Answer:
The Treatments written in the ALS-PCS are written left to right, in order of preferred treatment (especially in the case of dextrose over glucagon for the treatment of hypoglycemia).
Dextrose has an onset of action of 10 minutes, versus 20 minutes for Glucagon (see the Ask MAC from 28-Mar-2019). Glucagon has a common side effect of vomiting. Therefore, by giving dextrose you are providing more expedient treatment and potentially improving morbidity by correcting hypoglycemia sooner with fewer side effects.
If a patient is nauseous or vomiting and is being considered for the Nausea/Vomiting Medical Directive, they may also benefit from having an IV initiated.
If there are extenuating circumstances, wherein the non-IV partner must attend the patient, they can also treat these conditions. But, as reiterated in the Grey Zone presentation this year, asking yourself what is best for the patient should help guide who attends the call.