Do current methods for endotracheal tube cuff inflation create pressures above the recommended range? A review of the evidence

Evaluation of the endotracheal tube cuff pressure changes during cardiac operations under cardiopulmonary bypass

Introduction: Tracheal intubation is used for most operations under general anesthesia. Prolonged hyperinflation of the tube cuff can compromise tracheal mucosal perfusion, and low pressure of the cuff may cause some other complications. The aim of this study was the evaluation of changes in intra-cuff pressure in patients undergoing cardiac surgeries under cardiopulmonary bypass. Methods: In an observational study 120 patient's candidate to cardiac operations under cardiopulmonary bypass were enrolled. After induction of anesthesia and tracheal intubation by same tracheal tubes, tracheal tube cuff pressure was adjusted to 20-25 mm Hg (T0). Then the cuff pressure was measured at beginning of CPB (Cardio Pulmonary Bypass) (T1), at 30º hypothermia (T2) and after separation from CPB (T3). Results: The mean cuff pressure was 33.5±7.3, 28.9±5.4, 25.6±5.2 and 28.1±3.7 at T0, T1, T2 and T3 respectively. Intra- cuff pressure changed significantly during cardiopulmonary bypass. Conclusion: The mean intra-cuff pressure was decreased during hypothermic cardiopulmonary bypass. The decrease in cuff pressure may protect the tracheal mucosa against hypotensive ischemic injury in these patients.

Difficulty with cuff deflation of reinforced tracheal tube caused by inflation line occlusion with silk thread ligation and fixation

A reinforced tracheal tube, ligated with silk threads, was inserted into a tracheostomy orifice and fixed to the skin. The cuff inflation line of the reinforced tracheal tube became occluded. Reinforced 'armoured' tracheal tubes have a spiral of wire embedded into the wall of the tube to give strength and flexibility, and may be sharply bent without compromising the tube lumen. The tracheal cuff attached to the tube is inflated by injecting air through a narrow-diameter tube welded to the outside of the tracheal tube. When a reinforced tracheal tube is ligated and fixed with silk threads, it should be confirmed whether the tracheal tube cuff can be deflated and inflated after fixation. Moreover, because occlusion can be eliminated by removing all silk threads used to ligate a tracheal tube, they should be removed before extubation.