collected at the time of delivery and, after placental expulsion, blood samples were collected from the intervillous space, umbilical artery, and vein for determination of lidocaine and MEGX concentrations and analysis of the placental transfer of the drug. RESULTS: The following respective lidocaine ratios between the maternal and the fetal compartments were obtained for groups 1 and 2: umbilical vein/maternal peripheral blood, 0.60 and 0.46; intervillous space/maternal blood, 1.01 and 0.88; umbilical artery/umbilical vein, 0.77 and 0.91; and umbilical vein/intervillous space, 0.53 and 0.51. The following MEGX ratios for groups 1 and 2 were, respectively, fetal/maternal, 0.43 and 0.97; intervillous space/maternal blood, 0.64 and 0.90; umbilical artery/umbilical vein, 1.09 and 0.99; and umbilical vein/intervillous space, 0.55 and 0.78. CONCLUSION: Gestational diabetes mellitus did not affect the transplacental transfer of lidocaine but interfered with the transfer of MEGX, acting as a mechanism facilitating the transport of the metabolite.

Perioperative evaluation of tumescent anaesthesia technique in bitches submitted to unilateral mastectomy.

BACKGROUND: Tumescent anaesthesia (TA) is a widely used technique in oncologic surgeries necessitating large resection margins. This technique produces transoperative and postoperative analgesia, reduces surgical bleeding, and facilitates tissue divulsion. This prospective, randomised, blind study evaluated the use of TA in bitches submitted to mastectomy and compared the effect of TA with an intravenous fentanyl bolus. A 2.5-mcg/kg intravenous fentanyl bolus (n = 10) was compared with TA using 0.275% lidocaine (n = 10) in bitches submitted to unilateral mastectomy. Sedation was performed by intramuscular (IM) injection of 0.05 mg/kg of acepromazine combined with 2 mg/kg of meperidine. Anaesthesia was induced with 5 mg/kg of intravenous propofol and maintained with isoflurane/O2. Heart and respiratory rates; systolic, mean, and diastolic arterial blood pressures; central venous pressure; SpO2; ETCO2; inspired and expired isoflurane concentrations; and temperature were measured transoperatively. Visual analogue scales for sedation and pain and the Glasgow composite and Melbourne pain scales were used for postoperative assessment. The surgeon investigated the quality of the surgical approach, considering bleeding and resection ability, and the incidence of postoperative wound complications. RESULTS: The heart rate was lower and the end-tidal isoflurane concentration was higher in dogs treated with fentanyl than in dogs treated with TA. A fentanyl bolus was administered to 8 of 10 dogs treated with fentanyl and to none treated with TA. Intraoperative bleeding and the mammary gland excision time were lower in dogs treated with TA. The maximal mean and individual plasma lidocaine concentrations were 1426 ± 502 ng/ml and 2443 ng/ml at 90 minutes after infiltration, respectively. The Glasgow Composite Pain Scale scores were higher in dogs treated with fentanyl than in dogs treated with TA until 2 hours after extubation. CONCLUSIONS: Compared with intravenous fentanyl, TA in bitches: may be easily performed in non-inflamed, ulcerated, adhered mammary tumours; has an isoflurane-sparing effect; improves transoperative and immediate postoperative analgesia; is apparently safe for use in clinical conditions as evidenced by the fact that it did not produce any adverse signs or lidocaine plasma concentrations compatible with toxicity; does not modify the recovery time; and facilitates the surgical procedure without interfering with wound healing.

5% lidocaine medicated plaster use in children with neuropathic pain from burn sequelae.

OBJECTIVE: Neuropathic pain is a challenge in children with burn sequelae. Although relatively infrequent, the intensity and chronicity of neuropathic pain negatively impact functionality and quality of life. The use of 5% lidocaine medicated plaster has not previously been reported in children. We explored the effectiveness and safety of 5% lidocaine medicated plaster to treat neuropathic pain in children with burn sequelae. DESIGN: Three-month prospective, uncontrolled study. SETTING: Corporation of Aid to Burned Children (COANIQUEM), a nonprofit pediatric burn rehabilitation center in Chile. SUBJECTS: Fourteen pediatric patients with burn sequelae neuropathic pain. OUTCOME MEASURES: Demographics, burn and pain evolution (type, intensity [using Wong-Baker FACES], and Douleur Neuropathique 4 [DN4]), and patient functionality. Plasma lidocaine levels were measured at 0, 12, 36, and 60 hours after treatment commencement. RESULTS: Fourteen patients were evaluable for plasma lidocaine levels. Twelve patients were available for clinical assessment (two patients lost to follow-up) [mean (standard deviation)]: age, 11 years 7 months (2 years 6 months); weight, 45 kg (11.9 kg); burn evolution, 5 years 6 months (4 years); time between burn and pain onset, 3 years 6 months (3 years 2 months); time between pain onset and treatment, 5.1 months (4.8 months); lidocaine, between < and ½ plaster; initial pain intensity (FACES), 6.8 (1.6); final pain intensity, 0 in 11/12 patients; DN4, initial-6, final-2.3. All patients reported improved functionality. Plasma lidocaine levels were ≤27.45 ng/mL (>180 times below critical levels). No adverse reactions occurred. CONCLUSIONS: These are the first published data suggesting that 5% lidocaine medicated plaster improves patient functionality, and is effective and safe for the treatment of neuropathic pain in pediatric patients with burn sequelae.

