The Impact of Different Titration Endpoints of Propofol on Hemodynamics and Stress During the Induction Phase of General Anesthesia

Propofol can rapidly induce sleep in patients, creating favorable conditions for tracheal intubation, and is widely used for the induction of general anesthesia for tracheal intubation. However, its prominent drawback is circulatory depression. In clinical practice, propofol is still commonly administered for the induction of general anesthesia as a single intravenous bolus at the recommended dose (2-2.5 mg/kg). This method does not take into account individual differences and easily causes hypotension. In addition, target-controlled infusion under BIS monitoring is used in some cases. However, this approach requires high standards of equipment, has limited clinical applicability, and there is still controversy over whether the targetcontrolled model accurately reflects the concentration of propofol in blood or brain tissue.A 2020 retrospective study by Eric Y. et al. showed that the anesthetic induction dose of propofol for elderly patients was not adequately adjusted according to recommendations, resulting in an excessive actual dose. There are also studies on titrated administration of propofol, but the endpoints for titrated administration are still unclear.

Hypotension during the induction period has been identified as an independent predictor of adverse clinical outcomes. Early studies suggested that a mean arterial pressure (MAP) of <50-55 mmHg or a reduction in systolic blood pressure (SBP) or MAP by more than 40-50% from baseline can cause organ dysfunction.As research into the dangers of hypotension deepens, the minimum value that hypotension may cause damage is continuously increasing, and the harm brought by mild hypotension is increasingly being taken seriously. The impact of induced hypotension during the induction period on patients is related to the severity, duration of hypotension, and the patient's baseline condition.

Hypotension during the induction period of anesthesia is largely preventable and should be prevented. Therefore, finding appropriate endpoints for propofol titration can reduce the incidence of hypotension during the induction period, which is of ignificant significance for improving the prognosis of surgical patients.

Common methods for monitoring the depth of anesthesia during the induction period of general anesthesia include observer-based evaluations, such as the Observer's Assessment of Alertness/Sedation (OAA/S) score, and machinebased evaluations, such as the Bispectral Index (BIS) score.

The OAA/S score is a commonly used clinical observation tool that is simple and convenient to operate, requiring no additional equipment. It mainly assesses the depth of sedation by giving verbal commands and tactile stimuli to the patient. Various studies have shown that it correlates closely with machinebased indices for monitoring the depth of anesthesia, such as the BIS and the Index of Consciousness (IOC). As a straightforward, cost-effective method for monitoring the depth of anesthesia, the OAA/S score is closely related to clinical manifestations and is particularly suitable for monitoring the depth of anesthesia during the induction period.