Articles: nerve-block.
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This review focuses on available anesthetic techniques for cancer patients, the indications, and appropriate agents for these potent tools in a stepwise approach to cancer pain. Anesthetic procedures are desirable when they will not compromise bodily functions important to the patient, and when tumor-directed therapy and noninvasive or less-invasive, low-risk approaches (primarily pharmacologic tailoring of analgesic drugs) fail to control pain. Nondestructive techniques include the epidural/intrathecal use of opioids via an implanted catheter, and local anesthetic blocks of nerves and sympathetic ganglia. ⋯ Destructive anesthetic procedures comprise injections of neurolytic agents (most commonly phenol or alcohol), and insertion of freezing probes, into nerves and ganglia. The types of nerve blocks performed, their complications, and success rates, and limitations of commonly used neurolytic agents as well as their proper applications, are described. The importance of proper patient selection and knowledge of the pathophysiology of the pain being treated is stressed, as is the appropriate timing of anesthetic procedures in the course of the disease.
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Anesthesia and analgesia · Jun 1989
Subclavian perivascular block: influence of location of paresthesia.
Subclavian perivascular block of the brachial plexus was used in 156 adult patients undergoing orthopedic hand and forearm surgery. The location of the elicited paresthesia prior to deposition of 30 ml of a solution containing 1% mepivacaine, 0.2% tetracaine and 1.200,000 epinephrine was recorded. Twenty minutes later the quality of the block in the distribution of the superior, middle and inferior trunks of the brachial plexus was evaluated. ⋯ A superior trunk paresthesia was the paresthesia most often elicited. It resulted in a significantly lower incidence of inferior trunk anesthesia than did a middle or inferior trunk paresthesia. Complications included arterial puncture (25.6%), Horner's syndrome (64.1%), and recurrent laryngeal nerve block (1.3%), with no instances of symptomatic phrenic block or symptomatic pneumothorax.
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Regional anesthesia · May 1989
Comparative StudyAntinociceptive effects of localized administration of opioids compared with lidocaine.
To study possible antinociceptive effects of perineurally administered opioids, the rat infraorbital nerve block (IONB) model was employed for investigations of opioids (morphine, meperidine, buprenorphine, ethylketocyclazocine, and fentanyl) of differing receptor selectivity and physicochemical properties such as lipid solubility. Only meperidine in doses greater than 1 mg/kg produced localized analgesia, the duration of which increased dose-dependently. Naloxone failed to counteract the analgesic effects of meperidine. ⋯ The two agents caused a similar duration of sensory block in infiltration anesthesia. Meperidine was shorter than lidocaine in epidural anesthesia. The characteristics of blocks induced by the two agents may be explained by structural differences and associated differences in physicochemical properties such as lipid solubility and pKa.
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Randomized Controlled Trial Comparative Study Clinical Trial
Bupivacaine: a safe local anesthetic for wrist blocks.
Seventy-one patients having minor hand surgical procedures under wrist block anesthesia were studied, with the goal of identifying a possible neurotoxic potential of bupivacaine when used according to standard clinical practice. This drug was compared with lidocaine at equipotent analgesic concentrations (bupivacaine: 5 mg/ml; lidocaine: 20 mg/ml) by use of a double-blind randomized protocol. ⋯ In the remaining patient, anesthesia was induced with lidocaine, and no cause could be identified. It was concluded that bupivacaine, when used in clinical concentrations, is not associated with an increased incidence of neural complications.
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Regional-Anaesthesie · May 1989
[Does the development of methemoglobin in the newborn infant affect the suitability of prilocaine for pudendal anesthesia? A clinical study in the peripartum phase].
Pudendal block is a well established method of achieving analgesia during the second stage of labor. Whenever a large amount of a local anesthetic has to be injected in well vascularized tissue, local anesthetic drugs with low systemic toxicity should be used, to minimize side effects. This means that prilocaine is the drug of choice. ⋯ Formerly prilocaine was judged to be contraindicated in pregnant women during delivery because of the small redox capacity of fetal erythrocytes. Our study, however, demonstrates that 200 mg prilocaine for pudendal block does not induce methemoglobinemia in newborns to any significant extent. One explanation for this may be the increased renal elimination of local anesthetics in newborns and the low fetomaternal ratio.