Fluids And Electrolytes

Front 1

what are the 2 major body fluid compartments?

Back 1

intra and extracellular

Front 2

what are the 2 subcompartments of extracellular fluid?

Back 2

interstitial fluid (b/w cells), intravascular fluid (plasma)

Front 3

what % of body weight is in fluid?

Back 3

60%

Front 4

what % of body fluid is intracellular?

Back 4

66%

Front 5

what % of body fluid is extracellular

Back 5

33%

Front 6

what is the composition of body fluid

Back 6

fluids = 20% of total body weight; intracellular = 40% of TBW, extracell = 20% of TBW

Front 7

on average, what % of body weight does blood account for in adults?

Back 7

7%

Front 8

how many liters of blood are in a 70kg man?

Back 8

0.07 x 70 = 5 L

Front 9

what are the fluid requirements every 24 hr.s for each of the following substances: water, potassium, chloride, sodium

Back 9

H2O ~30-35 ml/kg; K+ ~1 mEq/kg, Cl- ~1.5 mEq/kg, Na+ ~1-2 mEq/kg

Front 10

what are the elvels and sources of normal daily water loss?

Back 10

urine (1200-1500 mL, 25-30 mL/kg), sweat (200-400 mL), resp losses (500-700 mL), feces (100-200 mL)

Front 11

what are the levels and sources of normal daily electrolyte loss

Back 11

sodium and potassium = 100 mEq, chloride = 150 mEq

Front 12

what are the levels of sodium and chloride in sweat?

Back 12

40 mEq/L

Front 13

what is the major electrolyte in colonic feculent fluid?

Back 13

potassium (65 mEq/L)

Front 14

what is the physiologic response to hypovolemia?

Back 14

sodium/H2O retention via renin --> aldosterone, water retention via ADH, vasoconstriction via angiotensin II and sympathetics, low urine output and tachycardia (early), hypotension (late)

Front 15

what is 3rd spacing?

Back 15

fluid accumulation in the interstitium of tissues, as in edema (e.g., loss of fluid into the interstitium and lumen of a paralytic bowel following surgery)

Front 16

when does 3rd spacing occur postop?

Back 16

3rd-spaced fluid tends to mobilize back into the intravascular space around POD #3 (beware of fluid overload at this time), switch to hypotonic fluid and decrease IV rate

Front 17

what are the classic signs of third spacing?

Back 17

tachycardia, decreased urine output

Front 18

what is the treatment of third spacing?

Back 18

IV hydration w/isotonic fluids

Front 19

what are the surgical causes of metabolic acidosis?

Back 19

loss of bicarb (diarrhea, ileus, fistula, high output ileostomy, carbonic anhydrase inhibitors), increase in acids (lactic acidosis (ischemia), ketoacidosis, renal failure, necrotic tissue)

Front 20

what are the surgical causes of hypochloremic alkalosis?

Back 20

NGT suction, loss of gastric HCl through vomiting/NGT

Front 21

what are the surgical causes of metabolic alkalosis?

Back 21

vomiting, NG suction, diuretics, alkali ingestion, mineralocorticoid excess

Front 22

what are the surgical causes of respiratory acidosis?

Back 22

hypoventilation (CNS depression, e.g.), drugs (morphine, e.g.), PTX, pleural effusion, parenchymal lung disease, acute airway obstruction

Front 23

what are the surgical causes of respiratory alkalosis?

Back 23

hyperventilation (e.g., anxiety, pain, fever, wrong ventilator settings)

Front 24

what is the classic acid-base finding w/significant vomiting or NGT suctioning

Back 24

hypokalemic hypochloremic metabolic alkalosis

Front 25

why hypokalemia w/NGT suctioning?

Back 25

loss in gastric fluid --> loss of HCl causes alkalosis, driving K+ into cells

Front 26

what is the tx for hypokalemic hypochloremic metabolic alkalosis

Back 26

IVF, Cl-/K+ replacement

Front 27

what is paradoxic alkalotic aciduria?

Back 27

seen in severe hypokalemic, hypovolemic, hypochloremic metabolic alkalosis w/paradoxic metabolic alkalosis of serum and acidic urine

Front 28

w/paradoxic alkalotic aciduria, why is H+ preferentially lost?

Back 28

H+ is exchanged preferentially into the urine instead of K+ b/c of the low concentration of K+

Front 29

how does paradoxic alkalotic aciduria occur?

Back 29

H+ is lost in the urine in exchange for Na+ in an attempt to restore volume

Front 30

what can be followed to assess fluid status?

