Final answer:
The tourniquet should not be left on the arm longer than 1 minute, and urine output will generally start to increase around 30 minutes after drinking a large glass of water.
Step-by-step explanation:
The tourniquet should not be left on the arm for longer than the recommended time to ensure patient safety and to avoid potential complications such as venous stasis, bruising, or erroneous lab results due to hemoconcentration. When it comes to venipuncture, a tourniquet should typically not be left on for more than 1 minute. Leaving it on for an extended period can cause harm to the patient and affect the quality of the blood sample.
As for the increase in urine output after drinking a large glass of water, this can typically start in about 30 minutes. This is because it takes some time for the water to be absorbed into the bloodstream, processed by the kidneys, and then finally excreted as urine.