[Accidentally opened adjustable pressure-limiting valve. Failure of manual ventilation].

In the case presented successful induction of anaesthesia was followed by failure to ventilate a patient during anaesthesia caused by a leakage in the anaesthesia circuit system during manual ventilation. The leakage problem could not be solved after checking the classical leakage sites (blocked tube, filter and tubes) and was due to a gas sensing line that caused a malfunction of the adjustable pressure-limiting valve.