Burn shock is a life-threatening medical complication that can develop after severe burn injuries. It is not an emotional state, but rather a profound physiological response involving widespread fluid loss from the bloodstream into surrounding tissues. This condition leads to a significant reduction in the body’s circulating blood volume, which can severely compromise organ function. Prompt recognition and treatment are crucial for managing this serious complication.
The Physiological Cascade of Burn Shock
Following a severe burn, the body initiates an immediate, intense inflammatory response. This response involves the release of various inflammatory mediators, such as histamines, prostaglandins, and cytokines, both at the injury site and throughout the body. These substances cause blood vessels to become “leaky,” a phenomenon known as increased capillary permeability. This allows plasma, proteins, and electrolytes to escape from the bloodstream into the interstitial spaces, leading to massive fluid shifts and the formation of edema.
The rapid and substantial loss of intravascular fluid leads to hypovolemia. Burn shock typically manifests in adults with burns affecting 20% or more of their total body surface area (TBSA). This initial period, characterized by decreased cardiac output and a lowered metabolic rate, is often referred to as the “ebb phase.” During this phase, up to 40% of circulating blood volume can be lost within the first 30 minutes if not addressed.
Systemic Impact on Major Organs
The massive fluid shift and resulting hypovolemia directly reduce blood flow and oxygen delivery to vital organs. This inadequate perfusion can have widespread consequences. The cardiovascular system experiences a diminished cardiac output, meaning the heart struggles to pump enough blood efficiently. This often leads to low blood pressure, also known as hypotension, and a compensatory increase in heart rate as the body attempts to maintain circulation.
The renal system is also affected by reduced blood flow. Insufficient blood supply can impair the kidneys’ ability to filter waste and produce urine, potentially leading to acute kidney injury or even complete kidney failure. The respiratory system can also develop complications, with a risk of pulmonary edema, where fluid accumulates in the lungs. This can occur despite the overall fluid depletion in the rest of the body, further compromising oxygen exchange.
Fluid Resuscitation Protocols
Restoring circulating blood volume is the primary medical intervention for burn shock, achieved through the administration of large amounts of intravenous (IV) fluids. The goal is to counteract fluid loss and maintain adequate organ perfusion. Lactated Ringer’s solution is the most commonly used fluid for this purpose due to its electrolyte composition.
The Parkland formula is a method used to calculate the estimated fluid volume needed during the first 24 hours after a burn. For adults, this formula typically recommends 4 milliliters of fluid per kilogram of body weight per percentage of total body surface area (TBSA) burned (4 mL/kg/%TBSA). Half of this calculated fluid volume is administered during the first 8 hours post-burn, with the remaining half delivered over the subsequent 16 hours. Fluid administration is monitored, often guided by urine output, to prevent both under-resuscitation, which can worsen shock, and over-resuscitation, which can lead to complications such as excessive swelling.
The Post-Shock Recovery Phase
After the initial 24 to 48 hours of burn shock stabilization, the body transitions into a physiological state known as the “flow” or hypermetabolic phase. This phase is characterized by a significantly increased metabolic rate as the body expends significant energy for wound healing and tissue repair. The body’s demand for calories and protein increases during this period to fuel recovery processes.
Patients may experience prolonged muscle protein breakdown and altered glucose metabolism, including insulin resistance. Nutritional support becomes important to counteract this catabolic state and provide building blocks for healing. While the immediate life threat of shock subsides, long-term complications such as organ damage can arise from the initial episode. Therefore, continued monitoring and tailored support are provided to aid the patient’s recovery.