Anesthesia bupivacaine

Chloroprocaine hydrochloride [3858-89-7] is characterized by low potency, rapid onset, short duration of action, and low systemic toxicity. It is indicated for infiltration anesthesia at 1—2% and for extradural anesthesia at 2—3% when short surgical procedures are performed under regional anesthesia. Chloroprocaine may be mixed with long duration agents such as bupivacaine (22, R = n-Q [) to afford a more rapid onset and shorter duration of action than bupivacaine 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. 

Spinal anesthesia Spinal anesthesia is the introduction of local anesthetics directly into the spinal fluid, which causes a sympathetic blockage, or loss of feeling as well as muscle relaxation resulting from the interaction of anesthetic with every spinal nerve tract. This method is used during major surgical interventions. As a rule, lidocaine, mepivacaine, and bupivacaine are used for this purpose. 

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. 

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. 

Epidural anesthesia is especially useful in obstetrics. Excellent analgesia occurs and the patient remains awake. Analgesia by the epidural route can be provided for labor and delivery or for cesarean section. Bupivacaine in lower concentrations has the advantage of providing excellent analgesia while minimally reducing motor strength. 

Answer Bupivacaine use for local anesthesia of this type is very safe and commonly done. However, SOMETIMES inadvertent vascular injection results in a large amount of anesthetic in the systemic circulation. Because the heart is beating, the excitable tissue in the heart is being depolarized repetitively. Local anesthetics bind to rapidly depolarizing tissues more than tissues at rest (frequency-dependent block). Also, bupivacaine has a long duration of action because of its long residence time at receptors (sodium channel). Thus, this combination of factors contributed to the catastrophic outcome of this case. Had the same case involved lidocaine, the resuscitation would have likely been successful. 

Topical local anesthesia is often used for eye, ear, nose, and throat procedures. Satisfactory topical local anesthesia requires an agent capable of rapid penetration across the skin or mucosa, and with limited tendency to diffuse away from the site of application. Cocaine, because of its excellent penetration and local vasoconstrictor effects, has been used extensively for ear, nose and throat (ENT) procedures. Cocaine is somewhat irritating and is therefore less popular for ophthalmic procedures. Recent concern about its potential cardiotoxicity when combined with epinephrine has led most otolaryngology surgeons to switch to a combination containing lidocaine and epinephrine. Other drugs used for topical anesthesia include lidocaine-bupivacaine combinations, tetracaine, pramoxine, dibucaine, benzocaine, and dyclonine. 

Bonnet, F., Buisson, V. B., Francois, Y., Catoire, P., Saada, M. Effects of oral and subarachnoid clonidine on spinal anesthesia with bupivacaine, Reg. Anesth. 1990, 75, 211-214. 

Clinical use Because of its long duration of action, bupivacaine is indicated for long surgical anesthesia where a considerable amount of postoperative pain is expected such as dental and oral surgeries. Infiltration using a 0.25 % solution of bupivacaine produces sensory anesthesia with an onset of 2 to 5 min and a duration of 2 to 4 h or greater (Tetzlaff, 2000). A nerve conduction block with a duration of between 4 to 8 h and occasionally up to 24 h is achieved with injection of 0.5 to 0.75 %... 

With local infiltration, toxic side-effects like convulsions and cardiovascular collaps occur in the dose range of 2.5 to 3 mg/kg body weight. Because of its systemic toxicity, bupivacaine is contraindicated for intravenous regional anesthesia. 

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. 

Borgeat A, Ekatodramis G, Blumenthal S. Interscalene brachial plexus anesthesia with ropivacaine 5 mg/mL and bupivacaine 5 mg/mL effects on electrocardiogram. Reg Anesth Pain Med. 2004 29 557-563. 

