Final answer:
Infusing a hypertonic solution causes fluid to shift out of cells due to the higher solute concentration outside the cell, leading to cellular shrinkage or crenation.
Step-by-step explanation:
When a nurse is infusing a hypertonic solution, the direction of fluid shifts will be out of the cells. This is because a hypertonic solution has a higher concentration of solutes compared to the cell's cytoplasm, resulting in a lower concentration of water outside the cell. Consequently, water tends to move from areas of higher concentration to areas of lower concentration to reach a state of equilibrium, in this case moving out of the cells and into the extracellular fluid, potentially causing the cells to shrink or crenate.