Please select the eligibility criteria that correspond to the clinical trial below.
Title: PeRioperative OXygen Fraction - Effect on Surgical Site Infection and Pulmonary Complications After Abdominal Surgery (The PROXI-trial)
Brief Summary: Aim: To investigate the effect of high intra- and postoperative oxygen concentration (80%, as opposed to normally 30%) on surgical wound infection and pulmonary complications after abdominal surgery.

Background: Surgical wound infection is a common and serious complication. Tissue oxygen tension is often low after surgery and the resistance against infection depends on this factor through bacterial killing by neutrophils. Oxygen is a substrate in this reaction, and it is hypothesized that by increasing the arterial oxygen tension, the risk of surgical wound infection is reduced. Previous studies to test this hypothesis have shown entirely different results. Hence, the clinical decision between high and normal oxygen concentration is still controversial.

Primary hypothesis of study: Use of 80% oxygen decreases the incidence of surgical wound infection after abdominal surgery.

Secondary objectives: To investigate the effect 80% oxygen on pulmonary complications (atelectasis, pneumonia, respiratory insufficiency), second operation, mortality and length of postoperative hospitalization and admission to intensive care unit after abdominal surgery.


Options:
A: Inclusion Criteria:

* Adults ≥ 18 years of age.
* Chest pain for \< 12 hours
* ST-elevation Myocardial Infarction including either: 1) Persistent ST-segment elevation of ≥1mm in two contiguous limb leads; 2) ST-segment elevation of ≥ 2mm in two contiguous chest leads, or; 3) New left bundle branch block (LBBB) pattern.
* Able to be transported to a participating hospital

Exclusion Criteria:

* Hypoxia with oxygen saturation measured on pulse oximeter \< 94% with the patient breathing air
* Bronchospasm requiring nebulised salbutamol therapy using oxygen
* Altered conscious state
B: Inclusion Criteria:

* Age 18 years or older.
* Laparotomy, acute or elective. In case of gynaecological surgery only if malignancy is suspected (defined as risk of ovarian malignancy index \>200 or a specimen with atypical or neoplastic cells).

Exclusion Criteria:

* Other surgery within 30 days (except surgery in local anaesthesia).
* Chemotherapy within 3 months.
* Inability to give informed consent.
* Inability to keep oxygen saturation above 90% without supplemental oxygen (measured preoperatively by pulse oximetry).
C: Inclusion Criteria:

* Colon resection expected to last \>2 and \<6 hours

Exclusion Criteria:

* Bowel obstruction
* Fever
D: Inclusion Criteria:

1. Males and females, age 18 years and over
2. Planned general anaesthesia for surgery that includes a skin incision and expected to exceed two hours, and the patient is expected to be in hospital for at least three days

Exclusion Criteria:

1. Endoscopic or radiological procedures
2. Cardiac surgery
3. Marked impairment of gas-exchange (requiring Fi02\> 0.3)
4. Thoracic surgery requiring one-lung ventilation (requiring Fi02\> 0.3)
5. Specific circumstances where N2O is contraindicated (eg. volvulus, pulmonary hypertension, raised intracranial pressure)
6. Lack of provision of N2O.

Answer: B