Acid-Base Lecture Flashcards
Normal metabolism produces ___ meq/L of non volatile (H ) acid together with volatile acid (CO2) daily.
1 meq/L
body fluid pH is tightly maintained at…
7.40
norm= 7.38-7.42
weak base
*levels regulated by kidneys and maintained for buffering
HCO3
Where is the bicarbonate buffer system located?
extracellular space
Total venous CO2 can be estimated by looking at….
HCO3 levels
Primary respiratory disorders effect….
pCO2
Primary metabolic disorders effect…
HCO3
Do compensatory changes totally correct the pH?
NO! …they move towards normal but do not fully compensate/correct
pH decreased, PCO2 increased, HCO3 increased (comp.), acute and chronic forms.
Respiratory acidosis
pH increased, PCO2 decreased, HCO3 decreased (comp.), acute and chronic forms.
Respiratory alkalosis
pH decreased, HCO3 decreased, PCO2 decreased (comp.)
Metabolic acidosis
pH increased, HCO3 increased, PCO2 increased (comp.)
Metabolic alkalosis
Compensatory mechanism includes:
*increase ventilatory drive, which will blow off more CO2 gas, causing a shift back towards normal pH
Metabolic acidosis
Compensatory mechanism: decrease ventilatory drive to hold onto CO2
Metabolic alkalosis
Primary defect is increased PCO2 as a result of decreased alveolar ventilation.
Respiratory acidosis
Trouble getting rid of CO2 gas in…
Respiratory acidosis
CO2 +H2O ⇔ H2CO3 ⇔ H + HCO3
which way will this equation shift in Respiratory acidosis?
Towards right
due to increase in CO2 gas
Conditions associated with decreased ventilation: severe COPD; asthmatic who tires; drug OD with suppression of ventilatory drive, neuromuscular diseases.
Symptoms: somnolence, confusion (CO2 narcosis), coma, resp. arrest.
Respiratory Acidosis
CO2 narcosis
somnolence
confusion
*seen in respiratory acidosis
first 24 hours of respiratory acidosis, what do HCO3 levels look like?
*when does compensation start
Normal in 24 hrs
*over about 3 days, HCO3 levels will increase..leading to compensation
Acute – the pH decreases 0.08 units for every 10mmHg increase in PCO2**
Respiratory acidosis
In ACUTE respiratory acidosis, every 10 mmHg increase in PCO2 leads to a decrease in pH of….
0.08 units
Chronic - HCO3 ↑1.1-3.5 mEq/liter per ↑10 mmHg PCO2; pH will move towards normal
Respiratory acidosis
Little Billy got into some of dad’s pain meds (oxycodone). He suffers a significant depression of mental status and respiration. You see him in the ED 3 hours after ingestion. He is somnolent with a respiratory rate of 4. A blood gas is obtained: pH- 7.16, PCO2- 70mmHg, HCO3- 24 meq/L
UNCOMPENSATED respiratory acidosis
*bicarb levels haven’t started to rise yet, so you know its uncompensated
(tx=ventilate and rapidly reverse effects of narcotics)
Ventilatory support until the underlying disorder can be corrected
*Narcotic antagonist if applicable
Tx for Respiratory Acidosis
Narcotic OD leading to decreased respirations can lead to….
Respiratory Acidosis