Acid-Base Balance

What is the normal blood pH range?

7.35 to 7.45

What pH level indicates a critically ill patient?

pH below 7.0

What does a pH below 7.35 indicate?

Acidosis (too acidic for human blood)

What does a pH above 7.45 indicate?

Alkalosis (too alkalotic for human blood)

How does hydrogen presence affect blood pH?

More hydrogen makes blood more acidic; less hydrogen makes it more alkalotic.

What is metabolic acidosis?

Excessive accumulation of free hydrogen causing pH to drop below 7.35.

What are common causes of metabolic acidosis?

Septic patients, diabetic ketoacidosis, hypoperfusion states, and lactic acidosis.

What happens during cellular processes in metabolic acidosis?

Cells switch from aerobic to anaerobic metabolism, producing excess CO2 and lactate.

What is the body's response to metabolic acidosis?

Increased respiratory rate to excrete CO2 and compensate for acidosis.

What defines respiratory acidosis?

CO2 levels above 45 mmHg due to impaired ventilation.

What are common causes of respiratory acidosis?

COPD exacerbation, pneumonia, lung cancer, asthma, and anaphylaxis.

How does the body compensate for respiratory acidosis?

By producing excessive bicarbonate over hours to days.

What defines respiratory alkalosis?

CO2 levels below 35 mmHg due to excessive CO2 excretion.

What are common causes of respiratory alkalosis?

Hyperventilation, anxiety, and compensation for metabolic acidosis.

What defines metabolic alkalosis?

pH rises above 7.45 due to hydrogen depletion or excessive bicarbonate.

What are common causes of metabolic alkalosis?

Excessive vomiting and over-ingestion of certain medications.

What is the bicarbonate and carbonic acid buffer system equation?

HCO3^- + H^+ ↔ H2CO3 ↔ CO2 + H2O

What role does bicarbonate play in pH balance?

It combines with free hydrogen to create carbonic acid, helping to buffer pH.

What is the significance of carbonic acid in the buffer system?

It is a weak acid that helps maintain pH balance in the blood.

What is Kussmaul respiration?

Elevated respiratory rate seen in severe metabolic acidosis.

What is the typical end-tidal CO2 level in metabolic acidosis?

Low to mid-30s or sometimes in the 20s.

How does lactic acidosis occur?

When cells cannot maintain aerobic metabolism, leading to lactate accumulation.

What is the effect of excessive bicarbonate in metabolic alkalosis?

It can lead to a rise in blood pH above 7.45.

What is carbonic acid composed of?

Bicarbonate and hydrogen.

How can carbonic acid be excreted from the body?

It can be split into CO2 and water for excretion via the lungs or kidneys.

What does a bidirectional arrow in an equation indicate?

Dynamic equilibrium, meaning components can freely morph between states.

What is the key advantage of buffering in acid-base balance?

It converts strong acids into weak acids, minimizing pH impact.

What happens to carbonic acid when ventilation is impaired?

It cannot be excreted and will eventually split back to hydrogen, causing acidosis.

Where does bicarbonate primarily originate?

From liver biotransformation of lactate produced during ATP generation.

What occurs during metabolic acidosis regarding bicarbonate?

Bicarbonate is rapidly consumed to buffer excess hydrogen, leading to low bicarbonate levels.

What is the process of respiratory compensation?

Lungs increase ventilation to excrete CO2 and reduce hydrogen levels.

What indicates that the respiratory system is compensating for metabolic acidosis?

Low CO2 with high hydrogen and low bicarbonate levels.

What is metabolic compensation and when does it occur?

Kidneys increase bicarbonate production/retention, occurring in chronic cases.

What are the two primary methods of pH control in the body?

Buffering and excretion.

What is the body's immediate response to pH changes?

It attempts to correct through buffering.

What are primary causes of pH derangement?

Increased metabolic demand, hypoperfusion/shock, ventilation compromise, and excess waste accumulation.

How frequently is acidosis encountered in clinical settings?

It is a major clinical problem, regularly encountered in pre-hospital care.

What does a low end-tidal CO2 (ETCO2) indicate in metabolic acidosis?

It indicates that respiratory compensation is occurring.

What does low bicarbonate indicate in blood gas analysis?

It indicates metabolic acidosis due to buffering of hydrogen.

What is the blood gas interpretation pattern for metabolic acidosis?

High H+, low HCO3-, normal-to-low CO2.

What is the blood gas interpretation pattern for respiratory acidosis?

High H+, normal HCO3-, high CO2 (acute) or high HCO3-, high CO2 (chronic).

What is the blood gas interpretation pattern for metabolic alkalosis?

Low H+, high HCO3-, normal-to-high CO2.

What is the blood gas interpretation pattern for respiratory alkalosis?

Low H+, normal HCO3-, low CO2 (acute) or low HCO3-, low CO2 (chronic).