Acid-Base Balance

Front 1

Balanced plasma conc. of what 2 ions regulate acid-base balance?

Back 1

Hydrogen & bicarbonate ions

Front 2

Acid-base balance is responsible for what 4 things?

Back 2

1. Enzyme activity
2. Hb saturation
3. Myocardial contractility
4. intracellular reactions

Front 3

What is an acid?

Back 3

-A subst. that when dissolved in H2O yields H+ ions thereby lowering pH.
-Proton donor (H+)

Front 4

What is a ptoton donor (H+)?

Back 4

Acid

Front 5

What is a base?

Back 5

-A subst. that when dissolved in H2O yields hydroxide ions (OH-)
-Proton acceptors (remove H+ from a solution)

Front 6

Proton acceptors?

Back 6

Base

Front 7

Hrdroxide ions have a stron affinity for what ion?

Back 7

-H+.
-ie. Bases are proton acceptors, they avidly bind to H+ & decrease H+

Front 8

What is produced as substrates are oxidized in the production of ATP?

Back 8

Hydrogen ions

Front 9

Normal H+ conc. in arterial blood and extracellular fluid at 37c ?

Back 9

35-45nmol/L

Front 10

H+ conc. of 35-45nmol/L is equivalent to arterial pH?

Back 10

7.35-7.45

Front 11

What is normal plasma bicorbonate ion conc.?

Back 11

22-26mEq/L

Front 12

The value of pH is inversely related to ?

Back 12

the level of free H+ ions in the body

Front 13

The lower the pH, the higher or lower level of free H+ ions?

Back 13

higher level of free H+ ions

Front 14

A change in 1 pH unit represents how much of a change in in free H+ ion conc.

Back 14

10 fold change

Front 15

a pH change of 1/10th (7.4-7.3) represents how much of a change in H+ ?

Back 15

a large increase in H+

Front 16

Flucuations in normal pH interfere w/ ?

Back 16

-shape & fxn of hormones & enzymes
-distribution of electrolytes
-Responses of excitable membranes in heart, nerves, skeletal muscle, & GI tract making them more or less excitable

Front 17

Acidic solutions have a pH lower than ?

Back 17

7. H+ ions prevail

Front 18

Alkaline solutions havs a pH above ?

Back 18

7. Hydroxide ions prevail

Front 19

A person could not survive long w/ a pH of ?

Back 19

Below 6.8 or above 7.7

Front 20

Quantitative measurement describing the equilibrium b/w plasma pH & ratio of plasma pCO2 & HCO3?

Back 20

Henderson Hasselbach equation

Front 21

Primary determinant of pH ?

Back 21

Ratio of pCO2 to HCO3 & not individual values

Front 22

An increase in CO2 or decrease in HCO3 will have what kind of change on pH?

Back 22

pH will decrease

Front 23

Body tries to maintain a constant pH by maintaining what ratio of HCO3 to dissolved CO2?

Back 23

20:1 which will = a pH of 7.40

Front 24

If HCO3 were to drop suddenly what happens to CO2?

Back 24

CO2 will also drop to make body more alkalotic

Front 25

3 basic systems to prevnt change in pHa?

Back 25

1. Buffer system
2. ventilatory response
3. Renal response

Front 26

What 2 buffering systems have quick responses but are incomplete correction?

Back 26

1. Buffering system
2. Ventilatory response

Front 27

Most powerful system for acid base regulation?

Back 27

Kidneys

Front 28

Renal response occurs in what time frame? & is it complete or incomplete correction?

Back 28

-12-48 hrs
-complete correction

Front 29

Name the 4 buffering systems?

Back 29

1. Bicarbonate buffering system
2. Hb buffering system
3. Proetib buffering system
4. Phosphate buffering system

Front 30

The most important buffering systen in ECF?

Back 30

Carbonic acid-bicarbonate buffer sys.

Front 31

According to lecture, The 2nd most important buffering sys. in ICF? (M&M book says ECF)

Back 31

Hb buffering sys.

Front 32

This buffering sys. occurs in ICF (minimal role) & in the urine?

