Glycopyrrolate is an anticholinergic medication commonly used in respiratory medicine for treating chronic obstructive pulmonary disease (COPD), bronchial asthma, and other conditions . In the perioperative period, it is often administered before anesthesia to reduce secretions in the salivary glands, bronchi, and pharynx . It is used during the recovery period to counteract the muscarinic effects of anticholinesterase inhibitors and can also be employed to prevent/treat vagal reflexes and related arrhythmias induced by surgery or medications .

Heart rate (HR) is influenced by both the sympathetic and parasympathetic nervous systems. The baseline HR of different patients may vary due to differing levels of sympathetic and parasympathetic nerve activity within the body. It remains unclear whether patients with different baseline HRs exhibit varying degrees of HR elevation after the administration of glycopyrrolate(i.e.,the parasympathetic activity in vivo is antagonized). The primary aim of this study is to explore the impact of glycopyrrolate administration on HR in patients with different baseline HRs. The secondary objective is to investigate the effects of glycopyrrolate on heart rate variability (HRV) in patients with different baseline HR.

Inclusion Criteria:

• 1.Weight not restricted; 2.American Society of Anesthesiologists (ASA) status I or II; 3.The operative time≥1 h; 4.Undergoing orthopedic or urological surgery.

Exclusion Criteria:

• 1.allergy to glycopyrrolate; 2.laparoscopic surgery; 3.liver or kidney dysfunction; 4.pre-existing abnormal electrocardiogram such as bradycardia; 5.concomitant glaucoma; 6.patients refusal to participate.