SH

Chapter25: Fluids&elctrolytespart4

CO2 Levels and pH Relationship

  • Grandpa's CO2 levels will increase as his disease progresses.

  • The reaction will run left to right to convert CO2 with water to carbonic acid.

  • Increasing CO2 results in more hydrogen ions, leading to decreased pH (more acidic).

Acid-Base Balance

  • Normal pH of blood: 7.35 to 7.45.

  • More hydrogen ions = lower pH (more acidic).

  • Less hydrogen ions = higher pH (more alkaline).

Key Relationships

  • Increase in CO2 → Increase in hydrogen ions → Decrease in pH.

  • Decrease in CO2 → Decrease in hydrogen ions → Increase in pH.

  • Grandpa's worsening condition means increased CO2 and hydrogen ions, leading to a decrease in pH.

Types of Acids

  • Fixed acids: nonvolatile, typically metabolic (e.g., lactic acid, ketone bodies).

  • Volatile acids: formed from carbonic acid; regulated by the respiratory system.

Respiratory System as Buffer

  • Quick response to eliminate CO2 by increasing respiratory rate.

  • Problems arise in respiratory conditions (e.g., pulmonary fibrosis), impacting CO2 elimination.

Chemical Buffers

  • Bicarbonate system: Most important in blood; maintains pH stability.

  • Protein buffer system: Involves hemoglobin and plasma proteins to bind hydrogen ions.

  • Phosphate buffer system: Operates intracellularly with hydrogen phosphate and dihydrogen phosphate.

Acid-Base Disturbances

  • Acidosis: pH < 7.35; potentially life-threatening due to prolonged pH imbalance.

  • Alkalosis: pH > 7.45.

  • Two categories: Respiratory or Metabolic.

Conditions Leading to Disturbances

  • Respiratory acidosis: Impaired CO2 elimination; causes include trauma, airway obstruction, decreased gas exchange.

  • Respiratory alkalosis: Decreased CO2 due to hyperventilation; causes include anxiety or high altitude.

  • Metabolic acidosis: Accumulation of fixed acids; examples include diabetes (ketoacidosis), lactic acid build-up.

  • Metabolic alkalosis: Loss of hydrogen ions (e.g., from vomiting); increased bicarbonate can also cause this.

Important Parameters

  • Normal CO2 pressure: 35-45 mmHg.

  • Normal bicarbonate levels: 22-26 mEq/L.

Summary

  • Grandpa is likely to be diagnosed with respiratory acidosis due to impaired gas exchange, with blood pH expected to be below 7.35.

  • Understanding acid-base balance is crucial for nursing practice.