The right answer is smelly garbage.
Infestation is the penetration into the body of a parasite whose nature is not microbial.
smelly garbage is not synonymous of infestation, because the olfactory system only detected smelly metabolites of these microorganisms. This does not necessarily mean that the microorganism has managed to penetrate the body.
By cons other proposals are signs and tools for infestation (torn packaging with food leaking out, dead insect bodysuits, feathers, and fur).
The nurse should check for abnormal cardiac rhythm using ECG
Elevated serum potassium level is called hyperkalemia. In this condition, the heart rhythm can be disrupted, resulting in an arrhythmia. arrhythmia condition can be dangerous as the heart is not pumping in a coordinated way, lowering the pump efficiency and have a high risk of sudden cardiac arrest.
That is why hyperkalemia condition is dangerous and need to be monitored.