Aspiration beyond endotracheal cuffs

Abstract

Large-volume low-pressure cuffs have been introduced in an endeavour to reduce the incidence of tracheal mucosal damage. These cuffs when inflated to clinical seal develop folds, which together with low clinical seal pressure may not protect against aspiration. This study compares the incidence of aspiration of dye past a variety of large-volume cuffed tubes and red rubber low-volume cuffs inflated to clinical seal in a group of 30 patients. The incidence of dye tracking past the large-volume cuffs studies was 100 per cent whereas no aspiration of dye was seen past the red rubber tubes. Increasing cuff pressure in the large-volume cuffs beyond clinical seal to 50 cm H2O did not obliterate the dye-filled cuff folds, despite wide variation in the thickness of the cuff material.

The effects of lidocaine spray and intracuff alkalinized lidocaine on the occurrence of cough at extubation: a double-blind randomized controlled trial

“…In addition, we hypothesize that the contact area between the tracheal mucosa and the highvolume/low-pressure cuff is smaller than that between the tracheal mucosa and a low-volume/high-pressure cuff, as used in other studies, thus contributing to the difference in our data vs previous studies. 23 We can also speculate that the duration of surgery in our case was too short to allow for substantial lidocaine diffusion through the ETT cuff, therefore resulting in the absence of clear physiological benefit on the pharyngolaryngeal mucosa using this approach. Indeed, Estebe et al have shown that it took three hours for 25% of alkalinized lidocaine (8.4% sodium bicarbonate) to diffuse through the semi-permeable membrane of a low-volume/high-pressure ETT cuff.…”

The Vexing Problem of Ventilator-Associated Pneumonia: Observations on Pathophysiology, Public Policy, and Clinical Science

“…66 The predominant source of VAP is chronic microaspiration of oropharyngeal secretions pooled above the ETT cuff that occurs in as many as 88 -100% of intubated patients. 67,68 These secretions accumulate in the subglottic space and therefore cannot be effectively removed by suctioning the oral cavity. The volume capacity of this space is ϳ10 mL, and the accumulation of large secretion volumes (100 -150 mL/d) has been reported.…”

“…70,71 As a result, the excess cuff volume forms longitudinal folds (microchannels) into which, depending upon secretion viscosity, infected oropharyngeal or gastric secretions chronically seep and inoculate the lungs, even under conditions of clinically excessive cuff-inflation pressures (50 cm H 2 O). 32,68,72 The human trachea is a dynamic, distensible organ of varying size, shape, and tone altered by drugs, posture, head position, and the mere act of ventilation. 73 It is essentially impossible, despite obtaining a good cuff seal, to fully prevent microaspiration.…”

Ventilator‐associated pneumoniaDiagnosis, pathogenesis and prevention

“…Dye placed in the subglottic space will pass along folds within the cuff wall to the trachea in 87-100% of cases [51][52][53]. In a ventilatory model [54] and in the cadaveric trachea [55], the rate of leakage along the cuff folds was found to be of the order of magnitude of millilitres per minute and leakage occurred despite increasing the cuff pressure above normal (Fig.…”

“…Cuff type HVLP tracheal tube cuffs do not provide the barrier to fluid entering the tracheobronchial tree afforded by lowvolume high-pressure (LVHP) cuffs [53]. Unfortunately LVHP cuffs are associated with tracheal wall injury and are unsuitable for use in long-term ventilation.…”