Flashcards in Test 2- Acid Base Deck (21):
What is pH determined bye?
pCO2! demonstrats changes in ventilation; Additional or
removal of acids (H+)- lacate, toxic metabolites of ethylene glycol, loss of H+; Strong ion movements – Na+, K+ and Cl-; Serum proteins, phosphates, and other weak acids`
what regulatory systems are put in place to maintain blood pH?
Extracelluar and intracellular buffers (Hgb, Bicarb); rate of alveolar
ventilation (pCO2); renal excretion of proton
What do buffer systems put in place do?
Minize the changes in [H+] and prevent suddent changes in pH. • Components- bicarbonate/carbonic acid.
o Non bicarb components! hemoglobin, plasma proteins, others
What is the bicarbonate/carbonic acid system? What happens if H+ is added to the system?
• H+ combines with bicarb to form HCC03 and then forms into C02
which is ecxhaled to maintain a balance.
What is the Henderson hasselbalch equation?
pH= Pk + Log10 (bicarb/h2CO3) bicarb represents metabolic- bicarb produed mostly by GI tract and regulated through the kidney). H2CO3 represents respiratory. ( H2CO3 is indirect equilbriruim w/ cO2
what is the difference between venous samples vs. arterial samples in reference to blood gas analysis?
Venous sample is good for evaluating acid base status- most useful to clinicians.
• Arterial samples measure pO2! useful for evaluating cardiopulmonary function
How do you Perform a blood gas analysis collection?
Make sure you avoid aerobic conditions- put collection in
anaerobic env’t. avoiding exposure to air b/c air has carbon dioxide in it which can change the same to produce bicarb and proton. Collet whole blood from free flowing vessel and put in heparinzed syringe or immediately cap in a heparinzed tube.
Evaluate ASAP or if youc ant put on ice if greater than 5
What does data from blood gas analyzer mean?
Measured- blood pH, pCO2, pO2; Calculated-bicarb and base excess
What is the difference between acidosis vs academia?
Acidosis is the dz process of having a low pH in the body
• Academia is the actually decrease pH level in the blood
What occurs in respiratory and CO2?
in he case of respiratory acidosis= hypoventilation leads to increase
• in the case of respiratory alkaloss- hyperventilation leads to
o think of pc02 as an acid.
What is a metabolic acidosis?
Increase acid in the absence of increase pCO2. Decrease base, decrease bicarb
What is a metabolic alkalosis?
Decrease acid in the absence of decrease PCO2, increase base, increase bicarb.
What is TCO2?
Estimate of plasma bicarbonate concentration. 95% of measured total CO2 (TCO2) in plasma is from bicarb. TCO2 is not a measurement of pCO2. Analyzers add acid to the sample pushing the equation to the left yielding c02 measuring the T co2.
What is base excess (BE)?
Characterized by the overall metabolic acid base status independent of the respiratory acid base status. If metabolic alkalosis (base excess) if metabolic acidosis (decreased base excess). Used to calculate bicarb dosage in IVF
What are 4 primary acid base abnormalities?
Respiratory acidosis, metabolic acidosis (loss of bicarb or increase in acid), respiratory alkalosis, metabolic alkalosis( los of acid or increase bicarb)
What is compensatory response to acid base disorders?
Body attempts to correct pH. Minimizes primary abnormalities effect on blood pH. Compensation- opposite system, opposite type. If metabolic alkalosis- going to have a respiratory acidosis. (hypoventilation)
• If metabolic acidosis- respiratory alkalosis (hyperventilation)
What are causes of respiratory alkalosis?
Hyperventilation: decreased C02 + water " decrease proton +
• Hypoxemia, pain, anxiety, hyperthermia, drugs that simulate the
medullary respiratory center
• Compensation! 2ndary metabolic acidosis= renal retention of H+
What is hypocholoremic metabolic alkalosis?
Causes- monogastrics: sever vomiting, pyloric outflow obstruction
• Ruminants- sequestration of fluid in abomasum and fore stomachs.
• Can result in paradoxical aciduria (hypovolemia +
hypochlremia + alkalosis (when you lose chloride bicarb is reabsorbed in the kidney to maintain electrical neutrality and therefore aciduria, worsening the alkalosis)
What are causes of excessive renal loss of proton leading to metabolic alkalosis?
Diuretics, increased mineralocorticoid activity
What compensatory mechanisms are involved in metabolic alkalosis?
Short term- decreased ventilation ! increased PCo2
• Long term- increased renal excretion of proton with both generation
and retention of bicarb?