Intravenous Fluid PDF

Intravenous fluid Intravenous fluid administration should be considered as any other pharmacological prescription. There are three main indications: Resuscitation Replacement Maintenance For maximizing benefits and minimizing harms intravenous fluid administration should follow th...

Intravenous fluid Intravenous fluid administration should be considered as any other pharmacological prescription. There are three main indications: Resuscitation Replacement Maintenance For maximizing benefits and minimizing harms intravenous fluid administration should follow the four Ds: Drug, Dosing, Duration, De-escalation. Concept of ‘four Ds’ when prescribing fluids Drug — consider the indication for the fluid and what effect is being sought. Duration of therapy — consider when to start and when to stop therapy. Dosing — consider how much fluid to give. De-escalation — consider when the fluid therapy is no longer effective or required. Osmolarity and Tonicity of a solution The osmolarity of a solution is equal to the number of osmoles per liter of solution. 23 Tonicity, a term that is often used interchangeably with osmolarity, refers to the effect a solution has on cell volume. An isotonic solution has no effect on cell volume. Hypotonic solutions increase cell volume. Hypertonic solutions decrease cell volume. Tonicity describes the effective osmolality of a fluid. Fluid's classification I.V fluids are classified as Crystalloids or Colloids based on their ability to diffuse through barriers separating body fluid compartments, i.e., intravascular and extravascular (interstitial) fluid compartments. Crystalloids passed readily through the membrane, whereas colloids did not (Greek word-glue). 24 Crystalloids and Colloids A Crystalloid solution is an aqueous solution composed of water and small solutes such as electrolytes and glucose. Crystalloid solutions can be further categorized as hypotonic, isotonic, or hypertonic. A Colloid solution contains large molecular weight particles such as proteins or hydroxyethyl starches (HES) suspended in a crystalloid solution. The intravascular half-life of a crystalloid solution is 20-30 min, most colloid solutions have intravascular half-lives between 3 and 6 h. Crystalloids when given in sufficient amounts 1. Are just as effective as colloids in restoring intravascular volume. 2. Replacing an intravascular volume deficit with three to four times the volume needed when using colloid 3. Severe intravascular fluid deficits can be more rapidly corrected using colloid solutions. 4. The rapid administration of large amounts of crystalloids (>4-5L) is more frequently associated with tissue edema. Some evidence suggests that marked tissue edema can impair oxygen transport, tissue healing, and return of bowel function following major surgery. 25 Comparison of Plasma and Crystalloid Resuscitation Fluids Infusion of common fluids Infusion of 1 L of 0.9% NACL adds 275 mL to the plasma volume and 825 mL to the interstitial volume Note: the total volume expansion (1100 mL) slightly greater than the infused volume. This is the result of a fluid shift from the ICF to extracellular space, because isotonic saline is slightly hypertonic to the Plasma 26 1. 0.9% Sodium Chloride (Normal Saline) Indications for the use of normal saline infusion that have been approved by the FDA: Extracellular fluid replacement (e.g., dehydration, hypovolemia, hemorrhage, sepsis). Treatment of metabolic alkalosis in the presence of fluid loss. Mild sodium depletion. Additionally: diluents for the infusion of compatible drug additives. Other indications Used also in traumatic brain injury or any brain edema. Replacement fluid in hyperkalemia. It is the preferred solution for diluting packed red blood cells prior to transfusion. It is used in DKA when there is severe hypovolemia and when serum sodium less than 140meq/L. 27 2. Hypertonic saline Hypertonic 3% saline is employed in therapy of severe symptomatic hyponatremia. Hypertonic 3%, 7.5% or 23.4% saline can be used in case of severe brain edema. 3. 0.45% Sodium Chloride A hypotonic concentration of sodium chloride. Hypotonic concentrations of sodium chloride (0.45%) are best for parenteral maintenance fluids rather than aggressive intravascular volume repletion. 4. Lactated Ringer's Ringer's solution: introduced in 1880 by Sydney Ringer (UK) who studied mechanisms of cardiac contraction. The solution was designed to promote the contraction of isolated frog hearts, and contained Ca+ and K+ in a sodium chloride diluent. In the 1930s Alexis Hartmann (American pediatrician) proposed the addition of sodium lactate buffer to Ringer's solution for the treatment of metabolic acidosis.The lactated Ringer's solution is also known as Hartmann's solution 28 Lactated Ringer's uses Have sodium, potassium and chloride contents similar to extracellular fluid have fewer adverse effects on acid-base balance (in case of hyperchloremic metabolic acidosis). It is used as a replacement fluid in burn patients when BSA >20% (Parkland formula). Lactated Ringer's disadvantages The calcium in lactated Ringers can bind to certain drugs and reduce their bioavailability and efficacy e.g., Amphotericin, Ampicillin, Thiopentone etc. Calcium binding to the citrated anticoagulant in blood products can inactivate the anticoagulant and promote the formation of clots in donor blood. For this reason, lactated Ringer's solution is contraindicated as a diluent for blood transfusions. 29 5. Dextrose solutions D5% is used to prevent protein breakdown in an NPO patients after consumption of endogenous glycogen (24-48hr). D5% (D5W) is used for replacement of pure water deficits and as a maintenance fluid for patients with hypernatremia. D10%, D20% or D50% are used in hypoglycemia. D20%, D25% or D50% are used in TPN (The use of 5% dextrose solutions to provide calories is obsolete). When glucose gets utilized, only water remains, Distribution: