SummaryCuffed tracheal tubes are becoming increasingly popular in paediatric anaesthesia and intensive care medicine. To avoid cuff related complications and airway morbidity, a thorough understanding of cuff volume ⁄ pressure behaviour and management is required. In this study, the outer cuff diameter and form stability of the cuff at high cuff pressure were assessed in a series of different paediatric cuffed tracheal tubes with internal diameter of between 3.0 and 5.0 mm. The main findings were that small amounts of inflated air led to a rapid increase in cuff pressure and volume and that the outer cuff diameters increased to 2-2.5 times the age-corresponding internal tracheal diameter following inadvertent syringe inflation. Careful cuff inflation under cuff pressure monitoring and ⁄ or automatic cuff pressure release is recommended in paediatric tracheal tube cuffs to prevent airway damage caused by manual inflation, pilot balloon compression and nitrous oxide diffusion. The use of cuffed tracheal tubes in small children is becoming increasingly popular in paediatric anaesthesia and intensive care medicine [1][2][3][4][5]. However, overinflation of tracheal tube cuffs is a known risk factor in producing airway morbidity and complications due to cuff pressure and volume increases, asymmetric cuff expansion, and possible herniation of the distal cuff producing airway obstruction [6][7][8]. Severe airway damage may occur especially if the cuff is inadvertently placed within the paediatric larynx [9,10].A wide variety of cuff sizes, differences in compliance, and a variety of materials are used to construct cuff membranes in paediatric tracheal tubes [11][12][13][14]. So far, expansion characteristics of different cuffs at higher cuff pressure levels have not been investigated. The aim of this study was to evaluate changes in outer cuff diameter, stability of cuffs and the risk of cuff herniation in currently available paediatric tracheal tube cuffs at higher cuff pressures.
MethodsIn an in vitro study, eight types of currently available paediatric cuffed tracheal tubes with internal diameters (ID) of 3.0 mm and 5.0 mm from five different manufacturers (Table 1) were studied.Assessment of outer cuff diameters was performed using a sliding calliper. The pilot balloons of the tested tube cuffs were connected to a cuff pressure manometer (Cuff pressure controller; Mallinckrodt, Athlone, Ireland) using a three-way tap.Cuff pressure was set to 20 cmH 2 O and was increased in steps of 10 cmH 2 0 up to a maximum of 120 cmH 2 O by inflating with air from a syringe connected via the three-way tap. At each level, the largest outer cuff diameter was measured. In addition, measurements were made after simulating inadvertent cuff hyperinflation by means of an air-filled 5-ml and 10-ml syringe in ID 3.0 mm, and ID 5.0 mm tracheal tubes, respectively.The volume of air required to achieve a cuff pressure of 20, 60 and 120 cmH 2 O was assessed. Experiments were performed using the cuff manometer-syringe assembly described above ...
