With so many different types of IV fluids available to suit specific patient needs, it can be hard to tell exactly what to give a patient who is hypertensive, especially if there are other conditions to factor in. In order to fully understand what options you have in treating hypertensive patients with IV fluids, it is important to understand what hypertension is, how it affects the body chemically, and understand the chemical reactions that the body uses to help counteract it.
Hypertension is essentially high blood pressure. This high blood pressure can be caused by a variety of factors. Blood clots and blockages in the blood vessels, chemical imbalances that cause either too high a blood plasma volume or too many ions to remain in the blood, and other hormonal conditions which affect the way blood vessels handle blood pressure regulation can all lead to hypertension, along with external factors like diet, smoking, and lack of exercise.
Your body combats hypertension through a number of physiological functions. The Cardiac Center of the brain can regulate the heart rate through one of three main ways:
- Increase the heart rate, increasing blood flow through the vessels and increasing heart rate
- Decreasing cardiac output, reducing blood flow through the vessels and decreasing heart rate
- Using the vasomotor center to initiate vasodilation, which causes vessels to constrict or relax, narrowing or widening the vessels
In addition to the heart, there are other mechanisms the body uses to increase blood pressure. One major way that the body can regulate blood pressure without affecting the heart rate is through the use of various hormones.
The kidneys release renin from the juxtaglomerular cells into the blood. The renin converts blood plasma into Angiotensin I, which then is eventually converted into Angiotensin II. Angiotensin II helps regulate blood pressure in two ways:
- It causes the blood vessels in the kidneys to constrict, increasing the blood pressure in the kidneys and reducing the blood flow to the kidneys
- The decrease in blood flow to the kidneys reduces the amount of blood filtered through the kidneys, increasing the amount of water in the blood and increasing blood volume, therefore increasing blood pressure
- Angiotensin II increases the output of Aldosterone, which promotes urine retention. This increases the H20 and Na+ retention in the kidneys, increasing blood volume
The Practical Applications
Now that you have a brief understanding of how the body regulates blood pressure, it’s time to apply that information and figure out which IV fluids can be given to patients suffering from hypertension. The first step is to see if you can determine what is causing their hypertension based on their medical history or symptoms and if they are taking medication to treat their hypertension. This will help give you a baseline of what fluids NOT to give them.
If a patient is hypertensive and you can not determine the reason, avoid using normal saline solutions or salt-based saline solutions. If their blood pressure is already high due to other factors, especially a high sodium concentration in their blood, the salts in a regular saline solution might exacerbate hypertension by increasing the blood volume further, forcing the body to struggle even more the keep their hypertension in check.
If they have hypertension due to blood sugar levels from either diet or conditions such as diabetes though, normal saline solutions are actually beneficial. A standard saline solution is created to have the same salt content as the natural salt content of the human body. The salt in the saline solution will ensure that essential electrolytes are not flushed from the blood, and the salt in the saline solution can actually prove to help lower blood sugar levels.
Considering medicine can be a very complex science with multiple factors in play, there really is no straight answer as to catch-all IV fluids to use on patients with hypertension. Depending on the patient, hypertension may be a non-factor as the other conditions are more pressing and/or are counteracting hypertension (such as needing to increase body fluid due to severe dehydration or blood loss). Always treat patients on a case to case basis when it comes to administering IV fluids, as hypertension isn’t the only factor that can determine what solution is best to use. If you have questions about what IV fluid treatments might be best for you if you even need, contact your physician for more information, as they know your medical history best. Call us at 205-352-9141.