OBJECTIVE: To probe into the effects of different loading doses of dexmedetomidine on postoperative recovery of intestinal function in patients with gastrointestinal tumor. METHODS: Totally 108 patients undergoing gastrointestinal tumor surgery in this hospital from Feb. 2019 to Mar. 2021 were extracted to be divided into the group A

B and C via the random number table

with 36 patients in each group. In group A and B

0. 5 μg/kg and1. 0 μg/kg of dexmedetomidine were pumped intravenously 10 min before anesthesia induction

and 0. 5 μg/（ kg·h）of dexmedetomidine was infused continuously until 10 min before the end of skin suture. In group C

the same volume of 0. 9% sodium chloride injection was pumped intravenously. Three groups were given anesthesia induction and maintenance in the same way. The mean arterial pressure（ MAP） and heart rate（ HR） were recorded before dexmedetomidine pumping（ T

0

）

after endotracheal intubation（ T

1

）

at withdrawal of dexmedetomidine（ T

2

）

immediately after extubation（ T

3

）

and 30 min after extubation（ T

4

） in three groups were recorded

the serum levels of cortisol（ Cor） and norepinephrine（ NE） were detected after collecting the blood samples at the above time points

the time of exhaust and defecation was recorded

and the incidence of postoperative anesthesia related complications was observed. RESULTS: From T

1

to T

4

the MAP

HR

serum Cor and NE levels in group A and B were significantly lower than those in group C

and the MAP

HR

serum Cor and NE levels in group B were significantly lower than those in group A

with statistically significant differences（ P

<

0. 05）. The time of exhaust and defecation in group A and B was significantly shorter than that in group C

and the time of exhaust and defecation in group B was significantly shorter than that in group A

with statistically significant differences（ P

<

0. 05）. The incidence of agitation during extubation in group B was significantly lower than that in group C

with statistically significant differences（ P

<

0. 05）. CONCLUSIONS: The application of dexmedetomidine during surgery in patients with gastrointestinal tumor can effectively control the hemodynamics and stress responses

significantly reduce the incidence of agitation during extubation

and shorten the recovery time of postoperative intestinal function; the effect of continuous infusion of dexmedetomidine at 0. 5 μg/（ kg·h） after 1. 0 μg/kg loading dose of intravenous pumping is better.