Acid Base Balance Flashcards
What mechanisms control bloods acid base balance?
Lungs
Kidneys
Buffer systems
How does the lungs help with acid base balance?
Release of CO2 from the lungs because CO2 is mildly acidic
Faster and deeper breathing results in what?
More CO2 released
Blood pH increases
How do kidneys helps with acid base balance?
Excretion of excess acids and bases affect blood pH
Kidneys have some ability to alter the amount of acid or base that is excreted
This compensation takes several days
What are the 3 buffer systems that help maintain pH?
Carbonic acid - sodium bicarbonate
Phosphate system
Protein system
What is the ratio of carbonic acid to sodium bicarbonate?
1:20
20 parts of sodium bicarbonate to 1 part of carbonic acid
Normal pH value?
7.35-7.45
What is PaCO2
Partial pressure of the CO2 dissolved in the blood
Value for PaCO2?
35-45 mm Hg
What is ABG?
Arterial blood gas
What is step 1 for interpretation of an ABG test?
Determine if patient is acidosis or alkalosis
<7.39 acidotic
7.40 normal pH
> 7.41 alkalotic
What is the 2nd step in interpreting an ABG
Is it respiratory or metabolic?
If it’s respiratory CO2 and pH will always be opposite
If it’s metabolic.. pH and bicarb will go in the same direction
What is the last step in interpreting ABGs?
Hypoxia presents?
Look at the PaO2 and O2 sat
What causes respiratory acidosis?
Hypo ventilation from any cause like myocardial infarction, cardiac arrest, CHF, aspiration
Pneumonia
Pulmonary edema
COPD
Any medication that depresses the respiratory rate
What are the signs and symptoms of respiratory acidosis?
Decreased LOC, confusion, lethargy
Tachycardia, palpitations
Flushed skin
How do you treat respiratory acidosis?
Improve ventilation
- Oxygen if needed
Pharmacologic therapies
Non-invasive positive pressure ventilation
-CPAP
-BiPAP
intubation and mechanical ventilation
What causes respiratory alkalosis
Hyper ventilation
Extreme anxiety
Early sepsis
High fever
Signs and symptoms of respiratory alkalosis
Lightheadedness, dizziness, confusion
Dry mouth, heart palpitations
How do you treat respiratory alkalosis?
Aimed at treating the underlying cause
Encourage patient to slow their breathing
Breathing into a paper bag
Sedatives
What is an anion gap?
The difference between the primary measured cations (Na and K) and the primary anions (Cl and HCO3)
Range from 3-11 mEq/L
What could be the reason for an increased anion gap?
DKA
Renal failure
Uremia
What could be the reason for a decreased anion gap?
Hypoalbuminemia
Bromide intoxication
Plasma cell dyscrasia
What causes metabolic acidosis?
DKA
- high anion gap
Renal failure
Lactic acidosis
Toxins
-high anion gap
Severe diarrhea
-normal anion gap
Hyperalimentation (TPN)
- normal anion gap
Signs and symptoms of metabolic acidosis
Headache, confusion, drowsiness
N/V
Tachypnea
