Regional anesthesia and pain medicine
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Reg Anesth Pain Med · May 2011
Randomized Controlled Trial Comparative Study Clinical TrialUltrasound-guided (needle-in-plane) perineural catheter insertion: the effect of catheter-insertion distance on postoperative analgesia.
When using ultrasound guidance to place a perineural catheter for a continuous peripheral nerve block, keeping the needle in plane and nerve in short axis results in a perpendicular needle-to-nerve orientation. Many have opined that when placing a perineural catheter via the needle, the acute angle may result in the catheter bypassing the target nerve when advanced beyond the needle tip. Theoretically, greater catheter tip-to-nerve distances result in less local anesthetic-to-nerve contact during the subsequent perineural infusion, leading to inferior analgesia. Although a potential solution may appear obvious-advancing the catheter tip only to the tip of the needle, leaving the catheter tip at the target nerve-this technique has not been prospectively evaluated. We therefore hypothesized that during needle in-plane ultrasound-guided perineural catheter placement, inserting the catheter a minimum distance (0-1 cm) past the needle tip is associated with improved postoperative analgesia compared with inserting the catheter a more traditional 5 to 6 cm past the needle tip. ⋯ This study did not find evidence to support the hypothesis that, for popliteal-sciatic perineural catheters placed using ultrasound guidance and a needle-in-plane technique, inserting the catheter a minimum distance (0-1 cm) past the needle tip improves (or worsens) postoperative analgesia compared with inserting the catheter a more traditional distance (5-6 cm). Caution is warranted if extrapolating these results to other catheter designs, ultrasound approaches, or anatomic insertion sites.
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Reg Anesth Pain Med · May 2011
Comparative StudyDoppler measurement of the changes of fetal umbilical and middle cerebral artery velocimetric indices during continuous epidural labor analgesia.
Although complications of the epidural technique are known to affect the fetus adversely, there are no data indicating that regional analgesia directly causes harmful effects to the fetus. Our purpose was to determine the effect of epidural labor analgesia on the Doppler velocimetric indices of the uterine and fetal umbilical and middle cerebral arteries. ⋯ These data suggest that although velocimetric indices of the maternal uterine artery are affected by continuous epidural labor analgesia, fetal circulation, as measured by Doppler velocimetric indices, is not altered.
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Reg Anesth Pain Med · May 2011
Randomized Controlled Trial Comparative StudyS-ketamine modulates hyperalgesia in patients with chronic pancreatitis pain.
Upper abdominal pain is a dominant feature of chronic pancreatitis. A key phenomenon in this context is hyperalgesia, typically associated with N-methyl-d-aspartate receptor activation. This exploratory study evaluates acute effects of S-ketamine, a noncompetitive N-methyl-d-aspartate antagonist, in modulating generalized hyperalgesia in chronic pancreatitis pain. ⋯ S-ketamine infusion is more effective than placebo in increasing PPTs in chronic pancreatitis pain patients immediately after infusion. This effect did not outlast the infusion. Further research is warranted into S-ketamine use for reducing generalized hyperalgesia and chronic pancreatitis pain.
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Reg Anesth Pain Med · May 2011
Randomized Controlled Trial Comparative StudyIs circumferential injection advantageous for ultrasound-guided popliteal sciatic nerve block?: A proof-of-concept study.
Ultrasound (US) guidance, in some instances, can increase the success rate and reduce the onset and procedure times for peripheral nerve blockade compared with traditional nerve localization techniques. The presumptive mechanism for these benefits is the ability to accurately inject local anesthetic circumferentially around the target nerve. We aimed to determine whether ensuring circumferential spread of local anesthetic is advantageous for US-guided popliteal sciatic nerve block. ⋯ Ultrasound-guided circumferential injection of local anesthetic around the sciatic nerve at the popliteal fossa can improve the rate of sensory block without an increase in block procedure time or block-related complications compared with a single-location injection technique.