Lidocaine epidural

A randomised, double-blind, placebo-controlled study involving 44 patients found that lidocaine epidural anaesthesia (15 mL of 2% plain lidocaine) reduced the MAC of sevoflurane required for general anaesthesia by approximately 50% (from 1.18 to 0.52%). This implies that a lower dose of inhalational anaesthetic provides adequate anaesthesia during combined epidural-general anaesthesia than for general anaesthesia alone. ... 

The primary site of action of epidurally administered agents is on the spinal nerve roots. As with spinal anesthesia, the choice of drug to be used is determined primarily by the duration of anesthesia desired. However, when a catheter has been placed, short-acting drugs can be administered repeatedly. Bupivacaine is typically used when a long duration of surgical block is needed. Lidocaine is used most often for intermediate length procedures chloroprocaine is used when only a very short duration of anesthesia is required. 

Bupivacaine is an anaesthetic with a slow onset but a long duration of action. It is indicated for continuous epidural analgesia in labour. Xylocoine is the proprietary preparation of lidocaine (lignocoine). Lidocoine injections ore used in dentistry. 

Epidural anesthesia This term is understood to be an introduction of local anesthetic into the spinal cord membrane of the intervertebral space. It is used during obstetrical and gynecological interventions that do not require a fast development of anesthesia. Drugs such as lidocaine, mepivacaine, bupivacaine, ethidocaine, and chloroprocaine are used for this purpose. 

Lidocaine is the most widely used local anesthetic. Its excellent therapeutic activity is fast-acting and lasts sufficiently long to make it suitable for practically any clinical use. It stabilizes cell membranes, blocks sodium channels, facilitates the secretion of potassium ions out of the cell, and speeds up the repolarization process in the cell membrane. It is used for terminal infiltration, block, epidural, and spinal anesthesia during operational interventions in dentistry, otolaryngology, obstetrics, and gynecology. It is also used for premature ventricular extrasystole and tachycardia, especially in the acute phase of cardiac infarction. Synonyms for this drug are xylocaine, neflurane, and many others. 

Amide-type agents include articaine, lidocaine, bupivacaine, prilocaine, mepivacain and ropiva-caine. These are metabolized in the liver by microsomal enzymes with amidase activity. The amide group is preferred for parenteral and local use. If by accident rapidly administered intravascularly these agents, especially bupivacaine but also lidocaine, can produce serious and potentially lethal adverse effects including convulsions and cardiac arrest. They can more easily accumulate after multiple administrations. Intravenous lidocaine is sometimes used for regional anesthesia, for infiltration procedures, for the induction of nerve blockade and for epidural anesthesia. However, it is also used as an antiarrhythmic. Bupivacaine is a long-acting local anesthetic used for peripheral nerve blocks and epidural anesthesia. 

Of all the local anaesthetics available, levobupivacaine and ropivacaine have the most favourable pharmacological characteristics for use in obstetrics. They have the lowest potential for cardiotoxicity and, unlike lidocaine and prilocaine, there is little risk of cumulation when they are administered by epidural infusion at effective doses. Elimination of all amides is prolonged in the neonate, exceeding 20 h in the case of bupivacaine. 

Lidocaine is used for all forms of infiltration anaesthesia, in addition to peripheral, regional, spinal and epidural block. Unlike bupivacaine, it is suitable for use in intravenous regional anaesthesia. Duration of anaesthesia is about 1 hour but this can be prolonged to 2 hours by the addition of adrenaline. The maximum doses are shown in Table 5.2. 

The choice of local anesthetic for infiltration, peripheral nerve blocks, and central neuraxis (spinal/epidural) blockade is usually based on the duration of action required. Procaine and chloroprocaine are short-acting lidocaine, mepivacaine, and prilocaine have an intermediate duration of action and tetracaine, bupivacaine, levobupivacaine, and ropivacaine are long-... 

Lidocaine Blockade of sodium channels Slows, then blocks action potential propagation Short-duration procedures epidural, spinal anesthesia Parenteral duration 30-60 min 2-6 h with epinephrine Toxicity CNS excitation... 

