Abstract: Objective To explore the effect of hydromorphone on hemodynamics after general anesthesia in elderly patients with hypertension under evaluation of Bioz noninvasive monitoring system.Methods Sixty elderly hypertension patients with selective abdominal operation under general anesthesia were randomly divided into hydromorphone group (HM group) and normal saline group (SP group),and 15 min before the end of surgery,hydromorphone was injected in the MH group,while the normal saline was injected in the control group.The indicators such as heart rate (HR),mean arterial pressure (MAP),cardiac output (CO),cardiac output index (CI) and systemic vascular resistance (SVR) were measured at different time points of before induction of anesthesia (T1),extubation (T2) and 10 min after extubation (T3).Recovery time of spontaneous breathing,awaking time,extubation time and out of PACU time were recorded.The visual analogue score (VAS),Ramsay sedation score at the PACU were also recorded at 5 min (H1),15 min (H2) and 30 min (H3).Results Compared with HM group,HR,MAP,SVR,VAS and Ramsay score increased significantly in the SP group (P ＜ 0.05).Compared with the indexes at T1,HR,MAP,SVR increased significantly while CO,CI decreased significantly at T2 (P ＜ 0.05).In both groups,SVR at T3 decreased but was significantly higher than that at T1 (P ＜ 0.0 5).compared between two groups at H1 time point in PACU,VAS and Ramsay score in group SP at H2,H3 time point were no different (P ＞ 0.05).VAS and Ramsay scores in HM group at H2,H3 were increased significantly (P ＜0.05).There were no significant differences in the recovery time of spontaneous breathing,awaking time and extubation time between two groups (P ＞ 0.05).Conclusion Bioz non-invasive hemodynamic monitoring system can provide effective hemodynamic information,and subcutaneous injection of 1 mg hydromorphone before the end of operation can effectively maintain the hemodynamic stability during the recovery period of general anesthesia in elderly patients with hypertension.