Median effective concentration of ropivacaine for paravertebral nerve block during single-port thoracoscopic lobectomy
ZHANG Shiyong
YANG Zhengxiong
ZHANG Yuanmei
Abstract：Objective To determine the median effective concentration of ropivacaine for paravertebral nerve block in single-port thoracoscopic lobectomy.Methods Thirty-four patients scheduled for single-port thoracoscopic lobectomy underwent ultrasound-guided paravertebral nerve block.An initial concentration of 0.3%ropivacaine at 0.3 mL/kg was administered.If the first patient achieved optimal analgesia(effective),the local anesthetic dose for the second patient was reduced by one step(decreased by 0.02%).If the first patient did not achieve optimal analgesia,the second patient's con-centration increased by 0.02%.This process continued until seven consecutive patients failed to achieve optimal analgesia,marking the drug concentration inflection point.The Probit probability unit regression method was used to calculate the me-dian effective concentration(EC50)of ropivacaine and its 95%confidence interval(CI).The following parameters were re-corded:heart rate,mean arterial pressure,and oxygen saturation at the following time points[entry into the operating room(T0),completion of nerve block(T1),after induction of anesthesia(T2),before surgical skin incision(T3),after surgical skin incision(T4),30 minutes into surgery(T5),and end of surgery(T6)].Pain was assessed using the visual analogue scale(VAS)at 5 min,2 h,12 h,and 24 h after block in resting and coughing states,and we instructed the patients in the use of patient-controlled analgesia(PCA)pump and took supplemental anesthesia measures.Results Among 34 pa-tients,18 responded effectively and 16 did not.Effective patients exhibited lower heart rate and mean arterial pressure at T1,T2,T3,T4,T5,and T6,while had higher SpO₂ at T3,and lower VAS scores at rest and during activity at 5 min,2 h,12 h,and 24 h after extubation than non-responders(all P<0.05).The proportion of responders using the PCA pump and re-quiring rescue measures was lower than that of non-responders(P<0.05).No bleeding or hematoma at the puncture site,no adverse reactions to local anesthetics such as dizziness or tinnitus,and no complications like pneumothorax or hemo-thorax occurred during anesthesia.The median effective concentration of ropivacaine for paravertebral nerve block in sin-gle-port thoracoscopic lobectomy was 0.220%(95%CI:0.197%-0.242%).Conclusion The median effective con-centration of ropivacaine for paravertebral nerve block in single-port thoracoscopic lobectomy was 0.220%(95%CI:0.197%-0.242%).
Keywords：ropivacainesingle-port thoracoscopic lobectomyparavertebral nerve blockmedian effective concen-trationlocal anesthesia
Publication Date：2025-09-25
Online Publishing Date：2025-10-22(First online date of this platform, not the publication date of the document)
Pages：5( 89-92,99 )