Comparison of endotracheal tube cuff pressures inflated with saline and air in the head down position in laparoscopic surgery

Introduction: Endotracheal intubation (ETI) is a commonly used method in anesthesia practice to maintain airway safely. Tracheal capillary perfusion may be impaired by increased pressure of the endotracheal tube (ETT), which is used to prevent aspiration of gastric contents into the lung during anesthesia. Impairments in the tracheal capillary perfusion may cause several postoperative complications; including sore throat, hoarseness, edema, ischemia, tracheal ulceration, necrosis, tracheal ruptures, tracheoesophageal fistula, and stenosis. Laparoscopic surgery has gained widespread use in recent years owing to its many advantages over open surgical methods; such as it allows for performing minimally invasive surgery, causes less pain in the postoperative period, and enables a faster recovery. Increased intrathoracic pressure and changes in pulmonary compliance developing in laparoscopic surgery due to the insufflation of the abdominal cavity with carbon dioxide (CO2) and bringing the patient to Trendelenburg position, respectively, may increase ETT cuff pressure, giving rise to complications. Aim: In our study, we aimed to investigate the impact of air- and saline-inflated ETT cuffs, comparing them whether they would cause potential increases in the cuff pressure and lead to postoperative complications in gynecological laparoscopic operations while the patient was in Trendelenburg position. Materials and Methods: This prospective study was carried on a total of 60 patients; who were in the age range from 18 to 65 years old, who had ASA scores of I-II-III, and who were scheduled to undergo gynecological laparoscopic surgery in Trendelenburg position with an estimated operation duration of 60-180 minutes. Patients included in the study were randomly divided into two groups as the saline-cuffed (Group S, n = 30) and air-cuffed (Group H, n = 30) groups, inflating their ETT cuffs to a pressure of 25 cmH ₂O by using a cuff manometer after ETI. Anesthesia was maintained in all patients with a 50% / 50% mixture of O2 and air mixed with 2-3% sevoflurane gas. Remifentanil infusion was administered to the patients intraoperatively for analgesia. The following parameters; including the heart rate, oxygen saturation, mean arterial pressure, BIS values, ETT cuff pressures, the highest cuff pressure values in Trendelenburg and supine positions, time to reach the highest cuff pressure, end-tidal carbon dioxide (EtCO₂), inhaled oxygen values, internal positive end-expiratory pressure (iPEEP), and peak airway pressure values were obtained from all patients and recorded before the anesthesia induction, after the intubation, at 10-minute intervals after the induction, and just before extubation. Results: The cuff pressures were significantly higher in the air-cuffed group at the 10th, 20th, 30th, 40th, and 50th minutes compared to the saline-cuffed group (p <0.05). The maximum cuff pressure in the supine and Trendelenburg positions were statistically significantly high in the air-cuffed group (p=0.04 and p<0.001, respectively). The airway pressures were statistically significantly higher in the saline group compared to the air group immediately after the intubation and at the 10th minute (p<0.001 and p0.001, respectively). The sore throat was evaluated with the Numeric Rating Scale (NRS), revealing significantly high scores during swallowing and not swallowing in the second and 24th postoperative hours in the air-cuffed group (p<0.05). Analgesic consumption was significantly higher in Group H than Group S in the 24 hours after surgery (p<0.05). Conclusion: It was concluded that the intraoperative ETT cuff pressures were significantly lower in the saline-cuffed group compared to the air-cuffed group, reducing postoperative sore throat and analgesic consumption in the gynecological laparoscopic operations with the patient was in Trendelenburg position. Key Words: Laparoscopic surgery, Trendelenburg position, sore throat, cuff pressure.