FLUID BALANCE AND ELECTROLYTES

Question

Answer

What percentage of body weight is water in a healthy person?

50–60% of body weight.

What is the minimum number of days a person can survive without water?

More than three days without water can result in death.

What does water transport throughout the body?

"Nutrients to cells; waste from cells; hormones; enzymes; blood platelets; and red and white blood cells."

What is the instructor's analogy for water's role in the body?

Water is the ship or transport system — it carries everything to and from the body.

Name six functions of water in the body.

"Transports substances; facilitates cell metabolism and cellular function; acts as a solvent for electrolytes; maintains body temperature; facilitates digestion; promotes elimination; and acts as a tissue lubricant."

What percentage of body weight is intracellular fluid?

35–40% of body weight.

What percentage of body weight is plasma?

5%.

What percentage of body weight is interstitial fluid?

10–15%.

What percentage of body weight is extracellular fluid?

15–20%.

What does intracellular mean?

Fluid inside the cells — found in platelets and cells.

What does extracellular mean?

Fluid outside the cells; floating in the surrounding space.

What are cations and give four examples?

"Cations carry positive charges. Examples: sodium; potassium; calcium; and magnesium."

What are anions and give two examples?

"Anions carry negative charges. Examples: chloride and phosphorus."

How are electrolytes measured?

In milliequivalents per liter (mEq/L); which measures the chemical activity of the electrolyte.

What is the recommended daily fluid intake?

Approximately 2;400–2;700 mL per day.

Name the hormones that regulate fluid balance mentioned in the lecture.

"Renin-angiotensin-aldosterone system; antidiuretic hormone (ADH); and atrial natriuretic peptide."

What are the measurable (sensible) ways the body loses fluid?

"Urine; stool; wound drainage; and GI drainage (JP drains; Hemovacs; Penrose drains; chest tubes; gastric suction; emesis)."

What are the non-measurable (insensible) ways the body loses fluid?

Sweat and respiratory exhalation.

What is 1 ounce equal to in milliliters?

30 mL.

What is 8 ounces equal to in milliliters?

240 mL.

What is 16 ounces equal to in milliliters?

480 mL.

What is 1 teaspoon equal to in milliliters?

5 mL.

What is 1 tablespoon equal to in milliliters?

15 mL.

What is 1 kilogram equal to in pounds?

2.2 pounds.

What is 1 kilogram equal to in liters of fluid?

1 kilogram equals 1 liter of fluid.

What foods and liquids count toward fluid intake?

"Gelatin; ice cream; soup; juice; pudding; yogurt; popsicles; milk; melted ice chips; liquid medications; IV fluids; tube feeding flushes; and liquid cough syrups."

Why are popsicles and ice chips measured at room temperature?

Because all fluid intake is measured at room temperature when it converts to liquid form.

What foods do NOT count toward fluid intake?

Solid foods like toast and green beans — only substances that are liquid at room temperature are counted.

At what time is daily input recorded in the hospital?

2350 (11:50 PM).

Where is the preferred site to assess skin turgor in adults?

"Over the clavicle; sternum; inner thigh; or forehead — NOT the hands in older adults."

Where is the preferred site to assess skin turgor in children?

The abdomen and thighs.

What is a normal skin turgor finding?

The skin returns to its normal position immediately after being pinched.

What is an abnormal skin turgor finding?

The skin remains tented for two to three seconds before returning — indicates dehydration.

Why is skin turgor less reliable in older adults?

Because aging causes a primary decrease in skin elasticity; making skin appear tented even when adequately hydrated.

What does the tongue look like in a dehydrated patient?

A line down the middle of the tongue and a white; dull appearance instead of pink and plump.

What do normal mucous membranes look like?

"Pink; moist; and glossy."

What do dehydrated mucous membranes look like?

"Dry; cracked; and dull lips and gums."

What is third spacing?

"When fluid bypasses the intracellular and extracellular compartments (because they are full) and accumulates in places it should not normally be — such as the lungs; abdomen; or tissue spaces."

Give three examples of third spacing.

"Pleural effusions; angioedema (lips; tongue; gums; face; throat; genitals); and ascites (fluid in the abdomen)."

What happens to body temperature when a patient is dehydrated?

Temperature rises because water is needed to regulate body temperature; without it the body overheats.

What happens to body temperature with fluid excess?

Body temperature is lower than normal.

How much does a temperature of 101–103°F increase 24-hour fluid requirements?

By at least 500 mL.

How much does a temperature over 103°F increase 24-hour fluid requirements?

By at least 1;000 mL.

What is the earliest sign of dehydration related to pulse?

Tachycardia — the heart compensates by beating faster to deliver oxygen with reduced fluid volume.

What does a bounding pulse indicate?

Fluid volume excess — the vessels are full.

What does a weak or thready pulse indicate?

Fluid volume deficit — there is not enough volume to create strong pressure.

What happens to blood pressure with fluid volume deficit?

Hypotension — not enough volume to generate pressure.

What happens to blood pressure with fluid volume excess?

Hypertension — excess volume increases pressure.

What does an irregular pulse suggest in relation to electrolytes?

Potassium or sodium imbalances.

What lung sound indicates fluid in the lungs?

Crackles.

What is frothy sputum a sign of?

Fluid coming out of the lungs — a sign of severe fluid volume excess.

What is dyspnea?

Subjective difficulty breathing — the patient reports they cannot breathe.

What is hypovolemia?

"Abnormally low fluid volume — a deficiency in water and electrolytes in the body; also known as dehydration."

What is hypervolemia?

"Excessive retention of water and sodium above normal amounts in extracellular spaces; also known as overhydration."

What is the key principle about sodium and water?