Evaluation of the effect of intravenous lidocaine on propofol requirements during total intravenous anaesthesia as measured by bispectral index.

BACKGROUND: I.V. lidocaine is increasingly used as an adjuvant during general anaesthesia. The aim of this study was to evaluate the effect of i.v. lidocaine in reducing propofol anaesthetic requirements during total i.v. anaesthesia (TIVA) maintenance and to evaluate its effect on early recovery from anaesthesia. METHODS: Forty adult patients undergoing elective laparoscopic cholecystectomy under TIVA were randomly allocated into the lidocaine group (administered 1.5 mg kg(-1) i.v. lidocaine over 5 min followed by 2 mg kg(-1) h(-1)) and the control group (administered an equal volume of saline). Propofol was administered using a target-controlled infusion to maintain the bispectral index values between 40 and 60. After surgery, all infusions were discontinued and the time to extubation was recorded. Serial arterial blood samples were drawn to assess drug plasma levels. RESULTS: The maintenance dose of propofol was significantly lower in the lidocaine group [6.00 (0.97) mg kg(-1) h(-1)] vs the control group [7.25 (1.13) mg kg(-1) h(-1); P=0.01]. Propofol plasma levels measured at the end of the infusion were 3.71 (0.89) µg ml(-1) in the lidocaine group and 3.67 (1.28) µg ml(-1) in the control group (P=0.91). The median time to extubation was longer (11.0 min; range: 10.0-21.0) in the lidocaine group vs the control group (8.3 min; range: 5.5-12.5; P=0.02). CONCLUSIONS: I.V. lidocaine reduces propofol requirements during the maintenance phase of TIVA, particularly during surgical stimulation. This sparing effect is associated with an increased time to extubation. Owing to its effect on early recovery from anaesthesia, i.v. lidocaine should be taken into account when used as a component of i.v. anaesthesia.

Automated analysis of lidocaine and its metabolite in plasma by in-tube solid-phase microextraction coupled with LC-UV for pharmacokinetic study.

A sensitive, selective, and reproducible in-tube solid-phase microextraction and liquid chromatographic (in-tube SPME/LC-UV) method for determination of lidocaine and its metabolite monoethylglycinexylidide (MEGX) in human plasma has been developed, validated, and further applied to pharmacokinetic study in pregnant women with gestational diabetes mellitus (GDM) subjected to epidural anesthesia. Important factors in the optimization of in-tube SPME performance are discussed, including the draw/eject sample volume, draw/eject cycle number, draw/eject flow rate, sample pH, and influence of plasma proteins. The limits of quantification of the in-tube SPME/LC method were 50 ng/mL for both metabolite and lidocaine. The interday and intraday precision had coefficients of variation lower than 8%, and accuracy ranged from 95 to 117%. The response of the in-tube SPME/LC method for analytes was linear over a dynamic range from 50 to 5000 ng/mL, with correlation coefficients higher than 0.9976. The developed in-tube SPME/LC method was successfully used to analyze lidocaine and its metabolite in plasma samples from pregnant women with GDM subjected to epidural anesthesia for pharmacokinetic study.

Pharmacokinetics of lidocaine and its metabolite in peridural anesthesia administered to pregnant women with gestational diabetes mellitus.

BACKGROUND: Peridural blockade with lidocaine, bupivacaine, and fentanyl is an anesthetic procedure extensively used in obstetrics, justifying the pharmacokinetic study of these drugs during labor. OBJECTIVE: To investigate the influence of the physiopathological changes of gestational diabetes mellitus (GDM) on the pharmacokinetics of lidocaine and its metabolite monoethylglycinexylidide (MEGX) in pregnant women subjected to peridural anesthesia. PATIENTS AND METHODS: Ten normal pregnant women (group 1) and six pregnant women with GDM (group 2) were studied, all of them at term. The patients received 200 mg 2% lidocaine hydrochloride without a vasoconstrictor by the peridural locoregional route. Maternal blood samples were collected at predetermined times for the analysis of lidocaine and MEGX by chromatography and pharmacokinetic analysis. RESULTS: The median pharmacokinetic parameters of lidocaine for groups 1 and 2 (P

Concentraçäo plasmática da lidocaína em mastoplastia sob anestesia local infiltrativa / Plasma levels of lidocaine in mastoplasty under local anesthesia

Cada vez mais procedimentos vem sendo realizados sob anestesia local, particularmente no campo da cirurgia plástica. Dentre as drogas anestésicas disponíveis, a lidocaína é a mais utilizada. Porém, temos na sua toxicidade a mais séria complicações e um fator limitante para sua utilização em grandes procedimentos cirúrgicos. A proposta deste estudo foi de avaliar as características do padrão de reabsorção da lidocaína após infiltração no tecido mamário, em mastoplastia redutora por técnicas infiltrativas em 20 pacientes. Para tal, foi padronizada a solução anestésica, sendo constituída por lidocaína a 2 por cento 40 ml, adrenalina milesimal a 1 ml, e solução salina 320 ml. O padrão de reabsorção da lidocaína foi bastante lento nos 20 casos avaliados, com níveis máximos predominando entre 6 e 10 horas, nunca excedendo um terço dos níveis considerados tóxicos.

