fluids flashcards

1. What is the body made of and why does balance matter? The body is composed of fluids, electrolytes, and acid-base components that must be in balance. Most diseases can disrupt this balance.

2. What percentage of the brain, blood, muscles, and bones is water? Brain: 75%, Blood: 83%, Muscles: 75%, Bones: 22%

3. What are the key functions of water in the body? Regulates temperature, moistens oxygen, helps convert food to energy, removes waste, cushions organs, and helps nutrient absorption.

4. What do electrolytes help with? Transmission of nerve impulses and muscle contraction.

5. Why is acid-base balance crucial? Body must maintain a narrow pH range to avoid disrupted biologic processes.

6. What are the three systems that regulate pH? Buffers, respiratory system (CO2), renal system (HCO3-)

7. What does pH tell you? Hydrogen ion concentration: Low pH = acidic = more H+; High pH = alkalotic = less H+

8. Normal pH values of body fluids? Urine: 5.0–6.0; Gastric: 1.0–3.0; Arterial Blood: 7.38–7.42; Venous Blood/CSF: 7.32–7.37; Pancreatic Fluid: 7.8–8.0

9. Major fluid compartments in the body? Intracellular Fluid (ICF) and Extracellular Fluid (ECF)

10. Major ICF ions? High K+, moderate Mg++, small amounts of Na+, Ca++, Cl-, HCO3-, phosphate

11. Major ECF ions? High Na+, Cl-, includes interstitial, intravascular, CSF, and other specialized fluids

12. TBW by age group? Newborns: 75%, Children: 60–65%, Adults: 50–60%, Older Adults: lower. Obesity = less water.

13. What is diffusion? Particles move from high to low concentration.

14. What is osmosis? Water moves across a membrane from lower solute to higher solute concentration.

15. What is tonicity? The osmotic effect on cells:

• Isotonic = no change

• Hypotonic = cells swell

• Hypertonic = cells shrink

16. How much water is needed daily? 100 mL per 100 calories. More with fever/exercise.

17. How does the body protect ECF volume? Via vasoconstriction, HR changes, and sodium/water balance.

18. What causes edema? Increased hydrostatic pressure, decreased oncotic pressure, increased permeability, lymph obstruction

19. Conditions that cause edema? CHF, renal/liver failure, DVT, pregnancy, lymph obstruction, malnutrition, inflammation

20. Types of edema? Localized, general, dependent, pitting

21. How to assess edema? Daily weight, visual checks, measuring limb, pitting test

22. How to treat edema? Elevate limbs, compression, reduce salt, diuretics

23. Water balance regulation mechanisms? Thirst (intake), ADH (output)

24. How to assess for body fluid loss? Weight, BP, HR, refill, volume signs, history

25. Where are electrolytes found? In both ICF and ECF, but concentrations differ

26. Main ICF electrolyte? Potassium (K+), also phosphate and organic ions

27. Main ECF electrolytes? Sodium (Na+), chloride (Cl-), bicarbonate (HCO3-)

28. Sodium regulation systems? Kidneys, SNS, RAAS, ADH, ANP

29. Normal Na+ levels and regulation? 135–145 mEq/L; regulated by aldosterone and water volume

30. Water balance control mechanisms? Baroreceptors, RAAS, ADH, ANP

31. Sodium roles? Osmotic regulation, nerve impulses, acid-base balance

32. Chloride roles? Main ECF anion, maintains neutrality, follows Na+

33. What is the role of aldosterone? Reabsorbs Na+, secretes K+, helps blood volume

34. What does ADH do? Reabsorbs water in response to high osmolality or low volume

35. Hypernatremia definition and signs? Na+ >145, causes dehydration; symptoms: seizures, twitching

36. Water deficit signs and treatment? Low BP, weak pulse, dry mucosa, treat with fluids

37. Hyponatremia and water excess? Na+ <135; causes swelling, cramps, lethargy; treat with restriction or hypertonic salineHyponatremia
Definition: Serum sodium < 135 mEq/L
Mechanism: Sodium deficit → plasma hypoosmolality → cellular swelling
Types: Hypovolemic, Euvolemic, Hypervolemic
S/S: Lethargy, headache, confusion, apprehension, seizures, coma
Tx: Treat underlying disorder; water restriction

Hypernatremia
S/S: Thirst, polydipsia, oliguria/anuria, dry mucous membranes, low turgor, headache, agitation, tachycardia, weak pulse
Effect: Cells shrink

Potassium Overview
ECF: 3.5–5.0 mEq/L
ICF: 140–150 mEq/L
Regulation: Na+/K+ pump, aldosterone, insulin, epinephrine, pH changes
Functions: Nerve conduction, cardiac rhythm, muscle contraction, glycogen storage

