Final answer:
Isotonic 0.9% normal saline (NS) is likely to be ordered by the nurse for a patient suffering from hypotension and heavy bleeding due to an MVA incident, as it helps to rapidly expand the intravascular volume and correct hypovolemia.
Step-by-step explanation:
The nurse working in the emergency department with a patient suffering from a motor vehicle accident (MVA) would likely anticipate an order for isotonic fluids to manage hypotension and blood loss. The initial blood pressure (BP) of 100/56 dropping slightly to 95/58, combined with heavy bleeding, suggests the patient is experiencing hypovolemia. The most appropriate option amongst the listed choices for rapidly expanding intravascular volume and increasing BP would be option (b) 0.9% normal saline (NS).
Isotonic fluids like 0.9% NS are commonly used in acute blood loss situations because they have a similar osmolality to blood and therefore do not cause significant shifts of fluids in or out of the body's cells, which is essential in maintaining hemodynamic stability. Options (a) D5 1/4 NS, (c) 3% NS, and (d) 0.45% NS are not typically chosen for initial resuscitation in cases of severe bleeding, as these solutions have different tonicity and would not be as effective in quickly correcting hypovolemia.