Treating Intraoperative Bradycardia in Non-cardiac Surgery Patients With Atropine at Heart Rates Below 60 Versus 30 Beats Per Minute and Norepinephrine Requirements

Inclusion Criteria: Consenting patients ≥50 years scheduled for elective non-cardiac surgery with general anesthesia that is expected to last ≥60 minutes with at least two of the following risk criteria for developing acute kidney injury: * Age ≥65 years * American Society of Anesthesiologists physical status III or IV * Chronic arterial hypertension * Diabetes mellitus requiring medication * Intraabdominal surgery * Preoperative renal insufficiency (serum creatinine ≥1.2 mg/dL) Exclusion Criteria: Patients with the following exclusion criteria: contraindication for atropine administration (e.g., myasthenia gravis, high-grade aortic stenosis, high-grade coronary artery disease, glaucoma, paralytic ileus, prostatic hypertrophy); renal replacement therapy within the previous 3 months; chronic kidney disease with an estimated glomerular filtration rate \<20 mL/min/1.73 m2; pregnancy.