Acid Base Disorders and ABG Interpretation

Comprehensive vocabulary flashcards covering acid-base physiology, primary respiratory and metabolic disorders, compensation mechanisms, and ABG interpretation based on the lecture material.

Acidosis

A process by which protons ($H^+$) are produced in a large amount, increasing the concentration within the extracellular fluid ($ECF$).

Alkalosis

A process by which protons ($H^+$) are produced in a smaller amount, leading to a basic effect on the blood.

Acidemia

A condition where the blood $pH$ is less than $7.35$ due to an increased proton concentration.

Alkalemia

A condition where the blood $pH$ is greater than $7.45$ due to a decreased proton concentration.

Carbonic anhydrase

An enzyme found in certain cells and membrane borders that converts $CO_2$ and $H_2O$ into carbonic acid ($H_2CO_3$).

Henderson-Hasselbalch Equation

A formula used to determine $pH$ based on bicarbonate ($HCO_3^-$) and carbon dioxide ($CO_2$): $pH = pKa + \text{log} \frac{[HCO_3^-]}{[CO_2]}$.

Respiratory Acidosis

An acid-base disorder caused by an increase in $pCO_2$ (hypercapnia), often resulting from $CNS$ depression, neuromuscular disorders, or obstructive lung diseases like $COPD$.

Respiratory Alkalosis

An acid-base disorder caused by a decrease in $pCO_2$ (hypocapnia), often resulting from $CNS$ hyperactivity (anxiety, fever, pain) or hypoxemia (pneumonia, pulmonary edema).

Metabolic Acidosis

An acid-base disorder characterized by a decrease in bicarbonate ($HCO_3^-$) levels, where $pH$ and $HCO_3^-$ move in the same downward direction.

Metabolic Alkalosis

An acid-base disorder characterized by an increase in bicarbonate ($HCO_3^-$) levels or a loss of protons ($H^+$), where $pH$ and $HCO_3^-$ move in the same upward direction.

Anion Gap ($AG$)

A calculation used to distinguish types of metabolic acidosis, defined as $AG = Na^+ - (Cl^- + HCO_3^-)$. The normal value is typically around $12$.

AGMA (High Anion Gap Metabolic Acidosis)

A subtype of metabolic acidosis where the calculated Anion Gap is greater than $12$.

NAGMA (Normal Anion Gap Metabolic Acidosis)

A subtype of metabolic acidosis where the Anion Gap is less than or equal to $12$, often associated with hyperchloremia.

MUDPILES

A mnemonic for causes of $AGMA$: Methanol, Uremia, Diabetic ketoacidosis, Propylene glycol, Isoniazid, Lactic acidosis, Ethylene glycol, and Salicylates.

HARD UP

A mnemonic for causes of $NAGMA$: Hyperalimentation ($TPN$), Acetazolamide, Renal tubular acidosis, Diarrhea, Ureteral diversion, and Pancreatic fistula.

VOMIT

A mnemonic for causes of metabolic alkalosis: Vomiting ($HCl$ loss), Overcorrection of hypercapnia, Mineralocorticoid excess (Aldosterone), Iatrogenic ($NaHCO_3^-$), and Total volume loss.

Delta Ratio

A formula used if $AGMA$ is present to identify concomitant disorders: $\frac{\text{Measured } AG - 12}{24 - \text{Measured } HCO_3^-}$.

SMORE

A mnemonic for $ABG$ interpretation: in metabolic disorders, $pH$ and $HCO_3^-$ move in the Same direction; in respiratory disorders, they move in the Opposite direction.

Normal $ABG$ Values

Reference ranges for arterial blood gases: $pH = 7.35 - 7.45$, $pCO_2 = 35 - 45\text{ mmHg}$, and $HCO_3^- = 22 - 26\text{ mEq/L}$.

Partial Respiratory Compensation

A physiological response to metabolic acidosis where the respiratory center increases the respiratory rate ($RR$) to breathe off $CO_2$ to help normalize $pH$.

Renal Compensation

A physiological response to respiratory disorders where the kidneys adjust proton ($H^+$) excretion and bicarbonate ($HCO_3^-$) reabsorption, which takes hours to days to take effect.