Investigating the Effect of Induced Hypotensive Anesthesia versus Normotensive Anesthesia on Perioperative Bleeding in Patients Undergoing Percutaneous Nephrolithotomy: A Randomized Controlled Clinical Trial

Determining the effect of induced hypotensive anesthesia against normotensive anesthesia on perioperative bleeding in patients undergoing percutaneous nephrolithotomy at Al-Zahra hospital

A randomized clinical trial with a control group, parallel groups with interventions of normotensive and hypotensive anesthesia, double blind, randomized with random allocation software, phase two, with 32 participants

This study will be conducted at Al-Zahra Hospital, Isfahan in 2023. After selecting the allocation of patients to the intervention groups randomly, the amount of bleeding and other information related to the outcome will be collected during and after the surgery. Blinding: the patient, the doctor who collects the information (with the help of the anesthesiologist supervising the patient) and the statistician (by coding the data)

Inclusion criteria: Patients candidate for percutaneous Nephrolithotomy (PCNL); Age of above 18 years; Exclusion criteria: Coagulopathy; Anatomical disorders that interfere with the proper positioning of the patient; Any disease that makes inducing the controlled hypotension impossible during surgery; Single kidney; Ectopic kidney; Active infection of the urinary system; Pregnancy

Control group (normotensive anesthesia): Administered general anesthesia with 4-5 mg/kg sodium thiopental, 3 microg/kg fentanyl, and 0.15 mg/kg cisatracurium. Intervention group (induced hypotensive anesthesia): After anesthesia induction, continuous remifentanil infusion at 0.2/mg/kg/min will induce hypotension, adjusting to maintain mean arterial pressure between 65-75 mm Hg.

Perioperative blood loss

The patients are allocated into either the intervention or control group using a non-stratified block randomization method to keep an even randomization ratio of (1:1). Random Allocation Software is used by our expert analytics to determine the list and group of patients. He is blinded to the selection process and pre-and post-operative assessments. The block size will be equal and is set to 4 and then the allocation code is set to sequential.

Patients are kept uninformed about the use of controlled blood pressure during the procedure. To ensure blinding, two researchers conduct the interventions. A an anesthesiologist or resident of anesthesiology, knowledgeable about the necessary interventions for each patient, carries out the procedures while monitoring the patient's condition. Simultaneously, another researcher, unaware of the specific interventions performed on each patient, assesses blood loss and gathers necessary information through patient examinations. Additionally, the coding of the investigated groups in the collected data is implemented to maintain blinding for the statistician.