Clinical use Mepivacaine has been employed for all types of infiltration and conduction nerve block anesthesia using solutions of 1.0 and 1.5 % lasting for 1.5 to 3 h. Epidural anesthesia with 2.0 % mepivacaine has a rapid onset with a dense motor block. Hyperbaric solutions of mepivacaine have also been used for spinal anesthesia (Tetzlaff, 2000). Mepivacaine has been used for topical applications, but other LA such as lidocaine are more effective. 

Lidocaine Xylocaine Rapid Intermediate Infiltration Peripheral Nerve Block Epidural Spinal Transdermal Topical Sympathetic block Intravenous regional block... 

Lidocaine is effective in producing analgesia when administered by infiltration, or by nerve, epidural, caudal, and spinal block. In addition, it is effective when applied topically, with an onset of action of 5 min and a duration of action of 15 to 30 min. Lidocaine (1.5 pg/ml) is the agent of choice for the acute suppression of most ventricular arrhythmias. 

Mepivacaine, which is ineffective topically, is used for infiltration plus nerve, epidural, and caudal block. Its potency and speed of action are similar to those of lidocaine. 

Etidocaine is a long-acting derivative of lidocaine but is far more potent. It is effective for infiltration anesthesia, peripheral nerve block, and epidural and caudal blockade. 

There are many types of steroid hormones in the body, such as the sex/gonadal hormones testosterone and estrogen, thyroid hormones, growth hormones, and stress hormones, which serve various normal functions. One type of steroid— corticosteroids or glucocorticoids—is secreted by the adrenal glands (located just above the kidneys). These steroids, particularly synthetic versions of them, have powerful antiinflammatory actions that help to relieve pain. They are often given as an epidural injection to relieve neck or back pain that results from a compressed or pinched nerve. They can also be injected directly into a joint to relieve pain caused by inflammation in conditions such as tendonitis (inflammation of the tendons), carpal tunnel syndrome, tennis elbow, bursitis (inflammation of sac-like cavities in tendons or muscles that allow them to slide easily over bone), or other joint pain. Professional athletes, who routinely experience one or more of these conditions, are often given local steroid injections. Frequently, the steroid is combined with a local anesthetic such as lidocaine. 

Kirihara et al. (2003) compared neurotoxicity of intrathecal and epidural lidocaine in rats. 

Kirihara et al. (2003) compared neurotoxicity of intrathecal and epidural lidocaine in rats. Male Sprague-Dawley rats were anesthetized with sodium pentobarbital (30 mg/kg i.p.) and 1.5% halothane. A catheter of stretched polyethylene tubing PE-10 was introduced into the subarachnoid or epidural space using an aseptic technique. Catheters were passed through the L4-L5 intervertebral space and advanced 1.3 cm in the caudal direction. Rats were allowed 4 days to rest for recovery from the operation. 

Kirihara Y, Saito Y, Sakura S et al. (2003) Comparative neurotoxicity of intrathecal and epidural lidocaine in rats. Anesthesiology 99 961-968... 

Bupivacaine is long-acting 3 h) (see Table 18.1) and is used for peripheral nerve blocks, and epidural and spinal anaesthesia. Whilst onset of effect is comparable to lidocaine, peak effect occurs later (30 min). 

When epidural anesthesia was used for cesarean section, bupivacaine (with oxytocin) produced a higher frequency of neonatal jaundice than similar treatment using lidocaine (SEDA-14, 111). 

The use of a continuous epidural infusion of lidocaine 0.4% plus fentanyl 1 pg/ml in combination with intravenous metamizol 40 mg/kg provided significantly better analgesia than epidural morphine 20 pg/kg plus intravenous metamizol 40 mg/kg during the first 3 postoperative days in 30 children undergoing orthopedic surgery, without increasing the incidence of adverse effects however, the difference in beneficial effect was small (70). 

Reinoso-Barbero F, Saavedra B, Hervilla S, de Vicente J, Tabares B, Gomez-Criado MS. Lidocaine with fentanyl, compared to morphine, marginally improves postoperative epidural analgesia in children. Can J Anaesth 2002 49(1) 67-71. 

The degree of hjrpotension occurring after epidural anesthesia with alkahnized lidocaine (with adrenahne) was greater than with a standard commercial solution (SED-12, 255) (19). 

