Evaluation of Respiratory Mechanics and Endotracheal Tube Dynamics during Prone Positioning under General Anaesthesia: A Prospective Observational Study

Introduction: Prone positioning is essential for various surgical procedures, including spinal surgeries, posterior cranial fossa procedures and urological interventions, as it provides optimal access to posterior anatomical structures. However, this positioning significantly alters respiratory mechanics and cardiovascular physiology, potentially affecting patient safety during general anaesthesia. Peak Airway Pressure (PAP) and Endotracheal Tube (ETT) cuff pressure are critical parameters that require careful monitoring during prone positioning to prevent complications such as barotrauma and tracheal injury. Aim: To evaluate simultaneous changes in PAP and ETT cuff pressure during prone positioning under general anaesthesia and to assess associated haemodynamic alterations. Materials and Methods: This prospective observational study was conducted at Department of Anaesthesiology and Critical Care, Adesh Institute of Medical Sciences and Research, Adesh University, Bathinda, Punjab, India. The study enrolled 105 consecutive American Society of Anaesthesiologists (ASA) I-II patients scheduled for elective procedures requiring prone positioning. Standardised protocols were used to document PAP, ETT cuff pressure and haemodynamic variables at multiple time points: baseline in the supine position, immediately after prone positioning and at 15-minute intervals throughout the procedure. Statistical analysis employed paired comparisons, with a significance threshold of p-value <0.05. Results: A total of 105 patients completed the study (mean age 45.36±10.26 years; 62.9% female; mean Body Mass Index (BMI) 21.41±2.56 kg/m²). Transitioning from supine to prone position produced significant respiratory mechanical alterations. Baseline supine PAP (19.03±3.35 cm H2 O) progressively increased to a maximum of 34.36±2.59 cm H2 O during prone maintenance (p-value <0.001), representing an 80.6% elevation. Similarly, ETT cuff pressure increased from baseline (24.64±2.99 cm H2 O) to 43.65±4.49 cm H2 O at maximum prone measurement (p-value <0.001). Cardiovascular parameters demonstrated significant alterations during the initial 15 minutes post-positioning before stabilising during the maintenance phase. Conclusion: In patients under general anaesthesia, the prone position significantly increases PAP and ETT cuff pressure. This finding underscores the importance of regular monitoring and timely interventions to limit the risks associated with elevated pressures.