Fluids / Resuscitation

    .

     

     

     

    Resuscitation Targets

    • Targets:
      • Used to be urine output and BP
      • Now:  (Reach in 24 hours)
        • Oxygen Uptake (VO2) > 100 mL/min/m^2
          • Defined by: VO2 = Q x Hb x 1.34 x (SaO2 - SvO2) x 10
        • Lactate < 2.0
        • Arterial Base Deficit > -2 mmol
    • Can predict fluid deficit:
      • Class I = 5 mL/kg
      • Class II = 15 mL/kg (postural tachycardia)
      • Class III = 25 mL/kg
      • Class IV = 35 mL/kg

     

    Different Fluids

    • Volume

      Infused

      Type of Fluid

      Plasma Volume

      Expansion (mL)

      1.000 mL D5W 100
      1,000 mL Lactated Ringer's 250
      1,000 mL 0.9% Saline 275
      250 mL 7.5% Hypertonic Saline 1,000
      1000 mL 5% Albumin 700
      100 mL 25% Albumin 450
      500 mL Pentastarch 500
        Plasma  
      Reference: "Fluid Resuscitation in Circulatory Shock" book
      And Paul Marino's "The Little ICU Book"

    Fluid Composition.pngFluid Distributions.png

    (From "Little ICU book" and Stapczynski JS et al (Emerg Med Prep 1994)
     

    • Isotonic Saline
      • Higher sodium, chloride, osmolality.
      • Drawbacks:
        • Hyperchloremic metabolic acidosis --> can create confusion esp in DKA management.
    • Lactated Ringer's
      • Ringer's introduced in 1880 as calcium containing solution (promotes cardiac contraction in frogs).
      • Lactate added as a buffer in 1930's
      • Physiologic concentration of free calcium (but as consequence sodium must be lower to balance charge)
        • Lactate used to drop chloride concentration to 109 mEq/L (close to plasma 103)
      • Recommended for surgery, DKA, trauma, burns
      • Drawbacks:
        • Calcium can bind drugs (amphotericin, ampicillin, thiopental) - do not mix solutions.
        • Calcium can bind citrated anticoagulant in blood products, causes clot formation in donor blood.
          • Contraindicated as a diluent for blood products.
    • Normal pH Fluid: Normosol / Isolyte / PlasmaLyte
      • Contain acetate and gluconate buffers (pH 7.4)
        • Also potassium (5 mEq/L) and Mg (3 mEq/L), and phosphate (1 mEq/L)
      • Not popular, but recommended as substitute for isotonic saline for washing salvaged RBC's.
    • Dextrose Solutions
      • Dextrose was initially a nutrient in IV fluids (1L of 5% D5W gives 170 kcal/L)
      • 3L daily = 500 kcal = enough to meet daily requirements without breaking down proteins.
      • Drawbacks:
        • Expands intracellular fluid (not desired effect), only small portion intravascular.
        • Metabolized by hypoxic tissues to lactate (more acidosis?)
        • Can cause poor glycemic control (worse outcomes).
    • Colloid Fluids
      • Large molecules that do not move out of vascular compartment.
      • Create "Colloid Osmotic Pressure" (COP)--> retains water in vascular compartment.
        • Most colloids have COP similar to plasma (stay in plasma), some have higher COP (draw fluid intro vascular space).
        • [i.e. 5% albumin COP = plasma COP]
      • Colloids MUCH (3 times) more effective than crystalloids in increasing plasma volume.
    • Fluid Mol. Wt. Manufacturer Duration

      Colloid

      Osm. Press.

      Plasma Volume

      to Infused Volume

      Unit Size

      Cost (AWP)

      2005 Redbook

      Crystalloids              
      Isotonic Saline   Hospira   - 0.275 1,000 mL $1.46
      Ringer's Lactate   Hospira   - 0.250 1,000 mL $1.48
      Colloids              
      5% Albumin 69 kDa Bayer 12h 20 mmHg 0.7 - 1.3 250 mL $30.63
      25% Albumin 69 kDa Bayer 12h 70 mmHg 4.0 - 5.0 50 mL $30.63
      6% Hetastarch 450 kDa Abbott 24h 30 mmHg 1.0 - 1.3 500 mL $27.63

      10% Dextran-40

      (6% Dextran-70)

