Risk Factors for Post-Induction Hypotension Following General Anesthesia in Geriatric Patients Undergoing Elective Non-Cardiac Surgery : A Prospective Study

The purpose of this study is to identify risk factors contributing to post-induction hypotension in geriatric patients undergoing elective non-cardiac surgery under general anesthesia at Dr. Cipto Mangunkusumo National Central Public Hospital. Post-induction hypotension is defined as a decrease in Mean Arterial Pressure (MAP) of more than 30% from baseline after anesthesia induction up to 20 minutes post-induction. This condition can lead to adverse effects such as myocardial injury, acute kidney injury, stroke, and even death.

This research aims to answer several key questions, including whether the following factors influence the risk of post-induction hypotension:

• Airway management with endotracheal intubation.
• Low albumin levels.
• Presence of comorbidities such as hypertension, cancer/malignancy, diabetes mellitus, chronic heart disease, and chronic kidney failure.
• Dose of propofol during anesthesia induction.
• Dose of fentanyl administered during anesthesia induction.
• Dose of midazolam administered during anesthesia induction.
• Frailty score.

This study is an observational analytical study with a prospective cohort design. Data will be collected from medical records and direct observation of geriatric patients who meet the inclusion and exclusion criteria. Sampling will be done using a consecutive sampling method. The targeted sample size is 333 subjects, accounting for a 10% dropout rate.

Study subjects will meet the inclusion criteria: geriatric patients over 60 years old undergoing elective non-cardiac surgery under general anesthesia with ASA (American Society of Anesthesiologists) classification I-IV. Exclusion criteria include patients receiving a combination of general anesthesia with regional or epidural anesthesia, more than 2 attempts at endotracheal intubation, patients already intubated before the surgical procedure, those receiving vasopressors or inotropics before general anesthesia induction, and intentional hypotension within 20 minutes after intubation.

The data to be recorded include patient characteristics, ASA classification, history of comorbidities, medications consumed, vital signs (before entering the operating room, upon arrival in the operating room, immediately after intubation, and at 5, 10, 15, and 20 minutes after intubation), type of surgery, anesthesia technique, type of anesthetic gas used, total doses of propofol, fentanyl, and midazolam with their administration times, laboratory results, chest X-ray results, presence or absence of endotracheal intubation procedure, administration of vasopressors or inotropics before induction, and patient position during blood pressure measurements. Data analysis will be performed using Graphpad Prism version 10 for MacOS, including descriptive analysis, normality tests, bivariate tests (Chi-square or Fisher's exact test, T-test or Mann-Whitney), and multivariate analysis using Cox regression to identify risk factors and determine relative risk.