A 27-year-old woman developed significant myocardial depression and pulmonary edema after administration of 5 ml of bupivacaine 0.5% via an epidural catheter (121). The bupivacaine followed a test dose of 3 ml lidocaine 2%. 

Although initial aspiration on the epidural catheter was negative, the most likely explanation must be inadvertent intravascular administration of lidocaine and bupivacaine. 

A watershed cerebral infarct with subsequent full recovery occurred in a 70-year-old man 8 hours after a hypotensive event following an incremental bolus of 1% lidocaine 10 ml via an established epidural catheter (131). 

The cauda has a tenuous blood supply, and in this patient with pre-existing vascular disease, perioperative hypotension and the use of intrathecal adrenaline may have precipitated ischemia in an area with very poor reserve. To follow this with an accidental large dose of lidocaine, which is neurotoxic in animals when directly applied and theorized to cause interruption of nerve blood supply, would add insult to injury. The authors questioned the wisdom of performing continuous epidural anesthesia in such patients, when frequent neurological assessments cannot be performed. 

In a careful meta-analysis, 29 randomized, controlled studies of the incidence of transient radicular irritation were identified (243). Lidocaine and mepivacaine were identified as the two local anesthetics that most commonly cause transient radicular irritation, while prilo-caine, bupivacaine, and ropivacaine had the lowest incidences. Owing to insufficient data, definitive statements could not be made about the effects of the baricity of the local anesthetic, the concentration, and the effect of vasoconstrictors, although all these factors seemed not to be relevant. With regard to intrathecal ropivacaine, the incidence in the formal studies was zero. However, there has been one previous report after intrathecal administration, and one report of transient radicular irritation following epidural anesthesia with ropivacaine the symptoms resolved within 24 hours (244). 

An epidural abscess and paraplegia occurred after paravertebral lidocaine infiltration for back pain (SEDA-21,133). 

Rygnestad T, Zahlsen K, Bergshen O, Dale O. Focus on mobilisation after lower abdominal surgery. A doubleblind randomised comparison of epidural bupivacaine with morphine vs. lidocaine with morphine for postoperative analgesia. Acta Anaesthesiol Scand 1999 43(4) 380-7. 

A 65-year-old woman, who had had normal preoperative serum electrolytes and a normal QT interval with sinus rhythm, received hydroxyzine and atropine premedication followed by thiopental and vecuronium for anesthetic induction. Endotracheal intubation was difficult and precipitated atrial fibrillation, which was refractory to disopyramide 100 mg. Anesthesia was then maintained with sevoflurane 2% and nitrous oxide 50%. Ten minutes later ventricular tachycardia ensued, refractory to intravenous lidocaine, disopyramide, and magnesium. DC cardioversion resulted in a change to a supraventricular tachycardia, which then deteriorated to torsade de pointes. External cardiac massage and further DC cardioversion were initially unsuccessful, but the cardiac rhythm reverted to atrial fibrillation 10 minutes after the sevoflurane was switched off. Two weeks later she had her operation under combined epidural and general anesthesia, with no changes in cardiac rhythm. 

Dunn SM, Connelly NR, Steinberg RB, Letvis TJ, Bazzell CM, Klatt JL, Parker RK. Intrathecal sufentanil versus epidural lidocaine with epinephrine and sufentanil for early labor analgesia. Anesth Analg 1998 87(2) 331-5. 

In an abaxial sessamoid local anaesthetic model, the highest no-effect dose for the local anaesthetic effect of lidocaine was 4 mg (Harkins et al 1998). For caudal epidural anesthesia, dose rates of lidocaine alone of 0.25 (Csik-Salmon et al 1996) or 0.35mg/kg (Pikes et al 1989) have been proposed (i.e. 6-10 ml of a 2% solution). A maximum of 200 ml should be used for field blocks. The dose rates quoted for i.v. administration of either a 1% or 2% solution of lidocaine (without epinephrine (adrenaline)) are for loading doses of 0.65-5 mg/kg followed by a constant i.v. infusion of 25-100 gg/kg/min (Brianceau et al 2002, Doherty Frazier 1998). 

Fikes L W, Lin H C, Thurmon J C 1989 A preliminary comparison of lidocaine and xylazine as epidural analgesics in ponies. Veterinary Surgery 18 85-86... 

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