UNASSIGNED: To determine the median effective volume (EV50) of 0.2% ropivacaine for ultrasound-guided supraclavicular brachial plexus block (SC-BPB) in children aged 1-6 years.
UNASSIGNED: Children aged from 1 to 6 years with an American Society of Anaesthesiologists (ASA) physical status I-II who were scheduled for unilateral upper extremity surgery at the Children\'s Hospital of Chongqing Medical University were recruited. All patients underwent surgery under general anaesthesia combined with brachial plexus block. SC-BPB was guided by ultrasound after anaesthesia induction, and 0.2% ropivacaine was given after localization. In the study, we used Dixon\'s up-and-down approach with an initial dose of 0.50 ml/kg. Considering the effect of the previous block, a successful or failed block could produce a 0.05 ml/kg decrement or increment in volume, correspondingly. The experiment was stopped when there were 7 inflection points. Using isotonic regression and bootstrapping algorithms, the EV50, the 95% effective volume (EV95) and the 95% confidence interval (CI) were calculated. The patients\' general information, postoperative pain scores, and adverse events were also recorded.
UNASSIGNED: Twenty-seven patients were involved in this study. The EV50 of 0.2% ropivacaine was 0.150 ml/kg (95% CI, 0.131-0.169 ml/kg) and the EV95 (secondary metric) was 0.195 ml/kg (95% CI, 0.188-0.197 ml/kg). No adverse events occurred during the research study.
UNASSIGNED: For ultrasound-guided SC-BPB in children aged 1-6 years undergoing unilateral upper extremity surgery, the EV50 of 0.2% ropivacaine was 0.150 ml/kg (95% CI, 0.131-0.169 ml/kg).

BACKGROUND: Ultrasound-guided needle placement has revolutionized the thoracic paravertebral block technique and can be applied in thoracoscopic surgery.
OBJECTIVE: This study investigated the median effective volume (EV50) of an ultrasound-guided single shot of 0.3% ropivacaine used as a thoracic paravertebral nerve block for the radical thoracoscopic resection of lung cancer.
METHODS: A total of 27 patients who received a single shot of ultrasound-guided thoracic paravertebral nerve block and underwent radical thoracoscopic resection of lung cancer were enrolled in this study between February 10 and August 13, 2018. All patients were rated as ASA grades I or II. Using ultrasound as a guide, the block needle was gradually pushed through the lateral costotransverse ligaments to the thoracic paravertebral space by the in-plane technique. After confirming the absence of blood or cerebrospinal fluid, 1-2 ml of 0.3% ropivacaine hydrochloride was injected to confirm that the position of the needle was appropriate, and a pre-determined volume of 0.3% ropivacaine hydrochloride was then administered to the patients. Sensory testing by pinprick was performed every 5 minutes for 30 minutes following the thoracic paravertebral block injection to identify the time segments during which the loss of sensation to the pinprick and its blocking effect occurred.
RESULTS: All patients completed the study and 14 (51.8%) had a successful block.
CONCLUSIONS: The EV50 of 0.3% ropivacaine was 18.46 ml (95% CI 17.09-19.95 ml) and the EV95 was 20.89 ml.