Irrigation Fluid Volume, Tube Cuff Pressure, and Neck Swelling During Shoulder Arthroscopy

Shoulder arthroscopy requires pressurized irrigation to expand the glenohumeral joint and subacromial space and maintain adequate surgical visualization. A portion of the irrigation fluid may pass into the periarticular tissues and extend along anatomical planes toward the shoulder girdle, supraclavicular region, chest wall, and neck. This fluid movement may cause cervical soft tissue edema and potentially affect endotracheal tube cuff pressure. However, prospective data combining standardized serial cuff pressure measurements with ultrasonographic assessment of anterior neck soft tissue thickness are limited.

This single-center, prospective observational cohort study will include approximately 60 adults undergoing elective shoulder arthroscopy in the beach-chair position under general anesthesia with orotracheal intubation. Participation in the study will not alter the surgical indication, anesthesia management, irrigation pump settings, or other clinical treatment. All clinical decisions will remain at the discretion of the responsible anesthesia and surgical teams.

After tracheal intubation, endotracheal tube cuff pressure will be measured with a calibrated manometer and adjusted to 25 cmH2O. Following placement in the beach-chair position, cuff pressure will be measured again after five minutes and readjusted to 25 cmH2O, which will serve as the standardized baseline. During surgery, cuff pressure will be recorded at 15, 30, 45, and 60 minutes after the start of irrigation and every 30 minutes thereafter while surgery continues. A final measurement will be obtained at the end of surgery while the participant remains in the beach-chair position. After each measurement, cuff pressure will be readjusted to 25 cmH2O to avoid prolonged exposure to elevated pressure. An additional measurement will be obtained five minutes after the participant is returned to the supine position.

The total volume of irrigation fluid, irrigation pump pressure, surgical duration, anesthesia duration, surgical procedure, intravenous crystalloid volume, estimated blood loss, and relevant airway and anesthesia variables will be recorded. The maximum increase in cuff pressure will be calculated as the highest measured intraoperative cuff pressure minus the standardized baseline pressure of 25 cmH2O.

Anterior neck soft tissue thickness will be measured before anesthesia and again before extubation with a high-frequency linear ultrasound probe. Measurements will be obtained at the level of the cricoid cartilage, from the skin to the anterior tracheal air-mucosa interface. Three measurements will be taken at each assessment, and their average will be used. Neck circumference will be measured at the same anatomical level before and after surgery.

Postoperative sore throat will be assessed using a 0-to-10 numerical rating scale, and hoarseness will be graded as absent, mild, moderate, or severe. Dysphagia, stridor, delayed extubation, and other airway-related events will also be recorded in the post-anesthesia care unit and at the postoperative sixth hour.

• Elective Shoulder Arthroscopy (Procedure): Participants will undergo elective shoulder arthroscopy in the beach-chair position under general anesthesia with orotracheal intubation as part of routine clinical care. The study will not assign or modify the surgical indication, arthroscopic procedure, patient positioning, irrigation fluid, irrigation pump settings, or anesthesia management. Researchers will observe and record the total irrigation fluid volume and will perform serial endotracheal tube cuff pressure measurements and preoperative and postoperative assessments of anterior neck soft tissue thickness and neck circumference.

Primary outcomes

• Maximum Increase in Endotracheal Tube Cuff Pressure (ΔPmax) [From 5 minutes after beach-chair positioning until completion of surgery, approximately 1 to 3 hours]: After the participant is placed in the beach-chair position, endotracheal tube cuff pressure will be adjusted to a standardized baseline of 25 cmH2O. Cuff pressure will then be measured immediately before readjustment at 15, 30, 45, and 60 minutes after the start of irrigation, every 30 minutes thereafter, and at the end of surgery. ΔPmax, expressed in cmH2O, will be calculated as the highest cuff pressure recorded during surgery minus the standardized baseline pressure of 25 cmH2O. Higher values indicate a greater increase in cuff pressure. The association between ΔPmax and total irrigation fluid volume, recorded in liters, will be evaluated.

