Intro to Acid Base Disturbances

Question 1

pH <7.4 and PCO2 is 35 and bicarb 12 mEq/L what would this be classified as?

Answer 1

Metabolic acidosis with respiratory compensation

Question 2

pH >7.4 PCO2 is 28 and bicarb is 22 what would this be classified as?

Answer 2

Respiratory alkalosis with renal compensation

Question 3

What happens to breathing in respiratory acidosis?

Answer 3

Alveolar Hypoventilation to increase PaCO2 to decrease pH

Question 4

What happens to ventilation with respiratory alkalosis?

Answer 4

Alveolar hyperventilation to decrease PaCO2 to increase the pH

Question 5

What is the compensatory response for Respiratory acidosis?

Answer 5

Renal bicarb reabsorption is increased

Question 6

What is the compensatory response for Respiratory alkalosis?

Answer 6

Renal bicarb reabsorption decreases

Question 7

Metabolic acidosis primary defect?

Answer 7

loss of bicarb or gain of H ions which decreases bicarb concentartion

Question 8

What is the primary defect with metabolic alkalosis?

Answer 8

Gain of bicarb or loss of H ions which increases bicarb concentration

Question 9

Compensatory response for metabolic acidosis?

Answer 9

Alveolar hyperventiation to increase pulmonary CO2 excretion which decreases PaCO2

Question 10

Compensatory response for metabolic alkalosis?

Answer 10

Alveolar hypoventilation to decrease pulmonary CO2 excretion to increase PaCO2

Question 11

What can cause respiratory acidosis?

Answer 11

CANS (acute)

• CNS depression
• Airway obstruction
• Neuromusclular disorders
• Severe pneumonia, embolism, edema

chronic:

• COPD
• anything else thats chronic impairing ventilation

Question 12

For every __ increase in PaCO2 in an acute response bicarb should ____.

Answer 12

For every 10 mmHg increase in PaCO2 in an acute response bicarb should increase by 1.

Question 13

For every __ increase in PaCO2 in a chronic response bicarb should ____.

Answer 13

For every 10 mmHg increase in PaCO2 in a chronic response bicarb should increase by 3.5

Question 14

Causes of respiratory alkalosis?

Answer 14

CHAMPS

• CNS disease —> hyperventilation
• Hypoxia
• Anxiety
• Mechanical Ventilators
• Progesterone
• Salicylates/Sepsis

Question 15

Respiratory alkalosis has a decreased PaCO2 what is the compensatory response for bicarb?

Answer 15

To decrease

Question 16

For every ____ decrease in PaCO2, bicarb should acutely ____ and chronically ___.

Answer 16

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*

Question 17

In metabolic acidosis you have low Bicarb, what will the compensatory PaCO2 response be?

Answer 17

To decrease

Question 18

Causes of metabolic acidosis?

Answer 18

• Decrease of bicarb or addition of an acid
• Will result in respiratory compensation of hyperventilation to decrease P_CO2
• Renal correction increases acid titration by increaseing acid in urine and increasing bicarb regeneration

Question 19

What is normal anion gap?

Answer 19

12 mEq/L

Question 20

Clinical causes of high anion gap metabolic acidosis metabolic acidosis?

Answer 20

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

Question 21

What are clinical causes of Non anion gap acidosis?

Answer 21

NAGMA —> HARDUPS

• Hyperalimentation
• Acetazolamide
• Renal tubular acidosis
• Diarrhea
• Ureterosigmoid fistula
• Posthypocapnia
• Spironolactone

Question 22

What is winters formula?

Answer 22

• PaCO₂= (1.5 x [bicarb] ) + 8_{+/- 2}

Question 23

what does a high serum anion gap indicate?

Answer 23

• There are other solutes in the plasma such as alcohols lactic acids or ketoacids

Question 24

What is renal tubular acidosis?

Answer 24

• acidemia + normal anion gap + normal serum creatine and no diarrhea

Question 25

RTA type 1?

Answer 25

* impaired distal hydrogen secretion * Impaired alpha intercalated cells * this is how new bicarb is generated

Question 26

RTA 4?

Answer 26

* 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

Question 27

RTA type 2?

Answer 27

* Proximal tubules don't reabsorb bicarb * Usually seen with fanconi syndrome * Very rare

Question 28

Metabolic alkalosis has high bicab what will the compensatory response of PaCO2 be?

Answer 28

Increase it

Question 29

What causes metabolic acidosis? (generally) What is the compensatory response and correction?

Answer 29

* 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

Question 30

Clinical causes of metabolic alkalosis?

Answer 30

**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)

Question 31

In metabolic alkalosis we are looking for Chloride responsive _or_ chloride resistance. What does that mean?

Answer 31

* 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

Question 32

Acute respiratory acidosis Sx?

Answer 32

* Headache * Confusion * Anxiety * Drowsiness * Stupor tremors * COnvulsions

Question 33

Chronic respiratory acidosis sx?

Answer 33

* Pay be well tolerated as it is slowly developing and stable * Patients may have memory loss * sleep disturbance * daytime sleepiness * personality changes

Question 34

Acute respiratory alkalosis sx?

Answer 34

* Light headed * Confusion * Peripheral and circumoral paresthesias * Cramps * Syncope * **tachypnea or hyperpnea** * carpopedal spasm due to hypocalcemia

Question 35

Chronic respiratory alkalosis sx?

Answer 35

* usually asymptomatic no distinctive signs

Question 36

What type of metabolic dysfunction is a loop diuretic assoc. with?

Answer 36

Metabolic alkalosis

Question 37

What acid base disturbance does COPD assoc. with?

Answer 37

Chronic respiratory acidosis