The Baux score is a simple, standardized tool utilized across burn centers globally to rapidly evaluate the severity of a burn injury. It offers a quick assessment of the patient’s prognosis immediately following the trauma. By providing an objective measure of injury severity, the Baux score assists medical professionals in making swift decisions regarding patient triage and resource allocation. The score’s primary function is to help determine the likelihood of mortality, ensuring that patients facing the highest risk receive specialized and intensive care without delay.
Calculation Based on Age and Burn Size
The foundation of the Baux scoring system relies on two primary biological factors that strongly influence a burn patient’s survival: age and the extent of the burn. The original calculation requires the simple addition of the patient’s age in years and the percentage of the body covered by the burn. The extent of the injury is measured by the Total Body Surface Area (TBSA), which represents the percentage of second-degree or third-degree burns. Medical teams estimate TBSA using standardized charts, such as the Rule of Nines for adults or the Lund and Browder chart for children. These two components, age and TBSA percentage, are considered the most significant non-modifiable factors determining survival in patients without complicating injuries.
The Critical Factor of Inhalation Injury
Modern burn care led to the development of the Revised Baux Score, which incorporates the presence of an inhalation injury, a factor that drastically worsens the patient’s outlook. If a patient has sustained an inhalation injury, a fixed value of 17 is added to the Age + TBSA calculation. The addition of 17 points is mathematically equivalent to either an extra 17 years of age or an additional 17% TBSA burned in terms of mortality risk. Smoke inhalation is particularly dangerous because the superheated air and toxic byproducts damage the airways and lung tissue. This internal trauma can lead to immediate respiratory failure, lung inflammation, and pneumonia, overwhelming the body’s ability to cope with the burn shock.
Understanding the Prognosis
The final calculated Baux score number provides a strong correlation with the patient’s probability of death. Historically, a score of 100 or greater was associated with a near 100% mortality rate, and scores exceeding 140 were considered unsurvivable. However, dramatic advancements in fluid resuscitation, infection control, and surgical techniques have significantly improved these outcomes in modern specialized burn units.
Today, the score functions as a measure of injury burden, where a higher number consistently predicts a need for more aggressive and prolonged care. For example, a patient with a score below 70 generally faces a favorable prognosis, while a score above 100 indicates a very high-risk case requiring immediate and intensive intervention. In high-performing centers, the LD50 (the point at which 50% of patients are expected to die) has shifted to a Revised Baux Score of 130 to 140.
The Baux score remains a prognostic tool and is always used in conjunction with a complete clinical assessment. This assessment includes evaluating pre-existing health conditions and the patient’s overall physiological response to the injury.