An older adult nursing home resident who has always been alert and oriented is now showing signs of dehydration and has become confused. Which electrolyte imbalance is most likely involved?

A. Hematoma: A hematoma typically results from bleeding into the tissue, causing swelling and bruising at the infusion site, but it doesn't usually cause warmth or pain in the same way as phlebitis.

B. Phlebitis: Phlebitis is inflammation of the vein, commonly caused by an IV catheter or medication, and it often presents with redness, warmth, pain, and swelling at the infusion site. It is the most likely complication here.

C. Speed Shock: Speed shock occurs when a medication or fluid is administered too rapidly, causing symptoms such as dizziness, chest tightness, and hypotension, not localized symptoms like redness and pain at the infusion site.

D. Thrombosis: Thrombosis refers to the formation of a blood clot within a vein, which can cause swelling, warmth, and discomfort but would also likely involve more significant blockage and would be associated with reduced blood flow, not just localized redness and pain.

A. Urine output 20 mL/hr: A urine output of 20 mL/hr is on the low side but can still be expected in dehydration, as the body attempts to conserve water. Normal urine output is 30 mL/hr or more, so this could still be a sign of dehydration.

B. Sodium 142 mEq/L (136 to 145 mEq/L): This sodium level is within the normal range. Dehydration may cause sodium to be elevated if water loss is more significant than sodium loss, but a normal value does not indicate dehydration.

C. Cool skin: Cool skin is a typical finding in dehydration, particularly in severe cases, due to reduced peripheral circulation and vasoconstriction as the body tries to maintain core temperature and blood pressure.

D. Bradycardia: Dehydration usually causes tachycardia as a compensatory mechanism to maintain blood pressure and perfusion, not bradycardia.