Effect of endotracheal tube cuff shape on postoperative sore throat in surgeries lasting more than 120 minutes in supine position

Introduction: One of the most important responsibilities of the anesthetist is to ensure airway safety and continuity in patients undergoing general anesthesia. Endotracheal intubation is one of the methods used to ensure airway safety. It allows positive pressure ventilation by preventing the leakage of fluid and gas between the cuff part of endotracheal intubation tube and the trachea wall. In addition, the aspiration of the stomach contents into the airway and the environmental pollution caused by the release of the used medical gases to the external environment are prevented. Postoperative complications such as sore throat, hoarseness, difficulty in swallowing, cough, and dry throat may be experienced in patients after intubation. The incidence of postoperative sore throat due to tracheal intubation is reported to be 21%-65%. Postoperative sore throat negatively affects patient comfort and may cause an unpleasant anesthesia experience. It is extremely important to maintain the endotracheal tube (ETT) cuff pressure between 20-30 cm H2O to prevent cuff-related complications in an intubated patient. Aim: It is known that cuff diameter and cuff-trachea contact area are smaller in a tapered shaped endotracheal tube cuff compared to the traditional cylindrical shaped ETT used in endotracheal intubation. In this study, we aimed to compare the effects of cylindrical and tapered endotracheal tubes inflated with saline on cuff pressures, postoperative sore throat, nausea-vomiting and postoperative analgesic consumption in surgeries lasting longer than 120 minutes. Materials and Methods: The study performed on 100 patients in ASA I, II,III risk groups, aged 18-65, with an expected operation time of more than 120 minutes, who underwent ürology, obstetrics and gynecology and aesthetic, plastic and reconstructive surgery in the supine position in the operating room of our hospital, who were informed about the study and gave their written and verbal consents. Patients included in the study were divided into two groups as patients whose cylindrical cuff was inflated with saline (Group S, n=50) and patients whose tapered cuff was inflated with saline (Group K, n=50) to 25 cm H2O with the help of a "cuff manometer" after endotracheal intubation. In the intraoperative period, heart rate, oxygen saturation, MAP, BIS, intracuff pressure values, maximum cuff pressure values, EtCO2, inspired oxygen values and airway pressure values of all patients were recorded during basal, intubation and 20- minute intervals after intubation and just before extubation. Results: When the cuff pressure changes of the groups were examined, all cuff pressure values and the highest cuff pressure values in the follow-up periods were significantly higher in Group S compared to Group K (p<0.05). The postoperative sore throat of the groups was evaluated using NRS and it was statistically significantly lower in Group K compared to Group S (p<0.05). The postoperative 24-hour total analgesic consumption of the groups and the total tramadol consumption of the patients in Group K were statistically significantly lower than those in Group S (p<0.05). In addition, the incidence of nausea was significantly higher in Group S than in Group K during first 2 hours after surgery (p<0.05). Conclusion: We concluded that the use of ETTs with a tapered cuff in longterm surgeries in the supine position prevents the increase in intraoperative cuff pressures, reduces the incidence of postoperative sore throat, and reduces the consumption of analgesics in the postoperative period and nausea in the early period, compared to ETTs with cylindrical cuff. Keywords: Endotracheal intubation tube with tapered cuff, Endotracheal intubation tube with cylindrical cuff, Postoperative sore throat, Cuff pressure