Final answer:
The nurse should turn off both IVs shortly before a veni-puncture to ensure accurate blood collection.
Step-by-step explanation:
When a patient has an IV in both arms, the nurse should turn off both IVs shortly before performing a veni-puncture. This is done to prevent the IV fluids from interfering with blood collection during the veni-puncture procedure. Turning off the IVs ensures that the blood sample obtained will accurately reflect the patient's condition and not be influenced by the IV fluids.
It is usually recommended to turn off the IVs around 2 minutes prior to the veni-puncture. However, the exact duration may vary depending on the specific circumstances and the IV fluid flow rate.
By turning off the IVs briefly before the veni-puncture, the nurse can obtain a more accurate blood sample and avoid potential complications or inaccurate test results.