Back 30

urine output, base deficit, lactic acid, vital signs, weight changes, skin turgor, JVD, mucosal membranes, rales (crackles), central venous pressure, PCWP, CXR findings

Front 31

w/hypovolemia, what changes occur in vital signs?

Back 31

tachycardia, tachypnea, initial rise in diastolic BP b/c of clamping down w/subsequent increase in both systolic and diastolic BPs

Front 32

what are insensible fluid losses?

Back 32

loss of fluid not measures: feces (100-200 mL/24 h.s), breathing (500-700 mL/24 h.s, increased w/fever and tachypnea), skin (300 mL/24 hs, increased w/fever)

Front 33

quantities of daily secretions: bile, gastric, pancreatic, sml intestine, saliva

Back 33

bile: 1000mL/24 hs, gastric: 2000 mL, pancreatic: 600 mL, small intestine: 3000 mL, saliva: 1500 mL (remember: BGS 123 --> B1L, G2L, S3L)

Front 34

what comprises normal saline (NS)? (how about 1/2 NS? 1/4 NS?)

Back 34

154 mEq of Cl, 154 mEq of Na (1/2 NS: 77 mEq Cl, 77 mEq Na, 1/4 NS: 39 mEq of Cl, 39 mEq of Na)

Front 35

what comprises lactated ringers?

Back 35

130 mEq Na, 109 mEq Cl, 28 mEq lactate, 4 mEq K+, 3 mEq Ca+

Front 36

what comprises D5W?

Back 36

5% dextrose (50g) in H2O

Front 37

what accounts for tonicity?

Back 37

mainly electrolytes (NS and LR are isotonic, 1/2 NS is hypotonic to serum)

Front 38

what happens to LR in the body?

Back 38

converted to bicarb, thus LR cannot be used as maintenance fluid (patients would become alkalotic)

Front 39

IVF replacement by anatomic site: gastric (NGT), biliary, pancreatic, small bowel (ileostomy), colonic (diarrhea)

Back 39

gastric (NGT): D5 1/2 NS + 20 KCl, biliary: LR +/- sodium bicarb, pancreatic: LR +/- sodium bicarb, sml bowel: LR, colonic: LR +/- sodium bicarb

Front 40

what is the 100/50/20 rule?

Back 40

maintenance IV fluids for a 24 hr period: 100 ml/kg for the 1st 10 kg, 50 ml/kg for the next 20 kg, 20 mL/g for every kg over 20 (divide by 24 for hourly rate)

Front 41

what is the 4/2/1 rule?

Back 41

maintenance IV fluids for hourly rate: 4 mL/kg for 1st 10 kg, 2 mL/kg for next 10 kg, 1 mL/g for every kg over 20

Front 42

maintenance fluids for a 70 kg man

Back 42

using 100/50/20: 2500 (100x10 + 50x10 + 20x50) for 24 hrs (104 mL/hr maintenance rate)

Front 43

what is the common adult maintenance fluid?

Back 43

D5 1/2 NS w/20 mEq KCl/L

Front 44

what is the common pediatric maintenance fluid?

Back 44

D5 1/4 NS w/20 mEq KClL (use 1/4 NS b/c of decreased ability of children to concentrate urine)

Front 45

why should sugar (dextrose) be added to maintenance fluid?

Back 45

inhibit muscle breakdown

Front 46

what is the best way to assess fluid status?

Back 46

urine output (unless patient has cardiac or renal dysfunction, in which case central venous pressure or wedge pressure is often used)

Front 47

what is minimal urine output for an adult on maintenance IV?

Back 47

30 mL/hr (0.5 cc/kg/hr)

Front 48

what is minimal urine output for an adult trauma patient?

Back 48

50 mL/hr

Front 49

how many mL are in 12 oz? 1 oz? 1 tsp?

Back 49

356 mL (12 oz), 30 mL (1 oz), 5 mL (1 tsp)

Front 50

what are common isotonic fluids?

Back 50

NS, LR

Front 51

what is a bolus?

Back 51

volume of fluid given IV rapidly (e.g., 1 L over 1 hr), used for increasing intravascular volume, isotonic fluids should be used

Front 52

why not combine bolus fluids w/dextrose?

Back 52

hyperglycemia may result

Front 53

what is the possible consequence of hyperglycemia in patient w/hypovolemia?

Back 53

osmotic diuresis

Front 54

why not combine bolus fluids w/a significant amt of potassium?

Back 54

hyperkalemia may result (potassium in LR is very low)

Front 55

why should isotonic fluids be given for resuscitation?

