Background Continuous interscalene nerve block （CISB） is considered to be the most effective method for postoperative analgesia after shoulder surgery with prolonged severe pain.This study was performed to evaluate ...Background Continuous interscalene nerve block （CISB） is considered to be the most effective method for postoperative analgesia after shoulder surgery with prolonged severe pain.This study was performed to evaluate the minimum effective background infusion rate and the effective background infusion rate of ropivacaine 0.2％ for CISB after arthroscopic rotator cuff repair surgery in 95％ of patients.Methods Patients scheduled for arthroscopic rotator cuff repair surgery under general anesthesia at Peking University Third Hospital were prospectively enrolled from December 2011 to May 2012.Preoperatively,an interscalene catheter （ISC） was placed under the guidance of ultrasound and nerve stimulation in each patient.Consecutively,30 patients with successful nerve block were included.A continuous infusion of ropivacaine 0.2％ with a 5 ml patient-controlled bolus available hourly was started at postoperative anesthesia care unit （PACU） after completion of surgery.The initial background infusion rate was 6 ml/h,which was subsequently varied for each consecutive patient according to the analgesic effects of the previous one.The minimum effective background rate was determined using the Dixon and Massey up-and-down method.The effective background rate in 95％ of patients was calculated using isotonic analysis.Results The minimum effective background rate based on the Dixon and Massey up-and-down method was 2.8 ml/h （95％ CI,2.3-3.3 ml/h）.The effective background rate in 95％ of patients calculated with the isotonic regression analysis was 4.4 ml/h （95％ CI,3.8-6.5 ml/h）.Conclusion The effective background rate for patient-controlled interscalene brachial plexus analgesia after shoulder surgery in 50％ and 95％ of the patients was 2.8 and 4.4 ml/h,respectively.展开更多
Two triblock polymers, tetraaniline-block-poly（N-isopropyl acrylamide）-block-poly（hydroxyethyl acrylate） （TA-b-PNIPAM-b-PHEA） and TA-b-PHEA-b-PNIPAM, were synthesized with unambiguous structure by a two step met...Two triblock polymers, tetraaniline-block-poly（N-isopropyl acrylamide）-block-poly（hydroxyethyl acrylate） （TA-b-PNIPAM-b-PHEA） and TA-b-PHEA-b-PNIPAM, were synthesized with unambiguous structure by a two step method. The difference of these two diblock polymers is the connection order of carboxyl group to block, e.g., carboxyl group to PNIPAM block for PNIPAM-b-PHEA and to PHEA block for PHEA-b-PNIPAM. Secondly, block tetraaniline was linked to the diblock polymer through amidation to yield the corresponding triblock copolymer. Both of them have almost the identical chemical compositions. The only difference is the connection order of each block in the triblock polymers. When they were self-assembled at 45℃ in a suitable solution, both of their aggregates have spherical shape with slight defects on their surface with the average diameter of about 400 nm. However, when their aggregate dispersion was cooled down to 20 ℃, only TA-b-PHEA-b-PNIPAM＇s morphology changed, forming worm-like aggregates with the diameter of about 100-200 nm transformed from spherical ag- gregates. Both amphiphilic property and position of each block in this triblock copolymer are very essential for this morphology transformation. Since the worm-like aggregates presented here by our group have hollow structure in- side, its controlled release properties for doxorubicin were evaluated. Drug release experiment indicated that along with the temperature changes, the rearrangement of the intermediate layer structure caused morphology change in aggregate, thus accelerating the speed of drug release.展开更多
文摘Background Continuous interscalene nerve block （CISB） is considered to be the most effective method for postoperative analgesia after shoulder surgery with prolonged severe pain.This study was performed to evaluate the minimum effective background infusion rate and the effective background infusion rate of ropivacaine 0.2％ for CISB after arthroscopic rotator cuff repair surgery in 95％ of patients.Methods Patients scheduled for arthroscopic rotator cuff repair surgery under general anesthesia at Peking University Third Hospital were prospectively enrolled from December 2011 to May 2012.Preoperatively,an interscalene catheter （ISC） was placed under the guidance of ultrasound and nerve stimulation in each patient.Consecutively,30 patients with successful nerve block were included.A continuous infusion of ropivacaine 0.2％ with a 5 ml patient-controlled bolus available hourly was started at postoperative anesthesia care unit （PACU） after completion of surgery.The initial background infusion rate was 6 ml/h,which was subsequently varied for each consecutive patient according to the analgesic effects of the previous one.The minimum effective background rate was determined using the Dixon and Massey up-and-down method.The effective background rate in 95％ of patients was calculated using isotonic analysis.Results The minimum effective background rate based on the Dixon and Massey up-and-down method was 2.8 ml/h （95％ CI,2.3-3.3 ml/h）.The effective background rate in 95％ of patients calculated with the isotonic regression analysis was 4.4 ml/h （95％ CI,3.8-6.5 ml/h）.Conclusion The effective background rate for patient-controlled interscalene brachial plexus analgesia after shoulder surgery in 50％ and 95％ of the patients was 2.8 and 4.4 ml/h,respectively.
基金This study was supported by the National Natural Science Foundation of China （No. 50903096）.
文摘Two triblock polymers, tetraaniline-block-poly（N-isopropyl acrylamide）-block-poly（hydroxyethyl acrylate） （TA-b-PNIPAM-b-PHEA） and TA-b-PHEA-b-PNIPAM, were synthesized with unambiguous structure by a two step method. The difference of these two diblock polymers is the connection order of carboxyl group to block, e.g., carboxyl group to PNIPAM block for PNIPAM-b-PHEA and to PHEA block for PHEA-b-PNIPAM. Secondly, block tetraaniline was linked to the diblock polymer through amidation to yield the corresponding triblock copolymer. Both of them have almost the identical chemical compositions. The only difference is the connection order of each block in the triblock polymers. When they were self-assembled at 45℃ in a suitable solution, both of their aggregates have spherical shape with slight defects on their surface with the average diameter of about 400 nm. However, when their aggregate dispersion was cooled down to 20 ℃, only TA-b-PHEA-b-PNIPAM＇s morphology changed, forming worm-like aggregates with the diameter of about 100-200 nm transformed from spherical ag- gregates. Both amphiphilic property and position of each block in this triblock copolymer are very essential for this morphology transformation. Since the worm-like aggregates presented here by our group have hollow structure in- side, its controlled release properties for doxorubicin were evaluated. Drug release experiment indicated that along with the temperature changes, the rearrangement of the intermediate layer structure caused morphology change in aggregate, thus accelerating the speed of drug release.