Secondary outcomes

• Maximum Endotracheal Tube Cuff Pressure [From 5 minutes after beach-chair positioning until completion of surgery, approximately 1 to 3 hours]: The highest endotracheal tube cuff pressure recorded in each participant at any prespecified intraoperative measurement time point before the pressure is readjusted to 25 cmH2O. The outcome will be reported in cmH2O. Higher values indicate greater maximum cuff pressure.
• Occurrence of Endotracheal Tube Cuff Pressure Above 30 cmH2O [From 5 minutes after beach-chair positioning until completion of surgery, approximately 1 to 3 hours]: The occurrence of at least one endotracheal tube cuff pressure measurement greater than 30 cmH2O before pressure readjustment at any prespecified intraoperative time point. The outcome will be reported as the number and percentage of participants with at least one measurement above 30 cmH2O.
• Change in Anterior Neck Soft Tissue Thickness [From the preoperative assessment before anesthesia induction to the postoperative assessment before extubation, approximately 1 to 3 hours]: Anterior neck soft tissue thickness will be measured by ultrasonography at the level of the cricoid cartilage, from the skin to the anterior tracheal air-mucosa interface. Three measurements will be obtained before anesthesia and after surgery before extubation, and the average will be calculated for each assessment. Change will be calculated as the postoperative average minus the preoperative average and reported in millimeters. Positive values indicate increased tissue thickness. Its association with total irrigation fluid volume will also be evaluated.
• Change in Neck Circumference [From the preoperative assessment before anesthesia induction to the postoperative assessment before extubation, approximately 1 to 3 hours]: Neck circumference will be measured with a non-stretchable measuring tape at the marked cricoid cartilage level before anesthesia and after surgery before extubation. Change will be calculated as the postoperative measurement minus the preoperative measurement and reported in centimeters. Positive values indicate an increase in neck circumference.
• Association Between Surgical Duration and Maximum Cuff Pressure Increase [During surgery, approximately 1 to 3 hours]: Surgical duration will be recorded in minutes, and the maximum increase in endotracheal tube cuff pressure will be calculated as the highest intraoperative cuff pressure minus the standardized baseline of 25 cmH2O. The association between surgical duration and maximum cuff pressure increase will be evaluated using a Pearson or Spearman correlation coefficient, depending on data distribution.
• Postoperative Sore Throat Intensity [At post-anesthesia care unit admission and 6 hours after surgery]: Sore throat intensity will be assessed using an 11-point numerical rating scale ranging from 0 to 10, where 0 indicates no sore throat and 10 indicates the worst possible sore throat. Assessments will be performed at admission to the post-anesthesia care unit and at the postoperative sixth hour. The association between sore throat scores and maximum cuff pressure increase will also be evaluated.
• Postoperative Hoarseness Severity [At post-anesthesia care unit admission and 6 hours after surgery]: Hoarseness will be assessed and categorized as absent, mild, moderate, or severe at admission to the post-anesthesia care unit and at the postoperative sixth hour. The number and percentage of participants in each category will be reported. The association between hoarseness severity and maximum cuff pressure increase will also be evaluated.

Sex: All, ages: 18 Years to 75 Years

Inclusion Criteria:

* Age 18 to 75 years
* American Society of Anesthesiologists physical status I-III
* Scheduled for elective shoulder arthroscopy in the beach-chair position under general anesthesia with orotracheal intubation
* Able to read and understand Turkish and provide written informed consent

Exclusion Criteria:

* Emergency surgery
* Pregnancy
* Preoperative hoarseness, sore throat, or dysphagia
* Upper respiratory tract infection within the previous 2 weeks
* Tracheostomy, known laryngeal or tracheal disease, or previous major neck surgery or radiotherapy
* Anticipated difficult airway, defined as Mallampati class III-IV or difficult airway predicted by the attending anesthesiologist
* More than two tracheal intubation attempts or traumatic intubation
* Surgery performed in the lateral decubitus position
* Intraoperative use of nitrous oxide
* Inability to obtain reliable ultrasonographic measurements