What kind of fluid is commonly used for maintaining blood pressure in hypovolemic patients?

Crystalloid solutions are the commonly used fluids for maintaining blood pressure in hypovolemic patients primarily due to their effectiveness in rapidly expanding intravascular volume. These solutions consist of water with dissolved salts and other substances, which help to distribute fluid into the extracellular space and increase blood volume promptly.

In cases of hypovolemic shock, a condition resulting from significant fluid loss, it is crucial to restore circulating volume to maintain tissue perfusion and blood pressure. Crystalloids, such as normal saline or lactated Ringer's solution, are readily available, inexpensive, and can be administered quickly to achieve this goal.

While colloid solutions can also be used in such scenarios, they are less commonly employed initially due to their higher cost and the potential for allergic reactions. Hypertonic solutions, on the other hand, can draw fluid from the interstitial space to the vascular space but are typically used in more specific situations rather than as the first line for hypovolemic patients. The term "not calculated solutions" is not applicable in this context, as it does not refer to any recognized category of fluid therapy.