Randomized comparison between epidural waveform analysis through the needle versus the catheter for thoracic epidural blocks

Abstract

BackgroundEpidural waveform analysis (EWA) provides a simple confirmatory adjunct for loss of resistance (LOR): when the needle/catheter tip is correctly positioned inside the epidural space, pressure measurement results in a pulsatile waveform. Epidural waveform analysis can be carried out through the tip of the needle (EWA-N) or the catheter (EWA-C). In this randomized trial, we compared the two methods. We hypothesized that, compared with EWA-C, EWA-N would result in a shorter performance time.MethodsOne hundred and twenty patients undergoing thoracic epidural blocks for thoracic or abdominal surgery were randomized to EWA-N or EWA-C. In the EWA-N group, LOR was confirmed by connecting the epidural needle to a pressure transducer. After obtaining a satisfactory waveform, the epidural catheter was advanced 5 cm beyond the needle tip. In the EWA-C group, the epidural catheter was first advanced 5 cm beyond the needle tip after the occurrence of LOR. Subsequently, the catheter was connected to the pressure transducer to detect the presence of waveforms. In both study groups, the block procedure was repeated at different intervertebral levels until positive waveforms could be obtained (through the needle or catheter as per the allocation) or until a predefined maximum of three intervertebral levels had been reached. Subsequently, the operator administered a 4 mL test dose of lidocaine 2% with epinephrine 5 µg/mL through the catheter. An investigator present during the performance of the block recorded the performance time (defined as the temporal interval between skin infiltration and local anesthetic administration through the epidural catheter). Fifteen minutes after the test dose, a blinded investigator assessed the patient for sensory block to ice. Success was defined as a bilateral block in at least two dermatomes. Furthermore, postoperative pain scores, local anesthetic consumption, and breakthrough analgesic consumption were recorded.ResultsNo intergroup differences were found in terms of performance time, success rate, postoperative pain, local anesthetic requirement, and breakthrough analgesic consumption.ConclusionEWA can be carried out through the needle or through the catheter with similar efficiency (performance time) and efficacy (success rate, postoperative analgesia).Trial registration numberNCT03603574.

Loss-of-Resistance Versus Dynamic Pressure-Sensing Technology for Successful Placement of Thoracic Epidural Catheters: A Randomized Clinical Trial

“…While fluoroscopic guidance offers benefits such as needle trajectory guidance and catheter location confirmation, 18 its implementation faces limitations such as availability, radiation exposure, and additional costs and time. Similarly, methods such as epidural waveform analysis and electrical stimulation, despite their promise, 19,25,26 also present technical difficulties and interpretation problems. Ultrasound-assisted or guided approaches are also valuable, [27][28][29] but face barriers due to their technical complexity and potential challenges in translating their benefits to broad clinical practice.…”

Anesthetic management of patients with class 3 obesity undergoing elective Cesarean delivery: a single-centre historical cohort study

“…Given the paramount importance of successful neuraxial anesthesia in these patients, we routinely use additional tests to confirm the accurate placement of the epidural catheter. The electrical stimulation test of the epidural catheter (Tsui test) 10 and the epidural waveform analysis through the needle 22 and/or the catheter 23 allow objective assessment of the catheter position prior to injection of local anesthetics, hence minimizing chances of a failed epidural anesthetic. Unfortunately, the use of these tests was not routinely charted, so we could not report their use across the BMI groups.…”