The Changes of Endotracheal Tube Cuff Pressures After Ear, Head and Neck Surgery-Related Positions: A Prospective Observational Study

Increased or decreased intracuff pressures (ICPs) of cuffed endotracheal tubes (cETTs) can lead to many morbidities. Guidelines recommend that the ICP should be kept between 20 and 30 cmH2O. Over inflation of the cuff can cause tracheal mucosal injury ,tracheal stenosis, tracheoesophageal fistula, postoperative stridor, laryngospasm, laryngeal nerve damage and tracheal rupture. However, under inflation can cause air leakage, aspiration and ventilation associated pneumonia.The cETT can be displaced by movement of the patients' heads and necks while positioning for surgeries of ear, head and neck. These positionings and displacements may be the reasons of changes in ICPs. The investigators performed this study to show the effect of the routine combination of neck positions on ICP whilst ear, head and neck surgeries.

After obtaining ethics committee approval and written informed consent, 90 patients with American Society of Anesthesiologists (ASA) physical status I-III and aged older than 18 years were enrolled to the study. The patients were allocated to 3 groups according to their surgery types. Groups 1 and 2 included the patients who underwent right and left ear surgeries, respectively. Group 3 included all patients undergoing head and neck surgery without considering the surgical site. After the general anesthesia induction, the patients were given a neutral position defined by Komasawa et al. The first ICP was measured and adjusted to 18,4 mm Hg (25 cmH2O) at neutral position just after taping the tube and monitoring the 3 consecutive respiration cycles. After neutral measurements, left or right neck rotation (approximately 60-70 degree to the opposite site) was applied to Group 1 or 2 in conformity with the ear operation site and ICP value was documented following 3 respiration cycles. Gel pillow with the height of 4,5 cm was placed under the shoulders of Group 3 patients to extend the neck. After waiting for 3 respiration cycles, the ICP was noted. Then, right or left neck rotation was applied depending on the operation site (approximately 60-70 degree to the opposite site). Following 3 respiration cycles, ICP was documented again. Additionally, ICP values were monitorized continuously in all patients during the surgeries, and documented at 15th, 30th, 60th and 90th minutes at related positions and just before extubation at neutral position. At any time point, if ICP value fell below 14,7 mmHg (20 cmH2O) or rose above 22 mmHg (30 cmH2O), ICP was adjusted to 18,4 mm Hg (25 cmH2O) again. After all data were collected, statistical analysis were performed by using Statistical Package for the Social Sciences (SPSS) version 22.