Spinal ultrasound versus palpation for epidural catheter insertion in labour A randomised controlled trial

BACKGROUND Ultrasound imaging of the spine is thought to reduce failed and traumatic neuraxial procedures. Most of the evidence supporting this assumption has been produced in the context of an expert sonographer performing the ultrasound assessment, and it remains unknown whether this technique is useful when used by multiple individual operators. OBJECTIVE To invesstigate the impact of preprocedural spinal ultrasound on the ease of insertion of labour epidurals by a group of trainees. We hypothesised that the ultrasound-assisted technique would improve the ease of insertion when compared with the conventional palpation technique. DESIGN A randomised controlled trial. SETTING Academic hospital in Toronto, Canada. PARTICIPANTS AND INTERVENTION A group of 17 second-year anaesthesia residents and five anaesthesia fellows underwent a training programme in ultrasound assessment of the spine. Parturients with easily palpable lumbar spines were randomised to either ultrasound or palpation group. Residents and fellows performed both the assessment (ultrasound or palpation) and the epidural procedure. MAIN OUTCOME MEASURES Primary outcome: ease of insertion of epidural catheter composed of the time taken to insert the epidural catheter, number of interspace levels attempted and number of needle passes. Secondary outcomes: total procedural time (assessment and insertion); first pass success rate; number of attempts required to thread the epidural catheter; failure of epidural analgesia; and patient satisfaction. RESULTS We analysed 128 epidural catheter insertions (residents 84, fellows 44). There was no difference in median (interquartile range, IQR) epidural insertion time between the ultrasound and palpation groups [174 (120 to 241) versus 180 (130 to 322.5) s, respectively; P = 0.14]. The number of interspace levels attempted and needle passes were also similar in both groups. The total procedural time was longer in the ultrasound group. CONCLUSION The use of preprocedural spinal ultrasound by a cohort of anaesthesia trainees did not improve the ease of insertion of labour epidural catheters in patients with easily palpable lumbar spines, as compared with the traditional palpation technique based on anatomical landmarks. TRIAL REGISTRATION ClinicalTrials.gov identifier: NCT00996905.