Regional anesthesia and pain medicine
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Reg Anesth Pain Med · Nov 2005
ReviewAcute toxicity of local anesthetics: underlying pharmacokinetic and pharmacodynamic concepts.
The risk of accidental intravascular injection and consequent acute toxicity is ever-present with most neural blockade techniques. The severity of cardiovascular and central nervous system (respectively, CVS and CNS) toxicity is directly related to the local anesthetic potency, dose, and rate of administration. Nonetheless, although the anesthetic potency of ropivacaine and levobupivacaine is similar to that of bupivacaine, at usual clinical doses, ropivacaine and levobupivacaine are less likely than bupivacaine to cause convulsions or lethal dysrhythmias. ⋯ This is an underlying tenet of dose fractionation, but the main advantage of dose fractionation is that the anesthesiologist is able to cease administration with less of the dose given if signs or symptoms of toxicity occur. Overall, it appears that the gains in safety from ropivacaine and levobupivacaine are due more to favorable pharmacodynamic enantioselectivity than to pharmacokinetic factors. This essay presents some pharmacokinetic aspects relevant to acute toxicity of local anesthetics, mainly using data from the authors' studies in a sheep model of simulated accidental intravenous administration.
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Reg Anesth Pain Med · Nov 2005
Correlation of postoperative pain to quality of recovery in the immediate postoperative period.
It is unclear whether the severity of postoperative pain may affect patients' quality of recovery in the immediate postoperative period (within 2 weeks of surgery). ⋯ Our findings suggest that an increase in postoperative pain is correlated with a decrease in a patient's quality of recovery in the immediate postoperative period.
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Reg Anesth Pain Med · Nov 2005
Nerve blocks at the wrist for carpal tunnel release revisited: the use of sensory-nerve and motor-nerve stimulation techniques.
Because the median nerve at the wrist has mainly sensory endings, the aim of this study was to assess the response of the median nerve to nerve stimulation at the wrist and to evaluate the quality of median nerve block. A control group of patients who received blinded injections was analyzed and compared post hoc. ⋯ This study describes how infrequently an initial motor response is identified when a nerve stimulator is used on the median nerve at the wrist. A very high success rate of median and ulnar nerve block at the wrist is obtained by use of sensory or sensory-motor-nerve stimulation and less than 10 mL of anesthetic solution.
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Reg Anesth Pain Med · Nov 2005
Clinical TrialA description of the spread of injectate after psoas compartment block using magnetic resonance imaging.
Magnetic resonance imaging (MRI) provides for excellent visualization of spread of solution after peripheral nerve block. The aim of this observational study was to utilize MRI to describe the distribution of injectate (gadopentetate dimeglumine) administered for continuous psoas compartment block (PCB) performed by use of two approaches (Capdevila and modified Winnie) and to describe the spread of injectate to the lumbar plexus. ⋯ The most common pattern of injectate spread seen on MRI with both approaches to PCB was spread within the body of the psoas muscle around the lumbar branches (L2-4), with cephalad spread to the lumbar nerve roots. One catheter resulted in injectate between the psoas and quadratus lumborum muscles.