Acid-Base Balance and Imbalances Lecture Review

Flashcards covering the physiological mechanisms, clinical disorders, ABG interpretation, and nursing management of acid-base imbalances as presented in the lecture notes.

Acid-Base Balance

The physiological process of regulating the concentration of hydrogen ions ($H^+$) in body fluids to maintain a stable pH between $7.35$ and $7.45$.

Chemical Buffer Systems

A regulatory mechanism that responds in seconds by binding or releasing hydrogen ions ($H^+$); examples include the Bicarbonate-Carbonic acid system.

Respiratory Regulation

A regulatory mechanism that acts within minutes to hours to regulate volatile acid ($CO_2$) through hyperventilation or hypoventilation.

Renal Regulation

The most powerful physiological regulatory system, acting over hours to days to excrete hydrogen ions ($H^+$) and reabsorb or generate bicarbonate ($HCO_3^-$).

Respiratory Alkalosis

An acid-base disorder characterized by a pH $> 7.45$ and a $PaCO_2 < 35\,mmHg$, common causes include hyperventilation, anxiety, and fever.

Metabolic Alkalosis

An acid-base disorder characterized by a pH $> 7.45$ and bicarbonate ($HCO_3^-$) levels $> 26\,mEq/L$, common causes include vomiting and NG suction.

Respiratory Acidosis

An acid-base disorder characterized by a pH $< 7.35$ and a $PaCO_2 > 45\,mmHg$, often caused by hypoventilation, COPD, or opioid overdose.

Metabolic Acidosis

An acid-base disorder characterized by a pH $< 7.35$ and bicarbonate ($HCO_3^-$) levels $< 22\,mEq/L$, often caused by DKA, lactic acidosis, or renal failure.

Anion Gap (AG)

A clinical measurement used to differentiate causes of metabolic acidosis, calculated by the formula: $AG = Na^+ - (Cl^- + HCO_3^-)$.

High Anion Gap (> 12 mEq/L)

An indicator of the accumulation of fixed acids like lactic acid, ketones, or salicylates in the blood.

Normal Anion Gap (8–12 mEq/L)

Also known as hyperchloremic acidosis, this occurs with the loss of bicarbonate, such as through severe diarrhea.

ROME Mnemonic

A memory aid for ABG interpretation where Respiratory Opposite ($pH$ and $PaCO_2$ move in opposite directions) and Metabolic Equal ($pH$ and $HCO_3^-$ move in the same direction).

Uncompensated State

An ABG status where the pH is abnormal and only one other parameter ($PaCO_2$ or $HCO_3^-$) is abnormal.

Partially Compensated State

An ABG status where the pH, $PaCO_2$, and $HCO_3^-$ are all abnormal, indicating the body is attempting to correct the pH.

Fully Compensated State

An ABG status where the pH is within the normal range ($7.35 - 7.45$), but both $PaCO_2$ and $HCO_3^-$ are abnormal.

Target Serum Bicarbonate in CKD

In patients with Chronic Kidney Disease (CKD), the recommended target range for bicarbonate is typically $24 - 26\,mmol/L$ to slow kidney function decline.

Salicylate Toxicity

A condition where initial respiratory alkalosis progresses to metabolic acidosis; treated with urine alkalinization using IV bicarbonate.

Lethal Arrhythmia Thresholds

Extreme pH deviations below $7.20$ or above $7.60$ that can trigger life-threatening cardiac rhythms.

Bicarbonate System

The primary extracellular buffer that relies on the equilibrium between carbon dioxide ($CO_2$), water ($H_2O$), and bicarbonate ($HCO_3^-$).

Net Acid Excretion

The renal process of excreting hydrogen ions ($H^+$) as ammonium ($NH_4^+$) or titratable acids like phosphate.