Objective To evaluate the effect of Dexmedetomidine and Midazolam on respiratory and circulation in patients experiencing open heart surgery under acupuncture-assisted general anesthesia.Methods Sixty patients undergoing open heart surgery(cardiac valve replacement surgery and aortic valve replacement surgery)were randomly and equally divided into Dexmedetomidine(D)and Midazolam(M)groups.Electroacupuncture(EA)was applied to bilateral Yunmen(LU 2)

Zhongfu(LU 1)

Lieque(LU 7)and Neiguan(PC 6).For patients of group D

Dexmedetomidine(i.v.

loading dose:1μg/kg

and succedent dose:0.2

1

μg·kg-1·h-1)was given.For patients of group M

Midazolam(i.v.

loading dose:0.05mg/kg

succedent dose:0.011μg·kg-1·h-1)was given.For patients of group M

Midazolam(i.v.

loading dose:0.05mg/kg

succedent dose:0.01

0

.03mg·kg-1·h-1)was given.Arterial oxygen pressure(PaO2)

arterial carbondioxide tension(PaCO2)

O2saturation(SPO2)

mean arterial pressure(MAP)

heart rate(HR)

anesthetic effect

time of spontaneous breathing recovery

and time of resuscitation were recorded before operation(T0)

immediately after skin incision(T1)

immediately after sternotomy(T2)

before suspension of cardiopulmonary bypass(CPB

T3)

immediately after cardiac re-beating(T4)

immediately after CPB cessation(T5)

and at the end of surgery(T6).Results Before operation

no significant differences were found between the group D and M in the levels of PaO2

PaCO2and SPO2(P

>

0.05).The PaO2and SPO2levels after skin incision

sternotomy

before suspension of CPB and at the end of surgery were significantly lower in group M than in group D(P

<

0.05)

while the levels of PaCO2after skin incision

sternotomy

before suspension of CPB and at the end of surgery

and HR after skin incision

sternotomy

before suspension of CPB

after heart re-beating

after CPB cessation and at the end of surgery in group M were considerably higher than those in group D(P

<

0.05).In addition

the time of spontaneous breathing recovery of group M was significantly later than that of group D(P

<

0.05).No significant differences were found between the two groups in MAP levels at the 6time-points during surgery

in the PaO2

PaCO2and SPO2levels at the time-points of post-cardiac re-beating

and after CPB cessation(P

>

0.05).It suggested that the respiration and circulation states in group D were more smoothly than those in group M.There was no significant difference between the two groups in the time of resuscitation(P

>

0.05).Conclusion Dexmedetomidine is superior to Midazolam in analgesia

and improving respiration and circulation functions for open heart surgery patients under acupuncture-assisted general anesthesia.