Back 32

Phosphate buffering sys.

Front 33

This buffering sys. regulates pH in ECF & ICF?

Back 33

Protein buffering sys.

Front 34

How does the bicarbonate buffering sys. work?

Back 34

-Body produces CO2 which gets hydrated in H2O to produce carbonic acid via carbonic anhydrase.
-Carbonic acid (H2CO3) further dissociates into H+ ions & HCO3
-HCO3 enters plasma & H+ ions are buffered by reduced Hb

Front 35

Explain how the Hb buffering sys. work?

Back 35

-CO2 diffuses into the erythrocytes down a conc. gradient & dissolves in H2O & forms carbonic acid via carbonic anhydrase
-Carbonic anhydrase dissociates into H+ & HCO3
-H+ ions bind to Hb & HCO3 ions are exchanged back into the plasma w/ extracellular Cl- (chloride shift) to maintain electrical neutrality

Front 36

Extracellular protein buffer?

Back 36

Albumin & globulin

Front 37

Intracellular protein buffer?

Back 37

Hb

Front 38

Most important extracellular protein buffer?

Back 38

Albumin

Front 39

In the ventilatory response this responds to changes in PCO2?

Back 39

Peripheral chemoreceptors in carotid bodies

Front 40

During the ventilatory response central chemorecptors in the medulla respond to changes in?

Back 40

CSF pH (b/c HCO3 diffuses back into blood so increase H+ in CSF)

Front 41

During ventilatory response, alveolar ventilation increases by how much?

Back 41

Increases 1-4 L/min for every 1 mmHg increase in PaCO2.

Front 42

3 important responses that occur during the renal response?

Back 42

1. Increased reabsorption of filtered HCO3
2. Increased excretion of H+ ions
3. Increased production of ammonia

Front 43

Where in the kidney is HCO3 completely filtered?

Back 43

Glomerulus

Front 44

During the renal response, how much HCO3 is reaborbed & where?

Back 44

85-90% HCO3 gets reabsorbed into the blood at the proximal tubule.

Front 45

Is HCO3 normally excreted in urine?

Back 45

No

Front 46

During the renal response, H+ ions are actively exchanged for what ion ? & where does this occur?

Back 46

H+ is exchanged for Na+ across the luminal membrane into the proximal tubule lumen

Front 47

During the renal response in the tubular lumen, H+ ions combine w/ _____ to form _____ ?

Back 47

H+ ions combine w/ HCO3 to form carbonic acid (H2CO3)

Front 48

During the renal response in the proximal tubule lumen, H2CO3 is broken down by _____ to form ______ ?

Back 48

H2CO3 is broken down by carbonic anhydrase to form CO2 & H2O.

Front 49

Why does filtered HCO3 combine w/ H+ in the proximal tubule lumen?

Back 49

b/c HCO3 alone is not diffusible so it combines w/ H+ to form H2CO3 which is broken down to CO2 & H2O which is diffusible into tubular cell or peritubular capillary

Front 50

During the renal response, for each H+ that the kidney excretes there is generation of ?

Back 50

1 new HCO3- ion added to ECF

Front 51

Explain Bicarbonate reabsorption during the renal response?

Back 51

Glomerulus secretes HCO3 into proximal tubule lumen. H+ gets secreted by tubular cell into proximal tubule lumen in exchange for 1 Na+. In the tubular lumen HCO3 + H+ = H2CO3. CA breaks up H2CO3 into CO2 & H2O. Now CO2 & H2O can diffuse into tubular cell or peritubular capillary. Inside tubular cell CA catalyze CO2 + H2O= H2CO3 which then dissociates into H+ & HCO3. H+ is again actively excreted into proximal tubule lumen in exchange for 1 Na+ & HCO3 is carried out of tubular cell by Na+ (NaHCO3) into peritubular capillary

Front 52

After all the body's HCO3 is exhausted & acidosis is still present, what other 2 ways can the kidney rid of H+ (list in order)?

Back 52

1.In tubular lumen H+HPO4 = H2PO4 which is not diffusible back into tubular cell & gets excreted in urine.
2. In tubular lumen fluid H+NH3=NH4+ which is not diffusible back into tubular cell & gets excreted in urine.

