Abstract 282: Fat Intravasation from Intraosseous Infusions

Abstract

Rapid vascular access is an essential element in advanced resuscitation procedures and intraosseous (IO) cannulation has proven to be both a rapid and effective alternative to intravenous access. Little attention has been given to refinements in IO procedures that may improve efficacy or reduce complications of use. This study was designed to assess fat intravasation with IO infusions. In this study, IO cannulas (15G, EZ IO, Vidacare Corp, San Antonio, TX) were inserted into the proximal tibias (N=14) and distal femurs (N=11) of seven anesthetized swine ( Sus scrofa, 50.1±3.5 Kg). A lipophilic fluorescent probe (Nile red: Excitation 480nm-Emission 535nm) was used to quantify fat intravasation in venous effluents by relative fluorescent (RFU). Blood for analysis was withdrawn from an 8F catheter placed by fluoroscopic guidance in the external iliac vein. The IO infusion regimen consisted of an initial IO saline flush (10cc), infusion with a pressurized bag (300 mmHg), and infusions at 0.3, 0.5, 1.0, 2.0 and 3.0 ml per second using a programmable pump. An ANOVA and post hoc tests were employed to assess the significance of treatment effects. Figure illustrates significant (*P<0.05) fat intravasation (mean ± SD) with initial flush and infusion rates ≥ 1ml per second. The post mortem assessment of lung tissue from these animals (N=79 samples) using formalin fixed H&E stained sections and frozen sections stained with oil-red-O revealed mild to moderate positive staining for lipid in all lung segments and rare bone marrow emboli consisting of mature adipocytes and hematopoietic cells within medium sized pulmonary arteries. In conclusion, this study suggests that both initial flush and high flow rates induce medullary damage and the embolization of bone marrow and fat. Further studies are needed to determine if refinements in IO flush and infusion practices can maintain the benefits of IO infusions and minimize fat embolization.