      26 kDa Hospira

      Dex-40: 6h

      Dex-70: 12h

      40 mmHg 1.0 - 1.5 500 mL $14.96
      Taken from "The ICU Book" by Marino 2008. 
      • Albumin
        • Heat-treated preparations of human albumin - available as 5% (50g/L) and 25% (250 g/L) in isotonic saline. 
        • Solution of 5% comes in aliquots of 250 mL (~70% plasma retention), but lost after 12 hours.
        • 25% albumin 3x COP of plasma, draws fluid into interstitial space (increment 4-5x infused volume).   Given in 50 mL aliquots where hypovolemia associated with edema (i.e. hypoalbulinemia).  
          • 25% albumin = no appropriate for replacing volume losses.
        • Old Research: Increased mortality attributed to albumin infusion
        • New Research: Cannot reproduce increase in mortality, but reduced morbidity (comp w/ crystalloid)
      • Hydroxyethyl Starch
        • Synthetic starch polymer available as 6% solution in isotonic saline.
        • 3 preparations (based on molecular weight [MW])
          • High MW, Medium MW, Low MW
        • Only High MW available in US.
        • Drawbacks:
          • Increased bleeding with High MW (decreased Factor VIII, and vWF, impaired platelets) [esp if >1.5L is infused in 24hrs]
          • Elevates amylase levels (2-3x ULN) for 1 week, making it look like pancreatitis.
            • (amylase cleaves hetastarch before renal clearance)
          • Accumulates in liver and kidney
        • Studies:
          • Increased death, AKI, dialysis with 10% HES solution (200kDa) --> caused lower kDa HES to be used.
          • Scandinavian trial 6% HES  vs. Ringer's Lactate in severe sepsis --> increases mortality.
          • CHEST Trial: 7000 adults in ICU 6% HES vs. saline --> no mortality difference, but more dialysis in HES group
        • Still used in military, and OR's for rapid volume expansion (but max 33-50 mL/kg)
      • Dextrans
        • Glucose polymers papared as 10% dextran-40 or 6% dextran-70 (different molecular weights)
          • (Both diluted with normal saline)
        • Dextran-70 preferred due to longer duration (12h vs. 6h)
        • Rarely used due to drawbacks
        • Drawbacks:
          • Bleeding tendency (Decr. platelet aggregation, Factor VIII, vWF, enhanced fibrinolysis) [not an issue if low-doses used < 20mL/kg/day]
          • Coat surface of RBCs, interfere with crossmatching blood. (must wash RBC's prior to Xmatching)
          • Also increase ESR (interact with sediment of RBCs)
          • Acute renal failure (suspected, not proven)

     

    Colloid vs. Crystalloid

    • Colloid Pros
      • Much more effective in plasma volume expansion
        • 1/3 to 1/4 of volume required to expand the same amount of intravascular volume as crystalloid
    • Colloid Cons
      • Expensive
      • No documented survival benefit (cannot justify expense)... many studies show equal efficacy
    • Crystalloid Pros
      • Can cause similar intravascular volume expansion, and much cheaper (must infuse more volume)
    • Crostalloid Cons
      • Not effective in intravascular volume expansion (goes interstitial)
    • Generally:
      • Select fluid type for each scenario
      • i.e. dehydration --> loss of extracellular fluid --> use crystalloids
      • i.e. hemorrhage --> loss of intravascular fluid --> use colloids

     

    Hypertonic Resuscitation

    • Using 7.5% NaCl
    • Infusing hypertonic saline causes double plasma volume expansion (moves water out of cells)
    • Note: No firm indications for hypertonic resuscitation at the present time (2008)
    • Potential uses:
      • Military (can carry smaller volumes of fluids for larger resuscitation)
      • Closed head injury trauma patients (limit cerebral edema)
      • Hemorrhage from vascular injury (limit loss from injured vessel)
      • Subarachnoid hemorrhage (6% hetastarch in hypertonic saline effective in reducing ICP)

     

    Important Trials

    • SAFE Study
      • No difference in mortality between Albumin and Normal Saline
      • Subgroup: increase in death at 2 years in pts with TBI (traumatic brain injury)
      • Albumin = higher ICP
    • Finfer 2011:
      • Albumin = mortality benefit at 28 days in pts with severe sepsis
      • Subgroup: no difference in pts with or without hypoalbuminemia.
    • FEAST Study (Fluid Expansion as Supportive Therapy)
      • African 3141 children presenting with febrile illness randomized to:
        • Fluid Bolus (20-40mL/kg) vs. Maintenance (albumin or crystalloid)
      • Result: Bolus = worse outcomes
      • Result: No difference albumin vs. crystalloid
    • Scandinavian trial 6% HES  vs. Ringer's Lactate in severe sepsis --> increases mortality.
    • CHEST Trial: 7000 adults in ICU 6% HES vs. saline --> no mortality difference, but more dialysis in HES group
    Tag page (Edit tags)
    • No tags
    Page statistics
    8646 view(s), 8 edit(s) and 14812 character(s)

    Comments

    You must login to post a comment.