Evaluation of Intravenous Lidocaine on Propofol EC50 During Target-Controlled Infusion for Gastroscopy in Adults: A Randomized, Double-Blind Study

The primary objective of this study is to evaluate the impact of an intravenous **Lidocaine** bolus (1.5 mg/kg ideal body weight) on the estimated median effective concentration (EC50) of **Propofol** used during intravenous target concentration anesthesia (AIVOC: Schnider model) for gastroscopy. This is clinically relevant as it may optimize the dosing of Propofol, potentially enhancing the safety and efficacy of sedation during gastroscopy procedures.

Secondary objectives include assessing the potential reduction in Propofol side effects such as arterial hypotension, desaturation, apnea, and bradycardia. Additionally, the study aims to evaluate the lower incidence of pain on Propofol injection, reduced coughing on gastroscope insertion, faster post-procedure recovery, decreased incidence of throat pain, shorter time in the post-anesthesia care unit, and at least equivalent patient and gastroenterologist satisfaction with the endoscopic procedure.

The clinical trial involves **participants** aged between 18 and 65 years, encompassing both **male** and **female** subjects. The study population is characterized by individuals who are scheduled to undergo **gastroscopy** under narcosis at the ERASME hospital. Participants are required to have an ASA score of I or II, indicating a generally healthy status with mild systemic disease, and a body mass index (BMI) ranging from 18 to 30 kg/m². All participants must be French speakers and have provided signed written informed consent. The trial does not include a vulnerable population. The sponsor has not provided information regarding the total number of participants. The selection criteria ensure a homogenous group in terms of health status and language proficiency, which is crucial for the study's objectives.

The clinical trial is designed to evaluate the impact of an **intravenous** lidocaine bolus on the median effective concentration (EC50) of **propofol** during target-controlled infusion for gastroscopy in adult patients. This study is a prospective, randomized, double-blind trial, ensuring that neither the participants nor the investigators are aware of the treatment allocations, thus minimizing bias. The trial is categorized as a low-intervention study, as both lidocaine and propofol are routinely used in clinical practice with established safety profiles. The trial is expected to commence on January 1, 2024, and conclude by August 31, 2024.

Participants will undergo a series of study visits, beginning with an inclusion visit where eligibility criteria are assessed. These criteria include age between 18-65 years, an ASA score of I or II, a body mass index between 18 and 30 kg/m², and proficiency in French. Informed consent must be obtained prior to participation. The primary endpoint is the estimated EC50 of propofol for gastroscope introduction without movements. Secondary endpoints include the incidence of moderate hypoxemia, hypotension, and other sedation-related events, as well as satisfaction scores from both the endoscopist and the patient.

The trial involves a single treatment period, with the administration of lidocaine and propofol occurring during the gastroscopy procedure. The maximum treatment period is one day, with the total duration of participant involvement expected to be approximately one hour post-procedure for recovery and assessment. Conditions that may lead to early termination from the study include adverse reactions to the medications or failure to meet ongoing eligibility criteria. The study aims to provide valuable insights into the optimization of sedation protocols for gastroscopy, enhancing both patient safety and procedural efficacy.

The clinical trial involves the administration of **NaCl 0.9% B. Braun**, a **solution for injection** containing the active substance **sodium chloride**. This product is manufactured by B. Braun Melsungen AG and is authorized for use in Belgium. The pharmaceutical form is a solution for injection, and it is administered via **intravenous use**. The maximum daily dose is 10 ml, with a total dose not exceeding 10 ml over the treatment period, which is limited to one day. This product serves as a **physiologic serum** in the study.

**Propofol B. Braun 1% (10 mg/ml)** is utilized as a **hypnotic agent** in the trial. It is an **emulsion for injection/infusion** containing the active substance **propofol**. Also produced by B. Braun Melsungen AG, this product is administered through **intravenous bolus injection or IV infusion**. The maximum daily and total dose is 12 mg/kg/h, with the treatment period restricted to one day. This product is used to evaluate the impact of an intravenous **lidocaine** bolus on the median effective concentration (EC50) of propofol during target-controlled infusion for gastroscopy.

The trial also includes **Linisol 2%**, a **solution for injection** containing **lidocaine hydrochloride monohydrate** as the active substance. Manufactured by B. Braun Melsungen AG, this product is administered via **intravenous bolus use**. The maximum daily dose is 1.5 mg, with a total dose not exceeding 400 mg over the treatment period, which is limited to one day. Linisol 2% functions as a **local anaesthetic** in the study, and its primary objective is to assess its effect on the EC50 of propofol during anesthesia for gastroscopy.

The efficacy of the clinical trial will be assessed by evaluating the impact of an intravenous **Lidocaine** bolus on the estimated median effective concentration (EC50) of **Propofol** during intravenous target concentration anesthesia for gastroscopy. The primary endpoint is the estimated EC50 of Propofol required for gastroscope introduction without patient movements. Secondary endpoints include the number of participants experiencing moderate hypoxemia, hypotension, cough, laryngospasm, involuntary movements, and side effects of Lidocaine administration such as metallic taste, tinnitus, and anaphylaxis. Additionally, the trial will assess endoscopist and patient satisfaction scores, throat pain using an analog digital scale, time to anesthesia recovery, and time for post-anesthetic care unit discharge.

Data collection will occur at specific timepoints, including during the procedure and at recovery room discharge, approximately one hour post-procedure. The efficacy parameters will be measured using validated scales and clinical observations. The analysis will focus on comparing the outcomes between the intervention and control groups to determine the effect of Lidocaine on Propofol's EC50 and the overall safety and satisfaction associated with the procedure.