Objective We determined whether regional haemodynamics and perfusion index (PI) could be reliable indicators of a successful sciatic nerve block (SNB).
Design Prospective observational trial.
Setting A tertiary teaching hospital in China from April 2020 to August 2020.
Participants We assessed 79 patients for eligibility to participate in this study. Nine patients were excluded for not meeting our inclusion criteria, and three patients were excluded due to missing measurements at all time points.
Interventions The patients underwent SNB. Pulsed-wave Doppler and PI measurements were performed.
Primary and secondary outcome measures The primary outcome measure was the diagnostic power of regional haemodynamic change and PI to predict successful SNB. The secondary outcome measure was the effect of SNB on the regional haemodynamics and PI in the lower extremity.
Results We assessed 79 patients in this study and 67 patients available for the final analysis. The SNB was successful in 59 patients and failed in eight patients. There were no significant differences in demographic characteristics between the patients with successful and failed SNB. Starting from 10 min after SNB, the peak systolic velocity (PSV), end-diastolic velocity, time-averaged maximum velocity and time-averaged mean velocity of the anterior tibial artery and posterior tibial artery of patients in the successful SNB group were significantly higher than those in the failed SNB group (p<0.05). The PSV percentage increase at 10 min after SNB has great potential to predict the block success. The area under the receiver operating characteristic curve (AUC) values were 0.893 (95% CI 0.7809 to 1.000) and 0.880 (95% CI 0.7901 to 0.9699). The corresponding cut-off values were 19.22 and 35.88, respectively. The PI increased during 5–45 min intervals in patients with successful SNB. The AUC for the PI percentage increases at 10 min after SNB was 0.853 (95% CI 0.7035 to 1.000), with a cut-off value of 93.09.
Conclusion The regional haemodynamic variables, PSV and PI in particular, can be used as alternative indicators for clinicians to evaluate the success of SNB objectively and early.
Trial registration number ChiCTR2000030772.
- anaesthesia in orthopaedics
- pain management
- adult anaesthesia
Data availability statement
Data are available on reasonable request.
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BL and JJ contributed equally.
Contributors BL is responsible for the overall content as guarantor. BL, QS and JC contributed conception and design of the study; BL wrote the manuscript; JJ and XL organised the database; BL, XL, QC, YC and QS conducted the study, collect and analysed data. All authors contributed to manuscript revision, read and approved the submitted version.
Funding This work was supported by grants from the Medical Scientific Research Foundation of Zhejiang Province, China (Grant No. 2020KY261, 2021ZH038, 2022KY323) and Key Medical Discipline of Ningbo (No. 2022-B10).
Disclaimer We declare that the funders had no role in the protocol design and collection, analysis, interpretation of data, either writing of the manuscript.
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Provenance and peer review Not commissioned; externally peer reviewed.