Usefulness of a visual aid in achieving optimal positioning for spinal anesthesia: a randomized trial

Optimal patient positioning is perceived as an essential factor to increase the success of performing neuraxial blockade. The primary objective of this study was to evaluate the benefit of using a visual image in addition to verbal instructions in order to optimize positioning for spinal block.

This was a prospective randomized controlled trial on 85 adult patients undergoing lower limb joint replacements at a tertiary academic hospital. Group 1(n = 43) randomized to receive standardized verbal instructions; Group 2 (n = 42) received standardized verbal instructions in conjunction with visual aids to achieve positioning for spinal anesthesia. The primary outcome measure was the time taken to successful dural puncture. Secondary endpoints were the number of skin punctures, number of intervertebral levels attempted, success at the first intervertebral space attempted and satisfaction of patients and anesthesiologists.

The unadjusted geometric mean time taken for the procedure using verbal instruction alone was 301 s (95% CI: 236-385) compared to 183 s (95% CI: 143-235) when both verbal and visual instructions were used. Out of the participants in group 2, 90% required ≤2 skin punctures and 10% required ≥3 skin punctures compared to 65% and 35% of the participants in group 1 respectively (p = 0.001). Group 1 required a second anesthesiologist to successfully complete the procedure in 6 patients out of 43 (14%) patients whereas the first anesthesiologist was noted to be successful in all the 42 cases in group 2 (p = 0.03). There were no significant differences in the satisfaction scores of anesthesiologists or patients between the groups. First-pass success was strongly associated with patient satisfaction (Odds ratio: 5.2; 95% CI: 1.0-9.5, p = 0.049).

Use of a visual aid in addition to verbal instructions to optimize positioning for a spinal block, significantly reduces the time taken for the procedure by an average of 2 min, reduces the number of skin punctures and increases the success rate of the first anesthesiologist. First pass success was strongly associated with patient satisfaction.

This study was retrospectively registered 30 August 2016, with the Australian New Zealand Clinical trials registry (ACTRN12616001197426).