Acid-Base Balance

Question 1

The terms acidosis and alklaosis refer to acid-base derangments that produce either excess ___ or excess ____, respectively that may be present regardless of pH.

Answer 1

H+ (hydrogen); OH- (hydroxide)

Question 2

The relationship of CO/HCO3 buffer system to pH is expressed by teh _____ equtaion.

Answer 2

Henderson-Hasselbalch

Question 3

What is the Henderson-Hasselbalch equation?

Answer 3

pH = 6.1 + log (serum bicarb concentration/0.03 x PaCO2)

Question 4

____ - chemical species that can act as a proton (H+) donor

Answer 4

acid

Question 5

_____ - chemical speciies that can act as a proton (H+) acceptor

Answer 5

Base

Question 6

What does pH stand for?

Answer 6

potential of hydrogen

Question 7

With increased pH, the hydrogen ion increases or decresaes?

Answer 7

decreases

Question 8

With decreased pH, the hydrogen ion increases or decreases?

Answer 8

increases

Question 9

What does the Henderson-Hasselbach equation describe?

Answer 9

The relationship between plasma pH and the ration of plasma PCO2 and HCO3

Question 10

What is the immediate buffer system?

Answer 10

carbonic acid-bicarbonate system

Question 11

What is the primary ECF buffer system?

Answer 11

Carbonic acid bicarbonate buffer system

Question 12

The carbonic acid-bicarbonate buffer system maintains a ratio of ____ bicarbonate to ____ carbonic acid.

Answer 12

20 parts; 1 part

Question 13

What uses the process of hydration of CO2 to break it down so it can be neutralized?

Answer 13

Carbonic acid-bicarbonate buffer system

Question 14

The respiatroy buffer system acts within ____ to ____.

Answer 14

minutes to 12-24 hours

Question 15

How does the respiratory buffer system work?

Answer 15

H2CO3 is converted to CO2 and excreted by lungs

Question 16

Alveolar ventilation increases as pH _____.

Answer 16

decreases

Question 17

How does renal buffer system work?

Answer 17

Regulates amount of bicarbonate absorbed or excreted; regulates ammonia and electrolytes

Question 18

Renal regulation of buffer system: Within the renal tubule CO2 combines with _____ in the presence of carbonic anhydrase to form H2CO3 which readily disassociates into ___ and ___. The proximal tubules normal reabsorb 80-90% of this filtered ______.

Answer 18

H2O; H+ and HCO3; HCO3

Question 19

What GI issues cause metabolic alkalosis?

Answer 19

vomiting, NG drainage, chloride wasting diarrhea

Question 20

What urinary issues cause metabolic alkalosis?

Answer 20

diuretic administration, hyperaldosteronism

Question 21

What are some examples of excessive HCO3 loads that can cuase metabolic alkalosis?

Answer 21

• NaHCO3 admin
• Lactate, acetate, citrate admin
• Alkali admin to patients w/ renal failure
• abrupt correction of chronic hypercapnia

Question 22

Metabolic alkaloses can be characterized as ___ responsive or resistant.

Answer 22

chloride

Question 23

How is volume-depletion metabolic alkalosis treated?

Answer 23

Chloride replacement along wtih fluid resuscitation using saline

Question 24

Salien is a weak acid or base?

Answer 24

acide

Question 25

If metabolic alkalosis has been caused by gastric losses of hydrohloric acid, _____ can be given to stop perpetuation of the alklaosis.

Answer 25

PPI

Question 26

Metabolic alkalosis associated with loop diuretics can be improved by adding or substituting ______ diuretics.

Answer 26

postassium-sparing

Question 27

What fluid is preferable in metabolic alkalosis treatment?

Answer 27

NS

Question 28

What happens to serum potassium with metabolic alkalosis?

Answer 28

decreases

Question 29

What happens to iCa with metabolic alklosis?

Answer 29

decreases

Question 30

A ___ shift in the oxyhemoglobin dissociation curve occurs with metabolic alkalosis.

Answer 30

leftward

Question 31

HCO3 decreases by ___ for each ___ mmHg decrease in PaCO2 below 40.

