Final answer:
Slowly aspirating on the syringe when administering saline prevents tissue damage. A dehydrated human patient typically receives isotonic saline intravenously. Injection with a non-isotonic solution could result in red blood cell destruction.
Step-by-step explanation:
When administering saline intravenously, particularly during aspiration, it is recommended to pull back on the syringe slowly rather than immediately. This practice helps to avoid creating negative pressure that can damage tissue and cause discomfort to the patient. In situations of dehydration, a dehydrated human patient is often given isotonic saline solution intravenously to restore fluid balance.
If a doctor injects what is believed to be an isotonic saline solution, and the patient experiences the destruction of many red blood cells, leading to death, it is likely that the solution was not truly isotonic. An isotonic solution should have a similar concentration of solutes as the blood to avoid osmotic pressure changes that can lead to cell lysis or shrinkage.
The pressure necessary to deliver an IV solution can be supplied by positioning an IV bottle at a certain height above the patient. For example, with the surface of the saline solution 1.61 meters above the entrance to the needle, and assuming negligible pressure drop in the tubing, the correct delivery pressure can be achieved.