Front 53

Where is ammonia (NH3)formed? & from what?

Back 53

Mitochondria of proximal tubular cells. Formed from deamination of glutamine

Front 54

What increases renal production of NH3?

Back 54

Acidemia b/c kidneys forms more NH3 to bind w/ H+ & form NH4 to be excreted in urine

Front 55

What is base excess?

Back 55

Amt. of acid or base required to return pHa to 7.4 & PaCO2 to 40mmHg at 37c & full O2 saturation

Front 56

What is the metabolic component of acid-base disturbance?

Back 56

Base excess

Front 57

A postive base excess indicates?

Back 57

Metabolic alkalosis

Front 58

A negative base excess indiates?

Back 58

Metabolic acidosis

Front 59

Acid-base disturbance resulting from changes in ventilation?

Back 59

Resp. acidosis/alkalosis

Front 60

Acid-base disturbance unrelated to alveolar ventilation?

Back 60

Metabolic acidosis/alkalosis

Front 61

Describes the secondary ventilatory or renal response to the intial disturbance?

Back 61

Compensation

Front 62

Adverse response to mild acidemia?

Back 62

Release of catecholamines, increase BP, HR, ect..

Front 63

Adverse response to pHa <7.2?

Back 63

Cardiac depression, decreased contractility, Smooth muscle depression, decreased PVR, hypotension, decreased response to catechol.
-Consider giving HCO3 to this pt (as per lecture)

Front 64

Which type of acidosis has worse effects on the heart?

Back 64

-Resp. acidosis
-Ventricular threshold for fib is reduced.

Front 65

Acidosis may lead to hypo/hyper K+ & why?

Back 65

-Potentailly lethal hyperK+ due to H-K shift across cell membrane.
-Movement of K+ out of cell in exchange for extracellular H+

Front 66

In acidosis what happens to plasma K+ (increase or decrease & by how much)?

Back 66

Plasma K+ increases by approx. 0.6mEq/L for each 0.10 decrease in pH

Front 67

Acidosis effects on Hb affinity for O2?

Back 67

R. shift, less affinity

Front 68

CNS depression is more prominent w/ what type of acid-base disturbance & why?

Back 68

-Resp. acidosis.
-CO2 narcosis, greatlt depresses neuronal activity & may lead to coma

Front 69

What does acidosis do to CBF?

Back 69

Increase CBF via vasodilation which can increase ICP & decrease CPP & cause cerebral ischemia

Front 70

What does acidosis do to Sz threshold?

Back 70

Increaes Sz threshold b/c depresses neuronal activity

Front 71

What does alkalosis do to Sz threshold?

Back 71

Decrease Sz threshold b/c alkalosis renders all tissues more excitable

Front 72

Respirtaory acidosis

Back 72

-Increase in PaCO2
-Drives reaction to R. (forming carbonic acid then H+ & HCO3) causing increase H+ & decrease pHa

Front 73

Respiratory acidosis is caused by ? (2 things)

Back 73

1. Hypoventilation
2. CO2 retention

Front 74

Explain central compensatory response to resp. acidosis?

Back 74

-CO2 rapidly crosses BBB leading to decrease CSF pH which stimulates central chemoreceptors in medulla which increase minute ventilation

Front 75

Explain peripheral compensatory response to resp. acidosis?

Back 75

Peripheral chemoreceptors in carotid bodies & aortic arch respond to changes in CO2 & O2 conc. If CO2 is high, will increase minute ventilation

Front 76

What do volatile anesthetics do to peripheral comp. mech.?

Back 76

Blunt carotid body mediated response to acidemia. (FYI: opioids blunt central response)

Front 77

Peripheral chemoreceptors in carotid bodies & aortic arch respond to changes in?

Back 77

CO2 & O2

Front 78

Causes of Resp. acidosis r/t alveolar ventilation:

Back 78

CNS depression, neuromuscular disorders, chest wall abn, pleural abn, airway obst. (upper/lower parenchymal lung disease, embolism, aspiration, pneumonia, ect..

