Effects of spiral deflation and warming on cuff diameter, insertion force, extubation, and sealing performance in polyvinyl chloride-cuffed tracheal tubes.

Cuffed tracheal tubes are widely used in paediatric airway management, but passage through the relatively narrow subglottic airway may increase insertion resistance and risk mucosal trauma. This study evaluated whether spiral deflation (i.e. folding the cuff inward like an umbrella) and warming the tube could reduce cuff diameter and insertion force in a simulated trachea. Four commercially available polyvinyl chloride-cuffed tubes with an internal diameter of 5.0 mm (PORTEX® (Smiths Medical International Ltd, Ashford, UK), Sheridan® (Teleflex Inc., Morrisville, NC, USA), Shiley™ (Medtronic, Minneapolis, MN, USA), and VentiSeal™ (Flexicare Medical Ltd, Mountain Ash, UK)) were examined. Spiral deflation significantly reduced cuff diameter, with reductions of (mean difference, MD) -3.6 mm (95% confidence intervals, CI -4.5 to -2.7, P <0.001), -2.8 mm (-4.0 to -1.6, P <0.001), -3.5 mm (-5.0 to -2.1, P=0.001), and -4.9 mm (-6.0 to -3.9, P <0.001), respectively. Spiral deflation also decreased insertion force, with reductions of (MD (CI)) -1.01 N (-1.52 to -0.50, P=0.008), -0.34 N (-0.63 to -0.05, P=0.115), -0.49 N (-0.61 to -0.37, P <0.001), and -2.33 N (-3.83 to -0.84, P=0.028), respectively. Additional warming at 40°C further lowered insertion force, with reductions of (MD (CI)) -0.12 N (-0.19 to -0.05, P=0.020), -0.06 N (-0.08 to -0.03, P=0.002), -0.07 N (-0.11 to -0.03, P=0.010), and -0.48 N (-0.86 to -0.11, P=0.068), respectively. Spiral deflation with warming did not affect extubation force or sealing performance. Overall, spiral deflation effectively reduced cuff diameter by approximately 25% and lowered insertion force, while warming further enhanced ease of insertion. These approaches did not compromise sealing or extubation performance.