Crystalloid/colloid

Crystalloid/colloid to achieve a pulmonary capillary wedge pressure (PCWP) between 15 and 18 mmHg... 

Compare and contrast the relative advantages and disadvantages of crystalloids, colloids, and blood products in the treatment of hypovolemic shock. 

Most clinicians agree that crystalloids should be the initial therapy of circulatory insufficiency. Crystalloids are preferred over colloids as initial therapy for burn patients because they are less likely to cause interstitial fluid accumulation. If volume resuscitation is suboptimal following several liters of crystalloid, colloids should be considered. Some patients may require blood products to assure maintenance of 02-carrying capacity, as well as clotting factors and platelets for blood hemostasis. 

Therapeutic plasma exchange (TPE), or plasmapheresis (PP), is an extracorporeal therapy most frequently used in the treatment of hematologic disorders, and autoimmune neuropathies and vasculitides [37]. This modality occasionally is also employed in the treatment of poisoning. The apparatus involves central venous access and a blood circuit between the patient and a pheresis machine. Cytopheresis by centrifugation or filtration then separates the formed elements of blood from plasma. The cells are returned to the patient while the plasma (with the poison) is discarded. Fluid volume is typically replaced with crystalloid, colloid, or fresh frozen plasma (FFP) if clotting factor repletion is necessary. 

A diffusion mechanism is also used in dialysis as a means of separating colloids from crystalloids. The rate of diffusion of molecules in gels is practically the same as in water, indicating the continuous nature of the aqueous phase. The diffusion of gases into a stream of vapour is of considerable importance in diffusion pumps. 

Rapid fluid resuscitation with a crystalloid or a colloid if hypotensive (large volumes may be required)... 

Use a crystalloid (normal saline or lactated Ringer s solution) or a colloid (hydroxyethyl starch or albumin 5%) intravenous boluses... 

Three major therapeutic options are available to clinicians for restoring circulating blood volume crystalloids (electrolyte-based solutions), colloids (large-molecular-weight solutions), and blood products. 

The volume of colloid administered is primarily confined to the intravascular space, in contrast to isotonic crystalloid solutions that distribute throughout the extracellular fluid space. 

Generally, the major adverse effects associated with colloids are fluid overload, dilutional coagulopathy, and anaphy-lactoid/anaphylactic reactions.24,32 Although derived from pooled human plasma, there is no risk of disease transmission from commercially available albumin or PPF products since they are heated and sterilized by ultrafiltration prior to distribution.24 Because of direct effects on the coagulation system with the hydroxyethyl starch and dextran products, they should be used cautiously in hemorrhagic shock patients. This is another reason why crystalloids maybe preferred in hemorrhagic shock. Furthermore, hetastarch can result in an increase in amylase not associated with pancreatitis. As such, the adverse-effect profiles of the various fluid types should also be considered when selecting a resuscitation fluid. 

Has the goal arterial blood pressure been achieved If not, give additional fluid therapy hourly blending crystalloids and isooncotic colloids based on inadequate blood pressure response. 

Therapeutic fluids include crystalloid and colloid solutions. The most commonly used crystalloids include normal saline, hypertonic saline, and lactated Ringer s solution. Examples of colloids include albumin, the dextrans, hetastarch, and fresh frozen plasma. 

Therapeutic intravenous (TV) fluids include crystalloid solutions, colloidal solutions, and oxygen-carrying resuscitation solutions. Crystalloids are composed of water and electrolytes, all of which pass freely through semipermeable membranes and remain in the intravascular space for shorter periods of time. As such, these solutions are very useful for correcting electrolyte imbalances but result in smaller hemodynamic changes for a given unit of volume. 

Administer a fluid challenge to hypovolemic patients (hypotension or lactic acidosis) crystalloids 500 to 1,000 mL colloids 300 to 500 mL. Administer over 30 minutes and repeat based on response (increase in blood pressure and urine output). 

Initial fluid resuscitation consists of isotonic crystalloid (0.9% sodium chloride or lariated Ringer s solution), colloid (5% Plasmanate or albumin, 6% hetastarch), or whole blood. Choice of solution is based on 02-carrying capacity (e.g., hemoglobin, hematocrit), cause of hypovolemic shock, accompanying disease states, degree of fluid loss, and required speed of fluid delivery. 

The primary disadvantage is the large volume necessary to replace or augment intravascular volume. Approximately 4 L of normal saline must be infused to replace 1 L of blood loss. In addition, dilution of colloid oncotic pressure leading to pulmonary edema is more likely to follow crystalloid than colloid resuscitation. 

Colloids are larger molecular weight solutions (more than 30,000 daltons) that have been recommended for use in conjunction with or as replacements for crystalloid solutions. Albumin is a monodisperse colloid because all of its molecules are of the same molecular weight, whereas hetastarch and dextran solutions are polydisperse compounds with molecules of varying molecular weights. 

The theoretical advantage of colloids is their prolonged intravascular retention time compared to crystalloid solutions. Isotonic crystalloid solutions have substantial interstitial distribution within minutes of IV administration, but colloids remain in the intravascular space for hours or days, depending on factors such as capillary permeability. However, even with intact capillary permeability, the colloid molecules eventually leak through capillary membranes. 

Colloids (especially albumin) are expensive solutions, and a large study involving almost 7,000 critically ill patients found no significant difference in 28-day mortality between patients resuscitated with either normal saline or 4% albumin. For these reasons, crystalloids should be considered first-line therapy in patients with hypovolemic shock. 

Whole blood could be used for large volume blood loss, but most institutions use component therapy, with crystalloids or colloids used for plasma expansion. 

Packed red blood cells contain hemoglobin that increases the 02-carrying capacity of blood, thereby increasing 02 delivery to tissues. This is a function not performed by crystalloids or colloids. Packed red cells are usually indicated in patients with continued deterioration after volume replacement or obvious exsanguination. The product needs to be warmed before administration, especially when used in children. 

There is no clinical outcome difference between colloids and crystalloids C... 

Iso-oncotic colloid solutions (plasma and plasma protein fractions), such as 5% albumin and 6% hetastarch, offer the advantage of more rapid restoration of intravascular volume with less volume infused, but there is no significant clinical outcome differences compared with crystalloids. 

Clinical outcome differences with the use of crystalloids or colloids have not been demonstrated, so crystalloids are generally recommended. 

---