What critical information is required for a pregnant patient with severe nausea and dehydration?

For a pregnant patient experiencing severe nausea and dehydration, the most critical information involves the need for IV hydration and lab tests. This situation often indicates a serious condition like hyperemesis gravidarum, where the patient may not be able to maintain hydration or nutrition due to extreme vomiting.

IV hydration is necessary to address the dehydration and to restore electrolyte balance, which is vital for both maternal and fetal health. Additionally, lab tests are essential to assess the levels of electrolytes, kidney function, and other parameters that could be affected by the dehydration. These tests provide crucial insights into the patient's overall health and any potential risks to the pregnancy.

Vision tests or sonogram assessments are not priorities in this scenario, as they do not directly address the immediate needs of managing severe nausea and dehydration. Observation alone would not be sufficient to ensure the safety and health of the pregnant patient; active intervention is required to prevent complications.