Comparison of single- and triple-injection methods for ultrasound-guided interscalene brachial plexus blockade.

Ultrasound-guided interscalene brachial plexus blockade (IBPB) has a relatively high success rate in shoulder surgery; however, whether multiple injections are superior to a single injection (SI) is currently unknown. In the present study, ultrasound-guided SI and triple-injection (TI) IBPBs were compared in a prospective randomized trial. A total of 111 patients undergoing arthroscopic shoulder surgery and presenting with an American Society of Anesthesiologists physical status grading of I-II were randomly allocated to receive IBPB with 15 ml of 1% ropivacaine as a SI or TI. Performance time, procedure-related pain scores, success rate and prevalence of complications were recorded. The distribution of sensory and motor block onset in the radial, median, ulnar and axillary nerves were assessed every 5 min until 30 min post-local anesthetic injection. The duration of sensory and motor blocks were also assessed. A significantly longer performance time was recorded in the TI group (P<0.001). No significant difference was observed in success rate (91% in TI vs. 88% in SI) 30 min post-injection, and the prevalence of complications and procedure-related pain were similar between the two groups. Sensory and motor blocks of the ulnar nerve in the TI group were significantly faster and more successful compared with the SI group at all time points (P<0.041). It was also observed that sensory and motor blocks in the TI group were prolonged compared with the SI group (P<0.041). In conclusion, the TI method exhibited a faster time of onset and resulted in a more successful blockade of the ulnar nerve. TI method may be a more effective approach for IBPB in a clinical setting.

Involvement of integrin ß1/FAK signaling in the analgesic effects induced by glial cell line-derived neurotrophic factor in neuropathic pain.

Treatment of neuropathic pain (NP) continues to be a clinical challenge and the underlying mechanisms of NP remain elusive. More evidence suggests that glial cell line-derived neurotrophic factor (GDNF) has potent anti-nociceptive effects on NP, but the underlying mechanisms are still largely unknown. Recent data have shown that integrin ß1 plays an important part in NP induction, and that the activity of integrin ß1 signaling is associated with the phosphorylation of the conserved threonines in the cytoplasmic domain and recruitment of focal adhesion kinase (FAK) to the integrin ß1 tail and phosphorylation. We assessed the effect of GDNF on integrinß1/FAK signaling in NP states. Immunostaining results showed that integrin ß1 was mainly observed in the superficial dorsal horn in the spinal cord of rats, and was mostly expressed in intrinsic neurons. Expression of p-integrin ß1 and the phosphorylation of integrin ß1-associated FAK, but not integrin ß1 itself, was up-regulated after chronic constriction injury (CCI), which could be reversed by GDNF, and the effect of GDNF on integrin ß1/FAK signaling was inhibited by pre-treatment with RET function-blocking antibody (RET Ab). Moreover, pre-treatment with RET Ab could antagonize the effect of GDNF on inhibiting the NP induced by CCI. These data suggest that GDNF can regulate integrin ß1 activity via a RET-related mechanism.

Efficacy of perineural dexamethasone with ropivacaine in adductor canal block for post-operative analgesia in patients undergoing total knee arthroplasty: A randomized controlled trial.

Adductor canal block (ACB) is an effective analgesic alternative to femoral nerve block after total knee arthroplasty (TKA). The aim of the present study was to investigate whether addition of dexamethasone to ropivacaine for ACB is able to prolong analgesia and reduce pain. Study participants were randomized into groups receiving ACB with either 0.5% ropivacaine + normal saline (control group; n=93) or 0.5% ropivacaine + 8 mg dexamethasone (dexamethasone group; n=93). All patients were subjected to identical peri-operative management. Patients were assessed for the duration of analgesia by the return of pinprick sensation. A numerical rating scale, ranging from 0 to 10, was used to assess post-operative pain at 6, 12, 18, 24 and 48 h. Opioid use was recorded. Serum C-reactive protein and interleukin-6 levels were measured at 3, 6, 12, 24 and 48 h after surgery. The results revealed that the duration of sensory block was significantly longer in the dexamethasone group (23.42±3.35 vs. 14.67±2.96 h in control group, P<0.05). The dexamethasone group also had significantly lower pain scores at 6, 12, 18 and 24 h after surgery (all P<0.001), and at 48 h, pain was comparable in the two groups. Reduction in post-operative pain was associated with a decrease in serum C-reactive protein. Morphine use in the first 24 h after surgery was also lower in the dexamethasone group (4.23±1.80 vs. 8.42±2.44 mg in control group, P<0.05). In conclusion, addition of dexamethasone to ropivacaine for ACB was able to prolong the duration of analgesia and decreased early post-operative pain following TKA.

Preconditioning of physiological cyclic stretch attenuated HMGB1 expression in pathologically mechanical stretch-activated A549 cells and ventilator-induced lung injury rats through inhibition of IL-6/STAT3/SOCS3.

Previous studies have shown that physiologically cyclic stretch (5% CS) attenuated both oxidative- and LPS-induced increases in HMGB1 expression via STAT3. However, little information exists about the effect of precondition of physiological cyclic stretch (CS) on the expression of HMGB 1, which play a crucial role in ventilator-induced lung injury (VILI). We found that 5% CS-preconditioning significantly inhibited HMGB 1 expression, but not HMGB 1 receptors. 5% CS-preconditioning inhibits the IL-6/STAT3 pathway, and the inhibitory effect on the expression of HMGB 1 induced by 5% CS-preconditioning is abolished by additional treatment of rmIL-6. 5% CS-preconditioning also induces SOCS3 upregulation, and 5% CS-preconditioning fails to inhibit the IL-6/STAT3 pathway in cells transfected with SOCS3 siRNA. Moreover, low tidal volume ventilation preconditioning also decreases the severity of VILI evidenced by the markedly improved pulmonary alveolar-capillary barrier dysfunction, wet/dry weight ratio, and histological analysis. These results suggest that preconditioning of physiological 5% CS can reduce the expression of HMGB 1 induced by pathologically mechanical stretch through IL-6/STAT3 pathway associated with up-regulated SOCS3 expression.