Sensory Testing of Distal Sural and Posterior Tibial Nerves Provides Early Prediction of Surgical Anesthesia After Single-Injection Infragluteal-Parabiceps Sciatic Nerve Block

Regional haemodynamic variables and perfusion index in the evaluation of sciatic nerve block: a prospective observational trial

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.

Dexmedetomidine combined with ropivacaine in ultrasound-guided tranversus abdominis plane block improves postoperative analgesia and recovery following laparoscopic colectomy

The present prospective, double blind, randomized clinical study was designed to evaluate whether dexmedetomidine (Dex) combined with ropivacaine for tranversus abdominis plane (TAP) block could improve analgesic quality and duration, and promote recovery following laparoscopic colectomy. Following induction of anesthesia, ultrasound-guided bilateral TAP block was performed in 60 patients scheduled for elective laparoscopic colectomy with either 20 ml of 0.375% ropivacaine plus 2 ml normal saline 0.9% (R group), or 20 ml of 0.375% ropivacaine plus 2 ml Dex (0.5 µg/kg) (RD group). Visual analogue scale (VAS) score for pain, sedation level, length of hospital stay (LOS), and bowel function recovery time and associated complications were recorded. Overall patient satisfaction with postoperative pain management was also assessed. The hemodynamic variables were not significantly different between the two groups during the surgery. However, the duration of analgesia was significantly longer in the RD group compared with the R group (P<0.05). VAS scores at 1, 2, 6 and 12 h following surgery were significantly decreased in the RD group compared with those in the R group (P<0.05). There was no significant difference in sedation level between the two groups. Notably, postoperative nausea and vomiting in the RD group was significantly decreased compared with those in the R group in the first 24 h (P<0.05). There were no serious adverse events in any group. Furthermore, 90.0 and 66.7% patients were satisfied with the postoperative pain management in the RD group and R group, respectively. The postoperative first bowel movement time was significantly shorter in the RD group compared with the R group (P<0.05). However, the LOS was not significantly different between the two groups. In conlusion, the addition of Dex to ropivacaine could significantly improve the analgesic quality and duration of TAP block, which in turn promotes recovery following laparoscopic colectomy.

Lower extremity regional anesthesia: essentials of our current understanding

The advent of ultrasound guidance has led to a renewed interest in regional anesthesia of the lower limb. In keeping with the American Society of Regional Anesthesia and Pain Medicine's ongoing commitment to provide intensive evidence-based education, this article presents a complete update of the 2005 comprehensive review on lower extremity peripheral nerve blocks. The current review article strives to (1) summarize the pertinent anatomy of the lumbar and sacral plexuses, (2) discuss the optimal approaches and techniques for lower limb regional anesthesia, (3) present evidence to guide the selection of pharmacological agents and adjuvants, (4) describe potential complications associated with lower extremity nerve blocks, and (5) identify informational gaps pertaining to outcomes, which warrant further investigation.

Blood flow index as an indicator of successful sciatic nerve block: a prospective observational study using laser speckle contrast imaging

BACKGROUND

Laser speckle contrast imaging allows real-time, non-invasive, quantitative measurements of regional blood flow. The objectives of this prospective observational study were to use laser speckle contrast imaging to evaluate blood flow changes after sciatic nerve block, and to determine whether this novel optical technique can evaluate block success.

METHODS

This observational study included 63 adult patients undergoing elective lower limb surgery with sciatic nerve block. Blood flow images and blood flow index (BFI) values of toes were recorded using laser speckle contrast imaging 5 min before nerve block and at 5 min intervals until 30 min after sciatic block. The sensitivity, specificity, and cut-off value of laser speckle contrast imaging for predicting successful sciatic block were determined by receiver operator characteristic (ROC) curve analysis.

RESULTS

The BFI values of toes were significantly increased at each time point after successful sciatic block, compared with the baseline value obtained 5 min before nerve block; in failed sciatic block, there were no significant differences. For successful sciatic block, the highest increase of BFI value was at the big toe. BFI increase of the big toe at 10 min after sciatic block has great potential as an indicator of block success. The area under the ROC curve was 0.954 at a cut-off value of 8.48 perfusion units (PU) with a sensitivity of 89% and a specificity of 100%.

CONCLUSIONS

Laser speckle contrast imaging might be an early, objective, quantitative, and reliable indicator of successful sciatic block. BFI increase of the big toe not reaching 8.48 PU within 10 min after sciatic block indicates block failure.

CLINICAL TRIAL REGISTRATION

NCT03169517.