Post-induction Hypotension (PIH)

From 15 minutes before to 15 minutes after anesthesia, Transcutaneous Electrical Acupoint Stimulation(TEAS) at different frequencies will be applied at Neiguan and Jian Shi. The changes in blood pressure during the anesthesia induction period will be compared among the high-frequency group ,the low-frequency group and the control group to explore the better frequency to reduce the incidence of post-induction hypotension(PIH) in the elderly.

This prospective observational study aims to evaluate whether the preoperative neutrophil percentage-to-albumin ratio (NPAR) is associated with post-induction hemodynamic vulnerability in adult patients undergoing elective major oncologic surgery under general anesthesia. NPAR will be calculated from routine preoperative laboratory results by dividing the neutrophil percentage by the serum albumin level. No additional laboratory tests, medications, invasive procedures, or changes in anesthesia management will be performed for the purposes of the study. Demographic characteristics, preoperative laboratory values, anesthetic data, and hemodynamic measurements will be recorded prospectively. Hemodynamic status will be evaluated during the period between induction of general anesthesia and surgical incision, with a maximum observation period of 20 minutes. Vasopressor use and administered doses will also be recorded. The study will assess the ability of preoperative NPAR to identify patients who may be more susceptible to early hemodynamic instability following induction of general anesthesia.

This prospective study aims to investigate the role of the passive leg raise maneuver prior to anesthesia induction in predicting post-induction hypotension among elective gastrointestinal tumor surgery patients using carotid artery Doppler parameters.

This observational clinical study aims to investigate the incidence and risk factors of post-induction hypotension (PIH) in geriatric cancer patients undergoing surgery under general anesthesia. PIH is defined as a drop in mean arterial pressure of ≥30% from baseline or below 65 mmHg within the first 20 minutes after anesthesia induction, prior to surgical stimulation. The primary objective is to determine the frequency of PIH in elderly oncology patients. Secondary objectives include evaluating the association of PIH with age, ASA score, cancer type, oncological treatments (chemotherapy/radiotherapy), comorbidities, medication use, anemia, biochemical parameters, and preoperative perfusion index (PI) and pleth variability index (PVI). Findings from this study are expected to contribute to improved perioperative management and to the development of tailored anesthesia protocols for geriatric oncology patients.