Lung & Kidney Buffer Systems Review

Lung & Kidney Buffer Systems

• The lungs and kidneys play critical roles in maintaining acid-base balance in the body by regulating hydrogen ion concentration.
• The lungs help regulate acid-base balance through the exhalation of carbon dioxide (CO2), which indirectly affects hydrogen ion levels in the blood.
• The kidneys contribute by excreting hydrogen ions and reabsorbing bicarbonate (HCO3-), which helps neutralize acidity.

Acidosis and Alkalosis

• Respiratory acidosis occurs when CO2 is retained due to inadequate ventilation, leading to increased acidity in the blood.
• Common causes of respiratory acidosis include chronic obstructive pulmonary disease (COPD), severe asthma, and respiratory failure.
• Metabolic acidosis can result from conditions such as kidney failure, lactic acidosis, or diabetic ketoacidosis, causing an accumulation of hydrogen ions in the blood.
• Respiratory alkalosis arises from excessive exhalation of CO2 often due to hyperventilation, decreasing blood acidity.
• Metabolic alkalosis may result from prolonged vomiting, excessive bicarbonate intake, or certain diuretics, which increase blood pH and reduce hydrogen ion concentration.

Lung and Kidney Buffer Systems

• Lungs and kidneys play crucial roles in maintaining acid-base balance in the body.
• Lungs regulate carbon dioxide (CO2) levels through respiration, affecting blood pH.
• Kidneys manage bicarbonate (HCO3-) levels and hydrogen ions (H+) to stabilize blood pH over longer periods.

Respiratory Acidosis and Alkalosis

• Respiratory acidosis occurs when there is excessive CO2 due to inadequate ventilation.
• Common causes of respiratory acidosis include chronic obstructive pulmonary disease (COPD), asthma, and respiratory failure.
• Respiratory alkalosis results from hyperventilation, causing low CO2 levels in the blood.
• Stress, anxiety, and high altitudes can trigger hyperventilation leading to respiratory alkalosis.

Metabolic Acidosis and Alkalosis

• Metabolic acidosis involves decreased bicarbonate or increased acids in the body, leading to lower pH.
• Causes include diabetic ketoacidosis, renal failure, and prolonged diarrhea.
• Metabolic alkalosis occurs when there is an excess of bicarbonate or loss of hydrogen ions.
• Vomiting and diuretics are common contributors to metabolic alkalosis.

Summary of Acid-Base Regulation

• The interplay between lung and kidney functions is essential for effective acid-base homeostasis.
• Understanding causes of acidosis and alkalosis helps in diagnosing and treating related conditions.

Movement of Gases in the Body

• The exchange of oxygen (O2) and carbon dioxide (CO2) in the body is driven by differences in partial pressures and diffusion.
• Variations in partial pressure can impact gas exchange in the body, influencing the efficiency of respiration.

Factors Influencing Gas Exchange

• Patient body position can affect lung mechanics and gas exchange efficiency.
• Using a bag valve mask increases pressure in the airway, facilitating ventilation but potentially altering gas exchange dynamics.
• Fluctuations in blood pressure may influence tissue perfusion and oxygen delivery.
• Pulmonary diseases, like COPD or asthma, impair the ability of lungs to exchange gases effectively.
• Chest trauma can disrupt normal lung function and hinder the movement of gases.

Carbon Dioxide Transport and Life Cycle

• The life cycle of carbon dioxide involves its production as a metabolic waste product and its transport to the lungs for exhalation.
• Carbon dioxide is primarily transported in three ways: dissolved in plasma, bound to hemoglobin, and as bicarbonate ions (HCO3-).
• The relationship between oxygen and carbon dioxide is crucial for maintaining acid-base balance in the body.

The Bohr Effect

• The Bohr Effect describes how increased levels of CO2 and decreased pH result in hemoglobin's reduced affinity for oxygen, facilitating oxygen release to tissues.
• Understanding the Bohr Effect is essential for interpreting the oxygen-hemoglobin dissociation curve, particularly in clinical assessments related to respiratory function.

Diffusion of Gases

• Oxygen and carbon dioxide move from areas of higher to lower concentrations through diffusion.

CO2 Partial Pressure

• Understanding gas movement relies on partial pressures and diffusion principles.
• Pressure changes affecting gas diffusion may arise from:
  • Patient body position
  • Use of bag valve mask
  • Blood pressure fluctuations
  • Pulmonary diseases
  • Chest trauma

Lactate and Base Excess (Deficit)

• Lactate is produced when the body is ill or injured, leading to metabolic acidosis.
• Arterial blood gas readings for base deficit assist in resuscitating shock patients; greater negative values indicate higher resuscitation needs.
• Lactate levels are critical in diagnosing septic shock or sepsis, with point-of-care monitors often used in EMS.
• Trauma patients experiencing shock show a higher mortality rate with a base deficit less than -9.

End-Tidal Capnography

• Introduction to end-tidal waveform capnography connects buffer systems with cellular metabolism.
• Key patient groups likely showing low end-tidal CO2 include:
  • Cardiac arrest
  • End-stage renal disease or failure
  • Severe hemorrhagic shock
  • Severe sepsis
  • Pulmonary embolism
  • Diabetic ketoacidosis, representing a mix of respiratory and metabolic issues
  • Aspirin overdose

Renin Angiotensin Aldosterone System (RAAS)

• RAAS is a compensatory mechanism managing blood pressure.
• Upon activation, it prevents the release of enzymes that cause blood vessel dilation.

Diagnosing with Arterial Blood Gas (ABG)

• Relationship between bicarbonate and metabolic processes (kidneys) emphasized.
• Relationship between carbon dioxide and respiratory processes (lungs) highlighted.
• eTCO2 helps identify respiratory alkalosis and acidosis.
• Risk factors for metabolic acidosis noted, with common severe cases including:
  • Cardiac arrest
  • End-stage renal disease
  • Severe hemorrhagic shock
  • Severe sepsis
  • Pulmonary embolism
  • Diabetic ketoacidosis as a mixed gas scenario
  • Aspirin overdose

Lung & Kidney Buffer Systems

• Overview of how lungs and kidneys balance hydrogen concentrations.
• Examination of causes for respiratory and metabolic acidosis and alkalosis.

Carbon Dioxide Life Cycle

• Review of oxygen and carbon dioxide life cycles and their interrelationship.
• Overview of carbon dioxide transport mechanisms.
• The Bohr Effect’s relevance to the oxygen-hemoglobin dissociation curve, pertinent for NREMT-P test questions.

This quiz focuses on the buffer systems related to the lungs and kidneys, specifically how they balance hydrogen levels in the body. It also covers the causes of respiratory and metabolic acidosis and alkalosis. Prepare to deepen your understanding of these essential physiological mechanisms.