Comparison of the Efficacy of Non-channelled Video Laryngoscopy Versus Direct Laryngoscopy in Terms of Stress Response and Intubation Time: a Single-blinded Randomized Controlled Trial

The research will be conducted as a single-blind study involving patients undergoing elective surgical processes that necessitate endotracheal intubation. Informed consent will be obtained from all patients. Participants will be randomly assigned through a computer-generated sequence number to either the DL (direct laryngoscopy) group or the VL (video laryngoscopy) group. Monitoring will include vital signs and measurements such as non-invasive blood pressure (NIBP), electrocardiography (ECG), and pulse oximetry (SpO2). Prior to the induction of anesthesia, each patient will undergo assessments including oxygen saturation, blood pressure, echocardiography, systolic, diastolic, and mean blood pressure, heart rate, and oxygen saturation. In addition to the stated observations, the same assessments will be done after one minute of induction, after three minutes of bag-mask ventilation, and one, three, and five minutes after intubation. The time taken to perform endotracheal intubation will also be noted for both direct laryngoscopy and video laryngoscopy. All subjects will be premedicated with Inj. midazolam 0.03 mg/kg. For all patients, the same general anesthesia protocol will be applied, with patients preoxygenated with 100% oxygen for three minutes prior to induction, which will be done with Inj. Nalbuphine 0.15 mg/kg and Inj. propofol 2 mg/kg I.V. After evaluating bag-mask ventilation, Inj. Atracurium at 0.6 mg/kg I.V. will be administered, and isoflurane at 1.2% (1 MAC) will be initiated. After three minutes of bag-mask ventilation, intubation will be performed using either direct laryngoscopy or a non-channelled video laryngoscope, and the time taken for laryngoscopy and intubation will be recorded. Based on the groups, one of the two methods will be utilized to insert the appropriate endotracheal tube. In Group A, endotracheal intubation will be conducted using an indirect non-channelled VL. In Group B, endotracheal intubation will be performed using DL. The placement of the tube will be verified through capnography and chest auscultation before it is secured in position.

Group A The intubation process will utilize the Besdata (BD-M7) Portable VL, which is an indirect laryngoscope without a channel. The investigator will use a curved rigid stylet that is pre-shaped to match the laryngoscope blade, allowing for intubation with either a size 3 or 4 blade. In this research, the time taken for intubation will be recorded using an external timer. This involves measuring the interval from when the blade is inserted into the patient's mouth to the detection of the first capnography wave, while simultaneously using the timer to monitor vital parameters.

Group B Endotracheal tube (ETT) insertion via DL with a blade size of either 3 or 4 in the patients; the same external timer will be used as for group A.

Laryngoscopy in both groups will be conducted by an anesthetist with a minimum of five years of experience in anesthesia practice, ensuring the provision of high-quality care across both groups.

Data Analysis: The data collected will be analyzed via the SPSS software package v.26.0. Numerical variables will be presented as means (standard deviations) for normally distributed variables and as medians (IQRs) for non-normally distributed variables. For categorical variables (as frequencies), and group comparisons between numerical and categorical variables will be performed via the unpaired t-tests and the chi-square tests, respectively.