Anurse is caring for a client with severe gastritis who vomited a large amount of blood. a lavage is prescribed by the healthcare provider. which response does the nurse expect when using a room temperature irrigating solution?

The answer would be: Constriction of blood vessels

Room temperature tends to be colder than the body temperature. A cold water will induce vasoconstriction of the blood vessel that could be beneficial to stop bleeding(if there is any). This will also reduce the pain that caused by the inflammation.
But most research found that the blood flow is not significantly reduced so irrigation using body temperature water might be better.