Patho: EXAM 1 Acid/Base Study Guide

Patho Exam 1

What are the normal blood pH, PaCO₂, and HCO₃⁻ values?

pH: 7.35–7.45, PaCO₂: 35–45 mmHg, HCO₃⁻: 22–26 mEq/L.

What is the overall rule for acid–base balance in the body?

pH is controlled by the ratio of CO₂ (acid) to HCO₃⁻ (base).

What causes respiratory acidosis? Give example disease 

Hypoventilation (not breathing out CO2 → CO₂ buildup), Examples: COPD (lungs trap air), drug overdose (slows breathing), pneumonia (impaired gas exchange).

Why does hypoventilation cause acidosis?

CO₂ + H₂O forms carbonic acid → excess CO₂ = more acid → ↓ pH.

What are the lab findings in respiratory acidosis?

pH ↓, CO₂ ↑, HCO₃⁻ normal (acute) or ↑ (chronic kidney compensation).

What are signs/symptoms of respiratory acidosis?

Headache, confusion, lethargy, because high CO₂ = sleepy brain (“CO₂ narcosis”).

What causes respiratory alkalosis? give examples

Hyperventilation (breathing too much CO2 → CO₂ loss), e.g., PASE: pain, anxiety, sepsis, early aspirin overdose.

Why does hyperventilation cause alkalosis?

Too little CO₂ = too little carbonic acid → blood becomes too basic → ↑ pH.

What are the lab findings in respiratory alkalosis?

pH ↑, CO₂ ↓, HCO₃⁻ normal (acute) or ↓ (chronic renal compensation).

What are signs/symptoms of respiratory alkalosis?

Lightheadedness, tingling, tetany, seizures (due to ↓ ionized Ca²⁺).

Which system acts fast to correct pH — lungs or kidneys?

Lungs act fast (minutes to hours). Kidneys act slow (hours to days).

What causes metabolic acidosis?

Too much acid (DKA, lactic acidosis, renal failure) or loss of HCO₃⁻ (diarrhea).

Why does too much acid or too little bicarbonate cause acidosis?

Extra H⁺ or decreased base lowers blood pH.

What are the lab findings in metabolic acidosis?

pH ↓, HCO₃⁻ ↓, CO₂ ↓ (if lungs hyperventilate to compensate).

What are signs/symptoms of metabolic acidosis?

K.C.H “Kush” = Kussmaul respirations (deep, rapid breathing), confusion, hypotension.

What causes metabolic alkalosis?

VAND = Vomitting, Antacid, NG tube, Diuretics

Why does vomiting or antacid use cause alkalosis?

Losing stomach acid (vomiting) or adding extra base (antacids) makes blood more alkaline (↑ pH).

What are the lab findings in metabolic alkalosis?

pH ↑, HCO₃⁻ ↑, CO₂ ↑ (if lungs hypoventilate to compensate).

What are signs/symptoms of metabolic alkalosis?

HAM = Hypokalemia, arrhythmias, muscle cramps. Muscles need K⁺ for strength & relaxation. Heart needs K⁺ for steady pumping.

What acid–base imbalance can diuretics cause?

Metabolic alkalosis. you pee out too much potassium and hydrogen so you lose acid. = blood turns alkaline

What acid–base imbalance does vomiting cause?

Metabolic alkalosis (loss of stomach acid → ↑ pH, ↑ HCO₃⁻).

What acid–base imbalance does diarrhea cause?

Metabolic acidosis (loss of bicarbonate → ↓ pH, ↓ HCO₃⁻).

How does the respiratory system compensate for acid–base imbalance?

Acts fast (minutes); adjusts CO₂ by changing ventilation (hyperventilation = blow off CO₂, hypoventilation = retain CO₂).

How does the renal system compensate for acid–base imbalance?

Acts slow (hours–days); adjusts HCO₃⁻ by reabsorbing or excreting it.

Give an example of respiratory compensation for metabolic acidosis.

Lungs hyperventilate to blow off CO₂ (acid) → pH rises toward normal.

Give an example of renal compensation for respiratory acidosis.

Kidneys retain HCO₃⁻ and excrete H⁺ to buffer the excess acid.

mnemonic for Respiratory Acidosis (cause + s/s)

CHPD (COPD, hypoventilation, pneumonia, drug overdose) + HCL (headache, confusion, lethargy sleepy brain)

mnemonic for Respiratory Alkalosis (cause + s/s)

HAPAS (hyperventilation, anxiety, pain, aspirin easy sign, sepsis) + TNT SL (tetany, numbing, tingling, seizure, lightheadedness)

mnemonic for Metabolic Acidosis (cause + s/s)

DDRL (diarrhea, DKA, renal failure, lactic acidosis) + KCH (kussmaul breathing, confusion, hypotension)

mnemonic for Metabolic Alkalosis (cause + s/s)

VAND (vomiting, antiacid, NG tube, diuretics) + HAM (hypokalemia, arrhythmia, muscle cramps)