Tehran University Medical Journal

Background: Endotracheal tube cuff pressure must be maintained in safe range. Many factors could be affecting on endotracheal tube cuff pressure in patients on mechanical ventilation. Patients undergoing mechanical ventilation (MV) in critical care settings require changing position for different reasons. The aim of this study was to determine the effect of changes in body position and head of bed on the endotracheal tube cuff pressure in patients with mechanical ventilation.
Methods: This quasi-experimental study (pre-post design) was performed from April to October 2016 on 70 patients with positive pressure mechanical ventilation in critical care settings in two university hospitals in the cities of Semnan and Shahroud, Semnan Province, Iran. At first, the endotracheal tube cuff pressure of patients was regulated on 25 cmH₂O in the bed position of 30 degree. Then the patients were randomly positioned on zero degree bed position, 45 degree bed position, lateral position of patients toward mechanical ventilation apparatus and lateral position opposite the MV apparatus. In each position cuff pressure was measured after 5 minutes pause and head and neck of the patients was not flexed or extended. Tube cuff pressure was measured and recorded in the end expiratory with aneroid manometer after each position change. Data analysis was performed with software of SPSS software, version 18 (Armonk, NY, USA) in the significant level of 0.05.
Results: Most of study patients (58.6%) were male and no smokers (81.4%). Age mean of patients were 63.37±20.9 years. Most of patients connected to MV because of respiratory failure. In each change positions and head of bed regulation, the mean of endotracheal tube cuff pressures were significantly increased (P<0.001). Endotracheal tube cuff pressure in the lateral position opposite to the apparatus had maximum increase (29.12±0.41 cmH₂O) and in the zero degree bed position tube cuff pressure had minimum increase (27.6±0.38 cmH₂O).
Conclusion: Findings of this study showed that changing position of bed and patients undergoing mechanical ventilation, especially in lateral position opposite to the apparatus could increase endotracheal tube cuff pressure. This increase may reach to abnormal range and cause tracheal injury.

Background: The Southern endotracheal tube facilitates surgical access and reduces the risk of tube torsion. Fiberoptic laryngoscopy also improves the accuracy and safety of intubation. Accordingly, the present study aimed to determine the precise placement of the Southern endotracheal tube using fiberoptic laryngoscopy in elective surgeries under general anesthesia.
Methods: This descriptive-analytical prospective study was conducted between April 2025 and July 2025 at Al-Zahra and Ayatollah Kashani Centers of Isfahan University of Medical Sciences. Sampling was performed using a convenience method, and the sample size was estimated at 100 patients (candidates for elective head, face, and nasal surgeries), considering possible dropouts. Data were collected using a checklist and analyzed with SPSS version 27.
Results: In this study, the demographic and clinical characteristics of the patients showed that the mean age was 38.88±15.92 years, and 53% were male, and 47% were female. The results indicated that body mass index, neck circumference, and the distance from the tip of the endotracheal tube to the anterior teeth differed significantly between male and female patients (P<0.05). Specifically, Body Mass Index (BMI) was significantly higher in females, neck circumference was significantly greater in males, and the distance from the tube tip to the anterior teeth was longer in males. Additionally, BMI, the distance from the carina to the anterior teeth, and the distance from the endotracheal tube to the carina showed significant differences among different age groups (P<0.05).
Conclusion: The present study demonstrated that the depth and placement of the endotracheal tube are influenced by factors such as BMI. These findings are consistent with previous studies emphasizing the importance of individual assessment to optimize airway management. Overall, fiberoptic-guided intubation should be considered the gold standard for achieving accurate tube positioning, minimizing the risk of airway complications, and improving intraoperative safety. It is suggested that future studies focus on developing predictive models for optimal tube depth based on demographic and anatomical variables, and on evaluating the impact of these strategies on postoperative outcomes.