What immediate action should be taken for a patient exhibiting signs of severe dehydration and shock?

The most appropriate immediate action for a patient showing signs of severe dehydration and shock is to initiate isotonic fluid resuscitation. In cases of significant dehydration and shock, the focus is on restoring intravascular volume and ensuring adequate tissue perfusion. Isotonic fluids, such as normal saline or lactated Ringer's solution, are crucial in rapidly rehydrating the patient and stabilizing their hemodynamic status. The prompt administration of these fluids helps to correct electrolyte imbalances and restore blood pressure, which is essential for preventing further organ damage.

While thorough physical examinations and laboratory tests like a CBC count are important in the overall assessment and management of the patient, they do not address the immediate need for fluid resuscitation. Sodium bicarbonate is not indicated in acute shock or dehydration unless there is an associated acid-base disorder requiring its use. Therefore, initiating isotonic fluid resuscitation is the critical first step in managing this patient’s condition effectively.