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dc.contributor.authorVanlapa Arnuntasupakulen_US
dc.contributor.authorTom C.R.V. Van Zunderten_US
dc.contributor.authorAmorn Vijitpavanen_US
dc.contributor.authorJulian Alisteen_US
dc.contributor.authorPhatthanaphol Engsusophonen_US
dc.contributor.authorPrangmalee Leurcharusmeeen_US
dc.contributor.authorSonia Ah-Kyeen_US
dc.contributor.authorRoderick J. Finlaysonen_US
dc.contributor.authorDe Q.H. Tranen_US
dc.description.abstract© 2016 American Society of Regional Anesthesia and Pain Medicine. Background and Objectives Epidural waveform analysis (EWA) provides a simple confirmatory adjunct for loss of resistance (LOR): when the needle tip is correctly positioned inside the epidural space, pressure measurement results in a pulsatile waveform. In this randomized trial, we compared conventional and EWA-confirmed LOR in 2 teaching centers. Our research hypothesis was that EWA-confirmed LOR would decrease the failure rate of thoracic epidural blocks. Methods One hundred patients undergoing thoracic epidural blocks for thoracic surgery, abdominal surgery, or rib fractures were randomized to conventional LOR or EWA-LOR. The operator was allowed as many attempts as necessary to achieve a satisfactory LOR (by feel) in the conventional group. In the EWA-LOR group, LOR was confirmed by connecting the epidural needle to a pressure transducer using a rigid extension tubing. Positive waveforms indicated that the needle tip was positioned inside the epidural space. The operator was allowed a maximum of 3 different intervertebral levels to obtain a positive waveform. If waveforms were still absent at the third level, the operator simply accepted LOR as the technical end point. However, the patient was retained in the EWA-LOR group (intent-to-treat analysis). After achieving a satisfactory tactile LOR (conventional group), positive waveforms (EWA-LOR group), or a third intervertebral level with LOR but no waveform (EWA-LOR group), the operator administered a 4-mL test dose of lidocaine 2% with epinephrine 5 μg/mL. Fifteen minutes after the test dose, a blinded investigator assessed the patient for sensory block to ice. Results Compared with LOR, EWA-LOR resulted in a lower rate of primary failure (2% vs 24%; P = 0.002). Subgroup analysis based on experience level reveals that EWA-LOR outperformed conventional LOR for novice (P = 0.001) but not expert operators. The performance time was longer in the EWA-LOR group (11.2 ± 6.2 vs 8.0 ± 4.6 minutes; P = 0.006). Both groups were comparable in terms of operator's level of expertise, depth of the epidural space, approach, and LOR medium. In the EWA-LOR group, operators obtained a pulsatile waveform with the first level attempted in 60% of patients. However, 40% of subjects required performance at a second or third level. Conclusions Compared with its conventional counterpart, EWA-confirmed LOR results in a lower failure rate for thoracic epidural blocks (2% vs 24%) in our teaching centers. Confirmatory EWA provides significant benefits for inexperienced operators.en_US
dc.titleA randomized comparison between conventional and waveform-confirmed loss of resistance for thoracic epidural blocksen_US
article.title.sourcetitleRegional Anesthesia and Pain Medicineen_US
article.volume41en_US Universityen_US University Health Centre, Montreal General Hospitalen_US Mai Universityen_US
Appears in Collections:CMUL: Journal Articles

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