Potassium Imbalances: Dx & Tx
Dx: Hx, physical, K+ levels, ECG
Tx:

• Calcium to antagonize K+ effects

• Sodium bicarbonate → K+ shift into cells

• Insulin + glucose → K+ shift into cells

• Increase renal excretion, reduce intake

Hypokalemia
K+ < 3.5 mEq/L
Causes: Reduced intake, increased entry into cells, loss via GI/renal/skin
S/S: Decreased excitability, confusion, weakness, cramps, atony, dysrhythmias, postural hypotension, U wave on ECG
Tx: Oral/IV K+ replacement

Hyperkalemia
K+ > 5.0 mEq/L (Rare due to efficient kidneys)
Causes: Intake, ICF → ECF shift, renal failure, trauma, acidosis, digitalis OD
S/S Mild: Tingling, restlessness, diarrhea, tall T waves
S/S Severe: Weakness, paralysis, dysrhythmias, wide QRS, prolonged PR
Tx: Calcium gluconate, insulin + glucose, buffered solution, dialysis

Calcium, Phosphate, Magnesium Regulation
Regulatory Hormones:

• PTH → increases Ca2+

• Vitamin D → increases Ca2+/PO4- absorption

• Calcitonin → decreases Ca2+

Calcium Overview
Ionized: 5.5–5.6 mg/dL
Total Location: 99% in bone, 1% in plasma/cells
Functions: Bone/teeth, clotting, hormone secretion, receptor, muscle contraction
Forms in ECF: Protein-bound (40%), complexed (10%), ionized (50%)

Hypocalcemia
Ca2+ < 9.0 mg/dL
Causes: Low intake/absorption, low PTH/Vit D, transfusions
S/S: Spasms, Chvostek/Trousseau, tetany, convulsions
Tx: Ca2+ replacement, decrease phosphate

Hypercalcemia
Ca2+ > 10.5 mg/dL
Causes: Hyperparathyroid, bone metastasis, vitamin D excess, immobilization, acidosis
S/S: Weakness, stones, constipation, heart block
Tx: Phosphate, IV NS, bisphosphonates, calcitonin, denosumab

Phosphate Overview
Serum: 2.5–4.5 mg/dL
Functions: ATP, buffer, DNA/RNA, RBC O2 delivery
Inverse relation with calcium

Hypophosphatemia
<2.0 mg/dL
Causes: Malabsorption, antacids, alcoholism, refeeding syndrome
S/S: Soft bones, muscle weakness, platelet dysfunction, leukocyte change, rickets
Tx: Treat cause (e.g. alkalosis), replace phosphate

Hyperphosphatemia
>4.7 mg/dL
Causes: Renal failure, phosphate enemas/laxatives, cell destruction
S/S: Like hypocalcemia, soft tissue calcification
Tx: Aluminum hydroxide, dialysis, treat cause

Magnesium Overview
Serum: 1.5–3.0 mg/dL
Stored in: Bone, muscle
Functions: ATP reactions, protein/nucleic acid synthesis, neuromuscular control

Hypomagnesemia
<1.8 mg/dL
Causes: Malabsorption, alcoholism, diarrhea
S/S: Tetany, seizures, increased reflexes, Chvostek, Trousseau, tachycardia
Tx: Magnesium sulfate

Hypermagnesemia
>3.0 mg/dL
Causes: Renal failure, magnesium-based meds
S/S: Weakness, hypotension, bradycardia, respiratory depression
Tx: Stop magnesium, dialysis

Acid-Base Balance Overview
pH Normal: 7.35–7.45
Main ions: H+ and HCO3⁻
Organs: Lungs, kidneys, bones

Buffer Systems
Major Buffers:

• Carbonic acid-bicarbonate (ECF)

• Protein buffering (hemoglobin)

• Renal buffering (urinary H+ excretion, HCO3⁻ reabsorption)

• Respiratory buffering (ventilation rate)

Acidosis vs. Alkalosis
Acidosis: pH < 7.35 (High H+)
Alkalosis: pH > 7.45 (Low H+)

Respiratory Acidosis
Cause: Hypoventilation (CO2 retention)
S/S: Headache, lethargy, tremors, coma
Tx: Improve ventilation

Respiratory Alkalosis
Cause: Hyperventilation (CO2 loss)
S/S: Dizziness, confusion, paresthesia, cramps
Tx: Slow breathing, rebreathing

Metabolic Acidosis
Cause: Acid gain or HCO3⁻ loss
S/S: Kussmaul respirations, headache, lethargy
Tx: Buffer, correct underlying cause
Anion gap: Used to ID cause

Metabolic Alkalosis
Cause: H+ loss, HCO3⁻ gain (e.g. vomiting, diuretics)
S/S: Weakness, cramps, hypocalcemia signs
Tx: Replace Cl⁻, K+, fluids