Final answer:
The most significant concern after nitro administration is a drop in blood pressure, as nitroglycerin is a vasodilator that can substantially lower blood pressure and cause hypotension.
Step-by-step explanation:
The greatest concern after nitroglycerin (nitro) administration is decreased blood pressure (hypotension). Nitroglycerin is a vasodilator, which means it relaxes and widens blood vessels, allowing blood to flow more easily. This effect can lead to a significant drop in blood pressure, which can cause symptoms such as dizziness, fainting, and potentially, shock if the decline is rapid and severe. Although nitroglycerin can also affect other variables such as heart rate or body temperature, the primary concern in the medical management of patients who have received nitroglycerin is monitoring and managing potential hypotension.