The effect of endotracheal administration of ketamine on sore throat after spinal surgery in patients under general anesthesia with endotracheal intubation: A randomized clinical trial

To evaluate the effect of endotracheal administration of ketamine on the incidence and severity of postoperative sore throat in patients undergoing elective spinal surgery under general anesthesia.

This is a double-blind, randomized, placebo-controlled, superiority trial with parallel group assignment. Thirty-four patients undergoing elective spinal surgery under general anesthesia with endotracheal intubation will be randomly allocated to ketamine or normal saline groups using a computer-generated list. Participants, care providers, and outcome assessors will be blinded to group allocation. The study will be conducted at a single center over 18 months.

This single-center study will be conducted at Shahid Beheshti and Rohani Hospitals, affiliated with Babol University of Medical Sciences. After obtaining ethical approval and written informed consent, eligible patients will be randomly assigned to one of two groups. The intervention will be administered preoperatively in the operating room, and data will be collected postoperatively by blinded assessors using a standardized questionnaire.

Adult patients aged 20 to 60 years, classified as ASA I or II, undergoing elective spinal surgery under general anesthesia with endotracheal intubation will be included. Patients with a history of sore throat, asthma, COPD, recent NSAID use, smoking, or those requiring difficult intubation will be excluded.

Intervention group: Patients receive 2 mL of ketamine (5 mg/mL) administered directly into the endotracheal tube before intubation. Control group: Patients receive 2 mL of normal saline administered in the same manner before intubation.

1-Incidence of sore throat after extubation 2-Severity of sore throat based on a 4-point scale 3-Time of onset of sore throat in hours after extubation

Patients who meet the inclusion criteria will be randomly assigned to two groups (ketamine or normal saline) in a 1:1 ratio using a computer-generated random number table. Each patient will receive a study drug according to a pre-coded syringe labeled with a 3-digit code, prepared in advance. The sequence of group allocation will be determined before the start of the study and followed throughout enrollment.

This study is designed as a double-blind randomized clinical trial. The patients, care providers, and outcome assessors are blinded to the group allocation. The study drugs (ketamine or normal saline) are prepared in identical syringes labeled with a unique 3-digit code. An anesthesia technician not involved in patient evaluation administers the drug according to the randomization list. Neither the patient nor the evaluating anesthesiology resident knows which drug has been administered. The codes will be revealed only after data collection is completed for all participants.