“…Less reliable is to listen carefully to the change of the noise emitting from the glottis during respiration [I]. If only intratracheal pressure is monitored [2], or if HFJV is used, an automatic cut-off of the jet at a safe pressure should be incorporated into the ventilator [3], because the time from total closure of the glottis to dangerously high pressure is too short for the anaesthetist to react. If monitoring of airway pressure is impossible, 'a safe overdose of muscle relaxant' should be used [4].…”