Combined ultrasound and nerve stimulator-guided deep nerve block may decrease the rate of local anesthetics systemic toxicity: a randomized clinical trial.
BACKGROUND
Ultrasound guidance might decrease the incidence of local anesthetics systemic toxicity (LAST) for many peripheral nerve blocks compared with nerve stimulator guidance. However, it remains uncertain whether ultrasound guidance is superior to nerve stimulator guidance for deep nerve block of the lower extremity. This study was designed to investigate whether deep nerve block with ultrasound guidance would decrease the incidence of LAST compared with that with nerve stimulator guidance, and to identify associated risk factors of LAST.


METHODS
Three hundred patients undergoing elective lower limb surgery and desiring lumbar plexus blocks (LPBs) and sciatic nerve blocks (SNBs) were enrolled in this study. The patients were randomly assigned to receive LPBs and SNBs with ultrasound guidance (group U), nerve stimulator guidance (group N) or dual guidance (group M). The primary outcome was the incidence of LAST. The secondary outcomes were the number of needle redirection, motor and sensory block onset and nerve distribution restoration time, as well as associated risk factors.


RESULTS
There were 18 patients with LAST, including 12 in group U, 4 in group N and 2 in group M. By multiple comparisons among the three groups, we found that the incidence of LAST in group U (12%) was significantly higher than that in group N (4%)(P = 0.037) and group M(2%)(P = 0.006). The OR of LAST with hepatitis B (HBV) infection and the female sex was 3.352 (95% CI,1.233-9.108, P = 0.013) and 9.488 (95% CI,2.142-42.093, P = 0.0004), respectively.


CONCLUSIONS
Ultrasound guidance, HBV infection and the female sex were risk factors of LAST with LPBs and SNBs. For patients infected with HBV or female patients receiving LPBs and SNBs, we recommended that combined ultrasound and nerve stimulator guidance should be used to improve the safety.


TRIAL REGISTRATION
This study was approved by the Ethical Committee of the First Affiliated Hospital of Army Medical University. The protocol was registered prospectively with the Chinese Clinical Trial Registry ( ChiCTR-IOR-16008099 ) on March 15, 2016.
['Zhang|Xu-Hao|XH|', 'Li|Yu-Jie|YJ|', 'He|Wen-Quan|WQ|', 'Yang|Chun-Yong|CY|', 'Gu|Jian-Teng|JT|', 'Lu|Kai-Zhi|KZ|', 'Yi|Bin|B|0000-0001-5840-2086']
D000328:Adult D000779:Anesthetics, Local D004311:Double-Blind Method D004558:Electric Stimulation D005260:Female D006801:Humans D008012:Lidocaine D008160:Lumbosacral Plexus D008297:Male D009407:Nerve Block D012307:Risk Factors D000077212:Ropivacaine D012584:Sciatic Nerve D018084:Ultrasonography, Interventional D055815:Young Adult
Ultrasound Nerve block LAST Nerve stimulation HBV Female