Acid-Base Disorders

Vocabulary flashcards covering primary acid-base disorders, buffer mechanisms, normal blood gas values, compensation responses, and serum anion gap calculations from lecture notes.

Acid

A substance that can donate protons (hydrogen ions, $H^+$), such as hydrochloric acid ($HCl$).

Base

A substance that can accept protons (hydrogen ions, $H^+$), such as ammonia ($NH_3$).

Acidemia

A clinical state characterized by low blood pH values ($<7.35$).

Alkalemia

A clinical state characterized by high blood pH values ($>7.45$).

Henderson-Hasselbalch Equation (Acid-Base)

The equation used to determine blood pH, expressed as $pH = 6.1 + \text{log}\frac{[HCO_3^-]}{0.03 \times pCO_2}$.

Basic Metabolic Panel (BMP) Bicarbonate Reporting

Laboratory reporting where bicarbonate is reported as $CO_2$ because it is measured as total dissolved $CO_2$, which is approximately $95\text{\%}$ bicarbonate.

Normal Arterial Blood Gas (ABG) Values

Standard arterial blood reference values: pH $7.35-7.45$, $PO_2$ of $80-100\text{\text{ mmHg}}$, $SaO_2$ of $95\text{\%}$, $PCO_2$ of $35-45\text{ mmHg}$, and $HCO_3^-$ of $22-26\text{ mEq/L}$.

Extracellular Buffering

The rapid first defense mechanism against a sudden increase in hydrogen ion concentration, comprising the bicarbonate/carbonic acid system, proteins, and phosphates.

Ventilatory Regulation

The second process maintaining acid-base homeostasis, in which changes in pulmonary ventilation alter blood $PCO_2$ to regulate carbonic acid levels, maintaining $PCO_2$ at approximately $40\text{ mmHg}$.

Renal Regulation

The renal process that independently regulates blood bicarbonate concentration by filtration at the glomerulus and reabsorption in the proximal tubule through the apical $Na^+-H^+$ exchanger, maintaining serum bicarbonate at approximately $24\text{ mEq/L}$.

Respiratory Acidosis

An acid-base disorder characterized by a $pH < 7.4$ with a primary disturbance of increased $PCO_2$ resulting from hypoventilation, compensated by an increased $HCO_3^-$ concentration.

Respiratory Alkalosis

An acid-base disorder characterized by a $pH > 7.4$ with a primary disturbance of decreased $PCO_2$ resulting from hyperventilation, compensated by a decreased $HCO_3^-$ concentration.

Metabolic Acidosis

An acid-base disorder characterized by a $pH < 7.4$ resulting from a primary decrease in serum bicarbonate ($HCO_3^-$) concentration, compensated by a decreased $PCO_2$.

Metabolic Alkalosis

An acid-base disorder characterized by a $pH > 7.4$ with a primary disturbance of increased $HCO_3^-$ resulting from gain of $HCO_3^-$ or loss of $H^+$, compensated by an increased $PCO_2$.

Respiratory Compensatory Response

A rapid compensatory response occurring within minutes to hours that alters the rate and depth of respiration to correct the $HCO_3^-$ to $PCO_2$ ratio.

Metabolic Compensatory Response

A slow compensatory response occurring over days that involves the excretion or reabsorption of $HCO_3^-$ by the kidneys, excretion of $H^+$, or generation of new $HCO_3^-$.

Serum Anion Gap (SAG)

A parameter calculated to maintain electroneutrality in serum using the formula $SAG = [Na^+] - [Cl^-] - [HCO_3^-]$, with a normal value of $10\text{ mEq/L}$ (range of $8-12\text{ mEq/L}$).

Serum Anion Gap Albumin Correction

An adjustment rule where for every decrease in serum albumin by $1\text{ g/dL}$ from normal ($4\text{ g/dL}$), the calculated serum anion gap decreases by $2.5\text{ mEq/L}$.

Anion-Gap Metabolic Acidosis (AGMA)

A category of metabolic acidosis resulting from excess formation of endogenous organic acids, such as in lactic acidosis, ketoacidosis, alcohol intoxication, starvation, or toxic ingestions of methanol or ethylene glycol.

Non-Anion Gap Metabolic Acidosis (NAGMA)

A category of metabolic acidosis caused primarily by renal or gastrointestinal loss of bicarbonate ($HCO_3^-$).