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Accuro ultrasound-based system with computer-aided image interpretation compared to traditional palpation technique for neuraxial anesthesia placement in obese parturients undergoing cesarean delivery: a randomized controlled trial

This article has been updated



Recently, a new handheld ultrasound-based device, called Accuro, has been commercialized with a real-time automated interpretation of lumbar ultrasound images. We hypothesized that the handheld ultrasound device would improve the efficacy and safety of combined spinal-epidural anesthesia (CSEA) for cesarean delivery in obese parturients.


Eighty parturients with a body mass index > 30 kg∙m−2 scheduled for elective cesarean delivery were randomly allocated equally (palpation group and ultrasound group). The primary outcome was the first insertion success rate. Secondary outcomes were the time taken to identify the needle puncture site, duration of CSEA procedure, the total time, the rate of parturients who require needle redirections, the number of skin punctures, changes in the intended interspace, and the incidence of complications.


Compared to the palpation group, the first insertion success rate was significantly higher (72.5% vs. 40.0%; P = 0.003), and time taken to identify the needle puncture site was less (30 [26–36] vs. 39 [32–49] seconds; P = 0.001) in the ultrasound group. The rate of parturients who required needle redirections (40.0% vs. 72.5%; P = 0.003) and the incidence of paresthesia were both lower (7.5% vs. 45.0%; P < 0.001). The other outcomes had no significant difference between groups. The mean difference between the epidural depth measured by the handheld ultrasound and needle depth was − 0.29 cm [95% limit of agreement, − 0.52 to − 0.05].


Our study suggests using the Accuro ultrasound device can enhance the efficacy and safety of CSEA in obese parturients when executed by experienced anesthesiologists, and its automated estimation of epidural depth is accurate.

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  • 10 June 2021

    Figure 3 was published incorrectly in PDF and corrected in this version.


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The authors thank the patients who participated in the study and all authors who contributed to the study.


This work was supported in part by the National Natural Science Foundation of China (81771188), Shanghai Municipal Commission of Health and Family Planning (201740072), Science and Technology Commission of Shanghai Municipality and Rivanna Medical provided the handheld ultrasound device for the study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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All authors contributed to the study conception and design. Data collection and analysis were performed by ML and SZ. The first draft of the manuscript was written by XN, and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

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Correspondence to Zhi-qiang Liu.

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Ni, X., Li, Mz., Zhou, Sq. et al. Accuro ultrasound-based system with computer-aided image interpretation compared to traditional palpation technique for neuraxial anesthesia placement in obese parturients undergoing cesarean delivery: a randomized controlled trial. J Anesth 35, 475–482 (2021).

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  • Accuro ultrasound
  • Neuraxial anesthesia
  • Obese