Phase 4
Completed N=7,112
The ENIGMA II Trial:Nitrous Oxide Anaesthesia and Cardiac Morbidity After Major Surgery: a Randomised Controlled Trial
Source: ClinicalTrials.gov NCT00430989 ↗Enrolled (actual)
7,112
Serious AEs
8.3%
Results posted
Jun 2019
Primary outcomePrimary: The Primary Endpoint is a Composite of Death and Cardiovascular Events (Clinical and Silent MI, Cardiac Failure, Cardiac Arrest, Pulmonary Embolism, and Stroke) Measured at 30 Days After Surgery. — 283; 296 participants
◆ Published Evidence
Highly cited
222citations · ~19 / year
The safety of addition of nitrous oxide to general anaesthesia in at-risk patients having major non-cardiac surgery (ENIGMA-II): a randomised, single-blind trial.
Summary
To investigate the safety of nitrous oxide (N2O) anaesthesia in patients with risk factors for coronary artery disease undergoing major surgery.
Linked Publications (5)
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The safety of addition of nitrous oxide to general anaesthesia in at-risk patients having major non-cardiac surgery (ENIGMA-II): a randomised, single-blind trial.
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Implication of Major Adverse Postoperative Events and Myocardial Injury on Disability and Survival: A Planned Subanalysis of the ENIGMA-II Trial.
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Nitrous oxide and perioperative cardiac morbidity (ENIGMA-II) Trial: rationale and design.
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Chronic postsurgical pain in the Evaluation of Nitrous Oxide in the Gas Mixture for Anaesthesia (ENIGMA)-II trial.
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Intraoperative dexamethasone does not increase the risk of postoperative wound infection: a propensity score-matched post hoc analysis of the ENIGMA-II trial (EnDEX).
Outcome Measures
| Outcome | Result | p-value |
|---|---|---|
| PRIMARY The Primary Endpoint is a Composite of Death and Cardiovascular Events (Clinical and Silent MI, Cardiac Failure, Cardiac Arrest, Pulmonary Embolism, and Stroke) Measured at 30 Days After Surgery. |
283; 296 | — |
| SECONDARY Myocardial Infarction (MI) |
215; 219 | — |
| SECONDARY Cardiac Arrest |
15; 19 | — |
| SECONDARY Pulmonary Embolism |
18; 22 | — |
| SECONDARY Stroke |
26; 19 | — |
| SECONDARY Wound Infection |
321; 311 | — |
| SECONDARY Hospital Stay (Days) |
6.1; 6.1 | — |
Eligibility Criteria
Inclusion Criteria
- Adult males and females age ≥ 45 years, undergoing noncardiac surgery and general anaesthesia expected to exceed two hours.
- At increased risk of cardiac events, defined as any of
- 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
- heart failure
- cerebrovascular disease thought due to atherothrombotic disease
- aortic or peripheral vascular disease
- 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
- having cardiac surgery
- marked impairment of gas-exchange expected to require Fi02> 0.5 intraoperatively
- specific circumstances where N2O is contraindicated (eg. volvulus, pulmonary hypertension, raised intracranial pressure) or the anaesthetist plans to use supplemental oxygen (eg. colorectal surgery)
- N2O unavailable for use.
Data sourced from ClinicalTrials.gov (NCT00430989) and the linked publication. Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication. Informational only — not medical advice.