Category: Medical Cardiac Arrest

Nitro & Cardiac Ischemia; Cardiac Arrest & Reversible Causes

Question #: 429


1. If you are presented with a suspected cardiac ischemia call where the pt denies any chest pain but has nausea, SOB and the 12 lead is STEMI +. Do you give nitro and ASA or solely ASA due to the lack of chest pain?

2. WIth reversible causes (H's and T's), do you leave after your first analysis /shock without ever completing the 2,3,4th analysis on-route?


Nitro administration when suspecting cardiac ischemia is not restricted to chest PAIN symptom. When looking at evidence on morbidity and mortality of nitro administration in cardiac ischemia, benefits are limited. Most of the benefits when administering nitro are seen when there is presence of suspected cardiac ischemia and ACTIVE ONGOING discomfort or symptoms (ex: chest heaviness, shortness of breath, indigestion). If suspecting cardiac ischemia WITHOUT active symptoms, please consider ASA as there are considerable benefits to morbidity and mortality. Please ensure information, clinical picture and pertinent +/- in your documentation support using or withholding nitro and ASA.

Answer to part 2

Please note that the BLS, ALS PCS, Companion Document and bypasses address most of the H’s and T’s, especially if an ACP crew. Here are a few examples: Trauma Medical Cardiac Arrest Medical Directive and bypass, Tension Pneumothorax Medical Directive (ACP), Hypoxia embedded in different standards within BLS, ALS PCS and companion document (Opioid Toxicity, Anaphylaxis, Asthma, ETCO2 and SPO2 target values, etc.), Hypovolemia within Medical Cardiac Arrest Medical Directive (bolus for PEA), Hypothermic Cardiac Arrest Medical Directive, Hypoglycemia Medical Directive and recommendations during Medical Cardiac Arrest, Hypo/Hyperkalemia (ACP).

The clinical consideration section in the Medical Cardiac arrest also mentions that if you suspect a “reversible cause” during a cardiac arrest, to consider “very early transport after the 1st analysis”. This applies especially if you don’t have tools to address any of the reversible causes (most PCP crews, sometimes ACP crews).

The reason for the 1 analysis/defibrillation for reversible causes is that the care goal is to increase the chances of a return of spontaneous circulation by reversing the cause of the arrest. If your crew does not have the tools to reverse the cause, the next priority will be to extricate and transport the patient earlier to a location/care facility that can assist with reversing the cause of the arrest and give the best chances of survival to your patient.

If you suspect refractory ventricular fibrillation (VF) during your cardiac arrest, it is recommended to plan for extrication and transport after the 3rd analysis (early defibrillation and CPR being the care goals and minimal morbidity/mortality impact seen after 4 analyses/defibrillation).

Further, “when en-route and using SAED mode, the ambulance MUST be stopped and when using manual mode, the ambulance SHOULD be stopped; to minimize artifact and the risk of an inaccurate rhythm interpretation/analysis” (Companion Document v 4.8). This may not always be safe to do so in our current system and may delay management of reversible causes and refractory VF.

Therefore, if you are considering very early transport due to reversible causes, it is acceptable practice not to analyse during transport even if only 1 analysis was completed on scene.

Please ensure information, clinical picture, pertinent +/- and rationale supporting your management plan are documented.

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