Q: 
Regarding protocol "2050 Chest Pain": Do we have to administer all three nitro before giving an opioid, if so what is the reasoning?
A: 
No, you may give opioid at any time. However, if you believe that pain is true angina, then nitro is the logical best choice, assuming no contraindication such as hypotension. Neither nitrates nor opioids have been shown to decrease mortality in acute coronary syndromes (ACS) and opioids have been associated with worse clinical outcomes in ACS, so are deemphasized in the treatment. The critical actions are to identify STEMI, treat hypotension and arrhythmias and administer aspirin for suspected ACS.