Final answer:
The nurse should immediately notify the healthcare provider about the client's symptoms, as they may indicate hypovolemic shock.
Step-by-step explanation:
The nurse should immediately notify the healthcare provider about the client's symptoms. Cool, clammy skin and excessive thirst can be signs of hypovolemic shock, a condition characterized by a severe decrease in blood volume and circulation. This is a medical emergency that requires immediate intervention and should be assessed by a healthcare provider.