Question: With reference to the cardiac ischemia protocol. Would it be possible to update the protocol for the administration of nitro (without a BHP consult) for normotensive patient on beta blockers by either: a) lowering the heart rate parameters from 60bpm to 50bpm or b) to lower heart rate parameter from 60bpm to 50bpm when patient is currently taking antihypertensive medications within the beta blocker family with an IV established?
Excellent question. You are correct that many patients on Beta Blockers may have low heart rates which (for them) are completely "normal". Many of these same patients also take their own NTG without complication at home every day.
The challenge is identifying those patients with bradycardia and coronary artery disease who are having chest pain and ensuring they can receive NTG safely. Remember, NTG has little if any impact upon outcome, it is purely symptom relief. If these patients are suffering an inferior or right ventricular MI (where bradycardia is common), then there is significant risk they may deteriorate with NTG.
Things to consider when modifying the Medical Directives is that these are now Provincial Directives. Regional Base Hospital Programs are unable to change them and any modification must then be implemented province wide. 12 lead ECG is not part of the mandatory equipment that paramedics must carry. As such, identifying those bradycardic patients at risk of deterioration is not as easily achieved everywhere in Ontario at present.
The Medical Directives are constantly being reviewed however, and your desire for change will be noted in the ongoing discussions in the future. Thanks for contributing!