Ultrasound Increases The Success Rate Of Spinal Needle Placement Through The Epidural Needle During Combined Spinal-Epidural Anaesthesia A Randomised Controlled Study

BACKGROUND Combined spinal-epidural anaesthesia (CSEA) using a needle-through-needle technique is currently widely used. However, successful epidural needle placement does not mean a successful spinal needle placement during CSEA. Whether ultrasound assistance could increase the first-pass success rate of spinal needle placement for CSEA remains unknown. OBJECTIVE The aim of this study was to investigate if ultrasound assistance could increase the first-pass success rate of spinal needle placement through the epidural needle during CSEA performed by experienced anaesthesiologists in patients undergoing caesarean section. DESIGN A prospective, randomised, double-blind study. SETTING Single centre, Department of Anaesthesiology, Shengjing Hospital, China Medical University, China, from June 2019 to September 2019. PATIENTS A total of 185 patients (aged 24 years to 52 years, American Society of Anesthesiologists grade (ASA) II-III, 38 to 40 weeks gestation) scheduled to undergo elective caesarean section under CSEA were enrolled. INTERVENTION The patients were randomised to either an ultrasound group (patients received a preprocedural ultrasound scan, and the puncture site was identified by ultrasound imaging) and a palpation group (patients received a sham procedural ultrasound scan, and the puncture site was identified by conventional palpation). MAIN OUTCOME MEASURES The primary outcome measure was the first-pass success rate for spinal needle placement through the epidural needle. Secondary outcome measures were total duration of CSEA, time required for successful epidural needle and spinal needle placement, number of epidural needle redirections and complications. RESULTS Preprocedural ultrasound imaging significantly increased the first-pass success rate of spinal needle placement through the epidural needle compared with conventional palpation (93.8 vs. 68.8%, P < 0.001). Preprocedural ultrasound imaging also decreased the total duration of CSEA (186.9 +/- 37.1 vs. 213 +/- 60.4 s, P = 0.0015) and the time required for successful spinal needle placement (78.3 +/- 22.9 vs. 100.1 +/- 53.7 s, P < 0.01) compared with conventional palpation. Fewer patients in the ultrasound group needed epidural needle redirections during the spinal needle placement procedure than in the palpation group (four patients vs. 20 patients, P < 0.01). CONCLUSION For experienced anaesthesiologists, preprocedural ultrasound imaging significantly increased the first-pass success rate of spinal needle placement through the epidural needle for obstetric patients undergoing caesarean section under CSEA.