Intro to Acid Base Disturbances Flashcards
pH <7.4 and PCO2 is 35 and bicarb 12 mEq/L what would this be classified as?
Metabolic acidosis with respiratory compensation
pH >7.4 PCO2 is 28 and bicarb is 22 what would this be classified as?
Respiratory alkalosis with renal compensation
What happens to breathing in respiratory acidosis?
Alveolar Hypoventilation to increase PaCO2 to decrease pH
What happens to ventilation with respiratory alkalosis?
Alveolar hyperventilation to decrease PaCO2 to increase the pH
What is the compensatory response for Respiratory acidosis?
Renal bicarb reabsorption is increased
What is the compensatory response for Respiratory alkalosis?
Renal bicarb reabsorption decreases
Metabolic acidosis primary defect?
loss of bicarb or gain of H ions which decreases bicarb concentartion
What is the primary defect with metabolic alkalosis?
Gain of bicarb or loss of H ions which increases bicarb concentration
Compensatory response for metabolic acidosis?
Alveolar hyperventiation to increase pulmonary CO2 excretion which decreases PaCO2
Compensatory response for metabolic alkalosis?
Alveolar hypoventilation to decrease pulmonary CO2 excretion to increase PaCO2
What can cause respiratory acidosis?
CANS (acute)
- CNS depression
- Airway obstruction
- Neuromusclular disorders
- Severe pneumonia, embolism, edema
chronic:
- COPD
- anything else thats chronic impairing ventilation
For every __ increase in PaCO2 in an acute response bicarb should ____.
For every 10 mmHg increase in PaCO2 in an acute response bicarb should increase by 1.
For every __ increase in PaCO2 in a chronic response bicarb should ____.
For every 10 mmHg increase in PaCO2 in a chronic response bicarb should increase by 3.5
Causes of respiratory alkalosis?
CHAMPS
- CNS disease —> hyperventilation
- Hypoxia
- Anxiety
- Mechanical Ventilators
- Progesterone
- Salicylates/Sepsis
Respiratory alkalosis has a decreased PaCO2 what is the compensatory response for bicarb?
To decrease
For every ____ decrease in PaCO2, bicarb should acutely ____ and chronically ___.
For every 10 mmHg decrease in PaCO2, bicarb should acutely decreasae by 2 and chronically decrease by 5.
- Respiratory alkalosis*
- When you look at blood gasses you can determine if it is mixed if values dont follow these trends*
In metabolic acidosis you have low Bicarb, what will the compensatory PaCO2 response be?
To decrease
Causes of metabolic acidosis?
- Decrease of bicarb or addition of an acid
- Will result in respiratory compensation of hyperventilation to decrease PCO2
- Renal correction increases acid titration by increaseing acid in urine and increasing bicarb regeneration
What is normal anion gap?
12 mEq/L
Clinical causes of high anion gap metabolic acidosis metabolic acidosis?
HAGMA —> GOLDMARK
- Glycols
- Oxoproline (tylenol overdose)
- L- lactate accumulates with lactic acidosis with ischemic tissue
- D-Lactate (appears with bowel resections and overproduction by lactobacilli after carb load)
- Methanol
- Aspirin
- Renal failure, cant secrete H
- Ketoacidosis
What are clinical causes of Non anion gap acidosis?
NAGMA —> HARDUPS
- Hyperalimentation
- Acetazolamide
- Renal tubular acidosis
- Diarrhea
- Ureterosigmoid fistula
- Posthypocapnia
- Spironolactone
What is winters formula?
- PaCO2= (1.5 x [bicarb] ) + 8+/- 2
what does a high serum anion gap indicate?
- There are other solutes in the plasma such as alcohols lactic acids or ketoacids
What is renal tubular acidosis?
- acidemia + normal anion gap + normal serum creatine and no diarrhea
RTA type 1?
- impaired distal hydrogen secretion
- Impaired alpha intercalated cells
- this is how new bicarb is generated
RTA 4?
- Lack of aldosterone or failure of kidney to respond to it
- Hyperkalemic
- Most common form of RTA
- high K leads to low ammonium synthesis by Prox tubule
- New bicarb is generated by having NH3 accept H forming NH4 to maintain acid base homeostasis
RTA type 2?
- Proximal tubules don’t reabsorb bicarb
- Usually seen with fanconi syndrome
- Very rare
Metabolic alkalosis has high bicab what will the compensatory response of PaCO2 be?
Increase it
What causes metabolic acidosis? (generally)
What is the compensatory response and correction?
- Addition of a base (bicarb)
- Loss of an acid (H)
- increases pH
- Respiratory compensation of hypoventilation occurs to increase PCO2
- Renal correction decrease reabsorption of bicarb
- To decrease pH
Clinical causes of metabolic alkalosis?
CLEVER PD
- Contraction (selective loss NaCl in urine, keep bicarb)
- Licorice
- Endocrine (Cushings, Conn)
- Vomiting (lose HCl)
- Excess alkali
- Refeeding alkalosis
- Post-hypercapnia
- Diuretics (vol. contract, K loss)
In metabolic alkalosis we are looking for Chloride responsive or chloride resistance. What does that mean?
- Chloride responsive: causes include vomiting,diuretics, nasogastric suction, villous adenoma
- spot urince Cl should be less than 10 mEq/L since kidney is conserving Cl
- Tx with normal saline should fix disturbance
- Chloride resistant: distal exchange site stimulation by aldosterone resulting in increased H and K excretion in exchange for resporption of Na as NaHCO3, ongoing diuretic use/abuse
- Spot urine high Cl despite fact kidney should be conserving Cl
- Tx cause of H loss to treat alkalosis
Acute respiratory acidosis Sx?
- Headache
- Confusion
- Anxiety
- Drowsiness
- Stupor tremors
- COnvulsions
Chronic respiratory acidosis sx?
- Pay be well tolerated as it is slowly developing and stable
- Patients may have memory loss
- sleep disturbance
- daytime sleepiness
- personality changes
Acute respiratory alkalosis sx?
- Light headed
- Confusion
- Peripheral and circumoral paresthesias
- Cramps
- Syncope
- tachypnea or hyperpnea
- carpopedal spasm due to hypocalcemia
Chronic respiratory alkalosis sx?
- usually asymptomatic no distinctive signs
What type of metabolic dysfunction is a loop diuretic assoc. with?
Metabolic alkalosis
What acid base disturbance does COPD assoc. with?
Chronic respiratory acidosis
