CCM Acid Base Flashcards
chapter 54 - traditional acid base
what pH is considered comparable with life in mammals?
6.8 - 8
WHat is the henderson-hasselbalch equation?
pH = 6.1 + log ([HCO3] /[0.03 xPCO2])
Where 6.1 is pKa in body fluids, and 0.03 is solubility coefficient for CO2
What three major processes regulate acid base balance?
alveolar ventilation,
buffering of acids by bicarbonate and non-bicarbonate buffer systems,
changes in renal excretion of acid or base
What is the advantage of using BE over bicarb?
it is independent of changes in the respiratory system. When
there are minimal changes in PCO2 present, the BE and bicarbonate
should correlate well.
In the face of substantial abnormalities in PCO2, the BE is a
more reliable measure of the metabolic component
What are the steps involved in traditional acid base analysis
- Confirm the sample collection and handling was appropriate
- Evaluate the pH
- Evaluate the respiratory component, PCO2
- Evaluate the metabolic component, HCO3 or SBE
- Define the primary process, either respiratory or metabolic
- Evaluate if compensation is as expected
- Determine the overall acid-base analysis
- Is a primary metabolic acidosis present?
If yes, calculate the anion gap.
WHat conditions may result in an increase in CO2 production?
hyperthermia, seizures, fever, and malignant
hyperthermia
What occurs in proximal vs distal RTA?
proximal RTA there is inadequate reabsorption of
bicarbonate in the proximal nephron
Distal RTA is a disorder involving inadequate hydrogen ion secretion
in the distal tubule that prevents maximal acidification of the urine
WHat are three important aspects of metabolic alkalosis treatment
(1) Ensure there is adequate effective circulating volume,
(2) normalize electrolytes, and, (3) when possible, correct the primary
disease
WHat are potential adverse effects of bicarb admin
hypercapnea, paradoxical intracellular acidosis, hypervolemia, hyperosmolality, hypernatremia,
hypocalcemia (ionized), hypokalemia, and decreases in PaO2, hypokalaemia, phlebitis
What is an approximate dose of bicarb?
0.3 x BW x base deficit
where 0.3 is distribution of bicarb, BW is in kg and base def is from blood gas machine or calc by taking patients bicarb and subtracting normal bicarb
This would return it to normal so often 1/3 - 2/3 of that is administered
Over what period of time should bicarb be administered?
30 mins unless diluted with sterile water
commercially available
8.4% sodium bicarbonate solution has an osmolality of approximately
2000 mOsm/L, so a dilution of 1 part sodium bicarbonate to
3 parts diluent (e.g., sterile water for injection) would be appropriate
for peripheral venous administration
Chapter 55 - NONTRADITIONAL ACID-BASE ANALYSIS
What are the three independent determinants of stewarts method
CO2, SID and total weak acids (Atot)
