Peripheral nerve block

Lidocaine hydrochloride [73-78-9] (Xylocaine), is the most versatile local anesthetic agent because of its moderate potency and duration of action, rapid onset, topical activity, and low toxicity. Its main indications are for infiltration, peripheral nerve blocks, extradural anesthesia, and in spinal anesthesia where a duration of 30 to 60 min is desirable. Because of its vasodilator activity, addition of the vasoconstrictor, epinephrine, increases the duration of action of Hdocaine markedly. It is also available in ointment or aerosol preparations for a variety of topical appHcations. 

Mepivacaine hydrochloride [1722-62-9] similar in profile to Hdocaine, is used for infiltration, peripheral nerve blocks, and extradural anesthesia. It appears to be less toxic than Hdocaine in adults but more toxic in newborns. The duration of action is longer than that of Hdocaine because of its lower vasodilator activity. Mepivacaine has Htde topical activity. 

Local anesthetics are used for topical anesthesia, local infiltration, peripheral nerve block, paravertebral anesthesia, intravenous block also known as regional anesthesia, epidural block, and spinal i.e. subarachnoid blockade. The local anesthetics may be divided into two main groups, the esters and the amide-type agents. 

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. 

Procaine is ineffective when administered through surface application, and is used only by injection. The onset of action for the drug is 2 to 5 minutes, and its duration of action is short. Vasoconstrictors are usually co-administered with this vasodilator drug to delay its absorption and to increase the duration of action. The drug is used for infiltration anesthesia, peripheral nerve block, and spinal anesthesia. 

Lignocaine injections are indicated for production of local or regional anaesthesia by infiltration techniques such as percutaneous injection, peripheral nerve block, spinal or subarachnoid block. 

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-... 

Resuscitation from bupivacaine cardiovascular toxicity is extremely difficult even for experienced clinicians. Recent studies suggest that propofol can be useful in resuscitating patients acutely exposed to toxic levels of bupivacaine. The (S)-isomer, levobupivacaine, appears to have a lower propensity for cardiovascular toxicity than the racemic mixture or the (7 >isomer and has been approved for clinical use. The clinical effects of ropivacaine are similar to those of bupivacaine, but ropivacaine is allegedly associated with a lower potential for cardiovascular toxicity. Ropivacaine is available only as the ( SJ-stereoisomer, which has inherently less affinity for the cardiac sodium channel. However, both cardiac toxicity and CNS toxicity have been reported when large doses of ropivacaine were used for peripheral nerve blocks. 

Sinnott CJ et al On the mechanism by which epinephrine potentiates lidocaine s peripheral nerve block. Anesthesiology 2003 98 181. [PMID 12502995]... 

Clinical use Etidocaine in combination with adrenaline is employed for infiltration anesthesia using solutions of 0.5% and peripheral nerve block at 0.5 and 1.0 % with a duration of 3 to 12 h (Tetzlaff, 2000). Epidural anesthesia is achieved with 1.0 to 1.5 % solutions with a duration of 3 to 5 h. Due to a profound motor block sometimes associated with unsatisfactory sensory block etidocaine is disadvantegous compared to bupivacaine. 

With infiltration of 0.5 to 1.0% prilocaine local anesthesia with a duration of 1 to 2 h is established. Peripheral nerve block is achieved with 1.5 to 2.0 % with a duration of 2 to 3... 

Clinical use Because of its poor penetration of intact mucous membranes, procaine is largely ineffective for topical applications and has been mainly used in injection in combination with adrenaline, although in general it has been replaced by other LAs such as lidocaine. For infiltration anesthesia, 0.25 to 0.5 % solutions of procaine have been used in doses up to 600 mg. For peripheral nerve block, a common dose of 500 mg of procaine has been given as a 0.5 to 2.0 % solution. 

According to Anderson Mehl (Ref 17), TEGDN is very toxic. It acts as a violent poison when ingested by rats or as a peripheral nerve block when selectively applied. Dermal application of 21mmoles/kg of body wt in rabbits causes death in 2 to 3 weeks. In a later study by Anderson et al (Ref 19) the 24 hr intraperitonal... 

Articane Septocaine Rapid Intermediate Peripheral nerve block... 

Bupivacaine Marcaine, Sensor-caine Slow to Intermediate Long Infiltration Peripheral nerve block Epidural Spinal Sympathetic block... 

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

Generic Name Procaine Trade Name(s) Novocain Onset of Action Intermediate Duration of Action Short Principle Use(s) Infiltration Peripheral nerve block Spinal... 

Peripheral nerve block. The anesthetic is injected close to the nerve trunk so that transmission along the peripheral nerve is interrupted.61 This type of local anesthesia is common in dental procedures (restorations, tooth extractions, and so on) and can also be used to block other peripheral nerves to allow certain surgical procedures of the hand, foot, shoulder, and so forth. ii.56.65 xnjection near larger nerves (femoral, sciatic) or around a nerve plexus (brachial plexus)... 

Grant SA, Nielsen KC, Greengrass RA, et al. Continuous peripheral nerve block for ambulatory surgery. Reg Anesth Pain Med. 2001 26 209-214. 

Shinaman RC, Mackey S. Continuous peripheral nerve blocks. Curr Pain Headache Rep. 2005 9 24-29. 

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. 

Pain referred from visceras to skin supplied by same spinal segment Peripheral nerve block (Bupivacaine)... 

Local Anesthetics for Regional Infiltration and Peripheral Nerve Block... 

When appropriate, peripheral nerve block with a local anaesthetic, or neural axis block, e.g., spinal or epidural, provides intraoperative analgesia and muscle relaxation. These local anaesthetic techniques provide excellent postoperative analgesia. 

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). 

Peripheral nerve block is created by injecting ethanol around the selected nerve. The effect of alcohol on nerve tissue has been examined in animal models and in postmortem specimens from patients who received neurolytic blocks (8,9). In general, alcohol causes destruction of nerve fibers, with subsequent Wallerian degeneration. The basal lamina around the Schwann cell usually remains intact. This leaves a tract available for axon regeneration without the formation of a neuroma. If the cell bodies are completely destroyed, regeneration will not occur. Contact of alcohol with unintended nerve roots underlies many of the more serious complications. Involvement of anterior rootlets sufficient to interrupt motor nerve function will result in muscle weakness or paralysis. Interruption of... 

Klein SM, Benveniste H. Anxiety, vocalization, and agitation following peripheral nerve block with ropivacaine. Reg Anesth Pain Med 1999 24(2) 175-8. 

Felsenthal G. Pharmacology of phenol in peripheral nerve blocks a review. Arch Phys Med Rehabil 1974 55(1) 13-16. 

Khalili AA, Betts HB. Peripheral nerve block with phenol in the management of spasticity. Indications and complications. JAMA 1967 200(13) 1155-7. 

Peripheral nerve block anesthesia involves injecting the drug near the nerves close to the area to be anesthetized. Epidural anesthesia results when the local anesthetic is injected into the epidural space between a lumbar and sacral vertebra. Several drugs can safely produce useful levels of anesthesia for obstetrics as well as postoperative pain. Another method of utilizing local anesthetics is to inject solutions into subarachnoid spaces (e.g., the spaces between certain vertebrae). 

Chloroprocaine (1 to 2% injection with methylparaben as a preservative) is indicated in the production of local anesthesia by infiltration and peripheral nerve block. Chloroprocaine without methylparaben is indicated in peripheral and central nerve block, including lumbar and caudal epidural blocks. Chloroprocaine has an onset of action of 6 to 12 minutes. 

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