AVOID Trial JC
- 1. JOURNAL CLUB O2 in STEMI By Nicholas Ngua Emergency Unit UHW
- 2. Air Versus Oxygen in ST-Segment Elevation Myocardial Infarction AVOID Study Published in Circulation. 2015 Jun 16;131(24):2143-50. doi: 10.1161/CIRCULATIONAHA.114.014494. Epub 2015 May 22 by Stub et al
- 3. Background Oxygen therapy commonly used in initial treatment in STEMI – MONA Morphine Oxygen Nitrates Aspirin There are a little evidence that suggest oxygen may do more harm than good Cochrane review in 2013 conclusion: no conclusive evidence – suggest an RCT
- 4. Clinical Question Among normoxic patients with STEMI, does supplemental oxygen therapy vs no supplemental oxygen therapy increase myocardial infarct size?
- 5. Design Multicenter, randomised, open label, randomised N = 441 Oxygen (n=218) No oxygen (n=223) Setting: 10 centers in Melbourne, Australia (24 hr PCI center) Enrollment: October 2011 till July 2014 Follow up: 6 months Analysis: Intention to treat Powe : Witholding O2 may influence myocardial injury by 20%, α-level set at 0.01
- 6. Population Inclusion Criteria ≥ 18 yr old Chest pain <12 hours Prehospital ECG – STEMI Exclusion Criteria SpO2 < 94% Bronchospasm requiring neb with O2 O2 prior to randomisation Altered conscious state Transport to non studied hospital
- 7. Intervention Facemask 8L/min – continued until transfer to cardiac care ward Control No oxygen unless O2 fell below 94% - NC 4L/min or Facemask 8L/min Both groups initiated on aspirin 300mg by paramedics
- 8. Results (Primary) Geometric Mean Peak Trop I Oxygen 57.4 mcg/L No Oxygen 48 mcg/L (p=0.18) Geometric Mean Peak CK Oxygen 1948 U/L No Oxygen 1543 U/L (p=0.01)
- 9. Results (Adverse Events) Death by Hospital Discharge Oxygen 1.8% No Oxygen 4.5% (p=0.11) Recurrent MI Oxygen 5.5% No Oxygen 0.9% (p=0.006) NNH = 21 Major Cardiac Arrthymia Oxygen 40.4% No Oxygen 31.4% (p=0.05)
- 10. Results (CMR) 32% underwent CMR Oxygen 65 No Oxygen 74 Median Infarct Size Oxygen 20.3g No Oxygen 13.1g (p=0.04) % Infarct of LV Oxygen 12.6% No Oxygen 9.0% (p=0.08)
- 11. Conclusion In normoxic patients, routine O2 administration was not associated with reduction in symptoms accompanied by harm as reflected by significant CK rise larger infarct size by CMR at 6 months
- 12. Questions Does the primary outcome reflects infarct size? Does infarct size reflects clinical outcome? What are the current guidelines on STEMI regarding oxygen supplements? What are your practices with STEMI or even NSE- ACS? Assuming the conclusion of the study is not a Type I error, how can you explain in terms of pathophysiology
- 13. Questions Does the actual PaO2 matters? Are you convinced after this paper regarding switching of practice of not giving routine oxygen supplementation?
- 15. Questions What is the primary outcome of this study? Do you think this is appropriate? What is intention to treat analysis? Give two advantages and two disadvantages of this method of analysis. At the end of this journal club, Dr Jo Mower asks you whether it should be introduced in your department. Give reasons to support your stand.
- 16. THANK YOU Thank Prof for editing the slides Next Journal Club on 9 September 2015 Feedback on how to improve journal club