Regional anesthesia and pain medicine
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Reg Anesth Pain Med · Jul 2009
Comparative StudyThe economic implications of a multimodal analgesic regimen for patients undergoing major orthopedic surgery: a comparative study of direct costs.
Total knee and total hip arthoplasty (THA) are 2 of the most common surgical procedures performed in the United States and represent the greatest single Medicare procedural expenditure. This study was designed to evaluate the economic impact of implementing a multimodal analgesic regimen (Total Joint Regional Anesthesia [TJRA] Clinical Pathway) on the estimated direct medical costs of patients undergoing lower extremity joint replacement surgery. ⋯ Use of a comprehensive, multimodal analgesic regimen (TJRA Clinical Pathway) in patients undergoing lower extremity joint replacement surgery provides a significant reduction in the estimated total direct medical costs. The reduction in mean cost is primarily associated with lower hospital-based (Medicare Part A) costs, with the greatest overall cost difference appearing among patients with significant comorbidities (ASA PS III-IV patients).
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Reg Anesth Pain Med · Jul 2009
Calcium chloride prolongs the effects of lidocaine and bupivacaine in rat sciatic nerve.
Elevated extracellular calcium ion has been shown to shift the voltage dependence of Na+- and K+-ion channels rightward, making the nerve less excitable. We hypothesized that calcium chloride (CaCl2) when used as an adjuvant prolongs and intensifies the block by local anesthetics (LAs). We investigated the effects of LAs combined with calcium in rat sciatic nerve blockade and in cultured rat GH3 cells expressing Na+ channels. Furthermore, we tested for histologic changes due to CaCl2. ⋯ The mechanism of prolonged nerve block of CaCl2 coadministered with LAs seems to be a raised threshold for nerve excitation. Major histopathologic changes at higher concentrations of CaCl2 are evident, and therefore, clinical application as an adjuvant to LAs seems unlikely.
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Reg Anesth Pain Med · Jul 2009
Measurement of shift of the cauda equina in the subarachnoid space by changing position.
To perform spinal anesthesia, patients are usually placed in the lateral decubitus position with the knees drawn up to the stomach, the legs fully flexed, and the neck flexed to curve the back outward. Because the nerve roots of the cauda equina have considerable mobility in the subarachnoid space, the position of the cauda equina in the lateral decubitus position may be different from that in the supine position. However, the anatomic position of the cauda equina in the lateral decubitus position with fully flexed legs has not been carefully studied. In the present study, we geometrically measured the movement of the cauda equina in the subarachnoid space by changing positions, using magnetic resonance imaging (MRI). ⋯ The present study using MRI showed dynamical movement of the spinal cord and cauda equina due to changing position. The most obvious movements by changing from supine to lateral decubitus position and fully flexed legs were observed at the L2/3 and L1/2 levels, respectively.
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The perception of high resistance during injection of a local anesthetic during regional anesthesia may indicate intraneural injection. Anesthetists' ability to detect high resistance by "syringe feel" has been questioned in the past. The aim of our study was to investigate the anesthetist's ability to detect abnormal resistance to injection using an animal model. ⋯ Under the conditions of this study model, anesthetists were unable to correctly identify intraneural injection by syringe feel during simulated regional anesthesia.