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 redirections, 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.

Background and Aims:The results of basic research im

Background: Ultrasound-guidance might decrease the incidence of local anesthetics systemic toxicity(LAST) for many peripheral nerve blocks compared to nerve stimulation. However, it remained uncertain whether ultrasound-guidance would be superior to the nerve stimulation for deep nerve block in the lower extremity. This study was designed to investigate that deep nerve block with ultrasound-guidance would result in a lower rate of LAST comparing to that with nerve stimulator-guidance. Methods: Three hundred patients who were for elective lower limb surgery and desiring lumbar plexus blocks(LPBs) and sciatic nerve blocks(SNBs) were enrolled in this study. Patients were randomly assigned to receive LPB and SNB with ultrasound-guidance (Group U), nerve stimulator-guidance (Group N) and dual-guidance (Group M). The primary outcome was the incidence of the LAST. The secondary outcomes were number of needle redirections, motor and sensory block onset and restoration times in the nerve distributions, and associated risk factors. Results: There were 18 patients with the LAST, including 12 in group U, 4 in group N and 2 in group M. For multiple comparisons among the tree 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 HBV infection and female gender 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: For patients undergoing LPBs and SNBs, use of ultrasound may increase the incidence of the LAST. HBV infection and female gender were risk factors for deep nerve block. Trial registration: This study was approved by the human research review committee at the southwest hospital of third military medical university. The protocol was registered prospectively with Chinese Clinical Trial Registry (ChiCTR-IOR-16008099) on March 15th，2016. Keywords: Ultrasound; nerve stimulation; nerve block; female; HBV; LAST

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 redirections, 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.

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 remained uncertain whether ultrasound-guidance would be superior to the nerve stimulator-guidance for deep nerve block in the lower extremity. This study was designed to investigate that whether ultrasound-guided deep nerve block would decrease the incidence of LAST comparing with those with nerve stimulator-guidance, and to find out associated risk factors for LAST. Methods: Three hundred patients for elective lower limb surgery and desiring lumbar plexus blocks(LPBs) and sciatic nerve blocks(SNBs) were enrolled in this study. 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 the LAST. The secondary outcomes were the number of needle redirection, motor and sensory block onset and restoration time in the nerve distributions, and associated risk factors. Results: There were 18 patients occurring with LAST, including 12 in group U, 4 in group N and 2 in group M. For 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 female gender were 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 female gender were risk factors for LAST in LPBs and SNBs. For patients with HBV infection or female gender undergoing 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 from the first affiliated hospital of Army Medical University. The protocol was registered prospectively with Chinese Clinical Trial Registry (ChiCTR-IOR-16008099) on March 15th，2016. Key words: ultrasound; nerve stimulation; nerve block; female; HBV; LAST