Fluids , Electrolytes, and Acid-Base

Question 1

What fraction of body water is found in extracellular space?

Answer 1

20% and 14 Liters
Major ions = Sodium, Chloride, Ca+, and Bicarb

Question 2

70kg adult has how many Liters of body water? Volume is what percent of weight?

Answer 2

42L and 60% of body weight

Question 3

Intracellular Volume

Answer 3

40% of total body weight
28L
Major ions = Potassium, Magnesium, and Phosphate

Question 4

ECV can be further divided into?

Answer 4

Interstitial fluid and plasma

-Interstitial fluid = 16% TBW or 11 L
-Plasma = 4% TBW or 3L

can be (15% and 5%)

Question 5

What population has the highest TBW of water?

Answer 5

Neonates 80%

Question 6

What population has the lowest TBW of water?

Answer 6

Females, the obese, and the elderly

Question 7

What determines the net movement of fluid between the intravascular space and interstitial spaces?

Answer 7

Starling forces and Glycocalyx

Question 8

Forces that move fluid from CAPILLARY to INTERSTITIAL SPACE

Answer 8

Pc= Capillary hydrostatic pressure (PUSHES fluid out of capillary)

^ if = Interstitial oncotic pressure (PULLS fluid out of capillary)

Question 9

Forces that move fluid from INTERSTITIAL space into CAPILLARY

Answer 9

P if= Interstitial hydrostatic pressure (pushes fluid into capillary)

^ c= Capillary oncotic pressure (pulls fluid into capillary)

Question 10

What is the pressure of a solution against a semipermeable membrane that prevents water from diffusing across that membrane?

Answer 10

Osmotic pressure

Question 11

Which solutes cannot diffuse across semipermeable membrane?

Answer 11

ions, protiens, glucose

carrier proteins transport these solutes from one side to the other

Question 12

Equation to calculate Plasma Osmolarity

Answer 12

(Na+ x 2) + (Glucose / 18) + BUN / 2.8)

Normal = 280- 290 (high is hyper and low is hypo)

Question 13

What is the most important determinant of plasma osmolarity?

Answer 13

Sodium

Question 14

Conditions that increase osmolarity include…..

Answer 14

hypernatremia, hyperglycemia, and uremia

Question 15

What does giving a hypotonic solution do to ECF, ICF and plasma osmolarity?

Answer 15

Increase ECF and ICF volumes
Decreases plasma osmolarity

Question 16

What fluid should you never give a patient with increase ICP?

Answer 16

HYPOTONIC!!!
poor expanders of intravascular volume

Question 17

What does giving isotonic solution do to ECF, ICF, and plasma osmolarity?

Answer 17

Increase ECF
ICF and plasma osmolarity stay the same!

Question 18

How long do Crystalloids stay in the intravascular space for?

Answer 18

30 minutes

Question 19

What can cause hypercholemic metabolic acidosis? What is given instead for large-volume resuscitation?

Answer 19

NaCl can cause it

LR is used (the lactate functions as a buffer because the lactate is converted to bicarb by the liver and kidneys)

Question 20

What fluids are given to dilute PRBCs?

Answer 20

NS and Plasmalyte

LR contains calcium which is why it is avoided. (book answer)

Question 21

What organ is the most important regulator of potassium homeostasis?

Answer 21

Kidneys (decreased GFR/renal failure increases serum potassium)

Question 22

Causes of Hypokalemia (< 3.5 mEq/L)

Answer 22

poor intake, GI loss, renal loss, or redistribution (K+ shifts IN to cells)

Question 23

Causes of Hyperkalemia ( > 5.5 mEq/L)

Answer 23

Increased total body potassium and redistribution (K+ shift OUT of cells)

Question 24

What is responsible for maintaining the intracellular distribution of potassium?

Answer 24

the Na+K+ATPase pump

Question 25

Hyperkalemia does what to membranes? Hypokalemia?

Answer 25

Hyperkalemia DEpolarizes membranes Hypokalemia HYPERpolarizes membranes

Question 26

HYPOkalemia symptoms

Answer 26

skeletal muscle cramps ---> weakness ----> paralysis Worsens Digoxin toxicity

Question 27

HYPERkalemia symptoms

Answer 27

Cardiac rhythm distrubances

Question 28

EKG findings of HYPOkalemia

Answer 28

LONG--> PR interval LONG--> QT interval FLAT--> T wave U wave

Question 29

EKG findings of HYPERkalemia

Answer 29

5.5 - 6.5 = Peaked T waves 6.5 - 7.5 = P wave flattened 7.0- 8.0 = QRS prolongation 8.5 or greater = VF or sine wave

Question 30

Most common electrolyte disorder in clinical practice?

