Does your mind ever just go blank trying to recall the "H's & T's" (i.e the reversible causes of cardiac arrest)?! Mine does! Here is how I have started to recall it:
For the H's: Think of the elements + bananas. "Air, Water, Fire, Ice, & Bananas!"
Air = Hypoxia
Water = Hypovolemia
Fire = (work with me on this one, if someone pours acid on you it would burn!) Acidemia
Ice = Hypothermia
Bananas = Hyperkalemia/Hypokalemia
For the T's: There are 2 heart things and 2 lung things.
Two are related to clots.
MI
PE
Two are related to obstruction.
Tamponade
Tension pneumothorax
Tox (have to remember, hopefully the history will hep).
You'll notice from the text overlayed in pink text (diagnostic test) and blue text (intervention), in many cases there are only three things you need to help rule out the Hs&Ts:
Vitals
iStat labs (e.g. VBG with lactate, POCT glucose, electrolytes)
POCUS +/- EKG