The Effect of Propofol Induction Based on Lean Body Weight on the Depth of Anesthesia

The Effect of Propofol Induction Using Total Body Weight and Lean Body Weight Obtained by Tomographic Measurements; on the Depth of Anesthesia in Patients Receiving General Anesthesia

Propofol has significant hemodynamic side effects. It is a lipophilic agent and is generally used at a dose of 2-2.5 mg/kg for induction. In patients with a body mass index (BMI) greater than 25, it can lead to serious complications. This patient group often has comorbidities such as hypertension, coronary artery disease, left ventricular hypertrophy, stroke, and obstructive sleep apnea.

Hemodynamic profile changes are influenced by both the rate of propofol administration and the total dose. Therefore, it is necessary to investigate the appropriate dose and infusion rate of propofol during anesthesia induction.

The primary aim of this study is to compare the effects of propofol induction doses, determined based on total body weight and lean body weight (calculated using tomography), on anesthesia depth using BIS and SedLine monitoring in patients with BMI >25.

The secondary aim of the study is to compare propofol induction doses calculated using two different methods in terms of:

• Mean arterial pressure (MAP),
• Frequency of hypotension (MAP <65),
• Frequency of Trendelenburg position or vasopressor requirement and their response,
• Tachycardia (heart rate >100 bpm),
• Frequency of hypertension (SBP >140). Additionally, the sensitivity and delay rates of BIS and SedLine monitoring in determining anesthesia depth were compared.

A total of 120 patients undergoing general anesthesia for urological surgeries at our hospital were included in the study. Patients were randomized into two groups (Group T/Group L). All patients were taken to the operating room, and in addition to routine monitoring, BIS and SedLine monitoring were provided. All patients received 1 mcg/kg of fentanyl.

• Group T received propofol at a dose of 2-2.5 mg/kg based on total body weight.
• Group L received propofol at a dose of 2-2.5 mg/kg based on lean body weight, which was calculated from CT imaging by a radiologist.
• Propofol was administered at a rate of 100 mg/min. The laryngeal mask will be placed once an adequate depth of anesthesia is achieved.

All data were recorded at 2-minute intervals for 6 minutes before and after induction. The collected data were statistically analyzed for comparison.

Inclusion Criteria:

• A total of 120 patients of both genders,
• Aged 18-65 years,
• BMI >25
• Scheduled for elective surgery under general anesthesia in the urology operating room

Exclusion Criteria:

• Patients under 18 years of age or over 65 years old
• Patients unable to read, understand, or sign the consent form
• Hemodynamically unstable patients
• Patients with contraindications to anesthetic drugs
• Patients who do not wish to participate in the study
• Patients deemed unsuitable by the researcher
• Patients with advanced dementia or behavioral disorders
• Patients using psychiatric medications or abusing drugs
• Patients requiring awake intubation
• Emergency surgical procedures
• Patients with more than a 5% weight change between the time of the CT scan and the surgery day
• A time gap of more than 2 months between the CT scan and the surgery day

The criteria for discontinuing the study are as follows:

• Patients who develop anaphylaxis
• Airway failure
• Patients who develop unexpected complications