title: [Influences of perioperative metoprolol on hemodynamics and myocardial ischaemia in elderly patients undergoing noncardiac surgery].
abstract: OBJECTIVE
  To observe the influences of metoprolol on hemodynamics and myocardial ischaemia in elderly patients undergoing noncardiac surgery.
  
  
  METHODS
  Thrity patients (60 approximately 75 years) undergoing elective noncardiac surgery were randomly divided into a metoprolol group (n = 15) and a control group (n = 15). In the metoprolol group, metoprolol (0. 5 mg and 1.5 mg) was slowly injected into the vein of patients before the induction of intravenous anesthesia and after the tracheal intubation. The hemodynamic indice (invasive BP, HR and rate pressure product-RPP), the myocardial ischaemia indice (reversible ST segment depression of ECG II, V5 leads more than 0.1 mv or reversible ST segment elevation more than 0.2 mv from the baseline, ST segment depression or elevation over 1 min), the myocardial damage indice (serum cardiac troponin I, cTn I), and the indice of metoprolol cardiac and the respiratory adverse effects (incidence of HR below 50 beats/min, average doses of atropine, airway peak pressure) were observed intraoperatively.
  
  
  RESULTS
  The HR and RPP were lower before the tracheal induction than the baseline (before anesthesia) in all patients, but there is no significant difference between the two groups (P > 0.05). During the tracheal intubation, the HR and RPP of the control group significantly increased, compared with the baseline (P < 0.05) and those of metoprolol group (P < 0.05). The incidence of perioperative hypertension was higher in the control group than that in the metoprolol group. The incidence of myocardical ischaemia episode was 30% in the control group, and 13% in the metoprolol group (P < 0.01). The release of cTn I was detected in 5 patients in the control group, and 2 patients in the metoprolol group (P < 0.05). The incidence of HR < 50 beats/min, and the average doses of atropine had no statistic difference between the two groups, but a tendency of high incidence of bradycardia in the metoprolol group occurred when abdominal viscera was tracted by surgical manupilation. There was no significant difference in airway peak pressure, SpO2 and PET CO2 between the two groups (P > 0.05).
  
  
  CONCLUSIONS
  Intravenous administration of 0.5 mg and 1. 5 mg metoprolol before the induction of anesthesia and after the tracheal intubation has several advantages, including the decrease of myocardial oxygen consumption, the improvement of hemodynamic stability, and the lowering perioperative incidence of myocardial ischeamia and damage, but the tendency of high bradycardia incidence caused by peritoneal traction should be noticed.
authors.affiliation: Department of Anaesthesia, Xiangya Hospital, Central South University, Changsha, China. liuyao9988@126.com
authors.forename: Yao
authors.initials: Y
authors.lastname: Liu
authors.forename: Chang-lin
authors.initials: CL
authors.lastname: Huang
authors.forename: Min
authors.initials: M
authors.lastname: He
authors.forename: Li-na
authors.initials: LN
authors.lastname: Zhang
authors.forename: Hong-wei
authors.initials: HW
authors.lastname: Cai
authors.forename: Qu-lian
authors.initials: QL
authors.lastname: Guo
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000368:Aged; D000771:Anesthesia, Intravenous; D004562:Electrocardiography; D016629:Esophagectomy; D005260:Female; D005743:Gastrectomy; D006439:Hemodynamics; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008790:Metoprolol / Q000627:therapeutic use*; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000517:prevention & control*; D019990:Perioperative Care; D011013:Pneumonectomy; D019210:Troponin I / Q000097:blood
chemical_list: D000319:Adrenergic beta-Antagonists; D019210:Troponin I; D008790:Metoprolol