Fifty-two patients entered ICU after heart operation with cardiopulmonary bypass. These patients with ventilation atracurium (ATC) were given 3 micrograms-6 micrograms/kg/min for 5-48 hours. No complications happened. After ATC was used, the patients could open eyes, and cooperate with the doctor when they regain consciousness. The circulation index was normal. The limbs of these patients relaxed. In the 52 cases, 30 did't use sedatives, and 22 used senall dose of sedatives for sleep at night. We conclude that ATC does not require hepatic or renal function for termination of effect and action is terminated by the "Hoffman elimination" the ester hydrolysis. The time of effect is short and there is no cumulation effect. There is no vagal or ganglionic blocking activity, so ATC does not influence circulation and myocardial function. Maintenance relaxation keeps ventilation steady and oxygen supply normal.