The investigator wants to investigate if there is an increased risk of postoperative pulmonary problems in patients who have had an intubation where there was need for more than a laryngoscope.

A difficult intubation is defined as an intubation in which more than a laryngoscope was needed.

Afterwards patient data retrieved from the Clinical Work Station: age, type of operation and time, date, type of anaesthesia, de tools needed for intubation, time needed for intubation and anaesthesia.

In the Clinical Work Station of the Hospital the investigator will search for the following data in these selected patients: preoperative comorbidities, home medication, type of postoperative pulmonary problems and the treatment that was given, time of hospital stay and which department the patient stayed.

Patients with a difficult intubation will be linked to a patient with a corresponding medical history and type of operation but without a difficult intubation. The investigator will look for the same parameters of these patients in the Clinical Work Station.

By means of an odds-ratio the relative risk of a pulmonary complication after a difficult intubation in connection with an easy intubation with different variables can be calculated.

Inclusion Criteria:

• Every patient who had an intubation where another device than a laryngoscope was necessary

Exclusion Criteria:

• N/A

Every patients who had an intubation where another device than a laryngoscope was necessary