What immediate action should be taken when encountering a patient with significant dyspnea?

The immediate action when encountering a patient with significant dyspnea is to maintain airway patency and provide supplemental oxygen if needed. This is critical because dyspnea, or difficulty breathing, can indicate a serious underlying respiratory issue that requires prompt intervention to ensure the airway remains open and that the patient receives adequate oxygenation.

In such situations, preserving the airway is the top priority, as compromised airways can lead to severe hypoxia and respiratory failure. Supplemental oxygen can significantly improve the patient's oxygen saturation and alleviate the immediate distress caused by dyspnea. Quick actions like these can stabilize the patient and may even be life-saving while waiting for further evaluation and treatment.

The other options, while they may be appropriate at different stages or in varying contexts, do not address the immediate needs of a patient struggling to breathe. Starting intravenous fluids or conducting a thorough diagnostic workup without any immediate treatment could delay necessary care and worsen the patient's condition. Waiting for advanced care could also lead to deterioration, especially in a dynamic and potentially life-threatening scenario.