Back 55

if hypotonic fluid is given, tonicity of intravasc space will be decreased and H2O will freely diffuse into interstitial and intracellular spaces

Front 56

what portion of 1L NS will stay in the intravascular space after a laparotomy?

Back 56

in 5 hr.s only ~200 cc (20%) will remain in the intravascular space

Front 57

what is the most common trauma resuscitation fluid?

Back 57

LR

Front 58

what is the most common postop IV fluid after a laparotomy?

Back 58

LR or D5LR for 24-36 hs, followed by maintenance fluid

Front 59

after a laparotomy, when should a patient's fluid be mobilized?

Back 59

classically, POD #3 (3rd space fluid back into intravasc space)

Front 60

what IVF is used to replace duodenal or pancreatic fluid loss?

Back 60

LR (bicarbonate loss)

Front 61

what is a common cause of electrolyte abnormalities?

Back 61

lab error

Front 62

what is a major extracellular cation? intracellular cation?

Back 62

Na+ (extra), K+ (intra)

Front 63

what is the normal range for potassium level?

Back 63

3.5-5.0 mEq/L

Front 64

what are the surgical causes of hyperkalemia?

Back 64

iatrogenic overdose, blood transfusion, renal failure, diuretics, acidosis, tissue destruction (injury/hemolysis)

Front 65

what are the signs/sx of hyperkalemia

Back 65

decreased deep tendon reflex or areflexia, weakness, paraesthesia, paralysis, respiratory failure

Front 66

what are the ECG findings of hyperkalemia?

Back 66

peaked T waves, depressed ST segment, prolonged PR, wide QRS, bradycardia, v. fib

Front 67

are critical K+ values of hyperkalemia?

Back 67

>6.5

Front 68

what is the urgent treatment of hyperkalemia?

Back 68

IV calcium (cardioprotective), ECG monitoring; sodium bicarb IV (alkalosis drives K+ intracellularly); glucose + insulin; albuterol; sodium polystyrene sulfonate (kayexalate) and furosemide (lasix); dialysis

Front 69

what is the nonacute treatment of hyperkalemia?

Back 69

furosemide, sodium polystyrene sulfonate

Front 70

CB DIAL K

Back 70

acronym for tx of acute symptomatic hyperkalemia --> calcium, bicarb; dialysis, insulin/dextrose, albuterol, lasix; kayexalate

Front 71

pseudohyperkalemia

Back 71

spurious hyperkalemia as a rsult of falsely elevated k+ in a sample from sample hemolysis

Front 72

what acid-base change lowers the serum potassium

Back 72

alkalosis (therefore, in hyperkalemia, give bicarb)

Front 73

what nebulizer treatment can help lower K+?

Back 73

albuterol

Front 74

what are the surgical causes of hypokalemia?

Back 74

diuretics, certain antibiotics, steroids, alkalosis, diarrhea, intestinal fistulae, NC aspiration, vomiting, insulin, insufficient supplementation, amphotericin

Front 75

signs/sx of hypokalemia

Back 75

weakness, tetany, nausea, vomiting, ILEUS, paraesthesia

Front 76

ECG findings of hypokalemia

Back 76

flattening of T waves, U waves, ST segment depression, PAC, PVC, a. fib

Front 77

rapid treatment of hypokalemia

Back 77

KCl IV

Front 78

maximum amount of KCl that can be given through a peripheral IV? central line?

Back 78

10 mEq/hr (peripheral IV), 20 mEq/hr (central line)

Front 79

chronic treatment of hypokalemia

Back 79

KCl PO

Front 80

what is the most common electrolyte-mediated ileus in the surgical patient?

Back 80

hypokalemia

Front 81

what electrolyte condition exacerbates digitalis toxicity?

Back 81

hypokalemia

Front 82

what electrolyte deficiency can actually cause hypokalemia?

Back 82

low magnesium

Front 83

what electrolyte must you replace 1st before replacing K+

Back 83

magnesium

Front 84

why does hypomagnesemia make replacement of K+ w/hypokalemia nearly impossible

Back 84

hypomagnesemia inhibits K+ reabsorption from the renal tubules

Front 85

what is the normal range for sodium level?

Back 85

135-145 mEq/L

Front 86

what ar the surgical causes of hypernatremia?

Back 86

inadequate hydration, diabetes insipidus, diuresis, vomiting, diarrhea, diaphoresis, tachypnea, iatrogenic (e.g., TPN)

Front 87

what are the signs/sx of hypernatremia

Back 87

seizures, confusion, stupor, pulm or peripheral edema, tremors, resp paralysis

Front 88

what is the usual treatment supplementation for hypernatremia slowly over days?

