AC Imbalance Flashcards
metabolism requires precise balance of acid and base in the body, which is reflected by?
the pH of extracellular fluid
What depends on a regulated pH?
membrane excitability, enzyme systems, chemical reactions
High concentration of H+ ions =
low pH & acidosis
Low concentration of H+ ions =
high pH & alkalosis
What is the body’s normal pH?
7.35-7.45
If AC imbalance is not corrected, what mechanisms will attempt to restore the pH?
compensatory mechanisms
Why can’t we use compensatory mechanisms all the time?
it correct pH but not underlying cause
What are the 3 major buffer systems that reduce or raise hydrogen ion concentration?
chemical buffer systems, respiratory compensation, renal compensation
What four buffers are chemical?
bicarbonate buffers, phosphate and ammonia buffers, hemoglobin and albumin and globulins, and potassium-hydrogen exchange
How do bicarbonate buffers work?
bind to or release hydrogen ions depending on whether pH needs to be raised or not
Phosphate and ammonia buffers are a response from the?
kidney
What protein is intracellular?
hemoglobin
What proteins are extracellular?
albumin and globulins
Hemoglobin, albumin, and globulins are protein buffers that?
raise or lower pH
What does the potassium- hydrogen exchange do?
substitutes reabsorption of potassium with hydrogen in the kidney
When does potassium-hydrogen exchange occur?
during acidosis
What 2 actions occur during potassium-hydrogen exchange?
- H+ and K+ move freely between ICF and ECF
- Excess H+ moves into cells in exchange for K+
Where does H+ move during alkalosis?
outside of cell
During respiratory compensation, CO2 is retained during?
alkalosis
During respiratory compensation, CO2 is blowing off during?
acidosis
When the metabolic system isn’t working, what is used?
respiratory compensation
What buffer system is the slowest?
renal compensation
During renal compensation, retention of bicarbonate is seen during?
alkalosis
During renal compensation, excretion of bicarbonate is seen during?
acidosis
During renal compensation, elimination of H+ in urine is only possible if…
kidneys are healthy
The product of renal compensation?
new bicarbonate
What is a normal waste product of cellular metabolism?
acid
The pH during acidosis?
<7.35
What is another name for carbonic acid?
volatile acid
What produces carbonic acid?
carbon dioxide and bicarbonate
What is the normal PCO2 level?
35-45mmHg
CO2 is dissolved in the?
bloodstream
Is carbonic acid easily eliminated?
yes, by changing respirations. but only if lungs are healthy.
What are the 2 ways metabolic acids are eliminated?
- neutralized by circulating basic compounds
- excreted by kidneys
What is the normal bicarbonate buffer (HCO3) level?
22-26 mEq/L
What are the 3 physiologic effects of acidosis?
- decreases cardiac contractility
- interferes with action of drugs
- nervous system changes
How does acidosis interfere with the actions of drugs?
can make ineffective or too effective
What are some nervous system changes that can be seen during acidosis?
weakness, confusion, coma
What is respiratory acidosis?
increase in PCO2 and decreased pH
The relationship between pH and CO2 is?
inverse
What are the 2 causes of respiratory acidosis?
- disorders of ventilation
- increased CO2 production
What are 4 examples of disorders of ventilation?
- respiratory part of brain damaged
- airway obstruction
- chest injuries
- drug overdose
What 4 things can cause increased CO2 production?
- sepsis
- burns
- fevers
- exercise
What are the 3 manifestations (signs & symptoms) of respiratory acidosis?
- headaches
- impaired consciousness
- carbon dioxide poisoning
What is metabolic acidosis?
deficient in base bicarbonate and decreased pH
What is the relationship between pH and HCO3?
direct
What are the 4 causes of metabolic acidosis?
- increased production of metabolic acids
- decreased renal function
- increased bicarbonate loss
- hyperchloremic acidosis
An increase in production of metabolic acids also means an increase in?
lactic acid
What occurs during decreased renal function?
kidneys cannot excrete hydrogen ions which indicates renal failure
How does the body increase bicarbonate loss?
by diarrhea and vomiting
How can hyperchloremic acidosis occur?
by certain drugs, toxins, and IVs
What are the 5 manifestations of metabolic acidosis?
- low BP
- abdominal pain
- vomiting
- headaches
- weakness/fatigue
What is alkalosis?
acid deficit or base excess
What is the pH during alkalosis?
pH >7.45
What is the principal base compound?
bicarbonate (HCO3)
How is bicarbonate regulated?
by kidneys
What are the 3 ways bicarbonate are formed?
- breakdown of carbonic acid
- GI intake of ingested bicarbonate
- renal absorption of bicarbonate
Alkalosis inhibits the release of?
O2 from RBCs which can cause hypoxia
How does alkalosis effect the cardiac system?
influences cardiac rhythm
In what 5 ways does alkalosis effect the nervous system?
- hyperactive reflexes
- confusion
- seizures
- tetany
- numbness/tingling
What is respiratory alkalosis?
decreased PCO2 and increased pH
What are the 3 causes of respiratory alkalosis?
- hyperventilation
- mechanical ventilation
- central stimulation of respiratory center
What occurs during hyperventilation?
blow off CO2
How can mechanical ventilation cause respiratory alkalosis?
someone’s settings on their ventilator are too high
What 5 stimuli can cause respiratory alkalosis?
- anxiety
- pain
- stress
- fever
- certain medications
What are the 4 manifestations of respiratory alkalosis and metabolic alkalosis?
- lightheaded
- dizzy
- constriction of blood vessels
- numbness/tingling in fingers and toes
What is metabolic alkalosis?
increased HCO3 and increased pH
What are the 3 causes of metabolic alkalosis?
- excess alkali intake
- bicarbonate retention
- gastrointestinal losses
How is excess alkali intake achieved?
orally or through IVs
(anti-acids and lactated ringers)
Bicarbonate retention is seen when there is impaired function of?
kidneys
How are gastric acids lost?
through vomiting or oral/GI suctioning
What is combined disturbances?
multiple organ systems being involved
ABG =
arterial blood gas
What is the purpose of laboratory blood gas analysis?
Reveal information about acid-base balance by evaluating the pH, HCO3- and CO2 levels
In what order do you do a systemic interpretation of AC imbalance?
pH-> pCO2-> HCO3
If pH is low, pCO2 is high, and the HCO3 is normal what is this patient experiencing?
respiratory acidosis
If pH is high, pCO2 is low, and the HCO3 is normal what is this patient experiencing?
respiratory alkalosis
If pH is low, pCO2 is normal, and HCO3 is low what is this patient experiencing?
metabolic acidosis
If pH is high, pCO2 is normal, and HCO3 is high what is this patient experiencing?
metabolic alkalosis