Front 79

Causes of Resp. acidosis r/t CO2 production?

Back 79

MH, thyroid storm, extensive burn injury, shivering, prolonged sz, lg. caloric loads (b/c carbohydrate breakdown into CO2)

Front 80

Compensation of acute resp. acidosis?

Back 80

-Limited resp. compensation
-Buffering (Hb-H, & H ion exchange for Na & K from ICF & bone)
-Very limited renal response (plasma HCO3 increases by 1mEq/L for every 10mmHg in PaCO2-above 40)

Front 81

Limited response in Resp. acidosis? (r/t HCO3 & PaCO2)

Back 81

Plasma HCO3 increases by 1mEq/L for every 10mmHg in PaCO2-above 40.

Front 82

Treatment of resp. acidosis?

Back 82

Mech. ventilation, NaHCO3 only if pH <7.10 & HCO3 <15mEq/L

Front 83

At what point would you give NaHCO3 during resp. acidosis?

Back 83

pH <7.10 & HCO3 <15mEq/L

Front 84

Compensation of chronic resp. acidosis?

Back 84

-Renal compensation (12-24h, may peak at 3-5days)
-Confirmed by normal pH & increased PaCO2
-Increased renal secretion of H+ ions results in increased plasma HCO3 conc.
-Treatment rarely involves mech. ventilation

Front 85

Goal of mech. ventilated pts w/ chronic resp. acidosis?

Back 85

-Return CO2 to their "normal" level & avoid resp. drive depression from excessive O2 therapy

Front 86

Metabolic acidosis?

Back 86

pH < 7.35 & HCO3 < 21mEq/L

Front 87

Metabolic occurs from (general)?

Back 87

1. Increase in blood H+ ion conc. caused by addition of acids (other than CO2)
2. Loss of bases from body fluid

Front 88

General causes of metabolic acidosis?

Back 88

-Increased metabolic production of H ions
-Decreased renal tubule elimination of H ions
-GI or renal losses
-Rapid dilution of ECF compartment w/ bicarbonate free fluid

Front 89

NS when given in lg. amts. can cause?

Back 89

Hypercholreimc metabolic acidosis

Front 90

Compensatory response to metabolic acidosis?

Back 90

-Increased alveolar ventilation(H+ stimulation of carotid bodies)
-Renal tubule secretion of H+ ions into the urine
-Buffers in bone neutralize acids in circulation
-Ventilatory response is unable to completely normalize pH

Front 91

What are ions?

Back 91

Molecules w/ a charge (positive or negative)

Front 92

What are cations & give 2 examples?

Back 92

Positively charged ions.
-Na+ & K+

Front 93

What are anions & give 2 examples?

Back 93

Negatively charged ions
Cl- & HCO3-

Front 94

What accounts for the largest fraction of anion gap?

Back 94

Albumin 11mEq/L

Front 95

Anion Gap equation:

Back 95

Na + K + unmeasured cations must = Cl + HCO3 + unmeasured anions

Front 96

Anion Gap: unmeasured cations include:

Back 96

Ca2+, Mg+, & minerals
(& K+ as per M&M)

Front 97

Anion Gap: unmeasured anions include:

Back 97

plasma proteins (albumin), phosphates, sulfates

Front 98

Normal anion gap? & how did you come up w/ this value?

Back 98

12mEq/L (7-14)
Na - (Cl+HCO3)= anion gap
ie. 140 -(104+24)=12mEq/L

Front 99

Used in determining differential diagnosis of metabolic acidosis?

Back 99

Anion Gap

Front 100

When there are excessive anions (acids) in the plasma, what happens to anion gap?

Back 100

Anion gap increase

Front 101

Any condition that increases umeasured anions or decreases unmeasured cations will cause anion gap to_____?

Back 101

Anion gap increase

Front 102

Any condition that decreases umeasured anions or increases unmeasured cations will cause anion gap to_____?

Back 102

Anion gap to decrease

Front 103

Anion gap > 30mEq/L indicates?

