This study compared intracuff pressure (ICP) during mechanical ventilation in a variety of currently used endotracheal (ET) and tracheostomy (trach) tube cuffs and related cuff physical characteristics. Tracheostomy tube physical characteristics were also measured. Variation was observed to exist between "just-seal" inspiratory and end-expiratory intracuff pressure during mechanical ventilation. Cuff diameter, thickness, compliance, geometry (shape), resting volume, and just-seal volume also varied. ICP varied with cuff diameter, thickness, compliance, geometry (shape), and trachea size, as well as tube curve and cuff position in the trachea. Thin, large-diameter, compliant cuffs generally "just seal" with relatively low ICPs. We recommend use of tracheal airways (endotracheal and tracheostomy) fitted with cuffs that seal in patients with low intracuff pressures. We also recommend nonrigid (soft) thermolabile tracheostomy tubes.