Regional anesthesia and pain medicine
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Reg Anesth Pain Med · Jan 1998
Defining the cross-sectional anatomy important to interscalene brachial plexus block with magnetic resonance imaging.
Interscalene brachial plexus block is a useful technique to provide anesthesia and analgesia for the shoulder and proximal upper extremity. The initial needle direction at the interscalene groove has been described as being "perpendicular to the skin in every plane" (1). A cross-sectional (axial) approach may offer a more easily conceptualized directed needle placement. The purpose of this study is to define the cross-sectional anatomy and idealized needle angles important to interscalene brachial plexus block. ⋯ These findings suggest initial needle placement at the interscalene groove should be angled less perpendicularly relative to the sagittal plane than is often observed. A cross-sectional approach enables more practical visualization of initial needle placement. A more accurate initial needle placement may minimize the number of needle passes necessary to contact the nerve roots, thereby more efficiently obtaining a successful block.
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Reg Anesth Pain Med · Jan 1998
Randomized Controlled Trial Clinical Trial2-Chloroprocaine and bupivacaine are unreliable indicators of intravascular injection in the premedicated patient.
Epinephrine-containing test doses for detection of intravascular injection during epidural anesthesia may be unreliable or hazardous in beta-blocked, elderly, or pregnant patients. Subtoxic injections of lidocaine have been used as an alternative marker of intravascular injection in unpremedicated patients. We studied two groups of premedicated patients and unpremedicated subjects to evaluate the reliability of the local anesthetics bupivacaine (B) and 2-chloroprocaine (2-CP) as test dose injections. ⋯ While 90 mg 2-CP or 25 mg B may be reliable alternatives to epinephrine test doses in unpremedicated subjects, they are unreliable indicators of intravascular injection in the premedicated patient.