INTRAVENOUS FLUIDS TREATMENT

Total Body Water (TBW)

• Varies with age, gender• 55% body weight in males• 45% body weight in females• 80% body weight in infants• Less in obese: fat contains little water

Body Water Compartments

• Intracellular water: 2/3 of TBW• Extracellular water: 1/3 TBW

- Extravascular water: 3/4 of extracellular water- Intravascular water: 1/4 of extracellular water

Crystalloids

Crystalloid Solutions that contain small molecules that flow easily across the cell membranes, allowing for transfer from the bloodstream into the cells and body tissues. This will increase fluid volume in both the interstitial and intravascular spaces (Extracellular)It is subdivided into: * Isotonic * Hypotonic * Hypertonic

Crystalloids

When to consider a solution isotonic?

When the concentration of the particles (solutes) is similar to that of plasma, So it doesn't move into cells and remains within the extracellular compartment thus increasing intravascular volume.

Types of isotonic solutions include: -0.9% sodium chloride (0.9% NaCl)-lactated Ringer's solution-5% dextrose in water (D5W) -Ringer’s solution

0.9% sodium chloride (Normal Saline)

Simply salt water that contains only water, sodium (154 mEq/L), and chloride (154 mEq/L).

It's called "normal saline solution" because the percentage of sodium chloride in the solution is similar to the concentration of sodium and chloride in the intravascular space

When to be given?1- to treat low extracellular fluid, as in fluid volume deficit from - Hemorrhage - Severe vomiting or diarrhea - Heavy drainage from GI suction, fistulas, or wounds2- Shock 3- Mild hyponatremia4- Metabolic acidosis (such as diabetic ketoacidosis)5- It’s the fluid of choice for resuscitation efforts.6- it's the only fluid used with administration of blood products.

Normal saline 0.9%

TAKE CARE:Because 0.9% sodium chloride replaces extracellular fluid, it should be used cautiously in certain patients (those with cardiac or renal disease) for fear of fluid volume overload.

When to be used?-To replace GI tract fluid losses ( Diarrhea or vomiting )-Fistula drainage-Fluid losses due to burns and trauma-Patients experiencing acute blood loss or hypovolemia due to third-space fluid shifts.

Notice. Both 0.9% sodium chloride and LR may be used in many clinical situations, but patients requiring electrolyte replacement (such as surgical or burn patients) will benefit more from an infusion of LR.

Dextrose 5%

It is considered an isotonic solution, but when the dextrose is metabolized, the solution actually becomes hypotonic and causes fluid to shift into cells.It provides 170 calories per liter, but it doesn't replace electrolytes. The supplied calories doesn't provide enough nutrition for prolonged use. But still can be added to provide some calories while the patient is NPO.

Take Care !- D5W is not good for patients with renal failure or cardiac problems since it could cause fluid overload. - patients at risk for intracranial pressure should not receive D5W since it could increase cerebral edema- D5W shouldn't be used in isolation to treat fluid volume deficit because it dilutes plasma electrolyte concentrations- Never mix dextrose with blood as it causes blood to hemolyze.-Not used for resuscitation, because the solution won't remain in the intravascular space.-Not used in the early postoperative period, because the body's reaction to the surgical stress may cause an increase in antidiuretic hormone secretion

Hypotonic solutionCompared with intracellular fluid (as well as compared with isotonic solutions), hypotonic solutions have a lower concentration of solutes (electrolytes). And osmolality less than 250 mOsm/L .Hypotonic crystalloid solutions lowers the serum osmolality within the vascular space, causing fluid to shift from the intravascular space to both the intracellular and interstitial spaces. These solutions will hydrate cells, although their use may deplete fluid within the circulatory system.

0.45% sodium chloride (0.45% NaCl), 0.33% sodium chloride, 0.2% sodium chloride, and 2.5% dextrose in water

Hypotonic fluids are used to treat patients with conditions causing intracellular dehydration, when fluid needs to be shifted into the cell , such as: Hypernatremia Diabetic ketoacidosis Hyperosmolar hyperglycemic state.

Hypertonic SolutionSolution that have a higher tonicity or solute concentration. Hypertonic fluids have an osmolarity of 375 mOsm/L or higher

The osmotic pressure gradient draws water out of the intracellular space, increasing extracellular fluid volume, so they are used as volume expanders.

