Please select the eligibility criteria that correspond to the clinical trial below.
Title: Large, Randomised, Parallel-group, Controlled Trial, With Patients Randomly Allocated to Either N2O-containing (70% N2O in Oxygen [FiO2 0.3]) or N2O-free (70% Nitrogen in Oxygen [FiO2 0.3]).
Brief Summary: To investigate the safety of nitrous oxide (N2O) anaesthesia in patients with risk factors for coronary artery disease undergoing major surgery.


Options:
A: Inclusion Criteria

1. Adult males and females age ≥ 45 years, undergoing noncardiac surgery and general anaesthesia expected to exceed two hours.
2. At increased risk of cardiac events, defined as any of

   1. history of coronary artery disease as defined by a history of any one of the following: i. angina ii. MI iii. segmental wall motion abnormality on echocardiography or a fixed defect on radionuclide imaging iv. a positive exercise stress test for cardiac ischaemia v. a positive radionuclide exercise, echocardiographic exercise, or pharmacological cardiovascular stress test for cardiac ischaemia vi. coronary revascularization (CABG or PTCA) vii. angiographic evidence of atherosclerotic stenosis \> 50% of the diameter of any coronary artery viii. ECG with pathological Q waves in two contiguous leads
   2. heart failure
   3. cerebrovascular disease thought due to atherothrombotic disease
   4. aortic or peripheral vascular disease
   5. or three or more of the following risk factors:

      * age ≥70 years
      * any history of congestive heart failure
      * diabetes and currently on an oral hypoglycaemic agent or insulin therapy
      * current treatment for hypertension
      * preoperative serum creatinine \>175 micro mol/L (\> 2.0 mg/dl)
      * current or previous high cholesterol ≥6.2 mmol/L (\> 240 mg/dl)
      * history of a transient ischemic attack (TIA) (i.e. a transient focal neurological deficit that lasted less than 24 hours and thought to be vascular in origin)
      * emergency/urgent surgery (i.e. surgery which must be undertaken within 24 hours of acute presentation to hospital)
      * high-risk type of surgery (i.e. intrathoracic or intraperitoneal)

Exclusion Criteria

1. having cardiac surgery
2. marked impairment of gas-exchange expected to require Fi02\> 0.5 intraoperatively
3. specific circumstances where N2O is contraindicated (eg. volvulus, pulmonary hypertension, raised intracranial pressure) or the anaesthetist plans to use supplemental oxygen (eg. colorectal surgery)
4. N2O unavailable for use.
B: Inclusion Criteria:

* At least 18 years of age, English-speaking, available for follow-up interview at one month.

Exclusion Criteria:

* Pre-existing neurologic or neuropsychiatric condition, surgical manipulation around forehead, not available for follow-up interview.
C: 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

   -
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: A