Answer 30

HYPOkalemia

Question 31

How fast to administer IV K+ ?

Answer 31

Peripheral = 10mEq per hour Central = 20mEq per hour

Question 32

Treating HYPOnatremia too quickly causes what?

Answer 32

Fluid to shift from ICF to ECF too quickly which can produce pontine myelinolysis

Question 33

Treating HYPERnatremia too quickly causes what?

Answer 33

Fluid shifts from ECF to ICF which produces cerebral EDEMA

Question 34

Rate to correct insensible fluid loss

Answer 34

2ml/kg/hr of crystalloid

Question 35

Administering a large volume of albumin can lead to __________.

Answer 35

HYPOcalcemia

Question 36

Acidosis _______ ionized calcium

Answer 36

INCREASES

Question 37

Parathyroid _________ serum calcium and calcitonin __________ serum calcium.

Answer 37

Raises, Lowers

Question 38

Which phase in the cardiac muscle cell action potential does Ca+ play a crucial role?

Answer 38

Phase 2

Question 39

Normal plasma calcium (total)

Answer 39

8.5-10.5 md/dL or 4.5- 5.5 mEq/L

Question 40

Normal ionized calcium level

Answer 40

4.65 - 5.28 mg/dL or 2.2 - 2.6 mEq/L

Question 41

Primary treatment for magnesium toxicity?

Answer 41

CALCIUM! it antagonizes the effects of magnesium at the NMJ

Question 42

What is the most abundant electrolyte in the body?

Answer 42

CALCIUM (nearly all stored in bone) Calcium is factor 4 in coagulation pathway

Question 43

Acidosis________ ionized calcium (albumin binds H+ and displaces Ca++ into plasma)

Answer 43

INCREASES

Question 44

Alkalosis_______ ionized calcium. (albumin binds Ca++ and displaces H+ into the plasma)

Answer 44

DECREASES

Question 45

Hypocalcemia EKG findings

Answer 45

LONG QT interval

Question 46

Hypercalemia EKG findings

Answer 46

SHORT QT interval

Question 47

Hypercalcemia Tx? Hypocalcemia Tx?

Answer 47

Hyper= 0.9 NS and Loop diuretic Hypo= calcium and vitamin D

Question 48

Magnesium _________ the effects of calcium.

Answer 48

antagonizes

Question 49

Tx for Pre-eclampsia

Answer 49

4g load IV over 10-15 minutes then 1g/hr for 24 hours. Mag crosses the placenta

Question 50

The Henderson-Hasselbalch equation details what?

Answer 50

How PaCO2 and HCO3- influence pH

Question 51

Acidosis effects (P50, SNS, CBF, ICP, K+, SNS tone)

Answer 51

Increase P50 (right = release) Increase SNS tone Increase risk of dysrhythmias decrease contractility increase CBF and ICP HYPERKALEMIA

Question 52

Alkalosis effects (P50, SNS, CBF, ICP, K+, SNS tone)

Answer 52

Decrease P50 (left = love) decrease coronary blood flow increase dyshrythmias decrease CBF and ICP HYPOKALEMIA decreased ionized calcium

Question 53

How does hypercarbia effect the lungs compared to the peripheral circulation?

Answer 53

in the lungs CO2 is a direct-acting vasoconstrictor where it can cause pulmonary HTN and increased RV workload (dilates periphery)

Question 54

Most common cause of Respiratory Acidosis?

Answer 54

Hypoventilation

Question 55

What happens when alveolar ventilation exceeds CO2 production?

Answer 55

Respiratory alkalosis

Question 56

Most common cause of Respiratory Alkalosis?

Answer 56

Iatrogenic ---> Mechanical Ventilation also pain, anxiety, pregnancy, PE

Question 57

How does the body compensate for Respiratory Alkalosis?

Answer 57

Kidenys excrete Bicarb to return pH to normal takes a few days

Question 58

Increased anion gap determines acidosis from what?

Answer 58

DKA, salicylates, and cyanide poisoning

Question 59

Normal anion gap determines acidosis from what?

Answer 59

Diarrhea, pancreatic fistula, NaCl solutions for resuscitation

Question 60

Causes of Metabolic Acidosis

Answer 60

accumulation of nonvolatile acids, loss of bicarb, or large volume resuscitation with NS

Question 61

Causes of Metabolic Alkalosis

Answer 61

increased bicarb, loss of acids (NG suction), increased mineralocorticoid activity (Cushing's syndrome)