Abstract: Objective To investigate the value of dexmedetomidine combined with ropivacaine type Ⅱ pectoral nerve block (PECS Ⅱ) in breast segmental resection.Methods A total of 168 patients who underwent elective breast segmental resection in our hospital from March 2020 to March 2022 were selected and divided into the combined group (dexmedetomidine combined with ropivacaine PECS Ⅱ,n=84) and the conventional group (ropivacaine PECS Ⅱ,n=84) according to the simple random method with a coin toss.The hemodynamics,quality of anesthesia recovery,perioperative pain stress factors,immune function,postoperative recovery and adverse reactions were compared at T0, 10 minutes after PECSⅡ (T1), immediately after intubation (T2), 5 minutes after intubation (T3), at extubation (T4), 5 minutes after extubation (T5).Results At T0, there was no significant difference in heart rate and mean arterial pressure between the two groups(P<0.05).At T1~T5,the heart rate and mean arterial pressure in the two groups were lower than those at T0 (P<0.05),and the heart rate and mean arterial pressure in the combind group were lower than those in the conventional group at the above time points,with statistically significant differences (P<0.05);The onset time of sensory block,extubation time and recovery time of spontaneous respiration in the combined group were (7.75±2.43) min,(14.59±1.53) min and (8.96±1.57) min,respectively,which was shorter than those in the conventional group[(10.23±3.02)min,(16.23±1.79)min,(11.63±2.79)min],and the maintenance time was (752.52±60.25) min,which was longer than that in the conventional group (489.36±90.14) min (P<0.05).The dosage of remifentanil and sufentanil in the combined group was (0.81±0.12) mg and (98.42±2.63) μg,respectively,which was less than that in the conventional group (0.93±0.22) mg and (103.52±1.44) μg,and the times of self-controlled analgesia pump were (2.01±0.35) times,which was less than those in the conventional group (3.35±0.55) times,with statistically significant differences (P<0.05).The levels of cortisol,norepinephrine and epinephrine in the combined group at 2 hours after operation were (311.71±50.53) mmol/L,(306.51±75.25) ng/ml and (80.02±21.02) ng/ml,respectively,which was lower than those in the conventional group [(398.61±98.14) mmol/L,(378.52±83.14) ng/ml,(101.75±25.01) ng/ml],and CD3+ and CD4+ were (50.02±5.79) % and (32.25±5.76) %,respectively,which was higher than those in the conventional group (47.52±6.71) % and (29.87±6.33) %,with statistically significant differences (P<0.05).1 day after surgery,the scores and total scores of all dimensions of the postoperative recovery quality scale in the combined group were higher than those in the conventional group,with statistically significant differences (P<0.05).There was no statistically significant difference in adverse reactions between the two groups (P>0.05).Conclusion Dexmedetomidine combined with ropivacaine PECSII can maintain the stability of intraoperative hemodynamics in patients with breast segmental resection,reduce surgical stress and influence on immune function,prolong analgesia time,improve the quality of anesthesia and postoperative recovery of patients,with high safety.

Key words: breast segmental resection, type Ⅱ pectoral nerve block, ropivacaine, dexmedetomidine