Back 103

A high anion gap acidosis

Front 104

High anion gap metabolic acidosis (>30mEq/L) can be due to:

Back 104

-Insufficient renal excretion of acids(ie. CRF decreased GFR<20ml/min)
-Increased endogenous acid production (lactic or ketoacidosis)
-Ingestion of exogenous acids (salicytes, methanol, ethylene glycol)

Front 105

Normal anion gap metabolic acidosis (<13mEq/L)is caused by?

Back 105

-Increased GI loss of HCO3
-Increased renal loss of HCO3
-Rapid expansion of extracellular fluid volume w/ bicarbonate free solution (0.9%NS)
-AA infusions (HAL)contain an excess of cations (Cl-)
Administration of lg. quantities of ammonium Cl- or arginine HCL

Front 106

What is normal anion gap metabolic acidosis characterized by?

Back 106

-Hyperchloremia due to plasma chloride replacing HCO3 that is lost due to GI loss of HCO3 (diarrhea, sm. bowel,billiary & pancreatic fluids contain HCO3)

Front 107

How does increased renal loss of HCO3 contributes to normal anion gap metabolic acidosis?

Back 107

-Increased renal loss of HCO3 is caused by failure to reabsorb HCO3 in the proximal tubule which then causes failure to secrete H+ ions, so H+ ions can not form H2PO4 & NH4
-Carbonic anhydrase inhibitors ie Acetazolamine (diamox) interfere w/ secretion of H+ ion

Front 108

How does rapid expansion of extracellular fluid volume w/ bicarbonate free solution (0.9%NS)cause normal anion gap metabolic acidosis?

Back 108

Cl- impairs bicarbonate reabsorption in the kidneys. Produces hyperchloremic metabolic acidosis

Front 109

Treatment of metabolic acidosis?

Back 109

-Resp. component should be corrected (lower PaCO2 to low 30's)
-Alkali therapy via ABG's
Hemodialysis in refractory or profound acidemia
-Correct cause (DKA,ect.)
-NaHCO3 if pH <7.10 & HCO3 <21mEq/L
-THAM (tromethamine)lacks Na+ & does not regenerate CO2as a byproduct of buffering

Front 110

Why avoid NaHCO3 in cardiac arrest & low flow states?

Back 110

-May improve MAP and ECF pH but does not improve ICF pH or CV response to catechol.
-It also reduces plasam ionized Ca2+ levels
-Increases CO2

Front 111

Treament goal for metabolic acidosis?

Back 111

Raise pH to at least above 7.25 to over come adverse effects of acidemia

Front 112

Bicarb is best reserved for what kind of pts?

Back 112

Pts w/ adequate ventilation & pH <7.20

Front 113

Lactic acidosis from inadequate tissue perfusion should be treated w/ ?

Back 113

Volume resusitation & oxygenation

Front 114

How do you calculate NaHCO3 dose?

Back 114

Body wt x BD(deviation of plasma HCO3 from 24mEq/L)x ECF volume as a fraction of body (0.3); then give 1/2 of this.
ie. 70kg pt w/ HCO3 of 12mEq/L
(70)(24-12)(0.3) = 252mEq; give 126mEq

Front 115

Anesthetic considerations in acidosis w/ opioids?

Back 115

Opioids are weak bases & may have increased fraction of drug in non-ionized form & increase penetration into brain

Front 116

Anesthetic considerations in acidosis?

Back 116

Acidemia can potentiate depressant effects of most sedtaives & anesthetic agents on CNS & circulatory

Front 117

Anesthetic considerations in acidosis r/t airway?

Back 117

Increased sedation & depression of airway reflexes predispose pulm. aspiration

Front 118

Anesthetic considerations in acidosis w/ PIA's & IV anesthetics?

Back 118

Circulatory depressants effects of PIA's & IV anesthetics can be exaggerated

Front 119

Which PIA is more arrhythmogenic in acidosis?

Back 119

Halothane

Front 120

Anesthetic considerations in acidosis w/ NMB's

Back 120

-Avoid SCh in hyperkalemia (acidosis causes hyperkalemia by exchanging H+ & K+)
-Respiratory (not metabolic)acidosis may augment NDNMB & prevent antagonsim by reversal agents.

