Homeostatic Case Study

Patient: Mr. Kaunda70-year-old man withrespiratory problems

History: A 70-year-old man with chronicrenal failure was in the hospital in serious condition recoveringfrom a heart attack. He had just undergone \"coronary angioplasty\"to redilate his left coronary artery, and was thus on an \"npo\" diet(i.e. he was not allowed to have food or drink by mouth). Hereceived fluid through an intravenous (IV) line.

Late one night, a new nurse who really did notunderstand the concept of osmolarity came into the patient's roomto replace the man's empty IV bag with a new one. Misreading thephysician's orders, he hooked up a fresh bag of IV fluid that was\"twice-normal\" saline rather than \"half-normal\" saline (in otherwords, the patient starting receiving a fluid that was four timessaltier than it should have been).

This mistake was not noticed until the followingmorning. At that time, Mr. Kaunda had marked pitting edema aroundthe hip region. He complained that it was difficult to breathe aswell. Blood was drawn, revealing the following:

Na⁺
159 mEq / liter (Normal = 136-145 mEq / liter)
K⁺       
4.9 mEq / liter (Normal = 3.5-5.0 mEq / liter)
C1^-
100 mEq / liter (Normal = 96-106 mEq / liter)

A chest x-ray revealed interstitial edema in thelungs.

Questions:

Will the interstitial fluid increase or decrease the\"osmolarity\"(concentration) due to the nurse's mistake?Whichelectrolytes were out of the normal range and in whichdirection? 

Given your knowledge of osmosis, will the patient’scells increase or decrease in size? Explain youranswer. 

Can you explain why the patient may haveedema? 

What is the function of aldosterone and how will theincrease in osmolarity affect the blood aldosteronelevels? 

Is Mr. Kaunda susceptible to hyponatrenia orhypernatremia? What possible symptoms could Mr. Kaunda develop fromhis present (osmotic) condition? 

Are there any other normal homeostatic mechanisms thatthe body has, to control the situation Kaunda faces? How might itreact in this situation?