A randomised controlled trial comparing needle movements during combined spinal‐epidural anaesthesia with and without ultrasound assistance

Abstract

Ultrasound assistance for neuraxial techniques may improve technical performance; however, it is unclear which populations benefit most. Our study aimed to investigate the efficacy of neuraxial ultrasound in women having caesarean section with combined spinal-epidural anaesthesia, and to identify factors associated with improved technical performance. Two-hundred and eighteen women were randomly allocated to ultrasound-assisted or control groups. All the women had a pre-procedure ultrasound, but only women in the ultrasound group had this information conveyed to the anaesthetist. Primary outcomes were first-pass success (a single needle insertion with no redirections) and procedure difficulty. Secondary outcomes were block quality, patient experience and complications. Exploratory sub-group analysis and regression analysis were used to identify factors associated with success. Data from 215 women were analysed. First-pass success was achieved in 67 (63.8%) and 42 (38.2%) women in the ultrasound and control groups, respectively (adjusted p = 0.001). Combined spinal-epidural anaesthesia was 'difficult' in 19 (18.1%) and 33 (30.0%) women in the ultrasound and control groups, respectively (adjusted p = 0.09). Secondary outcomes did not differ significantly. Anaesthetists misidentified the intervertebral level by two or more spaces in 23 (10.7%) women. Sub-group analysis demonstrated a benefit for ultrasound in women with easily palpable spinous processes (adjusted p = 0.027). Regression analysis identified use of ultrasound and easily palpable spinous processes to be associated with first-pass success.

The use of lumbar spine and gastric ultrasound in perioperative obstetric anesthesia

“…Interestingly, according to one study, ease of palpation of the iliac crest, BMI, and seniority of the anesthesiologists did not influence the odds of first-pass success. 34) In that study, only half of the anesthesiologists (50.7%) were able to identify the intervertebral level correctly. 34) Furthermore, major misidentification of the intervertebral level by two or more spaces was found in 10.7% of cases, and the best needle insertion point was marked at or above the L1-L2 interspace in 12.1% of cases (26/215; 21 at L1-2, 4 at T12-L1, 1 at T11-12).…”

“…34) In that study, only half of the anesthesiologists (50.7%) were able to identify the intervertebral level correctly. 34) Furthermore, major misidentification of the intervertebral level by two or more spaces was found in 10.7% of cases, and the best needle insertion point was marked at or above the L1-L2 interspace in 12.1% of cases (26/215; 21 at L1-2, 4 at T12-L1, 1 at T11-12). 34) This is a worrisome finding given the increased risk for developing neurological complications.…”

“…34) Furthermore, major misidentification of the intervertebral level by two or more spaces was found in 10.7% of cases, and the best needle insertion point was marked at or above the L1-L2 interspace in 12.1% of cases (26/215; 21 at L1-2, 4 at T12-L1, 1 at T11-12). 34) This is a worrisome finding given the increased risk for developing neurological complications. Arzola et al 31) studied the correlation between the actual distance from the skin to the epidural space, as measured by loss of resistance (LOR) and the distance measured by ultrasound.…”

“…Sahin et al 33) compared the number of puncture attempts, spinal procedure time, and the success rate in the ultrasound group and control group between lean (BMI < 30) and obese (BMI ≥ 30) parturients. Furthermore, a recent randomized control study 34) examined the first needle pass success rate with ultrasound pre-procedure scan. Their results were consistent with previous studies with regard to a lower number of puncture attempts, 33) fewer puncture levels, 33) a higher success rate in the first needle pass, 33,34) lower rate of needle redirection, 33) and shorter duration of the procedure 33) in the ultrasound group.…”

“…Furthermore, a recent randomized control study 34) examined the first needle pass success rate with ultrasound pre-procedure scan. Their results were consistent with previous studies with regard to a lower number of puncture attempts, 33) fewer puncture levels, 33) a higher success rate in the first needle pass, 33,34) lower rate of needle redirection, 33) and shorter duration of the procedure 33) in the ultrasound group. A systematic review and meta-analysis of ultrasound use for lumbar puncture and epidural catheterization 35) concluded that ultrasound imaging reduced the risk of failed procedures (odds ratio, 0.21; P < 0.001) and traumatic procedures (odds ratio, 0.27; P = 0.005).…”