25.6 Acid Base Balance disturbances

Which of the following correctly distinguishes between an acid-base disturbance, compensation, and an acid-base imbalance?

A disturbance occurs when buffering capacity is exceeded; compensation is the physiological response to restore pH; and an imbalance is a persistent, life-threatening pH change.

Respiratory acidosis is clinically recognized when arterial $PCO_2$ rises above 45 mm Hg. Which of the following best describes how this disturbance occurs and identifies a potential cause?

It occurs due to hypoventilation, leading to $CO_2$ accumulation and increased $H^+$ levels; a common cause is airway obstruction or emphysema.

Why are infants more susceptible to respiratory acidosis compared to healthy adults?

They have smaller lungs and a lower residual volume, making $CO_2$ elimination less effective.

Respiratory alkalosis is an acid-base disturbance characterized by a blood pH above 7.45. Which of the following correctly identifies the primary cause and the physiological mechanism behind this condition?

Hyperventilation; it leads to excessive elimination of CO_2, causing the chemical reaction to shift left and decrease H+ levels.

Which of the following best describes the fundamental difference between a respiratory acid-base disturbance and a metabolic acid-base disturbance?

Respiratory disturbances involve abnormal concentrations of CO_2, while metabolic disturbances involve abnormal concentrations of HCO_3- (bicarbonate).

Which of the following correctly defines a metabolic acid-base disturbance and matches it with a common clinical cause?

Metabolic acidosis is a decrease in HCO3- often caused by severe diarrhea or the accumulation of lactic acid.

Which of the following correctly describes the process of compensation used by the body to restore acid-base balance?

Respiratory compensation for metabolic acidosis involves increasing the breathing rate to "blow off" CO2, which lowers H+ levels.

Hypoventilation

breathing that is two slow or shallow; decline in breathing depth

In clinical practice, how is a compensated acid-base disturbance distinguished from an uncompensated acid-base imbalance?

In a compensated disturbance, the pH has returned to the normal range, whereas in an uncompensated imbalance, the pH remains outside the 7.35–7.45 range.

If an individual begins to hyperventilate (breathing that is too rapid or too deep), what shifts will occur in their arterial blood chemistry?

Blood CO2 decreases; H+ concentration decreases; Blood pH increases.

Metabolic alkalosis is characterized by a bicarbonate (HCO3-) level above 26 mEq/L. According to clinical data, what is the most common cause of this acid-base disturbance?

Persistent vomiting, which results in the significant loss of acidic stomach secretions.

How does renal compensation specifically affect blood plasma levels of bicarbonate (HCO3-) when the body is responding to respiratory acidosis?

Blood HCO3- levels increase because Type A intercalated cells synthesize and reabsorb new bicarbonate into the blood.

How does respiratory compensation affect arterial $Pa_{CO2}$ levels when the body is responding to metabolic acidosis?

$Pa_{CO2}$ decreases because the respiratory rate increases to "blow off" more $CO_2$.

Arterial Blood Gas (ABG) samples are a primary tool for clinicians managing patients with metabolic or respiratory disorders. What is the clinical purpose of an ABG, and which variables are measured?

To diagnose and monitor acid-base disturbance and compensation; it includes pH, $Pa_{CO2}$, and $HCO_3^-$.