Back 88

D5W, 1/4 NS, or 1/2 NS

Front 89

how fast should you lower the sodium level in hypernatremia

Back 89

<12 mEq/L per day

Front 90

what is the major complication of lowering the sodium level too fast?

Back 90

seizures (NOT central pontine myelinolysis)

Front 91

what are the surgical causes of hypovolemic hyponatremia?

Back 91

diuretic excess, hypoaldosteronism, vomiting, NG suction, burns, pancreatitis, diaphoresis

Front 92

what are the surgical causes of euvolemic hyponatremia?

Back 92

SIADH, CNS abnormalities, drugs

Front 93

what are the surgical causes of hypervolemic hyponatremia?

Back 93

renal failure, CHF, liver failure (cirrhosis), iatrogenic fluid overload (dilutional)

Front 94

what are the signs/sx of hyponatremia?

Back 94

seizures, coma, nausea, vomiting, ileus, lethargy, confusion, weakness

Front 95

what is the tx of hypovolemic hyponatremia

Back 95

NS IV, correct underlying cause

Front 96

tx of euvolemic hyponatremia

Back 96

SIADH: furosemide and NS acutely, fluid restriction

Front 97

tx of hypervolemic hyponatremia

Back 97

dilutional: fluid restriction and diuretics

Front 98

how fast should you increase the sodium level in hyponatremia?

Back 98

<12 mEq/L per day

Front 99

what may occur if you correct hyponatremia too quickly? what are the signs?

Back 99

central pontine myelinolysis --> 1. confusion, 2. spastic quadriplegia, 3. horizontal gaze paralysis

Front 100

what is the most common cause of mild postop hyponatremia?

Back 100

fluid overload

Front 101

what is the sodium level in SIADH?

Back 101

low (Sodium Is Always Down Here --> SIADH: hyponatremia)

Front 102

what is pseudohyponatremia?

Back 102

spurious lab value of hyponatremia as a result of hyperglycemia, hyperlipidemia, or hyperproteinemia

Front 103

what are the causes of hypercalcemia?

Back 103

(CHIMPANZEES) calcium supplementation IV, hyperparathyroidism (primary, tertiary)/hyperthyroidism, immobility/iatrogenic (thiazide diuretics), mets/milk alkali syndrome, paget's disease, addison's disease/acromegaly, neoplasm (colon, lung, breast, prostate, multiple myeloma), zollinger-ellison syndrome (part of MEN I), excessive vit D, excessive vit A, sarcoid

Front 104

what are the signs/sx of hypercalcemia?

Back 104

stones, bones, abd groans, psychiatric overtones; polydipsia, polyuria, constipation

Front 105

ECG findings of hypercalcemia

Back 105

short QT, prolonged PR

Front 106

acute treatment of hypercalcemic crisis

Back 106

volume expansion w/NS, diuresis w/furosemide (NOT THIAZIDES)

Front 107

what are options for lower Ca level?

Back 107

steroids, calcitonin, bisphosphonates, mithramycin, dialysis (last resort)

Front 108

how can the calcium level be determined w/hypoalbuminemia?

Back 108

(4-measured albumin level) x 0.8, then add this value to measured calcium level

Front 109

surgical causes of hypocalcemia

Back 109

short bowel syndrome, intestinal bypass, vit D deficiency, sepsis, acute pancreatitis, osteoblastic mets, aminoglycosides, diuretics, renal failure, hypomagnesemia, rhabdomyolysis

Front 110

chvostek's sign

Back 110

facial muscle spasm w/tapping of facial nerve (seen in hypocalcemia)

Front 111

trousseau's sign

Back 111

carpal spasm after occlduing blood flow in forear w/BP cuff (seen in hypocalcemia)

Front 112

signs/sx of hypocalcemia

Back 112

chvostek's and trousseau's signs, perioral paraesthesia (early), increased deep tendon reflexes (late), confusion, abd cramps, laryngospasm, stridor, seizures, tetany, psych abnormalities

Front 113

ECG findings of hypocalcemia

Back 113

prolonged QT and ST interval (peaked T waves also possible)

Front 114

acute tx of hypocalcemia

Back 114

calcium gluconate IV

Front 115

chronic tx of hypocalcemia

Back 115

calcium PO, vit D

Front 116

possible complication of infused calcium if the IV infiltrates

Back 116

tissue necrosis (never administer alcium peripherally unless absolutely necessary)

Front 117

best way to check the calcium level in the ICU?

Back 117

check ionized calcium

Front 118

normal range for magnesium level

Back 118

1.5-2.5 mEq/L

Front 119

surgical cause of hypermagnesemia?

