Inclusion criteria  Meet criteria of enhanced recovery after surgery (ERAS); Mechanical ventilated when enrolled and have estimation of more than 10 hours of mechanical ventilation in ICU Aged between 18-75 years old AND 18kg/m2 ≤ BMI ≤ 30 kg/m2; Clearly know the purpose and objective of this clinical study and voluntarily enrolled.  Criteria of ERAS: (1) without dysfunction of nervous system or Glasgow Coma Score > 12; (2) a satisfied glucose level (random blood glucose<11.1mmol/L during screening stage) for diabetes mellitus patients; (3) Without acute coronary syndrome in recent 6 months; (4) Without bradycardia and third-degree atrioventricular block (except for patients with pacemaker) during screening stage; (5) systolic blood pressure>90mmHg with no usage of vasoactive agent during screening stage; (6) without mental illness (schizophrenia, depressive disorder), cognitive dysfunction (identified by MMSE), epilepsy, history of abuse of psychotropic or anesthesia medication; (7) without disorder of coagulation function (PT/INR/APTT > 1.5×upper limit), bleeding tendency (active peptic ulcer), under treatment of thrombolysis and anticoagulant; (8) without disorder of liver function (ALT/AST > 2×upper limit and total bilirubin>1.5×upper limit); (9) without disorder of renal function (Creatine or BUN/Urea>1.5×upper limit); without dialysis patients.  Exclusion criteria  Allergy to component of Remimazolam besylate for injection; Woman in gestation and lactation period; Enrolled in other clinical trails in recent 3 months; Other circumstance that identified by researchers that do not suitable for this clinical trial.