Abstract: Objective To investigate the effect of dexmedetomidine combined with regional nerve block of lumbar quadratus muscle on postoperative delirium in elderly patients with colon cancer. Methods Eighty elderly colon cancer patients admitted to the Affiliated Hospital of Xuzhou Medical University from January 2021 to June 2022 were selected for retrospective analysis and grouped according to whether dexmedetomidine was applied in the pre-induction of anesthesia. 40 patients in the observation group had dexmedetomidine applied prior to the induction of anesthesia, while 40 patients in the control group were not applied. All patients underwent radical colon cancer, the control group patients received general anesthesia combined with trapezius regional nerve block, and the observation group increased dexmedetomidine before induction of general anesthesia combined with trapezius regional nerve block, and compared the expression levels of diastolic blood pressure (SBP), systolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR) in different time [base value (T1), sedation (T2), lens(T3), end (T4)], and the scores of visual analogue scale (VAS) under rest and exercise at different times between the two groups, adverse conditions and false incidence incidence. Results There was no significant difference in SBP, DBP, MAP and HR at T₁ between the two groups (P>0.05). There was no significant difference in SBP, DBP, MAP and HR at T₁, T₂, T₃, T₄ between the two groups (P>0.05). The levels of SBP, DBP, MAP and HR decreased from T₁ to T₂, and T₄ increased from T₃, SBP, DBP and MAP were higher than the control group, and SBP, DBP, and HR were lower than the control group (P<0.05); the resting state VAS score increased between 2 h and 12 h after surgery, and the observation group was lower (P<0.05); the exercise state VAS score gradually decreased from 12 h to 48 h after surgery, and the observation group was lower (P<0.05); the postoperative pain duration was significantly lower than the control group (P<0.05). There was no significant difference in the incidence of bradycardia, hypoxemia, hypotension and other adverse events between the two groups (P>0.05). The incidence of postoperative delirium of observation group was significantly lower than that of the control group (P<0.05). Conclusion The use of dexmedetomidine followed by general anesthesia combined with lumbar quadratus block in elderly patients with colon cancer can stabilize their blood pressure and heart rate, reduce the degree of pain in resting state and exercise state, reduce the incidence of postoperative delirium, and has a high safety.

Key words: dextrmedetomidine, regional nerve block of quadratus lumbaris muscle, colon cancer, delirium, vital signs