Author(s)

M.J. Turner

Abstract

Tracheal tubes used in infants are not cuffed. Some authorities recommend that a slight air leak at an airway pressure of 25-30 cm H^O must be present at all times if subglottic stenosis is to be prevented. If routine pulmonary function tests are to be made in mechanically ventilated infants then methods for performing these measurements in the presence of gas leak between the endotracheal tube and the trachea have to be found. This study used simulation to examine the effects of a leak on estimates of resistance (Re) and compliance (Ce) obtained with the least squares regression technique in mechanically ventilated infants. The ventilator was modelled as a critically damped second order system (10- 90% rise time = 150 ms) whose input was a rectangular wave. The respiratory system was modell

Keywords