Acid-Base Disorders Flashcards
maintenance of pH is important for
protein structure
metabolism and enzymes
T/F small changes in pH=large changes in [H+]
true
pH is determined by
- pCO2
- Addition or removal of acids (H+)
- Strong ion movements
- Serum proteins, phosphates, and other weak acids
regulatory systems
Extracellular and intracellular buffers
Rate of alveolar ventilation (pCO2)
Renal excretion of H+
buffer systems
minimize the changes in [H+]
prevent sudden changes in pH
components of the buffer system
Bicarbonate/carbonic acid
Non-bicarbonate components
- Hemoglobin
- Plasma proteins
what happens when you add H+ to the system
H+ combines with HCO3- to form H2O + CO2 –> CO2 is exhaled (CO2 thought of as an acid, increases with increase in H+)
venous blood samples
‒ Good for evaluating acid base status
‒ Useful in most clinical situations
arterial blood samples
‒ Evaluates pO2
‒ Useful for evaluating cardiopulmonary function
blood collection
Anaerobic: avoid exposure to air
Whole blood from a free flowing vessel –> heparin tube
Analyze ASAP (>15 min put on ice-ice-baby)
what is TCO2
BICARB!!!!
pCO2 represents
respiratory system
TCO2 represents
metabolic system (BICARB!!)
metabolic acidosis
↑ acid in the absence of ↑ pCO2
↓ base, ↓ HCO3-
metabolic alkalosis
↓ acid in the absence of ↓ pCO2
↑ base, ↑ HCO3-
T/F measurement of TCO2 is an estimate of bicarb
true
T/F TCO2 is NOT a measurement of pCO2
TRUE!!!
base excess: metabolic alkalosis
(+) BE
base excess: metabolic acidosis
(-) BE
what is base excess used to calculate
bicarb dosage in IVF
What are the 4 Primary Acid Base Abnormalities
- Respiratory acidosis
- Metabolic acidosis
- Respiratory alkalosis
- Metabolic alkalosis
compensation=
opposite system, opposite type
TCO2 is ________; pCO2 is ________.
Bicarb; an acid
respiratory acidosis
hypoventilation - Anesthesia - Diffuse pulmonary disease - Intrathoracic lesions - CNS disease
respiratory acidosis: compensation
Secondary metabolic alkalosis = retention of HCO3-
2 ways metabolic acidosis can happen
↑ in acid or ↓ in base (diarrhea cha cha cha)
High Anion Gap Acidosis (Metabolic acidosis)
Increase in nonvolatile acids (KLUE)
Ketones
Lactate
Uremic acids (phosphates, sulfates)
Ethylene glycol metabolites (toxins)
at what value is anion gap considered a problem
> 25
what is anion gap based on
the principle of electroneutrality
Used to detect unmeasured anions (KLUE)
anion gap equation
AG = (Na+ + K+) − (Cl− + HCO3−)
loss of HCO3-
‒ GI loss from diarrhea
‒ Intestinal ileus
‒ Salivation (ruminants) – choke
‒ Urinary loss
‒ Titration
short term metabolic acidosis compensation
secondary respiratory alkalosis –> ↑ ventilation with ↓ pCO2
long term metabolic acidosis compensation
Increased renal excretion of H+ with retention of HCO3
respiratory alkalosis
hyperventilation - Hypoxemia - Pain, anxiety, etc. - Hyperthermia - Drugs that stimulate the medullary respiratory center
respiratory alkalosis compensation
Secondary metabolic acidosis = renal retention of H+
2 ways metabolic alkalosis can happen
↓ in acid (vomitting) or ↑ in base
hypochloremic metabolic alkalosis
Monogastrics: severe vomiting, pyloric outflow obstruction (GDV)
Ruminants: sequestration of fluid in abomasum and forestomachs (LDA and RDA)
hypochloremic metabolic alkalosis can result in
paradoxical aciduria
what two things are required for paradoxical aciduria
hypochloremia
volume depletion
causes of excessive renal loss of H+
diuretics
increased mineralocorticoid activity
short term compensation for metabolic alkalosis
decreased ventilation=↑ PCO2
long term compensation for metabolic alkalosis
Increased renal retention of H+ with decreased generation of HCO3-
what are mixed disturbances
2 primary disturbances occurring simultaneously
when do we suspect a mixed disturbance
Animal with electrolyte disturbances
or
Animal with a disease associated with AB disturbance and normal blood gas values
example of mixed disturbance
cow with abomasal volvuus (hypochloremic metabolic alkalosis) and shock (metabolic acidosis- ↑ lactate)
T/F mixed disturbances can occur when the compensatory response in moving in the wrong direction
true
Horse with low intestinal obstruction (colic) that is hypoventilated when anesthetized for surgery