It would lower the red blood cell concentration, why is this better than having low blood pressure?
In: Biology
Yes, but in any case where the person is given IV fluids but not a blood transfusion, the benefits of the fluids outweigh the minimal dilution of red blood cells. It’s important to keep blood pressure up to make sure that oxygen and nutrients are getting into your cells (especially your brain). Obviously if you’ve lost a critical amount of blood, you need a blood transfusion and not just fluids.
This is exactly why there is discourse on using saline for hypovolemia. You’re upping pressure, but diluting what is there.
And someone might have low blood pressure because they are volume depleted or dehydrated, so in those cases the blood is actually a little too ‘concentrated’ and needs the extra volume.
Hydraulic pressure. It’s the same as a machine. Volume is necessary for pressure, pressure is flow, pressure is function. Even if there is minor dilution of red blood cells, it’s better than if there’s no volume for blood flow. The pump (heart) doesn’t work unless it has something to pump.
Benefit vs. Risk.
When a patients blood pressure drops so low that their Mean Arterial Pressure doesn’t allow them to perfuse any of their organs, diluting the blood is the least of their worries. Your body will make more blood cells, and eventually you’ll urinate the excess water.
But keep in mind, blood pressure has numerous mechanisms, so IV saline obviously isn’t a catchall. Just one way to address the issue depending on the cause.
Latest Answers