Fluid and Blood Therapy Flashcards

1
Q

TBW calculation

A

Total Body Water = 0.6% x Body Weight

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2
Q

TBW in L

A

TBW = 42 L (60%)

ECF = 1/3 or 14 L (20%)

ICF = 2/3 or 28 L (40%)

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3
Q

3 ECF Contents

A

Interstitial Fluid

Plasma

Transcellular Fluid

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4
Q

Interstitial Fluid

A

3/4 of ECF = 10.5 L or

15% body weight or

25% TBW

  • During surgery, capillary permeability increases and more fluid escapes to the interstitium.
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5
Q

Plasma

A

1/4 of ECF = 3 L or

5% body weight or

9% TBW

(85% venous, 15% arterial)

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6
Q

Transcellular Fluid

A

0.5 L

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7
Q

Classic Fluid Compartments Visual

A
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8
Q

Daily Fluid Output

A

Urine 0.5 - 1.5 L

Sweat/Respiratory 0.8 - 1.2 L

Feces 0.2 L

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9
Q

Daily Fluid Intake

A

Fluids

Fluids in Food

Metabolic Fluids

NPO after midnight

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10
Q

Third Space

A
  • nonfunctional space somewhere within the body that accumulates fluids that escape from the vasculature and the interstitium
  • does it really exist??? if so, needs replacement!
  • large volumes avoid renal failure
  • may precipitate ARDS
  • leads to abd compartment syndrome
  • probably doesn’t exist, ERAS leans towards restricted fluid administration
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11
Q

Hypovolemia contributes to what two things?

A
  • inadequate tissue perfusion
  • post op complications
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12
Q

S/S of Hypovolemia

A
  • tachycardia lacks sensitivity and specificity and is NOT a good indication of volume status
  • hypotension means hypoperfusion has already occurred
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13
Q

Volume Responsive

A
  • fluids should be given when patients require augmentation of perfusion and are volume responsive
  • if BP and HR come up/down after fluid challenge, they are RESPONSIVE (frank-starling)
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14
Q

Hypervolemia: Weight Gain

A

>10% of preop weight = 32% mortality rate

<10% = 10% mortality rate

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15
Q

Pulmonary Edema

A
  • occurs when volume infused is >67cc/kg/hr
  • Healthy Volunteers - fasted - 40 ml/kg/hr LR over 3 hours
  • decreased FEV1 and FVC for 8 hours
  • median weight gain of 0.85 kg 24 hours after bolus
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16
Q

Bowel Manipulation

A
  • results in a 5-10% increase in weight at the anastamosis
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17
Q

Tissue Edema leads to….

A

impaired wound healing 2/2 decreased oxygen tension

  • so if everything is swollen and blood/oxygen cells can’t get through the edematous cell membranes it causes probs w wound healing
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18
Q

Ideal Body Weight

A

When we replace fluid we want to replace the intravascular volume, we don’t need to hydrate the fat cells.

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19
Q

Euvolemia

A
  • maintains physiological homeostatis (HR, BP)
  • replace preop defecits (NPO = 1.4 cc/kg/hr)
  • replace maintenance fluids throughout surgery (basal rate = 100mL/hr)
  • replace surgical losses (EBL)
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20
Q

Fluid Maintenance Calculation

4:2:1 Rule IBW

A

NPO losses and maintenance (4:2:1 rule)

4cc(10kg) + 2cc(10kg) + 1cc/kg(>20kg)

1st 10 kg gets 4cc/kg, 2nd 10kg gets 2cc/kg, all other gets 1cc/kg

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21
Q

EBL Loss Replacement

A

3:1

22
Q

3rd Space Loss Replacement

A

2-10 cc/kg/hr

23
Q

Fluid Calc Visual

A
24
Q

Issues with classic fluid calculations

A
  • fasting patients don’t become hypovolemic (NPO after midnight)
  • insensible losses increase with incision is false
  • literature doesn’t support decrease in kidney failure with large volumes
  • 3rd space doesn’t exist
25
Q

Incisional Losses

A

0.5cc/kg/hr

small incision = 2cc/hour

medium = 8cc/hour

large = 32cc/hour

26
Q

Fluid Goals

A
  • optimize tissue perfusion
  • optimize vascular volume, SV, oxygenation (GDFT)
  • reduce m/m
  • euvolemia
27
Q

GDFT

A
  • optimized fluid therapy to ensure adequate tissue perfusion, tissue oxygen delivery and cellular oxygenation
  • prevent cell death and organ damage
28
Q

How to optimize tissue perfusion:

A
  • maintain appropriate intravascular volume
  • maintain preload, maintain CO
  • maintain adequate tissue BP
29
Q

Frank-Starling Visual

A
30
Q

PPV

A
  • art line pulse pressure
  • difference b/t systolic peak and diastolic bottom
  • PP(max) taken at end inspiration
  • PP(min) taken at end expiration
  • PP(mean) = [PP(max)+PP(min)]/2
31
Q

SPV

A

art-line SPV (same as PPV but you’re using systolic pressure)

  • difference b/t highest SBP and lowest SBP readings
  • SP at end inspiration
  • SP at end expiration

SPV=SP(max) - SP(min)

32
Q

Large PPV or SPV means what?

