Hypertonic solution example

3% sodium chloride

Hypertonic solution purpose

Shrink swollen cells by pulling water out

Isotonic solutions

0.9% NS, Lactated Ringer’s

D5W classification

Becomes hypotonic after metabolism

Older adults fluid risk

Higher dehydration risk due to decreased thirst and poor kidney regulation

Diabetes insipidus hallmark

Excessive dilute urine

DI treatment

Desmopressin (DDAVP)

SIADH mechanism

Too much ADH causing water retention

SIADH findings

Low urine output, no edema, headache, hyponatremia symptoms

Isotonic fluid volume deficit cause

Severe diarrhea (e.g., C. difficile)

Heat exhaustion signs

Sunken eyes, dizziness, mild fever

Heat exhaustion treatment

Oral electrolyte solution (not plain water)

Fluid volume excess signs

Bounding pulse, crackles, severe edema

Hyponatremia causes

Psychogenic polydipsia, SIADH, excess water intake

Hyponatremia symptoms

Muscle weakness, lethargy, headache, seizures

Hypokalemia ECG

Prominent U wave, flattened T wave

Hyperkalemia definition

K⁺ > 5.2 mEq/L

Hyperkalemia symptoms

Numbness, tingling, weakness, palpitations

Hyperkalemia risk

Life-threatening arrhythmias

Hypercalcemia cause

Hyperparathyroidism

Hypercalcemia complication

Kidney stones; check PTH level

Hypocalcemia signs

Muscle spasms, tingling, tetany

Hypocalcemia association

Seen in kidney disease

Phosphate replacement uses

Alcoholic ketoacidosis, platelet dysfunction, muscle weakness

Importance of pH

Chemical reactions require narrow pH range

Carbonic anhydrase role

Converts CO₂ + H₂O to carbonic acid; essential for acid–base balance

Metabolic acidosis causes

Ketoacidosis, lactic acidosis, renal failure

Metabolic acidosis diagnostics

Increased anion gap, base deficit

Ethylene glycol poisoning treatment

Fomepizole

Aspirin overdose early

Respiratory alkalosis (RR ~40)

Aspirin overdose ABG

pH ↑, CO₂ ↓, HCO₃ ↓

Aspirin overdose late

Mixed acidosis

Metabolic alkalosis causes

Excess antacids, vomiting, diuretics

Metabolic alkalosis treatment

IV KCl and volume correction

Respiratory acidosis causes

Hypoventilation, COPD exacerbation, opioid overdose

Respiratory acidosis symptoms

Headache, blurred vision, twitching, paresthesias, numbness

Respiratory alkalosis use

Used therapeutically to lower ICP

Respiratory acidosis compensation

Kidneys increase HCO₃⁻ reabsorption

Metabolic acidosis compensation

Lungs hyperventilate (Kussmaul breathing)

Respiratory acidosis ABG

pH ↓, CO₂ ↑, HCO₃ normal or ↑

Respiratory alkalosis ABG

pH ↑, CO₂ ↓, HCO₃ normal or ↓

Metabolic acidosis ABG

pH ↓, HCO₃ ↓, CO₂ ↓ (compensation)

Metabolic alkalosis ABG

pH ↑, HCO₃ ↑, CO₂ ↑ (compensation)

Post-bypass confusion cause

Lactic acidosis from rapid carbohydrate load

COPD oxygen target

SpO₂ 88–92%

COPD oxygen rule

Avoid rigid “no more than 3 L/min” rules

COPD oxygen device

Venturi mask for precise FiO₂