Abstract 14: Polyethylene Glycol-20k Improves Post-Resuscitation Cerebral Microcirculation in a Rat Model of Cardiac Arrest

Abstract

Introduction: Polyethylene glycol-20k (PEG-20k) reduces severity of post CPR cerebral dysfunction, however the mechanism is yet unproven. In other vascular beds, PEG-20k osmotically reverses ischemia-induced metabolic cell swelling and decompresses the microcirculation, which improves flow and oxygen transfer. Hypothesis: We hypothesized that PEG-20k improves neurologic function by preserving microcirculatory blood flow and decreasing brain swelling. Methods: 32 S-D rats weighting between 450-550g were randomized into 4 groups: 1) Control (CPR+SALINE); 2) Treated (CPR+PEG-20k); 3) NO CPR+SALINE; 4) NO CPR+PEG-20k. CPR was initiated after 8 min of untreated ventricular fibrillation and continued for 8 min, then defibrillation was performed. PEG-20k was administered at the beginning of chest compression. Cerebral microcirculation was visualized at baseline, 2, 4 and 6 h after CPR by side-stream dark-field (SDF) imaging with a 5х imaging objective. Animals were euthanized with Euthasol (150 mg/kg) and brain swelling was assessed by comparing wet-to-dry weight ratios at 6h post resuscitation. Results: The wet to dry ratio in the CPR+SALINE group was significantly higher than the other three groups (p<0.05). PEG-20k attenuated the wet to dry ratio (p<0.05) compared with the CPR+SALINE group (Fig 1). A significant improvement of cerebral microcirculation was also observed in the CPR+PEG-20k group when compared with the CPR+SALINE group (Fig 2). Conclusions: PEG-20k given during resuscitation improves cerebral microcirculatory flow by increasing microcirculation and decreasing brain tissue swelling in a rat model of CA.