Please select the eligibility criteria that correspond to the clinical trial below.
Title: Evaluation of Nitrous Oxide In the Gas Mixture for Anaesthesia: a Randomised Controlled Trial
Brief Summary: We aim to investigate the effectiveness and safety of nitrous oxide (N2O) in anaesthesia.

Hypothesis In patients undergoing anaesthesia for major surgery, avoidance of N2O will reduce hospital length of stay when compared with otherwise identically managed surgical patients receiving N2O as a component of their anaesthesia.


Options:
A: Inclusion Criteria:

* General anaesthesia with controlled ventilation

Exclusion Criteria:

* Age lower than 18 years
* Pregnant woman
* Allergy to the propofol or to a muscle myorelaxant
* Patients receiving a psychotropic treatment
* Presence of a central neurological disorder or a lesion cerebral
* Patients having an anomaly of blood cells count preoperative biological assessment
* Patients having had an anaesthesia in the previous month
B: Inclusion Criteria:

MUST HAVE:

General Anesthesia with volatile anesthetic

PATIENT CHARACTERISTICS

Major Criteria (Must have any 1 of the following:)

1. Planned open heart surgery
2. Medications - anticonvulsants, abuse of opiates, benzodiazepines, cocaine
3. EF\<40%
4. Prior history of awareness (recall)
5. History of difficult intubation or anticipated difficult intubation
6. ASA IV or V status
7. Aortic stenosis
8. End stage lung disease
9. Marginal exercise tolerance not secondary to musculoskeletal dysfunction
10. Pulmonary hypertension
11. Daily alcohol consumption

Exclusion Criteria:

1. Surgical procedure that prevents the use of the BIS (e.g. surgery of forehead)
2. Patient positioning prevents use of the BIS
3. Surgery with wake-up test.
4. Less than 18 years of age
5. Vulnerable populations, such as those with dementia and those unable to provide informed consent.
6. Stroke with residual neurological deficits

   -
C: 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.
D: Inclusion Criteria:

MUST HAVE:

General Anesthesia with volatile anesthetic

PATIENT CHARACTERISTICS

Major Criteria (any 1 of the following:)

1. Medications - anticonvulsants, abuse of opiates, benzodiazepines, cocaine
2. EF\<40%
3. Prior history of awareness (recall)
4. History of difficult intubation or anticipated difficult intubation
5. ASA IV or V status
6. Aortic stenosis
7. End stage lung disease
8. Marginal exercise tolerance not secondary to musculoskeletal dysfunction
9. Pulmonary hypertension
10. Daily alcohol consumption

Minor Criteria (any 2 of the following)

1. Beta blockers
2. COPD
3. Moderate exercise tolerance not secondary to musculoskeletal dysfunction
4. Smokes ≥2 packs per day
5. Morbid obesity BMI\>30 -

Exclusion Criteria:

1. Surgical procedure that prevents the use of the BIS (e.g surgery of forehead)
2. Patient positioning prevents use of the BIS
3. Surgery with wake-up test.
4. Less than 18 years of age
5. Vulnerable populations, such as those with dementia and those unable to provide informed consent.
6. Stroke with residual neurological deficits

Answer: C