Explain the Ebb or Shock Period - Dietary Management for Burns?
During the initial bums after injury, the focus is on counteracting the stress induced neurohormonal and physiologic responses that accelerate the body's metabolism by a series of events. Loss of skin on the burn site and exposure of extra cellular fluids lead to immediate loss of water and electrolytes, mainly sodium and also protein depletion. As a result, the body water shifts from extra cellular spaces in other parts of the body to the burn site adding to continuous loss of fluids and electrolytes. Due to this there are changes in the capillary fluid shift mechanism resulting in decreased volume hypotension, low haemo-concentration and diminished urine output. Intracellular water is also drawn out to balance extra cellular fluid losses leading to cellular dehydration. Patients with extensive burns need immediate fluid and electrolyte replacement during the first 12 to 24 hours after injury.
Abalanced salt solution such as lactated Ringer's solution is given to correct hypovolemia and prevent metabolic acidosis. Because the exact volume of fluid and infusion rate depends on the patient's response to fluid delivery, ongoing fluid replacement is based on close monitoring of the patient. The goal is ta maintain an adequate blood pressure and haematocrit and a urine output of > 50 to 100 ml/hr (0.5 to 1 ml/kg/hr) in an adult or 1 ml/kg/hr in a child while avoiding circulatory overload. A general formula for the first 24 hr is 0.5 ml/kg/% Body Surface Area (BSA) of colloid and 1.5ml/kg/% BSA of lactated Ringer's solution along with 100 mL/hr maintenance of lactated Ringer's solution.
One fourth of the fluid is given in the first 4 hr, 114 in the second 4 hr, 114 in the next 8 hr, and 1 - 14 in the last 8 hr- measured from the time of injury, not from the time of arrival at the emergency facility, because large amounts of intravascular fluid can move into tissues, leading to shock, which begins immediately after injury. A colloidal solution such as albumin or plasma is not effective at this stage because it passes into the extra vascular fluids due to the increased permeability of the vascular endothelium caused by the bum. Usually, vascular permeability returns to normal after the first day and colloidal solutions are then given to restore plasma volume. During this initial period, nutritional requirements of protein and energy are not attempted to be met as the entire focus is on rapid and effective fluid and electrolyte therapy so as to prevent shock.