A comparison of ultrasound-guided interscalene and supraclavicular blocks for post-operative analgesia after shoulder surgery

BACKGROUND

In contrast to interscalene block, there was little information regarding the analgesic efficacy of supraclavicular block for shoulder surgery. This study aimed to compare the analgesic efficacy and side effects of interscalene and supraclavicular blocks for shoulder surgery.

METHODS

Patients scheduled for shoulder surgery were assigned to receive either ultrasound-guided interscalene (n = 25) or supraclavicular block (n = 24) with 20 ml of 0.375% ropivacaine. We assessed the duration of post-operative analgesia as a primary outcome and pain scores, supplemental analgesia, diaphragmatic excursion, motor block, fingertip numbness, side effects, and patient satisfaction as secondary outcomes.

RESULTS

The duration of post-operative analgesia was not statistically different between groups: 868 (800-1440) min for supraclavicular block vs. 800 (731-922) min for interscalene block (median difference -85 min, 95% CI, -283 to 3 min, P = 0.095). The incidence of diaphragmatic paresis was significantly lower in the supraclavicular block group compared with that in the interscalene block group, both at 30 min after the block (66.7% vs. 92%, P = 0.021) and in the post-anaesthesia care unit (62.5% vs. 92%, P = 0.024). Motor block was higher in the supraclavicular block group in the post-anaesthesia care unit, however, not at 24 h. Other secondary outcomes were similar for both groups.

CONCLUSIONS

This study showed no statistically significant difference in the duration of post-operative analgesia between the supraclavicular and interscalene blocks. However, the supraclavicular block was associated with a lower incidence of diaphragmatic paresis compared with that of the interscalene block after shoulder surgery.

Gain recovery in a quantum dot semiconductor optical amplifier and corresponding pattern effects in amplified optical signals at 1.5 μm

Fast gain recovery observed in quantum-dot semiconductor-optical-amplifiers (QDSOAs) is useful for amplifying high-speed optical signals. The small but finite slow recovery component can deteriorate the signal amplification due to the accumulation of gain saturation during 10 Gb/s operation. A study of the gain recoveries and pattern effects in signals amplified using a 1.5 μm InAs/InGaAsP QDSOA reveals that the gain recovery is always fast, and pattern-effect-free amplification is observed at the ground state. However, at the excited state, the slow component increases with the current, and significant pattern effects are observed. Simulations of the pattern effects agreed with the observed experimental trends.

Comparative study of the inhibition of alpha-glucosidase, alpha-amylase, and cyclomaltodextrin glucanosyltransferase by acarbose, isoacarbose, and acarviosine-glucose

Bacillus stearothermophilus maltogenic amylase hydrolyzes the first glycosidic linkage of acarbose to give acarviosine-glucose. In the presence of carbohydrate acceptors, acarviosine-glucose is primarily transferred to the C-6 position of the acceptor. When d-glucose is the acceptor, isoacarbose is formed. Acarbose, acarviosine-glucose, and isoacarbose were compared as inhibitors of alpha-glucosidase, alpha-amylase, and cyclomaltodextrin glucanosyltransferase. The three inhibitors were found to be competitive inhibitors for alpha-glucosidase and mixed noncompetitive inhibitors for alpha-amylase and cyclomaltodextrin glucanosyltransferase. The K(i) values were dependent on the type of enzyme and their source. Acarviosine-glucose was a potent inhibitor for baker's yeast alpha-glucosidase, inhibiting 430 times more than acarbose, and was an excellent inhibitor for cyclomaltodextrin glucanosyltransferase, inhibiting 6 times more than acarbose. Isoacarbose was the most effective inhibitor of alpha-amylase and cyclomaltodextrin glucanosyltransferase, inhibiting 15.2 and 2.0 times more than acarbose, respectively.