Some examples and Indications: 1- 3% sodium chloride (3% NaCl): May be prescribed for patients in critical situations of severe hyponatremia. Patients with cerebral edema may benefit from an infusion of hypertonic sodium chloride 2- 5% Dextrose with normal saline (D5NS): which replaces sodium, chloride and some calories

ColloidsIt expand the intravascular volume by drawing fluid from the interstitial spaces into the intravascular compartment through their higher oncotic pressure.the same effect as hypertonic crystalloids solutions but it requires administration of less total volume and have a longer duration of action because the molecules remain within the intravascular space longer.Its effect can last for several days if capillary wall linings are intact and working properly.

Colloids

Precautions!Colloid solutions can interfere with platelet function and increase bleeding times, so monitor the patient's coagulation indexes.Anaphylactoid reactions are a rare but potentially lethal adverse reaction to colloids. Take a careful allergy history from patients receiving colloids (or any other drug or fluid), asking specifically if they've ever had a reaction to an I.V. infusion

Composition

Perioperative Evaluationof Fluid Status

• Factors to Assess:- h/o intake and output- blood pressure: supine and standing- heart rate- skin turgor- urinary output- serum electrolytes/osmolarity- mental status

Perioperative Fluid Requirements

The following factors must be taken into account:1- Maintenance fluid requirements2- NPO and other deficits: NG suction,

bowel prep3- Third space losses4- Replacement of blood loss5- Special additional losses: diarrhea

1- Maintenance Fluid Requirements• Insensible losses such as evaporation of water

from respiratory tract, sweat, feces, urinary excretion. Occurs continually.

• Adults: approximately 1.5 ml/kg/hr• “4-2-1 Rule”

- 4 ml/kg/hr for the first 10 kg of body weight- 2 ml/kg/hr for the second 10 kg body weight- 1 ml/kg/hr subsequent kg body weight- Extra fluid for fever, tracheotomy, denuded

surfaces

2- NPO and other deficits• Nbm deficit = number of hours Nbm x

maintenance fluid requirement.• Bowel prep may result in up to 1 L fluid loss.• Measurable fluid losses, e.g. NG suctioning,

vomiting, stoma output, biliary fistula and tube.

3- Third Space Losses• Isotonic transfer of ECF from functional body

fluid compartments to non-functional compartments.

• Depends on location and duration of surgical procedure, amount of tissue trauma, ambient temperature, room ventilation.

Replacing Third Space Losses• Superficial surgical trauma: 1-2 ml/kg/hr• Minimal Surgical Trauma: 3-4 ml/kg/hr

- head and neck, hernia, knee surgery• Moderate Surgical Trauma: 5-6 ml/kg/hr

- hysterectomy, chest surgery• Severe surgical trauma: 8-10 ml/kg/hr (or

more)- AAA repair, nehprectomy

4- Blood Loss• Replace 3 cc of crystalloid solution per cc

of blood loss (crystalloid solutions leave the intravascular space)

• When using blood products or colloids replace blood loss volume per volume

5- Other additional losses• Ongoing fluid losses from other sites:

- gastric drainage- stoma output- diarrhea

• Replace volume per volume with crystalloid solutions

Example• 62 y/o male, 80 kg, for hemicolectomy• nbm after 2200, surgery at 0800,

received bowel prep• 3 hr. procedure, 500 cc blood loss• What are his estimated intraoperative

fluid requirements?

Example (cont.)• Fluid deficit (NPO): 1.5 ml/kg/hr x 10 hrs = 1200

ml + 1000 ml for bowel prep = 2200 ml total deficit: (Replace 1/2 first hr, 1/4 2nd hr, 1/4 3rd hour).

• Maintenance: 1.5 ml/kg/hr x 3hrs = 360mls• Third Space Losses: 6 ml/kg/hr x 3 hrs =1440 mls• Blood Loss: 500ml x 3 = 1500ml• Total = 2200+360+1440+1500=5500mls

Clinical Evaluation of Fluid Replacement

1. Urine Output: at least 1.0 ml/kg/hr2. Vital Signs: BP and HR normal (How is the

patient doing?)3. Physical Assessment: Skin and mucous

membranes no dry; no thirst in an awake patient4. Invasive monitoring; CVP or PCWP may be used

as a guide5. Laboratory tests: periodic monitoring of

hemoglobin and hematocrit

Summary• Fluid therapy is critically important during the

perioperative period.• The most important goal is to maintain

hemodynamic stability and protect vital organs from hypoperfusion (heart, liver, brain, kidneys).

