Abstract: Abstract: Objective To investigate the effect of dexmedetomidine combined with ropivacaine transverse abdominis plane block on elderly patients undergoing radical resection of colorectal cancer. Methods From July 2018 to July 2020, 64 patients with colorectal cancer who underwent radical surgery in the Second Affiliated Hospital of Guangdong Medical University were selected as the
research objects and randomly divided into study group and control group, 32 cases in each group, The control group was given ropivacaine transversus abdominis plane block, and the study group was given dexmedetomidine on the basis of the control group. The operation recovery of the two groups were compared, including extubation cases, respiratory recovery time, rescue analgesia, recovery time, intraoperative blood loss, extubation time; the condition recovery, including eating time, hospitalization time, postoperative first exhaust time, first out of bed time, defecation time. The degree of postoperative pain was evaluated by visual analogue scale. The levels of immunoglobulin (Ig)G, IgA and IgM were detected by immunoturbidimetric method. The postoperative recovery quality scale was used to evaluate the recovery status of patients, and the incidence of arrhythmia, blood pressure drop, nausea, vomiting, headache, dizziness and other complications were compared between the two groups. Results There was no significant difference in intraoperative blood loss, extubation time, and extubation cases between the two groups (P>0.05). The rescue analgesia rate, respiratory recovery time and recovery time of the study group were less than those of the control group (P<0.05); At 2h, 6h, 12h and 24h after operation, the scores of visual analogue at cough and rest in the control group were higher than those in the study group, with significant difference (P<0.05); Before operation, there was no significant difference in IgM, IgG and IgA between the two groups (P>0.05); After operation, IgM, IgG and IgA in the two groups were increased, and those in the study group were higher than those in the control group, with significant difference (P<0.05); The time of getting out of bed for the first time, defecation time, postoperative first exhaust time and hospitalization time of the study group were less than those of the control group, with significant difference (P<0.05); There was no significant difference in the score of recovery quality scale between the two groups on the first day before operation (P>0.05); On the third day after operation,
the scores of physical comfort, total score of recovery quality scale, psychological support, pain and emotional state of the study group were higher than those of the control group In the control group, the difference was significant (P<0.05); The incidence of nausea, vomiting, headache and dizziness in the study group was lower than that in the control group, the difference was significant (P<0.05), and there was no significant difference in the incidence of arrhythmia and blood pressure drop between the two groups (P>0.05). Conclusion Dexmedetomidine combined with ropivacaine transversus abdominis plane block can significantly improve the analgesic effect of elderly patients with colorectal cancer radical operation, enhance the immune ability of patients, improve the motor and gastrointestinal function of patients, and improve the quality of recovery.

Key words: Key words: Ropivacaine, Colorectal cancer, Elderly, Transversus abdominis plane block, Dexmedetomidine