Regional anesthesia and pain medicine
-
Reg Anesth Pain Med · Mar 2010
ReviewUltrasound and review of evidence for lower extremity peripheral nerve blocks.
This qualitative systematic review summarizes existing evidence from randomized controlled trials (RCTs) comparing ultrasound (US) to alternative techniques for lower extremity peripheral nerve block. There were 11 RCTs of sufficient quality for inclusion. Jadad scores ranged from 1 to 4 with a median of 3. ⋯ In 2 studies, the optimal peripheral nerve stimulation technique may have not been used, resulting in a potential bias. No RCT reported US as inferior to alternative techniques in any outcome. There is level Ib evidence to make a grade A recommendation that US guidance provides improvements in onset and success of sensory block, a decrease in local anesthetic requirements, and decreased time to perform lower extremity peripheral nerve blocks.
-
Although new drugs and techniques may improve outcomes when unintended high blood levels of local anesthetics occur, the primary focus of daily practice should remain the prevention of such events. Although adoption of no single "safety step" will reliably prevent systemic toxicity, the combination of several procedures seems to have reduced the frequency of systemic toxicity since 1981. These include the use of minimum effective doses, careful aspiration, and incremental injection, coupled with the use of intravascular markers when large doses are used. ⋯ Fentanyl has also been confirmed to produce sedation in pregnant women when used as an alternative. The use of ultrasound observation of needle placement and injection may be useful, but has also been reported as not completely reliable. Constant vigilance and suspicion are still needed along with a combination of as many of these safety steps as practical.
-
Reg Anesth Pain Med · Mar 2010
Randomized Controlled TrialUltrasound-guided continuous femoral nerve block for analgesia after total knee arthroplasty: catheter perpendicular to the nerve versus catheter parallel to the nerve.
This study tested the hypothesis that, in continuous femoral nerve block (CFNB) under ultrasound guidance, placing a catheter perpendicular to the nerve can shorten the time of catheter insertion while providing a similar quality of analgesia compared with placing a catheter parallel to the nerve. ⋯ In CFNB under ultrasound guidance, using the catheter perpendicular to the nerve technique can shorten the time of catheter insertion while providing a similar quality of analgesia after total knee arthroplasty as compared with the catheter parallel to the nerve technique.
-
To summarize the existing evidence behind the role of ultrasonography in neuraxial anesthesia techniques. ⋯ Neuraxial ultrasonography has been recently introduced to regional anesthesia practice. The limited data available to date suggest that it is a useful adjunct to physical examination, allowing for a highly precise identification of regional landmarks and a precise estimation of epidural space depth, thus facilitating epidural catheter insertion. Further research is needed to conclusively establish its impact on procedure success and safety profile, particularly in the adult nonobstetric population.
-
Reg Anesth Pain Med · Mar 2010
Nerve expansion seen on ultrasound predicts histologic but not functional nerve injury after intraneural injection in pigs.
Intraneural injection can be seen as nerve expansion during ultrasound-guided regional anesthesia. The purpose of this animal study was to determine if nerve expansion seen on ultrasound during intraneural injection results in nerve injury. ⋯ This animal study suggests that nerve expansion seen on ultrasound during intraneural injection of clinically relevant volumes of LA results in histologic but not functional nerve injury.