Effects Of Thoracic Paravertebral Block Combined With S-Ketamine On Postoperative Pain And Cognitive Function After Thoracoscopic Surgery

Objectives:To assess the effects of thoracic paravertebral block and s-ketamine on postoperative pain and perioperative neurocognitive disorder（PND）in video-assisted thoracoscopic surgery.Methods:Patients（n=120）aged 45–65 undergoing video-assisted thoracoscopic surgery from April 2021 to February 2022 were allocated randomly into the following three groups:patients in the C group received general anaesthesia;patients in the thoracic paravertebral block group,i.e.the TP group,received general anaesthesia and ultrasound-guided paravertebral block;and patients in the s-ketamine combined with ultrasound-guided thoracic paravertebral nerve block group,i.e.the TS group,received combined anaesthesia,which was administered as follows:general anaesthesia+ultrasound-guided paravertebral block+perioperative s-ketamine（a bolus of 0.3 mg/kg,followed by an infusion of 0.2 mg//kg/h until 30 min before the end of the surgical procedure）.Each group has 40cases.The MAP and HR,intraoperative anaesthetic and vasoactive drug dosages were recorded at pre-operation（T₁）,immediately after initiating the operation（T₂）;end of the operation（T₃）;after the extubation（T₄）.The VAS scores after extubation and 1 day after surgery,the number of analgesic pump presses and the Ramsay score on the postoperative day were compared.The MMSE scale was applied to assess cognitive function1 day preoperatively,1 day postoperatively and 3 months postoperatively,and the incidence of perioperative neurocognitive disorder was determined by the Z-score method.The incidence of postoperative nausea and vomiting（PONV）,chest tube indwelling time and the occurrence of pulmonary complications（pneumonia and atelectasis）in the three groups were compared.Results:1、The difference of intraoperative vital signs between the three groups was statistically significant.Group C fluctuated more,and MAP and HR were significantly higher than the remaining two groups at T₂and T₄times（P<0.05）,and the postoperative remifentanil dosage was significantly lower in the TS group than in the TP and C groups（P=0.003）.2、The postoperative VAS score and number of analgesic pump presses were significantly lower in the TS group than in the other two groups,and the incidence of postoperative PONV and pulmonary complications was significantly lower（P<0.05）.The postoperative Ramsay score was significantly lower in the TS group than in the C group,but the difference was not statistically significant when compared with the TP group（P>0.05）.3、The MMSE score was significantly higher in group C one day after surgery compared to baseline（P<0.05）,while the difference between the TP and TS groups compared to baseline was not statistically significant（P>0.05）,and the difference in MMSE score at three months after surgery was not statistically significant（P>0.05）.Compared with group C,the incidence of PND was significantly lower in the TP and TS groups at one day and three months postoperatively,but the difference in the incidence of PND between the TP and TS groups was not statistically significant（P>0.05）.Conclusion:Ultrasound-guided thoracic paravertebral nerve block combined with S-ketamine can maintain intraoperative haemodynamic stability,reduce acute postoperative pain,and promote rapid postoperative recovery.However,continuous intraoperative application of s-ketamine did not improve neurocognitive function in patients with TPVB.