Back 119

TPN, renal failure, IV over supplementation

Front 120

signs/sx of hypermagnesemia

Back 120

resp failure, CNS depression, decreased DTRs

Front 121

tx of hypermagnesemia

Back 121

calcium gluconate IV< insulin + glucose, dialysis, furosemide (lasix)

Front 122

surgical causes of hypomagnesemia

Back 122

TPN, hypocalcemia, gastric suctioning, aminoglycosides, renal failure, diarrhea, vomiting

Front 123

signs/sx of hypomagnesemia

Back 123

increased DTRs, tetany, asterixis, tremor, chvostek's sign, ventricular ectopy, vertigo, tachycardia, dysrhythmias

Front 124

acute treatment of hypomagnesemia

Back 124

MgSO4 IV

Front 125

chronic tx of hypomagnesemia

Back 125

magnesium oxide PO (side effect: diarrhea)

Front 126

hypomagnesemia may make it impossible to correct ___

Back 126

hypokalemia (always fix hypomag w/hypokal)

Front 127

what are the surgical causes of hyperglycemia?

Back 127

diabetes (poor control), infection, stress, TPN, drugs, lab error, drawing over IV site, somatostatinoma, glucagonoma

Front 128

signs/sx of hyperglycemia

Back 128

polyuria, hypovolemia, confusion/coma, polydipsia, ileus, DKA (kussmaul breathing), abd pain, hyporeflexia

Front 129

tx of hyperglycemia

Back 129

insulin

Front 130

what is the weiss protocol?

Back 130

sliding scale insulin

Front 131

what is the goal glucose level in the ICU?

Back 131

80-110 mg/dL

Front 132

surgical causes of hypoglycemia

Back 132

excess insulin, decreased caloric intake, insulinoma, drugs, liver failure, adrenal insufficiency, gastrojejunostomy

Front 133

signs/sx of hypoglycemia

Back 133

sympathetic response (diaphoresis, tachycardia, palpitations), confusion, coma, h/a, diplopia, neurologic deficits, seizures

Front 134

tx of hypoglycemia

Back 134

glucose (IV or PO)

Front 135

normal range for phosphorous level

Back 135

2.5-4.5 mg/dL

Front 136

signs/sx of hypophosphatemia

Back 136

weakness, cardiomyopathy, neurologic dysfunction (ataxia), rhabdomyolysis, hemolysis, poor pressor response

Front 137

complication of severe hypophosphatemia

Back 137

respiratory failure

Front 138

critcial value of hypophosphatemia

Back 138

<1.0 mg/dL

Front 139

causes of hypophosphatemia

Back 139

GI losses, inadequate supplementation, meds, sepsis, alcohol abuse, renal loss

Front 140

tx of hypophosphatemia

Back 140

supplement sodium phosphate or potassium phosphate IV (depending on K+ level)

Front 141

signs/sx of hyperphosphatemia

Back 141

calcification (ectopic), heart block

Front 142

causes of hyperphosphatemia

Back 142

renal failure, sepsis, chemotx, hyperthyroidism

Front 143

tx of hyperphosphatemia

Back 143

aluminum hydroxide (binds phosphate)

Front 144

peaked T waves should make you think of ___

Back 144

hyperkalemia

Front 145

if hyperkalemia is left untreated, what can occur?

Back 145

v.tach/v.fib --> death

Front 146

which electrolyte is an inotrope?

Back 146

calcium

Front 147

what are the major cardiac electrolytes?

Back 147

potassium (dysrhythmias), magnesium (dysrhythmias), calcium (dysrhythmias/inotrope)

Front 148

ch electrolyte must be monitored closely in patients on digitalis?

Back 148

potasium

Front 149

what is the most common cause of electrolyte-mediated ileus?

Back 149

hypokalemia

Front 150

what is the rationale for using an albumin-furosemide sandwich?

Back 150

albumin will pull interstitial fluid into the intravascular space and the furosemide will then help excrete the fluid as urine

Front 151

what is a colloid fluid?

Back 151

protein containing fluid (albumin)

Front 152

an elderly patient goes into CHF on POD #3 after a laparotomy. what's going on?

Back 152

mobilization of third-space fluid into the intravasc space, resulting in fluid overload and resultant CHF. (But must also rule out MI)

Front 153

what fluid is used to replace NGT (gastric) aspirate?

Back 153

D5 1/2 NS w/20 KCl

Front 154

what electrolyte imbalance is associated w/succinylcholine?

Back 154

hyperkalemia