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.

Evaluation of the tourniquet leak during forearm intravenous regional anesthesia [manual vs automatic pump injection]

The present study was conducted to compare the effect of pump injection versus manual injection on the venous pressure, during forearm intravenous regional anesthesia [IVRA] and the incidence and the magnitude of lidocaine leak,. A crossover randomized study of IVRA with a forearm tourniquet was conducted on 14 male healthy volunteers. This study was performed, once using manual injection of local anesthetic and once using automatic pump injection, on two separate sessions. In both techniques, 0.3 ml/kg lidocaine 0.5% was injected over 90 seconds. The occlusion pressure, continuous venous pressure and the serum lidocaine two minutes at end of injection, were recorded. The mean occlusion pressure 161.6 [17.2] mmHg was always higher than the mean initial arm systolic blood pressure 131.7[11]. The maximum venous pressure was significantly higher in the manual technique 176.7 [15.4] mmHg than in the pump technique 161.3 [12.3] mmHg [p = 0.04]. The incidence of lidocaine leak was significantly lower [35.71%] in the pump technique compared to [78.5%] in the manual technique [p = 0.02]. Moreover; the mean lidocaine plasma concentrations was significantly higher [0.86 [0.5] microg.ml[-1]] in the manual technique compared to [0.32 [0.4] microg.ml[-1]] the pump technique [p = 0.04]. The use of pump injection for forearm IVRA could significantly decrease the maximum venous pressure, and decrease the incidence and the magnitude of lidocaine leak past the tourniquet

Effect of clonidine on plasma lidocaine concentrations during continuous thoracic epidural anaesthesia in chidren

This study was performed to assess the concentrations of plasma lidocaine and its major metabolite [monoethylglycinexylidide [MEGX]] in children receiving continuous thoracic epidural anesthesia after oral clonidine premedication. Ten pediatric patients, aged 1-9 years, were randomly allocated to the control or clonidine 4 mug/kg group [n = 5 each]. Anesthesia was induced and maintained with sevoflurane in oxygen and air [F1O2 40%] epidural puncture and tubing was carefully performed at the thoracic 11-12 intervertebral space. An initial dose of 1% lidocaine [5 mg/kg] was injected through a catheter in the epidural space, followed by 2.5 mg/kg/hr. The plasma concentrations of lidocaine and MEGX were measured at 15 minutes, 30 minutes and every 60 minutes for 4 hours after the initiation of continuous epidural injection. The concentrations of lidocaine and MEGX were measured using high-pressure liquid chromatography with ultraviolet detection. The hemodynamic variables were similar between the control and clonidine groups during anesthesia. The clonidine group showed significantly smaller lidocaine concentrations and the concentration of MEGX tended to be smaller in the plasma of the clonidine group for the initial four hours after the initiation of epidural infusion. In conclusion, oral clonidine pre-anesthetic medication at a dose of 4 mug/kg decreases plasma lidocaine concentration in children

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.

Intrapulmonary route for drug administration: effects on plasma concentrations and blood gases

This work aimed to compare four different methods of endotracheal and bronchial lidocaine administration with respect to the site of administration. Forty-eight patients undergoing elective operations with an anesthetic risk ASA I and II were included in this study. In this study, all other patients received lidocaine under bronchoscopic control through the side channel of bronchoscope either deep endotracheal, into the right main bronchus and into the right lower lobe bronchus. At 10 points of time after drug administration, blood samples were taken for measurements of lidocaine plasma concentration [using high pressure liquid chromatography] and blood gas analysis. Therapeutic blood concentrations [>/ 1.4 mug/ml] could be achieved and toxic blood concentrations [>/ 6 mug/ml] could be avoided with all methods of administration. No significant difference was found between the different methods with regard to peak concentration, time to peak, onset and duration of therapeutic levels or relative bioavailability. A significant decrease in PaO2 to 75% of the baseline was seen with all methods used

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.