Overview
A large burn can trigger a severe form of shock in which blood vessels leak fluid, tissues swell, and the body requires rapid intravenous resuscitation to maintain circulation and organ perfusion. This study, ABRUPT2, tested whether adding 5% albumin to lactated Ringer’s solution during the first 48 hours after major burn injury could reduce the amount of fluid needed compared with lactated Ringer’s alone.
The trial was designed as a prospective, randomized, multicenter study, meaning patients were enrolled ahead of time, assigned by chance to one of two treatment strategies, and treated across many burn centers. The key finding was that 5% albumin significantly reduced fluid requirements during early burn resuscitation without worsening major outcomes such as death, acute kidney injury, or time to healing.
Why burn resuscitation matters
After a major burn, the body loses its normal ability to keep fluid inside the bloodstream. Capillaries become more permeable, and large amounts of fluid shift into injured tissue. If too little fluid is given, blood pressure and organ blood flow can fall. If too much fluid is given, swelling can become dangerous, increasing the risk of respiratory compromise, compartment syndromes, and other complications. This challenge is often called burn resuscitation, and it is one of the most important early treatments in severe burn care.
Lactated Ringer’s solution has long been the standard starting fluid because it is balanced and widely available. Albumin, a blood protein that helps keep fluid in the bloodstream, has been considered as an adjunct when fluid needs become excessive. However, practice has varied because of uncertainty about when to use albumin and whether it truly lowers fluid requirements in a meaningful way.
Background from the earlier ABRUPT study
The earlier ABRUPT observational study suggested that starting albumin early in patients with burns involving 20% or more of total body surface area could lower fluid input and improve urine output. Those findings were encouraging, but observational studies cannot prove cause and effect as well as randomized trials. ABRUPT2 was therefore designed to provide stronger evidence by directly comparing two resuscitation strategies in a randomized fashion.
Based on the earlier study, ABRUPT2 focused on more severely injured patients, expanding eligibility to those with at least 25% total body surface area burned and at least 20% full-thickness injury. Adults 18 years and older were included.
Study design and treatment groups
Patients were randomized to one of two initial resuscitation strategies:
1. Lactated Ringer’s alone
2. A mixture of 2/3 lactated Ringer’s and 1/3 5% albumin
The starting fluid rate was 2 to 4 mL/kg per percent total body surface area burned, then adjusted according to urine output, with a goal of 0.5 to 1 mL/kg/hour. This goal is commonly used in burn resuscitation because urine output serves as a practical marker of whether circulation is being supported adequately.
For safety reasons, or if fluid volumes became excessive, investigators were allowed to switch a patient from one arm to the other. This was especially important when the total fluid administered exceeded 250 mL/kg in 24 hours, a level that can signal risk of over-resuscitation.
Who was enrolled
The study planned to recruit more patients, but enrollment slowed across participating centers and the trial was stopped early at 99 subjects. Of these, 48 were assigned to the albumin group and 51 to the lactated Ringer’s group.
The burns were severe, with a mean burn size of 46% total body surface area. This indicates that the trial population had extensive injuries and high resuscitation needs, making the results highly relevant to major burn care.
Main findings
The most important result was that patients in the lactated Ringer’s-only group required significantly more fluid in the first 48 hours than those who received albumin.
Twenty-six patients in the lactated Ringer’s group, or 51%, were crossed over to albumin because of clinical concerns or high fluid requirements. No patients crossed over from albumin to lactated Ringer’s. Even with these crossovers, analysis by the intention-to-treat principle still showed clear differences favoring albumin.
At 24 and 48 hours, the lactated Ringer’s group received statistically significantly more fluid than the albumin group. In practical terms, the lactated Ringer’s group averaged about 1.5 times higher fluid requirements at 24 hours and about 2.1 times higher fluid requirements at 48 hours compared with the albumin group.
This finding supports the idea that albumin can help reduce the so-called “fluid creep” problem, in which burn patients receive increasingly large volumes of crystalloid fluid during resuscitation.
Clinical outcomes
Although albumin reduced fluid requirements, the study did not find differences between groups in several major clinical outcomes, including:
– Mortality
– Time to wound healing
– Acute kidney injury
This is an important point. Lower fluid requirements are valuable because they may reduce the risk of edema-related complications and simplify resuscitation, but the trial did not show that albumin improved survival or shortened recovery in this dataset. The study may also have been too small, or stopped too early, to detect differences in these harder outcomes.
What the results mean for practice
ABRUPT2 adds randomized evidence that 5% albumin can reduce intravenous fluid requirements during the first 48 hours after major burn injury. For burn centers, this may support earlier or more selective albumin use in patients with large burns who need escalating amounts of crystalloid.
Still, the results should be interpreted carefully. The study was stopped early because of declining enrollment, which limits statistical power. Also, many patients assigned to lactated Ringer’s eventually crossed over to albumin, reflecting real-world concern about high fluid needs but also making interpretation more complex. Even so, the direction of effect was consistent and clinically meaningful.
In practice, clinicians must balance several considerations when choosing resuscitation fluids:
– Burn size and depth
– Time since injury
– Urine output and hemodynamic status
– Risk of edema and compartment syndrome
– Availability of albumin and institutional protocols
Albumin is not a replacement for careful monitoring. It is best viewed as one possible adjunct in selected patients with major burns, especially when crystalloid requirements become excessive.
Why albumin may work
Albumin is a plasma protein that helps maintain oncotic pressure, which is the force that keeps fluid within blood vessels. In the setting of a burn, when capillaries leak and inflammation is intense, giving albumin may help retain more fluid intravascularly compared with crystalloid alone. That means less total fluid may be needed to achieve the same urine output and perfusion goals.
However, burn shock is complex. Capillary leak, inflammation, tissue injury, and changes in vascular tone all interact. Albumin may help in some phases of resuscitation, but its effect is not guaranteed for every patient. That is why protocolized monitoring remains essential.
Strengths and limitations
The major strengths of ABRUPT2 include its randomized design, multicenter participation, and focus on a clinically important problem in severe burn care. The trial also used a practical resuscitation approach tied to urine output, reflecting how burn patients are treated in real clinical settings.
Limitations include the following:
– Early termination due to low enrollment
– Small sample size relative to the complexity of burn shock
– Crossovers from lactated Ringer’s to albumin, which may dilute group differences
– Limited ability to assess mortality or uncommon complications
Because of these limitations, the study is best seen as strong supportive evidence rather than the final word on albumin use in burn resuscitation.
Take-home message
For adults with major burns, early use of 5% albumin during resuscitation reduced fluid requirements compared with lactated Ringer’s alone in the first 48 hours after injury. The treatment did not show clear advantages in survival, kidney injury, or healing time, but it may help clinicians avoid excessive crystalloid administration and the complications that can come with it.
Clinical perspective
The findings from ABRUPT2 are likely to be of interest to burn surgeons, intensivists, emergency physicians, and critical care teams. They reinforce a growing view that very large-volume crystalloid resuscitation is not always the best strategy in severe burns. Instead, a more tailored approach that includes albumin in selected patients may improve fluid management.
Future research will need to clarify which patients benefit most, when albumin should be started, and whether reducing fluid requirements ultimately translates into better long-term outcomes. For now, ABRUPT2 provides important evidence that albumin can play a meaningful role in early resuscitation of large burns.
