Operation, Effectiveness, and Limitations of Continuous Serratus Anterior Plane Blocks for Thoracoscopic Surgery in Adults

PURPOSE: This randomized, double-blind study evaluated the effectiveness and limitations of continuous serratus anterior plane block (cSAPB) by comparing the effect of cSAPB to patient-controlled intravenous analgesia (PCIA) on postoperative acute pain after thoracoscopic surgery in adults. PATIENTS AND METHODS: Sixty-six patients who underwent elective video-assisted thoracoscopic surgery (VATS) were randomly allocated to cSAPB or PCIA groups (n=33 per group) after surgery. For the cSAPB group, patients were treated by an initial does of 20 mL ropivacaine (0.375%), followed by continuous infusion at a rate of 5 mL/h of ropivacaine (0.2%) and a patient-controlled bolus of 5 mL ropivacaine (0.2%). PCIA started with an initial does of 0.03 µg/kg sufentanil, followed by a basal infusion of 0.03 µg/kg/h sufentanil and a patient-controlled bolus of 0.03 µg/kg sufentanil. Visual analog scale (VAS) and other items were examined postoperatively. The area under the curve of VAS-time (AUC(VAS-time)) at rest and on coughing in the first 24 hours postoperatively were primary outcomes. RESULTS: At the first 24 hours postoperatively, patients in the cSAPB group exhibited a smaller AUC(VAS-time) at rest (44.0±17.1 vs 68.9±11.8 cm·h, P<0.001) and AUC(VAS-time) on coughing (67.1±8.8 vs 78.0±12.5 cm·h, P<0.001) compared with those in the PCIA group. The differences in means of VAS score at rest were more than 1.0 cm between the two groups, however, on coughing they were less than 1.0 cm at each observation point. Additionally, patients in the cSAPB group had a longer time to first patient-controlled bolus (15.8±7.6 vs 10.6±8.6 hours, P=0.011). Furthermore, a higher rank of satisfaction was recorded with patients in the cSAPB group. CONCLUSION: cSAPB using PCA devices might be superior to traditional intravenous continuous analgesia, particularly with an advantage of pain relief at rest following VATS operation. Meanwhile, cSAPB lacks a satisfactory analgesic effect on cough.