give fluids to lower blood pressure?

[onthemark]

I work at a LTC facility. Last night a patient said she had a headache, felt a little nauseous, and thought if she took another Lasix, her bp would come down and she'd feel better. Her bp was 163/80. The nurse I was working with asked the patient if she had had a lot to drink during the day, and when the patient answered that she had only had coffee and tea at breakfast and lunch the nurse said that she definitely shouldn't have a Lasix because she was already low on fluids, and that what she needed was to drink fluids. During the next hour, the patient drank a ginger ale and glass of juice. After the hour, the patient reported feeling MUCH better and her blood pressure had come down to 145/67.

What was going on here? I realize she was dehydrated but I thought that increased fluids would make her bp go higher. Would someone please explain?

[KatieMI, BSN, MSN, RN]

Headache (for whatever reason) plus possibly very slight dehydration. As soon as she calmed down and relaxed, her blood pressure came back. Plus a bit of free water let her kidneys start working better and promptly pee out some volume, although you'll need numbers to know if the latter thing really took place.

Hypernatremia causes elevation of BP and it is treated by low-sodium fluids or free water.

Another thing that might happen is slight hypoglycemia (very common reason for headache), then juice should increase blood glucose, headache will be gone, patient calmed down and blood pressure decrease.

[onthemark]

Thanks so much, KatieMI! This all makes sense.

[akulahawkRN, ADN, RN, EMT-P]

If everything is working like it should, when people become dehydrated, the body will start shunting blood from the periphery to the core. One of those results is because peripheral vascular resistance has increased, the BP increases. When you start replacing fluids, the body will notice and reverse the shunting and the BP drops. The problem in dehydrated patients is that if you administer vasodilators to them, you shut down the shunting that's occurring and BP drops more than you'd otherwise expect.

[KatieMI, BSN, MSN, RN]

The problem in dehydrated patients is that if you administer vasodilators to them, you shut down the shunting that's occurring and BP drops more than you'd otherwise expect.

I like to name this effect "putting body regulation into *** mode".

The general rule of thumb is to never, ever give patient anything affecting X system before making absolutely sure this drug has enough substrate to work with. No playing with blood pressure before, or at least simultaneously with, optimizing hydration status. No laxatives before finding bowel sounds. No antibiotics if there are no strong suspucions of bacterial infection. One got to have water in there before spilling it out, so no Lasix on dehydrated patient. Etc.

[onthemark]

Thanks so much, akulalawkRN and KatieMI! I really appreciate your both taking the time to explain.