Mixed Acid Base Flashcards
What is a mixed acid base disorder?
characterized by the presence of two or more separate primary acid-base abnormalities occurring in the same patient
How long may respiratory compensation to a metabolic alkalosis take to be complete in the dog?
17-24hrs
. Discuss the two phases of compensation to a respiratory acidosis
first phase represents titration of nonbicarbonate buffers, whereas in respiratory alkalosis, the first phase represents release of H from nonbicarbonate buffers within cells.
- Complete in 15 minutes
The second phase reflects renal adaptation and consists of increased net acid excretion and increased HCO3 _ reabsorption (decreased Cl _ reabsorption) in respiratory acidosis and a decrease in net acid excretion in respiratory alkalosis.
Do cats compensate for metabolic or resp disorders?
They appear to compensate for resp disorders – maybe. Can increase HCO3 in response to an increase in CO2
What is dibart’s clinical approach to acid base disorders
History, clinical exam, Chem + UA, blood gas primary disorder calc expected compensation – if not within 2mmHg or mEq/L then likely mixed disorder.
What effect does increases or decrease in chloride cause?
Increases in chloride lead to metabolic acidosis
by decreasing SID, whereas decreases in chloride cause
metabolic alkalosis by increasing SID
Plasma chloride and bicarb tend to change in opposite directions
How may the chloride gap be calculated?
cl- gap = cl (normal) - Cl (corrected)
cl gap = cl (normal) - cl (patient) x na (normal)/na (patient)
What do chloride gap values mean
Values greater than 4 mEq/L are associated with
hypochloremic alkalosis, whereas values less than
4 mEq/L are associated with hyperchloremic acidosis.
what is the common AG equation?
AG = Na + K - Cl + HCO3
A decrease in what will result in a falsely decreased AG
Albumin - can be corrected with an equation utilising TP or alb
What does the base excess algorithm assess
method to estimate
unmeasured strong ions
Values less than
-5 mmol/L are suggestive of an increase in unmeasured
strong anions
What is the strong ion gap?
difference between all
unmeasured strong anion charges and all unmeasured
strong cation charges
Increase in unmeasured strong anions is suspected whenever
SIGsimplified is less than -5 mEq/L
Mixed Acid-Base Disturbances Examples
What is an example of a condition that may cause a resp acidosis and a metabolic alkalosis
gastric dilatation-volvulus that can present
with metabolic alkalosis caused by loss of gastric acid
and respiratory acidosis resulting from diaphragmatic
compression caused by the distended stomach.
What is an example of a condition causing resp alk and metabolic acidosis
Dogs with heat stroke also initially have respiratory alkalosis
and later develop mixed respiratory alkalosis and
metabolic acidosis
What are some examples of Metabolic Acidosis and Metabolic Alkalosis
Gastric dilatation-volvulus
Renal failure with vomiting
Vomiting and lactic acidosis
Why may resp acid and metabolic acid occur concurrently?
commonly in acute severe
respiratory compromise (e.g., thoracic trauma, pulmonary
edema, cardiopulmonary arrest, acute neuromuscular
junctional disruption such as with toxic or metabolic
or junctionopathies) that also have lactic acidosis as a result of hypoxemia, shock, or poor cardiac output
Why is bicarb admin contraindicated in patients with metabolic and resp mixed acidosis
they cannot excrete
the CO2 generated by NaHCO3 administration. The CO2 will diffuse into the cells and further decrease intracellular pH.
What often causes a mixed hyperchloremic and high AG acidosis?
Renal disease.
The pH and
[HCO3 are low, and the diagnosis is suggested by an
increase in unmeasured anions and a chloride gap of less
than -4 mEq/L
What is an example of a condition that may cause a triple mixed disorder?
GDV - can have metabolic alkalosis and lactic acidosis.29,37,61 These patients also can develop respiratory alkalosis as a result of a pain-induced increase in ventilation37 or sepsis.2 Respiratory acidosis also can develop if ventilation is impaired by a grossly overdistended stomach
How should mixed disorders be treated?
- treat the most life threatening abnormality first
- treat the most treatable
- direct pH manipulation not often required
- always assess the pH
- Always think about what treatment will do to the other abnormality