Where salt goes; water follows.

What is the minimum acceptable urine output per hour?

30 mL per hour. Below 30 mL/hr requires notifying the healthcare provider.

How do you calculate hourly urine output from a 24-hour total?

Divide the total milliliters by 24 to get mL per hour.

Name six causes of hypovolemia.

"Vomiting; diarrhea; sweating; polyuria (e.g. from diabetes); high fever; nasogastric suction; abnormal wound or drain losses; insufficient fluid intake; overuse of diuretics; and prolonged heat exposure."

Name four risk factors for hypervolemia.

"Excess sodium diet; certain IV fluids such as normal saline; medications like steroids; heart failure; and kidney failure."

What is the formula for converting pounds of weight gain to liters of fluid retained?

Divide pounds by 2.2 to get kilograms. Since 1 kg = 1 liter; the number of kilograms equals liters of fluid retained.

How much fluid is retained if a patient gains 7 pounds?

7 ÷ 2.2 = 3.18 kg which equals approximately 3.18 liters of fluid retained.

How much daily weight change is considered abnormal and must be reported?

More than 2 pounds gained or lost in 24 hours.

How should patients weigh themselves for accurate fluid monitoring?

"Same time each day; on the same scale; wearing the same clothing."

What are the skin findings in hypervolemia?

"Edema; tight skin; weeping or oozing fluid from the skin surface; extra moist mucous membranes."

What are the cardiovascular findings in hypervolemia?

"Bounding pulse; jugular venous distension (JVD); tachycardia; and hypertension."

What are the respiratory findings in hypervolemia?

"Increased respiratory rate; crackles in the lungs; frothy sputum; and dyspnea."

What neurological symptoms can occur with hypervolemia?

"Confusion; disorientation; and headache — due to decreased oxygen availability from fluid overload."

What are the skin findings in hypovolemia?

"Dry; flaky; cracked skin; decreased skin turgor."

What are the mucous membrane findings in hypovolemia?

"Dry; cracked; dull mucous membranes — not glossy or pink."

What cardiovascular findings occur with hypovolemia?

"Orthostatic hypotension; delayed capillary refill; flat jugular veins; tachycardia; and weak or thready pulse."

What are the respiratory findings in hypovolemia?

Clear lung sounds — no crackles and no third spacing present.

What GI symptoms occur with hypovolemia?

"Hypoactive bowel sounds and constipation — the bowel pulls water from stool making it hard and dry; difficult to move."

What neurological symptoms occur with hypovolemia?

"Confusion; dizziness; disorientation; and headache."

What is orthostatic hypotension?

A drop in blood pressure when moving from lying or sitting to standing — a sign of dehydration or hypovolemia.

Why are dehydrated patients hard to start an IV on?

Dehydration causes veins to flatten and collapse; making venipuncture difficult.

What diagnostic tests are used to assess fluid and electrolyte balance?

"CBC; urinalysis (UA); urine specific gravity; serum calcium; magnesium; BMP (sodium; potassium; BUN; creatinine); CMP; chest X-ray; and echocardiogram."

What does urine color indicate about hydration?

"Dark or amber or yellow = dehydrated. Clear = overhydrated (hypervolemia). Normal = yellow and clear."

What is the normal urine specific gravity range?

1.005 to 1.030.

What does an increased urine specific gravity indicate?

Dehydration or heart failure.

What does a decreased urine specific gravity indicate?

Renal damage.

What is the normal urine pH range?

4.5 to 8.0.

What is the normal serum sodium level?

135–145 mEq/L.

What is the role of sodium in the body?

Fluid balance regulation; it has a direct effect on mental status and neurological health because it controls water balance.

What is hypernatremia and its primary symptom?

Too much sodium; the primary symptom is thirst and dryness.

What is hyponatremia and its symptoms?

"Not enough sodium; causes weakness; lethargy; and decreased level of consciousness."

What are high-sodium foods mentioned in the lecture?

"Canned foods; processed foods; ramen; fast food; bacon; canned soups; pickles; popcorn; and diet soda."

What is the normal serum potassium level?

3.5–5.0 mEq/L.

Why is potassium especially dangerous outside its normal range?

It has a profound effect on heart rate and rhythm — levels outside normal can cause life-threatening arrhythmias.

What is the role of potassium in the body?

"Vital for cardiac; skeletal; and smooth muscle contraction."

What is hyperkalemia and what cardiac effect does it cause?

"Too much potassium; causes bradycardia (slow heart rate); low blood pressure; and muscle twitching."

What is hypokalemia and what does it cause?

"Not enough potassium; causes cardiac fatigue and hypotension."

What should a nurse do if a patient's potassium is 2.8 mEq/L?

Call the doctor immediately — it is an emergency. Also check and document vital signs.

Where is potassium typically administered and why is it monitored so closely?

Usually in the ICU or closely monitored med-surg settings with a specific drip rate because it directly affects the heart and can cause a fatal cardiac event if given incorrectly.

Name four potassium-rich foods mentioned in the lecture.

"Bananas; avocados; dried fruits; and beef."

Why do people with muscle cramps get told to eat bananas?

Bananas are high in potassium which is essential for muscle contraction; low potassium can cause cramping.

What is the normal serum magnesium level?

1.5–2.5 mEq/L.

What are the three functions of magnesium in the body?

"Muscle and nerve function; energy production; and blood pressure regulation."

What is hypermagnesemia and its effects?

Too much magnesium; causes decreased respiration and bradycardia — requires urgent intervention.

What is hypomagnesemia and its effects?

"Not enough magnesium; causes tremors; muscle weakness; and cardiac dysrhythmias — requires urgent intervention."