Anesthesia of the lower extremities and abdomen may be induced by the introduction of anesthetic drugs into the subarachnoid space (Figure 23.6). The drug most often used for this purpose is bupivacaine. The latency period plus the duration of the maximal cephalad level for both plain and hyperbaric bupivacaine lasts from 10 to 60 min. A bupivacaine solution is made hyperbaric by the addition of 5 to 8% glucose. The distribution of bupivacaine in the cerebrospinal fluid (CSF) is affected by gravity and is therefore influenced by the patient s position. With a dose of 15 mg of plain 0.5% bupivacaine, a half-life of about 3 h is achieved. The addition of epinephrine to bupivacaine prolongs the duration of block. 

Feldman HS, Dvoskin S, Halldin MH et al. (1997) Comparative anesthetic efficacy and pharmacokinetics of epidurally administered ropivacaine and bupivacaine in the sheep. Regional Anesthesia 22 451 160... 

The addition of epinephrine, a vasoconstrictor, to an injectable anesthetic prolongs the duration of anesthesia and decreases the rate of systemic absorption, thereby decreasing the risk of systemic toxicity. The duration of some anesthetics, such as bupivacaine, a long-acting anesthetic, cannot be significantly extended by adding epinephrine. Epinephrine also decreases local bleeding. Effective vasoconstriction is obtained with a concentration of 1 to 100,000 or even 1 to 200,000. The usual... 

Cataract patients, in general, have relatively little immediate postoperative pain. This absence of pain is, at least in part, due to the long duration of action (up to 12 hours) of bupivacaine used in retrobulbar anesthesia. Some practitioners recommend the use of oral analgesics, such as acetaminophen or ibuprofen, as needed, if the patient experiences minor discomfort in the immediate postsur-gical period.Topical NSAIDs are also reported to decrease immediate postoperative pain. Significant or persistent postoperative pain is considered to be abnormal and may be a symptom of such complications as corneal abrasion, bullous keratopathy, high lOP, or endophthalmitis. 

Infusions of 0.25% bupivacaine into pig coronary arteries caused ventricular fibrillation at lower rates of infusion than 0.25% bupivacaine with 1% lidocaine (10). The lidocaine/bupivacaine mixture did not have a greater myocardial depressant effect than bupivacaine alone. The authors suggested that when regional anesthesia requires high doses of local anesthetics, bupivacaine should not be used alone but in a mixture with lidocaine, and that lidocaine should be useful in the management of bupivacaine-induced ventricular fibrillation. 

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). 

A formulation of bupivacaine called Regibloc (bupivacaine HCl Intramed, South Africa) was the only common factor in a series of serious complications after regional anesthesia (21). 

Pape R, Ammer W. Holter-EKG-Uberwachung bei Periduralanaesthesie mit Bupivacain 0.75%. [Holier ECG monitoring during peridural anesthesia with bupivacaine 0.75%.] Reg Anaesth 1986 9(3) 74-8. 

Bridenbaugh PO, Hagenouw RR, Gielen MJ, Edstrom HH. Addition of glucose to bupivacaine in spinal anesthesia increases incidence of tourniquet pain. Anesth Analg 1986 65(ll) 1181-5. 

A 71-year-old man received intrathecal anesthesia using 0.3% cinchocaine 2 ml for a transurethral prostatectomy (8). He had a history of allergic rhinitis, and 2 months before had had an uneventful prostate biopsy and cystoscopy, also under spinal anesthesia with iso-baric bupivacaine. Within 45 minutes of the spinal injection he complained of periorbital itching, started to shake, and developed muscle rigidity. He rapidly became unconscious, with a systolic blood pressure of 40 mmHg and widespread erythema. He was treated with hydrocortisone and antihistamines and required an infusion of adrenaline. Intradermal testing after full recovery was positive with cinchocaine. 

Kaabachi O, Ben Rajeb A, Mebazaa M, Safi H, Jelel C, Ben Ghachem M, Ben Ammar M. La rachianesthesie chez I enfant etude comparative de la bupivacaine hyperbare avec et sans clonidine. [Spinal anesthesia in children comparative study of hyperbaric bupivacaine with or without clonidine.] Ann Fr Anesth Reanim 2002 21(8) 617-21. 

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