Chapter 6: acid base balance Flashcards
What are buffers of pH?
Chemicals that combine with an acid or base to change pH
What do buffers do?
Immediate reaction to counteract pH variations until compensation is initiated
What are the four major buffer mechanisms?
Four major buffer mechanisms—the bicarbonate–carbonic acid system, phosphate system, hemoglobin system, and protein system
Where is the Bicarbonate–Carbonic Acid System most significant?
Most significant in the extracellular fluid.
What are the key players in the Bicarbonate–Carbonic
Acid System?
Carbonic acid and bicarbonate are the key players.
How does carbonic acid form?
Carbonic acid forms from carbon dioxide reacting with water.
What is the equation of acid base compensation?
CO2 + H2O H2CO3 H+ + HCO3−
What does potassium do to maintain pH?
Potassium and hydrogen move interchangeably into and out of the cell to balance pH.
What happens with extracellular excess of potassium?
With extracellular excess, hydrogen moves inside the cell for buffering; in exchange, potassium moves out.
Can potassium imbalances lead to pH imbalances?
yes
What does respiratory regulation do to maintain pH
Manages pH by altering carbon dioxide excretion.
What does breathing faster do to pH?
Breathing faster will excrete more carbon dioxide, decreasing acidity.
What does breathing slower do to pH?
Breathing slower will excrete less carbon dioxide, increasing acidity.
What does respiratory regulation use?
chemoreceptors
Is respiratory regulation fast or slow?
fast
What does renal regulation do to maintain pH?
Alters the excretion or retention of hydrogen or bicarbonate
When is renal regulation more effective?
More effective as hydrogen removed
Is renal regulation fast or slow?
Responds the slowest
What does compensation do to maintain pH?
Diseases are compensated by different organs in the bodies
Where are metabolic diseases compensated for?
Metabolic disease is compensated by the lungs.
If kidney disease impairs acid excretion what do the lungs do?
get rid of excess acid as CO2
Where is pulmonary disease compensated?
the kidneys
If pulmonary disease impairs excretion of CO what do the kidneys do?
retain bicarbonate and excrete H
What is the arterial blood gas value of pH?
7.35-7.45
What is the arterial blood gas value of PCO2?
35-45 mm Hg
What is the arterial blood gas value of PO2?
80 -100 mmHg
What is the arterial blood gas value of HCO^3?
22-26 mEq/L
What happens when there is a respiratory acid base imbalance?
impaired ventilation
What are the acid base imbalances with respiratory acidosis?
low ph and high pco2
What are the acid base imbalances with respiratory alkalosis?
high ph and low pco2
What happens when there is a metabolic acid base imbalance?
renal issues
What are the acid base imbalances with metabolic acidosis?
low ph and low hco3
What are the acid base imbalances with metabolic alkalosis?
high ph and high hco3
What would be the mixed combinations of primary imbalances?
low ph high pco2, and low hco3
high ph low pco2, and high hco3
How do you compensate for respiratory acidosis?
high hco3
How do you compensate for respiratory alkalosis?
low hco3
How do you compensate for metabolic acidosis?
low pco2
How do you compensate for metabolic alkalosis?
high pco2
What causes respiratory acidosis?
Caused by conditions that result in hypoventilation or decreased gas exchange
-Include pulmonary disease/infection, airway obstructions, pulmonary edema, drug overdose, respiratory failure, and nervous system depression
What are the manifestations of respiratory acidosis?
- Appear as regulatory systems fail to maintain pH within normal range
- Occur in combination with manifestations of underlying condition
- Include disorientation, lethargy, coma, decreased vascular tone, decreased myocardial contractility, dysrhythmias
What are the causes of respiratory alkalosis?
Caused by conditions that result in hyperventilation
-Include acute anxiety, pain, fever, hypoxia, medications, and hypermetabolic states
What are the manifestations of respiratory alkalosis?
- Appear as pH outside of normal range
- Occur with manifestations of underlying condition
- Include dizziness, seizures, and coma (decreased cerebral blood flow)
What are the causes of metabolic acidosis?
Causes
Bicarbonate deficit: intestinal and renal losses
Acid excess: tissue hypoxia resulting in lactic acid accumulation (anaerobic metabolism, hypermetabolism), ketoacidosis (DKA, alcoholism, starvation), and renal retention
What are the manifestations of metabolic acidosis?
- Appear as pH outside of normal range
- Occur with manifestations of underlying condition
- Include fatigue, coma, nausea, vomiting, hypotension, dysrhythmias, Kussmaul’s respirations, and hyperkalemia
What is the anion gap and what is it helpful with?
- Identifies the anions that are not measured.
- Helpful in determining the cause of metabolic acidosis.
What will increase the anion gap?
conditions that cause the excess acid
What are the causes of metabolic alkalosis?
Excess bicarbonate: excessive antacid use, use of bicarbonate-containing fluids
Deficient acid: gastrointestinal loss, hypokalemia, renal loss, hypovolemia
What are the manifestations of metabolic alkalosis?
Appear as pH outside of normal range
Occur with manifestations of underlying condition
Include mental confusion, hyperactive reflexes, seizures, respiratory depression, dysrhythmias
What is the arterial blood gas interpretation of pH?
serum hydrogen concentration
Indicates acid–base status
What is the arterial blood gas interpretation of PaCO2?
partial pressure of carbon dioxide
Indicates the adequacy of pulmonary ventilation
What is the arterial blood gas interpretation of HCO3?
bicarbonate
Indicates the activity in the kidneys to retain or excrete bicarbonate
What is the arterial blood gas interpretation of PaO2?
partial pressure of oxygen
Indicates serum oxygen concentration