Front 121

Adverse effects of alkalosis on K+ ? How much?

Back 121

-Hypokalemia=cardiac dysrhythmias
-With alkalosis, serum K+ decreases as H+ diffuses out of cell in exchange for K+
-Plasma k+ decreases 0.6mEq/L for each 0.10 increase in pH

Front 122

Adverse effects of alkalosis on oxyHb dissociation curve?
(shift right or left)

Back 122

Left b/c alkalosis increases affinity of Hb for O2

Front 123

Adverse effects of alkalosis on Ca2+ ?

Back 123

-Enhanced binding for Ca+ on plasma proteins, decreasing ionized plasma Ca levels
-incr. # of anionic binding sites for Ca on plasma proteins=decr. iCa
-circulatory depression & neuromuscular irritability

Front 124

Adverse effects of resp. alkalosis on bronchial tone & ventilatory effort? & PVR as per M&M?

Back 124

-Increases bronchial tone (bronchoconstriction) & decreases ventilatory effort contributing to atelectasis
-Decrease pulm. vascular resistance (M&M p720)

Front 125

Adverse effects of alkalosis on SVR?

Back 125

Increase SVR & possibly coronary vasospasm

Front 126

Adverse effects of Resp. alkalosis on CBF?

Back 126

Decrease CBF (norm:50ml/100g/min @ 40mmHg PaCO2)

Front 127

Metabolic alkalosis may trigger compensatory hypo/hyperventilation?

Back 127

-Compensatory hypoventilation (to incr.PaCO2) causing hypoxemia.

Front 128

Resp. Alkalosis is characterized by pH____ & PaCO2____?

Back 128

-pH >7.45 & PaCO2 <35

Front 129

What does resp. alkalosis do to minute ventilation?

Back 129

-Increase in minute ventilation to a level greater than required to excrete the metabolic production of Co2

Front 130

pH of severe alkalemia?

Back 130

pH >7.6

Front 131

During resp. alkalosis, what happens to plasma HCO3 for every 10mmHg acute decrease in PaCO2 below 40mmHg?

Back 131

Plasma HCO3 will decrease 2-5mEq/L for each 10mmHg acute decrease in PaCo2 below 40mmHg (M&M p720)

Front 132

Treament for resp. alkalosis?
How about severe alkalemia pH >7.6?

Back 132

-Correction of underlying problem
-Severe alkalemia: IV HCL acid, arginine Cl, or NH4 Cl(M&M p720)

Front 133

Causes for resp. alkalosis r/t incr. Co2 elimination?

Back 133

-Incr. Co2 elimination (mech., self induced, dx, preg, pain, anxiety, decr. barometric pressure,CNS injury, art. hypoxemia, pulm. emboli, liver cirrhosis, sepsis

Front 134

Causes for resp. alkalosis r/t decr. Co2 production?

Back 134

hypothermia, hypothyroidism, skeletal muscle paralysis by NBA

Front 135

Causes of metabolic alkalosis?

Back 135

1. Increased in plasma HCO3
2. Cl sensitive (NaCl deficiency & ECF depletion)
3. Cl resistant (enhanced mineralocorticoid activity)

Front 136

Explain metabolic alkalosis due to Cl sensitive?

Back 136

-Depletion of ECF (diuretic tx)enhances Na reabsorption at renal tubules back into blood so that H2O can follow. B/c there is not enough Cl to accompany all the Na ions reabsorbed, incr. H+ is secreted to maintain electroneutrality & those extra H+ ions bind HCO3 in tubule lumen. HCO3 ions that should have been excreted are reaborbed into blood.
This happens b/c maint. of ECF has priority over acid-base balance
-K+ secretion is also enhanced to maintain electroneutrality during ECF depletion.
-Hypokalemia(due to ECF depletion)enhances H+ secretion & HCO3 reabsorption

Front 137

Causes of metabolic alkalosis due to Cl sensitive?

