TY - JOUR
T1 - Color flow Doppler in spinal ultrasound
T2 - A novel technique for assessment of catheter position in labor epidurals
AU - van den Bosch, Oscar F. C.
AU - Gleicher, Yehoshua
AU - Arzola, Cristian
AU - Siddiqui, Naveed
AU - Downey, Kristi
AU - Carvalho, Jose C. A.
N1 - Funding Information: JCAC is supported by the Merit Awards Program from the Department of Anesthesiology and Pain Medicine, University of Toronto. Publisher Copyright: © 2022 BMJ Publishing Group. All rights reserved.
PY - 2022/9/7
Y1 - 2022/9/7
N2 - Background: Ultrasound is commonly used to facilitate epidural catheter placement. However, data are lacking regarding its potential to confirm its position in the epidural space. Our aim was to visualize flow in the epidural space of patients receiving epidural analgesia for labor using color flow Doppler ultrasound. Methods: We conducted a prospective observational cohort study that included patients who had delivered vaginally under epidural analgesia. We used a 5-2 mHz curvilinear probe in a left and right paramedian longitudinal oblique view to visualize the anterior and posterior complex at the interspace of epidural catheter insertion, one and two interspaces above and below. At each window, the color flow Doppler function was used to visualize flow within the epidural space on injection of normal saline (1 mL). If no flow was visualized at any interspace, one assessment at the level of insertion was repeated with a 1 mL air/saline mixture. We studied a convenience sample size of 40 patients. Results: We visualized flow in the epidural space in all 40 patients. Flow was visualized on injection of 1 mL of saline in 37/40 patients (93%). In the remaining 3/40 patients (7%), flow was visualized with an air/saline mixture. Flow on injection of saline was visualized only at the interspace of insertion in 26/37 patients (70%), at the interspace of insertion and one interspace above in 10/37 (27%), or only at one interspace above in 1/37 (3%). Flow was visualized only on the left or on the right paramedian view in 19/37 patients (51%), despite a symmetrical sensory block in all patients. Conclusion: Color flow Doppler ultrasound is a feasible and fast way to determine flow in the epidural space in the obstetric population. Its potential clinical uses are confirmation of the epidural catheter position after placement, as well as troubleshooting of unsatisfactory epidural analgesia. Interestingly, our results suggest that epidural catheters predominantly remain at the interspace of insertion. Trial registration number: NCT05126745.
AB - Background: Ultrasound is commonly used to facilitate epidural catheter placement. However, data are lacking regarding its potential to confirm its position in the epidural space. Our aim was to visualize flow in the epidural space of patients receiving epidural analgesia for labor using color flow Doppler ultrasound. Methods: We conducted a prospective observational cohort study that included patients who had delivered vaginally under epidural analgesia. We used a 5-2 mHz curvilinear probe in a left and right paramedian longitudinal oblique view to visualize the anterior and posterior complex at the interspace of epidural catheter insertion, one and two interspaces above and below. At each window, the color flow Doppler function was used to visualize flow within the epidural space on injection of normal saline (1 mL). If no flow was visualized at any interspace, one assessment at the level of insertion was repeated with a 1 mL air/saline mixture. We studied a convenience sample size of 40 patients. Results: We visualized flow in the epidural space in all 40 patients. Flow was visualized on injection of 1 mL of saline in 37/40 patients (93%). In the remaining 3/40 patients (7%), flow was visualized with an air/saline mixture. Flow on injection of saline was visualized only at the interspace of insertion in 26/37 patients (70%), at the interspace of insertion and one interspace above in 10/37 (27%), or only at one interspace above in 1/37 (3%). Flow was visualized only on the left or on the right paramedian view in 19/37 patients (51%), despite a symmetrical sensory block in all patients. Conclusion: Color flow Doppler ultrasound is a feasible and fast way to determine flow in the epidural space in the obstetric population. Its potential clinical uses are confirmation of the epidural catheter position after placement, as well as troubleshooting of unsatisfactory epidural analgesia. Interestingly, our results suggest that epidural catheters predominantly remain at the interspace of insertion. Trial registration number: NCT05126745.
KW - Obstetrics
KW - REGIONAL ANESTHESIA
KW - TECHNOLOGY
KW - Ultrasonography
KW - analgesia
UR - http://www.scopus.com/inward/record.url?scp=85137737435&partnerID=8YFLogxK
U2 - https://doi.org/10.1136/rapm-2022-103948
DO - https://doi.org/10.1136/rapm-2022-103948
M3 - Article
C2 - 36215115
SN - 1098-7339
VL - 47
SP - 775
EP - 779
JO - Regional anesthesia and pain medicine
JF - Regional anesthesia and pain medicine
IS - 12
M1 - rapm-2022-103948
ER -