Final answer:
Tocolytic use is contraindicated in patients with hypotension and preload-dependent heart lesions such as aortic insufficiency is true. If red blood cells burst after injection of saline, the solution was hypotonic, not isotonic.
Step-by-step explanation:
The statement "Tocolytic use is contraindicated in patients with hypotension and preload-dependent heart lesions such as aortic insufficiency" is True. Tocolytics, which are medications used to suppress premature labor, can further lower blood pressure, which is dangerous for patients with hypotension. Additionally, conditions like aortic insufficiency rely on adequate preload to maintain cardiac output, and tocolytics might exacerbate the situation.
Regarding the isotonic saline question, if a patient's red blood cells burst after being injected with a saline solution, it is a sign that the solution was actually hypotonic, meaning option c is correct. A hypotonic solution has a lower concentration of solutes compared to the inside of the red blood cells, which can cause water to move into the cells via osmosis, leading to cell lysis, or bursting.