• All sources of fluid losses must be accounted for.

• Good fluid management goes a long way toward preventing problems.

Transfusion Therapy

- 60% of transfusions occur perioperatively.- responsibility of transfusing perioperatively

is with the anesthesiologist.

When is Transfusion Necessary?• “Transfusion Trigger”: Hgb level at which

transfusion should be given.- Varies with patients and procedures

• Tolerance of acute anemia depends on:- Maintenance of intravascular volume- Ability to increase cardiac output- Increases in 2,3-DPG to deliver more of the

carried oxygen to tissues

Type and Screen• Donated blood that has been tested for

ABO/Rh antigens and screened for common antibodies (not mixed with recipient blood).- Used when usage of blood is unlikely, but

needs to be available (hysterectomy).- Allows blood to available for other patients.- Chance of hemolytic reaction: 1:10,000.

Component Therapy• A unit of whole blood is divided into components;

Allows prolonged storage and specific treatment of underlying problem with increased efficiency:

- packed red blood cells (pRBC’s)- platelet concentrate- fresh frozen plasma (contains all clotting factors)- cryoprecipitate (contains factors VIII and fibrinogen; used

in Von Willebrand’s disease)- albumin - plasma protein fraction- leukocyte poor blood - factor VIII- antibody concentrates

Packed Red Blood Cells

• 1 unit = 250 ml. Hct. = 70-80%.• 1 unit pRBC’s raises Hgb 1 gm/dL.• Mixed with saline: LR has Calcium which

may cause clotting if mixed with pRBC’s.

Platelet Concentrate• Treatment of thrombocytopenia• Intraoperatively used if platlet count drops

below 50,000 cells-mm3 (lab analysis).• 1 unit of platelets increases platelet count

5000-10000 cells-mm3.

• Risks:- Sensitization due to HLA on platelets- Viral transmission

Fresh Frozen Plasma• Plasma from whole blood frozen within 6 hours

of collection.- Contains coagulation factors except platelets- Used for treatment of isolated factor deficiences,

reversal of Coumadin effect, TTP, etc.- Used when PT and PTT are >1.5 normal

• Risks:- Viral transmission- Allergy

Complications of Blood Therapy• Transfusion Reactions:

- Febrile; most common, usually controlled by slowing infusion and giving antipyretics- Allergic; increased body temp., pruritis,

urticaria. Rx: antihistamine,discontinuation. Examination of plasma and urine for free hemoglobin helps rule out hemolytic reactions.

Complications of Blood Therapy (cont.)

• Hemolytic: - Wrong blood type administered (oops).- Activation of complement system leads to intravascular

hemolysis, spontaneous hemorrhage.- Signs: hypotension,fever, chills, dyspnea, skin flushing,

substernal pain. Signs are easily masked by general anesthesia.

- Free Hgb in plasma or urine - Acute renal failure- Disseminated Intravascular Coagulation (DIC)

Complications (cont.)• Transmission of Viral Diseases:

- Hepatitis C; 1:30,000 per unit- Hepatitis B; 1:200,000 per unit- HIV; 1:450,000-1:600,000 per unit- 22 day window for HIV infection and test detection- CMV may be the most common agent transmitted,

but only effects immuno-compromised patients- Parasitic and bacterial transmission very low

Treatment of Acute Hemolytic Reactions

• Immediate discontinuation of blood products and send blood bags to lab.

• Maintenance of urine output with crystalloid infusions

Administering Blood Products

- Consent necessary for elective transfusion- Unit is checked by 2 people for Unit #, patient ID,

expiration date, physical appearance.- pRBC’s are mixed with saline solution (not LR)- Products are warmed mechanically and given

slowly if condition permits- Close observation of patient for signs of

complications- If complications suspected, infusion discontinued,

blood bank notified, proper steps taken.

Transfusion Therapy Summary

• Decision to transfuse involves many factors• Availability of component factors allows

treatment of specific deficiency• Risks of transfusion must be understood

and explained to patients• Vigilance necessary when transfusing any

blood product