Comparative Analysis of Phenylephrine and Noradrenaline on Hemodynamics and Cerebral Perfusion in Anesthetized Patients with Brain Tumors

The primary objective of this study is to evaluate the impact of two commonly used **vasopressor** agents, phenylephrine and noradrenaline, on cerebral circulation and oxygenation in patients undergoing brain tumor resection. This is clinically relevant as optimizing cerebral perfusion and oxygenation during surgery is crucial for improving neurological outcomes and minimizing potential complications associated with low blood pressure during anesthesia. Additionally, the study aims to understand the effects of vasopressor-induced changes in systemic hemodynamics on regional perfusion in vital organs, including the brain, heart, and muscle.

The clinical trial involves participants diagnosed with **low blood pressure during anesthesia**. The study population comprises both male and female subjects aged between 18 and 75 years. Participants are scheduled for elective craniotomy for supratentorial tumors with a minimum size of 3 cm, measured as the largest diameter in any plane. The trial does not include a vulnerable population. The sponsor has not provided information regarding the total number of participants. The selection of the trial population is based on specific inclusion criteria, focusing on individuals undergoing brain tumor resection. Lifestyle considerations such as diet, physical activity, or habits are not specified in the available data.

The clinical trial is designed to evaluate the impact of two **vasoactive substances**, **phenylephrine** and **noradrenaline tartrate**, on systemic hemodynamics and cerebral tissue circulation and oxygenation in patients undergoing brain tumor resection. This study is a randomized, double-blind, controlled trial, ensuring that neither the participants nor the researchers know which treatment is being administered, thus minimizing bias. The trial is expected to run from October 2022 to December 2025, with participant involvement lasting for a maximum of one day, corresponding to the duration of the surgical procedure.

Participants will be screened based on specific inclusion criteria, which require subjects to be aged 18-75 years and scheduled for elective craniotomy for supratentorial tumors with a minimum size of 3 cm. The screening visit will confirm eligibility and obtain informed consent. The primary endpoint of the study is the between-group difference in the change in cerebral blood flow (ΔCBF) from pre-treatment to post-treatment. The trial does not specify secondary endpoints.

Study visits will include the initial screening visit, the treatment visit during the surgical procedure, and an end-of-study visit to assess outcomes. The treatment involves the intravenous administration of either **phenylephrine** or **noradrenaline tartrate**. Participants will be monitored for changes in systemic hemodynamics and cerebral circulation during the procedure. The study may terminate early for individual participants if adverse events occur or if the participant withdraws consent. The trial aims to provide insights into the effects of these vasopressors on cerebral and systemic circulation, potentially influencing future anesthetic management in similar clinical settings.

The clinical trial involves the administration of **Noradrenaline Tartrate**, a vasoactive substance used to prevent and treat hypotension. The pharmaceutical form of this medication is a **solution for infusion**. The active substance, noradrenaline tartrate, is of chemical origin. The medication is administered intravenously with a maximum daily dose of 100 mg and a maximum total dose of 100 mg over a treatment period of one day. The administration of noradrenaline tartrate is monitored to ensure compliance with the dosing schedule and to assess its impact on systemic hemodynamics and cerebral tissue circulation and oxygenation in patients undergoing brain tumor resection.

Another experimental medication used in the trial is **Phenylephrine**, also a vasoactive substance aimed at preventing and treating hypotension. Phenylephrine is provided as a **solution for injection** and is administered intravenously. Similar to noradrenaline tartrate, the maximum daily and total dose is 100 mg, with a treatment period limited to one day. The active substance, phenylephrine, is chemically derived. The trial seeks to evaluate the effects of phenylephrine on cerebral circulation and oxygenation, as well as its influence on systemic hemodynamics and regional perfusion in various organs, including the brain, heart, and muscle.

Efficacy in this clinical trial will be assessed by evaluating the primary endpoint, which is the between-group difference in **ΔCBF** (Δ = posttreatment value - pretreatment value). This parameter will measure the change in cerebral blood flow (CBF) following treatment with either phenylephrine or noradrenaline in patients undergoing brain tumor resection. The trial aims to understand the impact of these vasopressor agents on cerebral circulation and oxygenation, as well as their effects on systemic hemodynamics and regional perfusion in organs such as the brain, heart, and muscle.