Back 137

-diuretics(furosemide & thiazide)incr. Na,Cl, & K+ excretion=decr.NaCl & hypokalemia
-Loss of GI fluids H+, Na+, K+, & Cl depletion(vomiting NG sx)

Front 138

Explain metabolic alkalosis r/t Cl resistant?

Back 138

-Incr. mineralocorticoid activity cause Na retention & expansion of ECF volume
-Kidneys secrete H+ & K+ to balance neutrality

Front 139

Co2 in blood is carried as?

Back 139

Bicarbonate

Front 140

Measurement of total Co2 on electrolyte reports should be ____ greater/lower than HCO3 & why?

Back 140

Total Co2 should be about 1mEq greater than HCO3 b/c Co2 in blood is carried by bicarbonate

Front 141

If normal HCO3 on ABG is 24,
what is normal Co2 on serum electrolyte?

Back 141

tCo2=25 on serum electrolyte

Front 142

If pt's HCO3 or serum Co2 exceeds normal by >4 what would you suspect?

Back 142

-primary metabolic alkalosis
-conserved HCO3 in response to chronic hypercarbia

Front 143

If pts serum HCO3 level is elevated, what do you suspect?

Back 143

-hypovolemia(body trying to conserve Na & as a result due to incr. H+ will have incr. HCO3 reabsorption
-hypokalemia(augments H+ secretion & HCO3 reabsorption)

Front 144

Treatment of metabolic alkalosis?

Back 144

-Expansion of intravascular volume to incr. renal perfusion
-Administration of K+ to reverse hypokalemia
-Intraop infusion of NS instead of LR to incr. Cl & decr. HCO3

Front 145

Treatment of metabolic alkalosis due to Cl resistant?

Back 145

-Spirinolactone (aldosterone antagonist) treats incr. mineralcortiocoid activity

Front 146

Treatment of metabolic alkalosis due to Cl sensitive?

Back 146

-NS (NaCl) & KCl(M&M p721)

Front 147

Can resp. acidosis/alkalosis be completely compensated?

Back 147

Yes

Front 148

Can metabolic acidosis/alkalosis be completely compensated?

Back 148

No

Front 149

Acid base disturbances in post op period?

Back 149

-Resp. acidosis
-Metabolic acidosis
-Resp. alkalosis

Front 150

Why would post-op pt. develop Resp. acidosis?

Back 150

-Residual anesthetics & NMB which blunt response to Co2

Front 151

Why would post-op pt. develop Metabolic acidosis?

Back 151

-Surgical blood loss or 3rd space losses are under appreciated & volume resuscitation is inadequate

Front 152

Why would post-op pt. develop Resp. alkalosis?

Back 152

-Pain & anxiety

Front 153

For every 10mmHg decr. in PaCo2 what will happen to pH & HCO3? & by how much?

Back 153

-pH will incr. by 0.10
-HCO3 will decr. by 2mEq/L

Front 154

What will happen to pH & HCO3 w/ chronic 10mmHg decr. in PaCo2? & by how much?

Back 154

-pH will normalize
-HCO3 will decr. by 5-6mEq/L

Front 155

For every acute 10mmHg incr in PaCo2 what will happen to pH & HCO3? & by how much?

Back 155

-pH will decr. by 0.05
-HCO3 will incr. by 1mEq/L

Front 156

What will happen to pH & HCO3 w/ chronic 10mmHg incr. in PaCo2? & by how much?

Back 156

-pH will normalize
-HCO3 will incr.by 4-5mEq/L

Front 157

Venous blood pH is usually ___ lower/higher than arterial blood pH?

Back 157

-0.05U lower

Front 158

Venous Co2 is usually ___ lower/higher than PaCo2?

Back 158

4-6mmHg higher than PaCo2

Front 159

Calculated bicarbonate is ___ lower/higher than arterial bicarbonate?

Back 159

2mEq/L higher than arterial bicarb

Front 160

How can heparin coated syringes used for ABG sample affect results?

Back 160

False decreases in pH b/c acidic

Front 161

How do air bubbles affect ABG sample?

Back 161

Prevent equilibration of O2 & Co2 Pp