None listed
Conditions
Brief summary
It is routine clinical practice to administer high flow oxygen to all patients with a heart attack. However, there is evidence to suggest that this approach may be harmful, particularly to those patients who are not hypoxic. High flow oxygen causing hyperoxia has been shown to increase blood pressure and reduce cardiac output, and possibly also reduce coronary artery blood flow. As a result it is crucial that the effects of high flow oxygen on myocardial ischaemia is investigated further in patients with ischaemic heart disease. A double-blind randomised controlled cross-over trial using exercise treadmill testing is an ideal method to measure the effect of supplementary oxygen on myocardial ischaemia.
Interventions
Patients will receive two oxygen regimes in a cross over fashion: room air (placebo) for 5 minutes before the start and continued until the end of the ETT, and high flow oxygen (15/L minute) (comparator) via a non-rebreather mask for 5 minutes before the start and continued until the end of the ETT. The order that the regimes are received will be allocated randomly and there will be approximately 90 minutes between tests. Exercise will be standardised according to the Bruce protocol for exercise
Patients will receive two oxygen regimes in a cross over fashion: room air (placebo) for 5 minutes before the start and continued until the end of the ETT, and high flow oxygen (15/L minute) (comparator) via a non-rebreather mask for 5 minutes before the start and continued until the end of the ETT. The order that the regimes are received will be allocated randomly and there will be approximately 90 minutes between tests. Exercise will be standardised according to the Bruce protocol for exercise stress tests. The ETT will be stopped for any of the following reasons ST elevation, LBBB or arrhythmia occurs The patient requests to stop the test The development of diagnostic ECG ischaemia for 15 seconds The cardiology registrar determines that the ETT should be stopped If none of these endpoints are reached then the duration of the ETT will be determined by the exercise capacity of the patient.
Sponsors
Dr Mark Simmonds
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Treatment
Masking
Blinded (masking used)
Eligibility
Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
Inducible ischaemia on ETT with chest pain.
Exclusion criteria
Abnormal resting electrocardiogram (ECG)ST-elevation during the ETTGlobal ischaemia during the ETT suggesting a possible left main stem lesionArrythmia during the ETTUnstable angina (daily episodes at rest)Left bundle branch block developing during the ETTCongestive heart failureSevere hypertension (systolic >200mmHg)Chronic obstructive respiratory disease or other respiratory disease with oxygen saturations measured at <92% on room airPatients who do not develop chest pain despite evidence of inducible ischaemiaUnstable gaitPatients with contraindication to aspirin, metoprolol or simvastatin.
Outcome results
None listed