This study aims at comparing a perioperative pulmonary atelectasis score, measured by pulmonary ultrasound, in patients operated undergoing orthopedic surgery under general anesthesia, spinal anesthesia or peripheral nerve block. The association between the atelectasis score and previously identified risk factors will be studied.

Atelectasis is one of the most common pulmonary complications in the perioperative period, occurring in 85% to 90% of patients under general anesthesia. It can be responsible for hypoxemia and be associated with postoperative pulmonary complications such as pneumonia. The consequences are a prolongation of the hospital stay and an increase in mortality.

The appearance of perioperative atelectasis is mainly secondary to the induction of general anesthesia with an incidence up to 90%. The different causes are, for example, the administration of muscle relaxants, mechanical ventilation and the position of the patient.

In orthopedic surgery, many procedures are performed under spinal anesthesia or under peripheral nerve block. At present, there are no studies measuring the incidence of atelectasis in patients operated under these two techniques of locoregional anesthesia, with the exception of parturients undergoing cesarean section.

This study aims at comparing a perioperative pulmonary atelectasis score, measured by pulmonary ultrasound, in patients operated undergoing orthopedic surgery under general anesthesia, spinal anesthesia or peripheral nerve block. The association between the atelectasis score and previously identified risk factors will be studied.

Inclusion Criteria:

• Patients over the age of 18;
• Patients scheduled for an elective operation at the Orthopedic Hospital of CHUV;
• Signature of the study consent

Exclusion Criteria:

• Thoracic deformities preventing the performance of pulmonary ultrasound (dressings, drains, fractures, etc.);
• Refusal to participate;
• Patient does not speak French.
• Inability to discern

Participants will be patients scheduled for elective surgery at the Orthopedic Hospital from CHUV.

Fully anonymised IPD will be shared upon reasonable request.