Help with homework, hypo/hypernatremia?

My fellow nursing student and I are working on extra credit homework and we are having a really hard time figuring this out. Below is the case study with the questions

**The main things we need to know are whether this person has hypernatremia or hyponatremia---and how do we know if we have SIADH?

Thank you SO much

Smith is a 73 year old white female with lung cancer, and has been receiving chemotherapy on an outpatient basis. She completed her third treatment 5 days ago and has been experiencing nausea and vomiting for 2 days even though she has been given Zofran orally as directed. Smith's daughter brings her to the hospital where she is admitted to the medical unit. The admitting nurse performs a throughout assessment.

Subjective

• Complains of lethargy, weakness, dizzines, and a dry mouth
  
• States she has been too nauseated to eat or drink anything for 2 days
  

Objective

• Heart rate 100 beats/min, pulse thready
  
• BP 100/65
  
• Weight loss of 5 lbs since she received her chemotherapy 5 days ago
  
• Dry oral mucous membranes
  

Questions

1. Based on her clinical manifestations, what fluid imbalance does Ms. Smith have? (WE SAID: HYPOVOLEMIA)
   
2. What additional assessment data should the nurse obtain? (WE SAID: CHECK FOR ORTHOSTATIC HYPOTENSION, RESPIRATORY RATE, LEVEL OF CONSCIOUSNESS, PUPILS, VOLUNTARY MOVEMENT, CAPILLARY REFILL, SKIN TURGOR, TEMPERATURE, EDEMA, AND FEEL TEMPERATURE OF SKIN)
   
3. What are the patient's risk factors for fluid and electrolyte imbalances? (WE SAID: NAUSEA, VOMITING, NOT DRINKING FLUIDS, AND OLDER AGE)
   
4. The nurse draws blood for a serum chemistry evaluation. What electrolyte imbalances are likely and why?
   
5. The physician orders dextrose 5% in 0.45% saline to infuse at 100 mL/hr. What type of solution is this and how will it help Smith's fluid imbalance? (WE SAID: HYPERTONIC; IT WILL RAISE THE OSMOLALITY OF THE ECF AND THEN THE FREE WATER WILL EXPAND THE ECF AND ICF)
   
6. What are the priority nursing inventions for Smith? (WE SAID: I & O, MONITOR CARDIAC CHANGES AND RESPIRATORY STATUS, SKIN ASSESSMENT, AND DAILY WEIGHTS)
   
7. Because of the nature of her disease process, Smith is at risk for the development of SIADH. How would the nurse recognize this complication and what is the anticipated treatment?
   
8. Based on the assessment data presented, write one or more appropriate nursing diagnoses. Are there any collaborative problems?