Answer 31

2-5; 10

Question 32

What are causes of respiratory alklaosis? (6)

Answer 32

- iatrogenic (hyperventilation) - high altitude - CNS injury - hepatic disease - pregnancy - ASA OD

Question 33

____ OD is associated with respiratory alklosis?

Answer 33

Salicylate (ASA)

Question 34

The ____ and ___ that may co-exist with respiratory alklosis may also require treatment.

Answer 34

hypokalemia and hypochloremia

Question 35

T/F: Seizures, bradycardia, hyperkalemia, and lethargy and confusion are associated with respiratory alkalosis.

Answer 35

false - seizures, tachycardia, hypokalemia, & lethargy and confusion

Question 36

What are 8 causes of respiratory acidosis?

Answer 36

1. drug-induced ventilatory depression 2. permissive hypercapnia 3. UA obstruction 4. status asthmaticus 5. restriction of ventilation 6. disorders of NM function 7. MH 8. hyperalimentation

Question 37

What acid base condition occurs with status asthmatiuc?

Answer 37

respiratory acidosis

Question 38

What patient population do you want to be careful when correcting respiratory acidosis?

Answer 38

COPD/those used to chronic incrased PaCO2 ... rapid lowering of PaCO2 in these patients decreases body stores of CO2 more rapidly than the kidneys can produce corresponding decrease in HCO3 (this metabolic alklaosis --> seizures, etc.)

Question 39

Hyperkalemia or hypokalemia occurs with respiratory acidosis?

Answer 39

hyperkalemia

Question 40

Metabolic acidosis with signficant reduction of pH can cause what 4 physiologic effects?

Answer 40

1. increased PVR 2. reduced myocardial contractiliy 3. decreased SVR 4. impaired response of CV system to catecholamines

Question 41

Metabolic acidosis is divided into what 2 groups?

Answer 41

normal anion gap and high anion gap

Question 42

When does a high anion gap occur?

Answer 42

When a fixed acid is added to the extracellular space, the acid dissociates, the H+ ion combines with bicarbonate form in carbonic acid, and the decreased bicarbonate concentration produced an increased anion gap

Question 43

What are some examples of high anion gap metabolic acidosis?

Answer 43

Lactic acidosis, DKA, renal failure, poisonings

Question 44

Non-anion gap metabolic acidosis is the result of __________.

Answer 44

a net increase in Cl concentration

Question 45

A normal anion gap acidosis is also known as?

Answer 45

hyperchloremic metabolic acidosis

Question 46

What are the most common causes of a normal-anion gap acidosis?

Answer 46

IV infusion of NS and GI and renal losses of bicarb (diarrhea, renal tubular acidosis, early renal faiure)

Question 47

What type of respiration occurs with metabolic acidosis?

Answer 47

Kussmaul

Question 48

What poisonings and intoxications are assoicated with metabolic acidosis?

Answer 48

intoxicaiton - methanol, ethylene glycol, ASA poisoning - cyanide, carbon monoxide

Question 49

What acid-base disorder is associated with rhabdo?

Answer 49

metabolic acidosis

Question 50

What can cause lactic acidosis?

Answer 50

severe tissue hypoxia d/t hypoxemia, hypoperfusion, ischemia, or inability to use O2 (cyanide)

Question 51

Define base excess.

Answer 51

Amount of acid or base that must be added to return blood pH to 7.4 and PaCO2 to 40 at full O2 sat and 37C.

Question 52

A ____ value base excess indicates metabolic alkalosis.

Answer 52

positive

Question 53

A ____ value base excess indicates metabolic acidosis.

Answer 53

negative

Question 54

How is metabolic acidosis commonly treated?

Answer 54

sodium bicarbonate

Question 55

How does sodium bicarbonate work?

Answer 55

Bicarbonate combines with hydrogen ions and in the presence of the enzyme carbonic anhydrase becomes CO2 and H2O.

Question 56

Sodium bicarbonate is best reserved for patients with adequate ventilation and pH ____

Answer 56

<7.2

Question 57

What is the first treatment for lactic acidosis?

Answer 57

Fluids/volume resuscitation and oxygenation