Swelling of the Subcutaneous Adipose, but not the Dermis, in Burn Wound Edema is Exacerbated by IV Fluids

Abstract

Intravenous (IV) resuscitation of burn patients has greatly improved outcomes and become a cornerstone of modern burn care. However, the large volumes of crystalloid given can lead to various comorbidities such as compartment syndromes and acute respiratory distress syndrome. Simultaneously, it is well established that vascular leak leads to significant edema in the severely burned patient. The objective of this study was to begin to examine the interaction of edema of burn wounds and IV fluids. Anesthetized Yorkshire swine sustained 40% total body surface area (TBSA) full‐thickness contact burns with brass probes heated to 100°C placed on the skin for 30 seconds. Animals were recovered from anesthesia and randomized to one of four treatment groups: no IV fluids (n=6), IV lactated Ringer's (LR) resuscitation with the modified Brooke formula (MB; 2 ml/kg/%TBSA, n=6), 15 mL/kg/d of IV LR (LR: n=6), or 15 mL/kg/d fresh frozen plasma (FFP: n=6). Unburned sham animals (n=4) and injured animals were assessed for 48 hours, at which point animals were humanely euthanized and dorsal and ventral dermis was taken to determine wet to dry weight ratios. Additionally, 3 biopsies to include dermis and the entire subcutaneous fat were taken from both the dorsal and ventral aspects of the animal for histological determination of tissue thickness. Burn wound edema was demonstrated by a significantly higher wet:dry ratio in all groups compared to sham animals for dorsal (P=0.017) and ventral (P=0.044) dermis. However, there was no difference amongst the various IV regimens. Moreover, neither burn nor IV fluids induced a difference in the thickness of the dermis on dorsal or ventral locations. In contrast, the thickness of the subcutaneous fat was significantly elevated in both dorsal (P=0.028) and ventral (P=0.0045) samples, depending on IV fluid regimen. Thickness of the dorsal fat layer was 1865 ± 327 μm, 2170 ± 205 μm, 3466 ± 421 μm, 2452 ± 271 μm, and 2707 ± 302 μm for Sham, no IV, MB, LR, and FFP groups, respectively. Thickness of the ventral fat layer was 1557 ± 164 μm, 2728 ± 184 μm, 2618 ± 172 μm, 2368 ± 236 μm, and 3329 ± 352 μm for Sham, no IV, MB, LR, and FFP groups, respectively. Collectively, these data demonstrate that volumes and types of IV fluids can alter burn‐induced edema in an anatomically‐dependent manner. Elucidating the specific drivers of burn wound edema may lead to personalized medicine approaches that can minimize comorbidities associated with over/under resuscitation of the burn patient.Support or Funding InformationThis study was supported by Military Burn Research Program Award# W81XWH‐16‐2‐0041.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.