Amin D Jaskille | PubMed Health

PubMedDate not supplied

Repetitive ischemia-reperfusion injury: a plausible mechanism for documented clinical burn-depth progression after thermal injury.

Our previous studies confirmed the phenomenon of burn depth progression despite adequate Parkland formula resuscitation [Kim et al. J Burn Care Rehabil 2001;22960:406-6]. Repetitive ischemia-reperfusion injury (I-R) is a plausible explanation and is suggested by the concomitant swings we have observed in serum base deficit (BD) during resuscitation from burn shock. We chose to explore whether laser Doppler imaging (LDI) evidence of burn depth progression mirrored cycles of I-R (episodic swings in continuously measured BD). Positive findings would support the hypothesis that repetitive episodes of I-R is a factor in burn depth progression despite apparently adequate resuscitation. A total of 14 patients with severe life-threatening burns (median 51% TBSA) underwent continuous BD monitoring using a Paratrend 7 (Malvern PA) during 48 hours of resuscitation. Fluid needs were estimated using the Parkland formula, then were titrated to urine output. The slopes of BD changes were then analyzed. Worsening of BD greater than 0.2 mmol/l/min was noted, and a proportion derived relative to pooled data on 5-minute intervals. In four of the patients, LDI scans were performed on six representative areas sequentially every 4 hours. The analysis of median flux in these LDI images provided real-time determination of burn depth progression. Eight patients eventually died. Only four patients achieved a normal BD within 12 hours of monitoring despite exceeding the Parkland formula estimate and meeting urinary output parameters. Our analysis also showed cyclical peaks and valleys in the BD curve (P < .001), suggesting repetitive I-R insults. All increases in BD preceded changes that could be detected in vital signs or urine output. Finally, LDI confirmed that the burn depths continued to progress despite apparently adequate resuscitation, and also showed that there are similar peaks and valleys in the perfusion of the wounds (P < .0001), which mimic the changes in the BD curve. Responses to fluid resuscitation do not follow a linear pattern in the case of massive burns. These results in repetitive periods of tissue hypoperfusion evidenced by BD alterations and may contribute to progressive deepening of the burn wound.

Acid-Base Imbalance↗

PubMedDate not supplied

Seven years' experience with Integra as a reconstructive tool.

The bilayered dermal substitute Integra (Integra Life Sciences Corp., Plainsboro, NJ) was developed and has been widely used as primary coverage for excised acute burns. Our take has been slightly different, finding it most useful in the management of complex soft-tissue loss and threatened extremities as the result of tendon, joint, or bone exposure. Often tasked to fill significant volume loss, we have become adept at stacked multiple-layer applications. Creative use of this material has resulted in unexpected successes with distal limb salvage; the technique takes its place beside adjacent tissue transfer, composite flaps, and vascular pedicle flaps in our burn reconstructive practice. A prospective registry (44 patients) has been kept during the past 7 years that catalogs wounds with complex soft-tissue loss treated with Integra grafts. Many of these patients were at risk of extremity loss because of exposed tendons, joints, or bone. Integra was applied after 1:1 meshing. With profound soft-tissue defects, multiple layers of Integra were serially applied 1 to 2 weeks apart for reconstitution of soft-tissue contours. Local Integra graft infections were managed by silicone unroofing followed by topical sulfamylon liquid dressings. Wounds addressed included fourth-degree burns, necrotizing fasciitis, pit-viper envenomations, and total abdominal wall avulsion in one patient after being run over by a bus. Patients generally were free of pain from their wounds during the maturation phase of the Integra neodermis. Restoration of tissue contour was significantly better when using multiple layers for deep defects. Second and third layers of Integra were successfully applied after an abbreviated first graft maturation period of 7 days. Epithelial autografts on multilayer Integra applications frequently "ghosted"; they would auto-digest to dispersed cells followed subsequently by the reappearance of a confluent epithelial layer. Final grafted skin morphology over palmar and plantar surfaces assumed the type and fingerprint pattern of the original tissues. Infections were readily visible. Early recognition kept them to easily treated circumscribed areas, which did not jeopardize the entire wound. Lengths of stay were long (range, 2-246 days) but not significantly greater than with traditional techniques. The specific reconstructive use of Integra permitted unexpected salvage of several threatened extremities by protecting exposed tendons, bones and joints. Long-term histologic examination revealed unexpected persistence of Integra collagen. Large volume loss wounds benefited from the ability to fill voids with multilayered applications.

Abdominal Injuries↗