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:

* ≥2 positive SIRS-criteria:

  * Temperature \>38 deg.C or hypothermia \<36 deg.C
  * Heart rate \>90 bpm
  * Respiratory rate \>20 /min or pCO2 \<32 mmHg (4.3 kPa)
  * Number of leucocytes \>12 x 10\^9/l of \<4 x 10\^9/l of \>10% bands
* Within 12 hours of admittance to the ICU
* Expected stay of more than 48 hours as estimated by the attending physician

Exclusion Criteria:

* Elective surgery
* Carbon monoxide poisoning
* Cyanide intoxication
* Methemoglobinemia
* Sickle cell anemia
* Severe pulmonary arterial hypertension (WHO class III or IV)
* Known severe Acute Respiratory Distress Syndrome (ARDS) (PaO2/FiO2 ≤100 mmHg and PEEP ≥ 5 cm H2O)
* Known cardiac right to left shunting
* Pregnancy
* Severe Chronic Obstructive Pulmonary Disease (COPD) (Gold class III or IV) or other severe chronic pulmonary disease
* Patients participating in other interventional trials
B: Inclusion Criteria:

1. Age ≥18 years
2. OHCA of presumed cardiac cause
3. Sustained ROSC
4. Unconsciousness (GCS \<8) (patients not able to obey verbal commands) after sustained ROSC

Exclusion Criteria:

1. Conscious patients (obeying verbal commands)
2. Females of childbearing potential (unless a negative HCG test can rule out pregnancy within the inclusion window)
3. In-hospital cardiac arrest (IHCA)
4. OHCA of presumed non-cardiac cause, e.g. after trauma or dissection/rupture of major artery OR Cardiac arrest caused by initial hypoxia (i.e. drowning, suffocation, hanging).
5. Known bleeding diathesis (medically induced coagulopathy (e.g. warfarin, NOAC, clopidogrel) does not exclude the patient).
6. Suspected or confirmed acute intracranial bleeding
7. Suspected or confirmed acute stroke
8. Unwitnessed asystole
9. Known limitations in therapy and Do Not Resuscitate-order
10. Known disease making 180 days survival unlikely
11. Known pre-arrest CPC 3 or 4
12. \>4 hours (240 minutes) from ROSC to screening
13. Systolic blood pressure \<80 mm Hg in spite of fluid loading/vasopressor and/or inotropic medication/intra-aortic balloon pump/axial flow device
14. Temperature on admission \<30°C.
C: 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).
D: Inclusion Criteria:

1. Age ≥ 18 years
2. Receiving mechanical ventilation through an endotracheal tube or tracheostomy
3. Admitted to the study ICU or admission to the study ICU from the emergency department is planned

Exclusion Criteria:

1. Known pregnancy or beta hCG level greater than the laboratory upper limit of normal in a patient capable of becoming pregnant
2. Known to be a prisoner

Answer: C