Lidocaine and monoethylglycinexylidide serum determinations to analyze liver function of cirrhotic patients after oral administration.

Our aim was to compare standard liver function tests (serum bilirubin, serum albumin and prothrombin concentration), with lidocaine and monoethylglycinexylidide pharmacokinetic parameters, after oral lidocaine administration, to assess hepatic function of cirrhotic individuals. Twenty-one consecutive cirrhotic patients, nine consecutive acute hepatitis patients, and nine healthy individuals received oral lidocaine. Lidocaine and monoethylglycinexylidide serum concentrations were determined by the TDx system. Cirrhotic patients had higher lidocaine and lower monoethylglycinexylidide serum concentrations and differences in its pharmacokinetic variables, compared to control and hepatitis groups (P < 0.05). Sensitivity of lidocaine serum determinations (100%) was greater than sensitivity of serum bilirubin (57%), serum albumin (62%), and prothrombin concentrations (43%) and monoethylglycinexylidide serum concentrations (57%) in differentiating cirrhotic individuals from controls. In conclusion, after oral administration, lidocaine and monoethylglycinexylidide pharmacokinetic parameters are significantly altered in cirrhotic patients compared to normal and acute hepatitis subjects. Lidocaine pharmacokinetic parameters would be better than those of monoethylglycinexylidide and standard liver function tests in the evaluation of liver function of cirrhotic patients.

Serum lidocaine concentrations after subcutaneous administration in patients undergoing cardiac catheterization in a pediatric institution.

OBJECTIVE: We wished to determine serum lidocaine concentrations after subcutaneous injection during cardiac catheterization. METHOD: Serum lidocaine concentrations were measured in 50 patients during catheterization. RESULTS: Serum concentration was linearly related to dose per kilogram of body weight. Lidocaine concentrations were therapeutic in 38% of patients. CONCLUSION: Lidocaine dose must be considered when the drug is used for local anesthesia in children.

[Serum level determination of local anesthetics using high pressure liquid chromatography]. / Determinación sérica de anestésicos locales por cromatografía líquida de alta resolución.

We report a high resolution liquid chromatography method for simultaneous determination of lidocaine, mepivacaine and bupivacaine in serum using cyclicine as a standard. Drugs are extracted from serum using dichloromethane in an alkaline medium type columns in a mobile phase with 0.1 M phosphate buffer at pH 7.5, methanol and acetonitrile (33:17:50) were used for separation. Spectrophotometric measurement was performed at 207 nm. In a concentration ranging from 0.5 to 8 micrograms/ml, r values of 0.997, 0.989 and 0.998 were obtained for lidocaine, mepivacaine and bupivacaine, respectively. The coefficient of variation estimated at 2 micrograms/ml was 2, 19, 2.76 and 2.48%, respectively. A maximal error of 4.5%, 3.6% and 2.9% found for "inter day" repeated measurement at the above concentration for each drug. Thus, high sensitivity, reproducibility and relative simpleness of the method are demonstrated for its clinical use in determination of serum levels of local anesthetics.

Morfina-Lidocaina intratecal y niveles sanguíneos de glucosa en pacientes / Intrathecal morphine-lidocaine and blood glucose levels in patients

Los efectos de la lidocaína o de morfina combinada con lidocaína sobre la glucosa sanguínea se evaluaron en un estudio doble-ciego y al azar en 19 pacientes a quienes se practicó prostatectomía transversal. Al grupo control se le administró lidocaína (100 mg). Al agregar morfina (1.0 ó 10 mg) a los grupos tratados, se produjo una leve caida en los niveles promedio de glucosa, P>0.05. Sin embargo, un paciente que recibió la dosis baja de morfina (1.0 mg), presentó una hipoglicemia severa, 1.1 mmol (20 mg%), que ocurrió 180 minutos después de la inyección intratecal. La similitud de su respuesta con la observada en animales, comprueba que este efecto importante de la morfina también sucede en el hombre. Se discute las implicaciones de tal hallazgo en relación con la farmacodinamia de los opiáceos. Se postula que la morfina activa un mecanismo de tipo encefalinérgico, descubierto recientemente, que es el encargado del paso intracelular de glucosa en los tejidos nerviosos. Se recomienda vigilar la glicemia en pacientes a quienes se administra morfina intratecal, no deben aplicarse dosis mayores de 1.0 mg en pacientes que no han desarrollado tolerancia a los opiáceos debido a la frecuencia alta de efectos colaterales severos.