Color Doppler ultrasonography of an agitated solution is predictive of accurate catheter placement for a continuous popliteal sciatic nerve block

Clifford Bowens,Brian Frazer Scott Allen,Eric Russell Briggs,Yaping Shi,Randall John Malchow,Rajnish Kumar Gupta,Christopher Loredo Canlas,John Matthew Corey,Ignacio J Badiola,Lisa Michelle Jaeger,Jonathan Scott Schildcrout

doi:10.1186/s13741-021-00229-w

Abstract

BackgroundContinuous peripheral nerve catheters (PNCs) have been shown to provide superior postoperative analgesia, decrease opioid consumption, and improve patient satisfaction compared with single injection techniques. In order to achieve success and reliability, accurate catheter positioning is an essential element of PNC placement. An agitated solution of normal saline, D5W, or a local anesthetic solution can be produced by the introduction of air to the injectate, creating air bubbles that can enhance ultrasonographic visualization and possibly improve block success.MethodsEighty-three patients were enrolled. Ultrasound-guided continuous popliteal sciatic nerve blocks were performed by positioning the tip of a Tuohy needle between the tibial and common peroneal branches of the sciatic nerve and threading a catheter. An agitated local anesthetic solution was injected through the catheter, viewed with color Doppler ultrasound and video recorded. A peripheral block score (lower score = greater blockade, range 0-14) was calculated based upon the motor and sensory testing at 10, 20, and 30 min after block completion. The color Doppler agitation coverage pattern for the branches of the sciatic nerve was graded as follows: complete (> 50%), partial (> 0%, ≤ 50%), or none (0%).ResultsThe degree of nerve blockade at 30 min as judged by median (10th, 90th percentile) peripheral block score was significant for partial or complete color Doppler coverage of the sciatic nerve injectate compared to no coverage [3 (0, 7) vs 8 (4, 14); p < 0.01] and block onset was faster (p = 0.03). The block success was higher in groups with partial or complete coverage of the branches of the sciatic nerve vs no coverage (96% vs 70%; p = 0.02).ConclusionsInjection of an agitated solution through a popliteal sciatic perineural catheter is predictive of accurate catheter placement when partial or complete coverage of the sciatic nerve branches is visualized with color Doppler ultrasound.Trial registrationNCT01591603

Highlights

Continuous peripheral nerve catheters (PNCs) have been shown to provide superior postoperative analgesia, decrease opioid consumption, and improve patient satisfaction compared with single injection techniques (Ding et al, 2015; Mariano et al, 2009; Ilfeld et al, 2003)
We hypothesized that the coverage of the sciatic nerve branches with an agitated solution injection, visualized with 2D color Doppler ultrasound, would correlate with accurate placement of a continuous popliteal sciatic nerve block
There were no significant differences among the groups with respect to gender, age, body mass index (BMI), American Society of Anesthesiologists (ASA) classification, diabetes mellitus, surgical region, catheter depth, or sciatic nerve visualization (Table 1)

Summary

Introduction

Continuous peripheral nerve catheters (PNCs) have been shown to provide superior postoperative analgesia, decrease opioid consumption, and improve patient satisfaction compared with single injection techniques. An agitated solution of normal saline, D5W, or a local anesthetic solution can be produced by the introduction of air to the injectate, creating air bubbles that can enhance ultrasonographic visualization and possibly improve block success. Continuous peripheral nerve catheters (PNCs) have been shown to provide superior postoperative analgesia, decrease opioid consumption, and improve patient satisfaction compared with single injection techniques (Ding et al, 2015; Mariano et al, 2009; Ilfeld et al, 2003). An agitated solution of normal saline, D5W, or a local anesthetic solution is produced by the introduction air to the solution, creating air bubbles that can enhance ultrasonographic visualization. We hypothesized that the coverage of the sciatic nerve branches with an agitated solution injection, visualized with 2D color Doppler ultrasound, would correlate with accurate placement of a continuous popliteal sciatic nerve block

Methods

Results

Conclusion