A

hypovolemia

  • accurate tools for guidance of fluid management but rely on mechanical ventilation and art lines
33
Q

Fluid Challenges

A
  • test the functional reserve of the CV system
  • can be repeated as long as the response is positive (increased BP by 10-15% after challenge increase CO and indicates success)
  • no response means you’ve maxed the F-S curve and additional challenges will cause fluid overload
34
Q

Fluid Challenge Effect on BP

A
  • increase BP via increase CO 2/2 increased SV
  • hypoperfusion 2/2 hypotension 2/2 hypovolemia
35
Q

GDFT Outcomes

A
36
Q

DUMC GDFT Protocol

A
  • 250cc carbohydrate drink (Gatorade) 1hr before arrival
  • infuse 3cc/kg/hr per IBW
  • preop baseline SV assessment
  • after incision give 250cc colloid bolus <15 min
  • if SV increases >10% repeat bolus
  • if SV increases <10% no further bolus
  • record peak SV (new baseline)
  • if hypotensive give phenylephrine 100-200 mcg bolus or infusion
  • give additional colloid bolus when SV decreases 10% from peak SV
  • repeat cycle
37
Q

Hypotonic

A
  • osmolality lower than plasma, poor expanders, distributes to all body compartments
  • Na+ concentrate less than 130mEq/L = osmolarity <280 mOsm/L
    ie: 0.45% NS
38
Q

Isotonic

A
  • osmolality close to extracellular osmolality of body, expands ECV
  • Na+ concentration 130-155 mEq/L = osmolarity 280-310 mOsm/L
    ie: LR, 0.9% NS
39
Q

Hypertonic

A

osmolality higher than ECF, expands by mobilizing water from ICV

  • Na+ concentration >155 mEq/L = osmolarity >310 mOsm/L
    ie: 3% NS, mannitol
40
Q

Crystalloids: Cost, Composition and Use

A
  • NS
  • LR
  • D5W
  • cost: 2$/bag
  • move freely between intravascular and interstitial fluid compartments
  • cheap, easy, no allergic reactions
  • contain water, electrolytes and glucose
41
Q

0.9% NS

A

– Isotonic and isosmotic to plasma Na + but less Cl-

– Large volumes result in mild hypernatremia and hyperchloremia (non-ion gap acidosis)

42
Q

LR

A

– Intended to mimic composition of plasma better

– Has minimal amounts of electrolytes added and frequently some sort of buffer (lactate in LR)

43
Q

Hypertonic 3% Saline

A

– Used for replacement in the case of hyponatremia

– Used to reduce cerebral swelling (just as effective as Mannitol)

  • moves fluid from ICF to ECF
44
Q

Glucose Containing Solutions

A

D5W, D5NS, D10W

– Used to replace glucose in pts who need the sugar – D10W is base for most parenteral nutrition formulas – D 50 W comes in 50cc syringes for treatment of acute hypoglycemic shock

– Glucose is rarely ever used as a standard maintenance IV fluid because patients rarely need the sugar. Outcomes of arrest patients are worse when given glucose containing solu;ons.

45
Q

Colloids

A
  • albumin
  • hetastarch
  • dextrans
46
Q

Colloid Composition, Use, and Downsides

A
  • contain large molecular weight protein or glucose polymer particles
  • create an osmotic force that keeps water intravascular and stay intravascular longer than crystalloids
  • downside: more expensive, allergic reacitons, cause osmotic diuresis and coagulopathies
  • colloids not superior in recusitation or long term outcomes
  • beneficial in pts who need volume support but would go into CHF w crystalloids
    cost: $50-1000/L but can be givin in smaller amounts
47
Q

Crystalloid T1/2

A

15 min

  • one hour after giving 1L crystalloid, only 250cc remains in intravascular space (the other 750cc is EDEMA!)
  • must keep giving to maintain hydration and BP
48
Q

Osmolarity of Crystalloids

A

Hypotonic Osmolarity <280 mOsm/L

Na+ <130mEq/L, 0.45%NS

Isotonic 280-310 mOsm/L

Na+ 130-155 mEq/L, 0.9% NS or LR

Hypertonic >310 mOsm/L

Na+ >155mEq/L, 3% NS

49
Q

What does current evidence suggest re: high risk patients and major surgical procedures?

A

these pts do better w GDFT plans aimed at maximizing CO and tissue oxygenation

50
Q

Benefits of GDFT and ERAS

A
  • morbidity rates for major surgical procedures like esophagectomy, pelvic exenteration, pancreatectomy, colectomy, gastrectomy, and liver resection range from 25% - 55%
  • one postop complication = $6,400
  • two = $12,800
  • three = $43,000 (average $18k)

prevention saves moneY!!

51
Q

What is the #1 determinant of decreased postop survival?

A

– Complications within 30 days postop is #1 determinant of decreased postop survival

– Complications decrease postop survival by 69%

52
Q

ERAS Graphic

A