What vital signs changes can indicate dehydration?

The changes in vital signs that indicate dehydration primarily include an increased heart rate and low blood pressure. When a person is dehydrated, the body loses significant fluid which leads to a decrease in blood volume. As a compensatory mechanism, the heart rate increases to maintain adequate cardiac output and ensure that organs receive enough blood supply despite the lower volume. Additionally, low blood pressure occurs due to reduced blood volume, which can lead to a state of hypovolemia.

Pupil response and respiratory rate can also change under various conditions but are not primary indicators of dehydration. While decreased pupil response can signify other medical issues, it is not a direct result of dehydration. Similarly, a high respiratory rate may occur due to multiple factors, such as anxiety or underlying respiratory conditions, rather than being a specific sign of dehydration. Therefore, the most reliable indicators are the increased heart rate and low blood pressure, making the first choice the most accurate representation of vital sign changes in dehydration.