Chapter 35 - Hydration and Homeostasis

Fundamentals of Nursing; Exam 6

What is intracellular fluid and its significance?

Intracellular fluid is contained within cells, essential for cell function and metabolism, accounting for approximately 40% of body weight.

What is extracellular fluid (ECF) and its role?

Extracellular fluid is outside the cells, carrying water, electrolytes, nutrients, and oxygen to cells while removing waste products. It accounts for 20% of body weight.

What are the three main locations of extracellular fluid?

Interstitial fluid, intravascular fluid, and transcellular fluid.

What is interstitial fluid?

Fluid that lies in the spaces between body cells; excess fluid in this space is called edema.

What is intravascular fluid?

Plasma within the blood, primarily responsible for transporting blood cells.

What is transcellular fluid?

Specialized fluids such as cerebrospinal, pleural, peritoneal, and synovial fluid, as well as digestive juices.

What is third spacing in fluid movement?

Fluid movement into an area that makes it physiologically unavailable, such as peritoneal space in ascites or pericardial space in effusion.

What is osmosis?

The movement of water across a membrane from an area of less concentrated solution to an area of more concentrated solution.

What is diffusion?

A passive process where solute molecules move through a membrane from an area of higher concentration to lower concentration until equalized.

What is filtration in the context of fluid movement?

The movement of water and smaller particles from an area of high pressure to low pressure, driven by hydrostatic pressure.

What is active transport?

The movement of molecules across cell membranes from low to high concentration, requiring energy (ATP).

How is fluid intake primarily achieved?

Through drinking fluids, with recommendations of 2,700 mL/day for women and 3,700 mL/day for men, plus 20% from food/metabolism.

What regulates fluid intake?

Thirst regulated by changes in plasma osmolality, controlled by the hypothalamus.

What are the main routes of fluid output?

Urine (1,500 mL/day), skin (perspiration), lungs (exhalation), and feces (100 to 200 mL/day).

What is the role of antidiuretic hormone (ADH) in fluid regulation?

ADH causes kidneys to retain fluid; its release is stimulated by low fluid volume or increased serum osmolality.

What is the renin-angiotensin system?

A response to decreased extracellular fluid volume that triggers renin release, leading to sodium and water retention.

How does aldosterone affect fluid balance?

Aldosterone stimulates sodium reabsorption in the kidneys, leading to passive water reabsorption and increased plasma volume.

What is the effect of thyroid hormone on fluid volume?

Thyroid hormone influences cardiac output, affecting glomerular filtration rate and urine output.

What is natriuresis?

The discharge of sodium through urine, which can indicate heart failure with fluid excess.

What is the function of calcium in the body?

Calcium is crucial for bone health, neuromuscular function, cardiac function, and blood clotting.

What can lead to calcium insufficiency?

Insufficient calcium can lead to osteoporosis.

What is the role of magnesium in the body?

Magnesium is found in intracellular fluid and bones, supporting many cellular functions.

What can cause low levels of magnesium?

Alcoholism can lead to low magnesium levels.

What is chloride's role in the body?

Chloride is an extracellular fluid component, typically bound to other ions.

What happens to calcium levels when serum levels drop?

Calcium leaches from the bones into the blood to compensate.

What condition can result from prolonged calcium deficiency?

Osteoporosis.

Where is most magnesium found in the body?

99% of magnesium is found in the intracellular fluid (ICF) and bone.

What can cause magnesium depletion?

High alcohol intake and certain malabsorption disorders.

What is chloride's role in the extracellular fluid?

Chloride is the most abundant anion and is usually bound with sodium or potassium.

How much chloride should a healthy adult consume daily?

2.3 grams of chloride along with 1.5 grams of sodium.

What is hypovolemia?

A proportional loss of fluid and electrolytes from the extracellular fluid (ECF).

What is dehydration?

A state of negative fluid balance with loss of water from various body compartments.

What percentage of body weight loss is considered clinically significant?

A sudden loss of 5% of body weight.

What are signs of fluid overload?

Elevated blood pressure, bounding pulse, increased and shallow respirations, distended neck veins, and edema.

What lab values indicate fluid volume deficit?

Elevated blood urea nitrogen (BUN)-to-creatinine ratio and elevated hematocrit.

What is acidosis?

A condition with serum pH below 7.35.

What causes respiratory acidosis?

Retention of CO2.

What is alkalosis?

A condition with serum pH above 7.45.

What is the first step in interpreting arterial blood gases?

Examine the pH to determine if it is acidotic, alkalotic, or normal.

What dietary changes can promote fluid and electrolyte balance?

Limit sodium intake and increase dietary potassium and calcium.

What should clients be cautious about when using potassium supplements?

Salt substitutes may contain potassium, which can lead to excess intake.

What is the purpose of isotonic solutions in IV therapy?

They remain inside the blood vessels and are useful for clients with hypotension or hypovolemia.

What is a risk of administering hypotonic solutions?

They can exacerbate cerebral edema in patients at risk for increased intracranial pressure (ICP).

What is the effect of hypertonic fluids?

They pull fluids and electrolytes from intracellular and interstitial compartments into the intravascular compartment.

What are the signs of severe fluid overload?

Moist crackles in the lungs, dyspnea, and ascites.

What are the types of vascular access approaches?

Peripheral, Central, Intraosseous, and Subcutaneous infusions.

What is an over-the-needle catheter also known as?

An angiocath or angiocatheters.

What is the maximum length of an over-the-needle catheter?

Less than 7.5 cm (3 inches).

What types of solutions should not be administered through an over-the-needle catheter?

Highly irritating or hyperosmolar solutions.

What is the purpose of a butterfly needle?

Used for single-dose medications and drawing blood.

What is the typical duration for using a midline peripheral catheter?

1 to 4 weeks.

What is a peripheral intravenous lock?

A venous route established for clients needing intermittent infusion therapy.

What is a PICC line?

A peripherally inserted central catheter used for prolonged IV therapy.

Where is a nontunneled central venous catheter typically inserted?

Into the jugular, subclavian, or occasionally femoral veins.

What is the advantage of tunneled central venous catheters?

They have a lower risk of infection due to being tunneled through the skin.

What is the purpose of implanted ports?

To provide a completely implanted subcutaneous reservoir for medication administration.

What is the most common access site for intraosseous devices?

The proximal tibia.

What are the advantages of subcutaneous infusions?

Low cost, ease of use, and low infection and complication rates.

What should be done before starting a blood transfusion?

Verify the written prescription and obtain a set of vital signs.

What is the recommended action if a transfusion reaction occurs?

Stop the transfusion, assess the patient, and notify the provider.

What is critical to identify when transfusing blood?

The patient and the blood product.

What should be monitored during the first 5-10 minutes of a blood transfusion?

Monitor for transfusion reactions.

What should be done if a patient's temperature is elevated before a transfusion?

Inform the primary care provider.

What is the purpose of keeping the vein open with normal saline during a transfusion reaction?

To maintain venous access while addressing the reaction.

What is the role of premedication before a transfusion?

To help prevent transfusion reactions in patients with elevated temperatures.