Peroperative Use of Positive End-expiratory Pressure Prevents Formation of Atelectasis as Studied by Computerised Tomography at End of Surgery

Peroperative Use of Positive End-expiratory Pressure Prevents Formation of Atelectasis as Studied by Computerised Tomography at End of Surgery

Atelectasis is common during and after general anaesthesia and a number of interventions have been suggested in order to prevent their formation. The use of Positive End Expiratory Pressure (PEEP) during general anaesthesia has in recent years been questioned.

The investigators hypothesize that the use of PEEP as a single intervention improves oxygenation and prevents atelectasis as investigated by computed tomography compared to a control group with zero PEEP.

Inclusion Criteria:

• Healthy subjects, American Society of Anesthesiology (ASA) I-II.
• Patients scheduled for non-abdominal day case surgery under general anaesthesia.

Exclusion Criteria:

• ASA class III or higher.
• Body Mass Index (BMI) 30 or higher.
• Arterial oxygen saturation (SpO2) <96% breathing air.
• Chronic Obstructive Pulmonary Disease (COPD).
• Ischaemic heart disease.
• Known or anticipated difficult airway.
• Active smokers and ex-smokers with a history of more than 6 pack years.
• Need for interscalene or supraclavicular plexus block for postoperative pain relief (risk of phrenic nerve paralysis).