Final answer:
A fluid bolus of NS and ephedrine can be given in emergency situations of severe allergic reactions known as anaphylaxis. Epinephrine is used to counteract the effects of anaphylaxis.
Step-by-step explanation:
A fluid bolus of NS (normal saline) and ephedrine can be given in emergency situations of severe allergic reactions known as anaphylaxis. Anaphylaxis is a potentially life-threatening condition that can occur within 20 to 30 minutes if untreated. It is characterized by a drop in blood pressure and bronchial smooth muscle contractions caused by mast cell degranulation in response to an allergen. To counteract these effects, epinephrine is routinely used, and it raises blood pressure and relaxes the bronchial smooth muscle.