With the growth of ultrasound-guided regional anesthesia, so has the requirement for training tools to practice needle guidance skills and evaluate echogenic needles. Ethically, skills in ultrasound-guided needle placement should be gained in a phantom before performance of nerve blocks on patients in clinical practice. However, phantom technology is varied, and critical evaluation of the images is needed to understand their application to clinical use. Needle visibility depends on the echogenicity of the needle relative to the echogenicity of the tissue adjacent the needle. We demonstrate this point using images of echogenic and nonechogenic needles in 5 different phantoms at both shallow angles (20 degrees) and steep angles (45 degrees). The echogenicity of phantoms varies enormously, and this impacts on how needles are visualized. Water is anechoic, making all needles highly visible, but does not fix the needle to allow practice placement. Gelatin phantoms and Blue Phantoms provide tactile feedback but have very low background echogenicity, which greatly exaggerates needle visibility. This makes skill acquisition easier but can lead to false confidence in regard to clinical ability. Fresh-frozen cadavers retain much of the textural feel of live human tissue and are nearly as echogenic. Similar to clinical practice, this makes needles inserted at steep angles practically invisible, unless they are highly echogenic. This review describes the uses and pitfalls of phantoms that have been described or commercially produced.
Good echogenic needles should increase safety, efficacy, and simplicity, and hopefully further drive the adoption of ultrasound-guided techniques, to the benefit of our patients.
Background and objectivesDocumentation is important for quality improvement, education, and research. There is currently a lack of recommendations regarding key aspects of documentation in regional anesthesia. The aim of this study was to establish recommendations for documentation in regional anesthesia.MethodsFollowing the formation of the executive committee and a directed literature review, a long list of potential documentation components was created. A modified Delphi process was then employed to achieve consensus amongst a group of international experts in regional anesthesia. This consisted of 2 rounds of anonymous electronic voting and a final virtual round table discussion with live polling on items not yet excluded or accepted from previous rounds. Progression or exclusion of potential components through the rounds was based on the achievement of strong consensus. Strong consensus was defined as ≥75% agreement and weak consensus as 50%–74% agreement.ResultsSeventy-seven collaborators participated in both rounds 1 and 2, while 50 collaborators took part in round 3. In total, experts voted on 83 items and achieved a strong consensus on 51 items, weak consensus on 3 and rejected 29.ConclusionBy means of a modified Delphi process, we have established expert consensus on documentation in regional anesthesia.
Continuous peripheral nerve blockade is a common technique in the analgesic management for many procedures. Leakage of local anaesthetic from around the nerve catheter insertion site can increase the chance of catheter dislodgement, risks infective complications, and could divert anaesthetic away from the nerve causing the block to fail. We conducted a randomised controlled trial to assess whether the type of nerve catheter influenced local anaesthetic leak rate. One hundred and ten patients scheduled for elective unilateral total knee arthroplasty were randomised to receive a perineural catheter with either a catheter over needle (CON) system (Pajunk® E-Cath) (PAJUNK® GmbH, Medizintechnologie, Geisingen, Germany), or catheter through needle (CTN) system (Pajunk® SonoLong) (PAJUNK® GmbH, Medizintechnologie, Geisingen, Germany). There was no statistically significant difference in the rate of leaking catheters between groups (CON 1.8% versus CTN 3.7%; P=0.618), however, the overall leak rate was much lower than anticipated from pilot data. The CON system was on average faster to insert (CON 357 seconds versus CTN 482 seconds; P=0.004), but associated with poorer needle visibility under ultrasound (Likert scale 1-5, mean [SD], CON 3.31 [0.96] versus CTN 3.89 [0.84]; P=0.001). All seven instances of inadvertent catheter dislodgement occurred in the CTN group (P=0.006). There was no statistically significant difference between groups in the proportion of patients who had adequate analgesia on day one (CON 80% versus CTN 86.5%; P=0.294) and day two postoperatively (CON 85.5% versus CTN 91.8%; P=0.369). Our findings show the overall leak rate to be very low with both catheter systems; however, the CON system may have advantages in terms of speed of use and rate of inadvertent catheter dislodgement.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.