Anesthetic Substitute of Intraoperative Regional Anesthesia of Nonintubated or Endotracheal-intubated Video-assisted Thoracoscopic Surgery With Thoracoscopic Multilevel Intercostal Nerve Blocks: a Randomized Study
Authors: Chan Kuang-Cheng , Wu Li-Lin , Han Su-Chuan , Chen Jin-Shing , Cheng Ya-Jung 
Published: July 2021

Abstract
Background:A reduced need for general anesthetics and enhanced effectiveness of postoperative analgesia have been reported for multimodal anesthesia, which involves combining regional and general anesthesia. Ideal regional anesthesia to combine with general anesthesia should match but not overdo with the surgical stress from corresponding operations. However, as thoracic operation becomes less invasive, the substitute effects on intraoperative analgesia or consciousness by regional anesthesia such as with thoracoscopic intercostal nerve blocks (TINBs) for managing corresponding surgical stress in intubated or non-intubated video-assisted thoracoscopic surgery (VATS) have been inadequately studied. The goals of this study is to investigate the substituve of TINBs on analgesia and consciousness for intubated and non-intubated uniport VATS operations.Methods:Sixty patients who received VATS with target-controlled infusions of propofol and remifentanil were recruited. Patients were randomized into intubated and nonintubated groups. Intraoperative multilevel (T3–T8) TINBs were performed after artificial pneumothorax and before VATS operations. The effects of substitute on analgesia by TINBs for VATS operations were indicated by changes on blood pressure and the Ce of remifentanil to maintain normotension. EEG data with a density spectral array (DSA) and data on the effect-site concentration (Ce) of propofol goaled with bispectral index (BIS) levels between 40-60were compared to determine whether TINBs affect consciousness. Results:TINBs with 0.5% bupivacaine provide substitute more than required on analgesia for intubated and non-intubated uniport VATS operations. The Ce of remifentanil was significantly decreased beginning 10 min after TINBs in both groups (p < 0.001). In the nonintubated VATS (NIVATS) group, a significantly lower mean arterial pressure after introducing TINBs persisted for 20 min. TINBs demonstrated a DSA smoothing effect despite the subsequent VATS. The Ce of the propofol infusion decreased 5 min after TINBs in both NIVATS (p < 0.001) and intubated VATS (IVATS; p = 0.252) groups. The Ce of remifentanil was significantly higher in parallel for the IVATS group than for the NIVATS group (p < 0.001).Conclusions:Intraoperative TINBs with 0.5 % bupivacaine provides substitutes on analgesia and hyponosis more than required for uniportal intubated or non-intubated VATS operations. Situations involving endotracheal tubes required more analgesia but does not affect the substitute effects of TINBs.Trial registration: ClinicalTrials. gov, NCT03874403. This study was approved by the Research Ethics Committee of National Taiwan University Hospital, Taipei, Taiwan (201712125RINB) on February 2, 2018. We then enrolled our first case on November 1, 2018 - Retrospective registered on February 28, 2019, https://clinicaltrials.gov/ct2/show/record/NCT03874403