Abstract P-559: FLUID RESUSCITATION WITH 0.9% SALINE IMPAIRS MYOCARDIAL CONTRACTILITY IN AN OVINE MODEL OF ENDOTOXEMIC SHOCK

Aims & Objectives: In 2011, the FEAST randomised controlled clinical trial showed higher mortality in bolus-fluid resuscitated septic shock that was mainly due to cardiovascular terminal clinical events. Despite this, fluid boluses continue to be recommended to-date in clinical guidelines for resuscitation of septic shock. We therefore conducted a collaborative randomised pre-clinical trial to determine effects of fluid resuscitation with 0.9% saline on myocardial contractile strain in an ovine model of endotoxemic shock. Methods Endotoxaemic shock was induced in sixteen merino ewes by infusing an escalating dose of lipopolysaccharide (E.coli 055:B5) after which they either received 40mls/kg of 0.9% saline resuscitation, SS (n=8) or no fluid resuscitation, NS (n=8). Echocardiogram scans were performed to assess myocardial function over time up to 12 hours post-sepsis and resuscitation. Myocardial strain in the circumferential and radial axes was analysed in EchoPac (GE Healthcare™) and data comparison between the two groups was done using STATA®. Data distribution was determined using Shapiro-Wilk test. Results Myocardial strain in both the circumferential and radial axes showed significant difference between the two-groups at 16 hours (p=0.02 and p<0.02 respectively), graph 1 below. Circumferential strain data were normally distributed. At 16-hours the mean circumferential strain SS group was -19.0 (SD, 10.5) and NS group -38.4 (SD, 9.9) while the median radial strain SS group was 10.2 (IQR, 4.2–20.2) and NS group 34.3 (IQR, 28.0 – 37.3). These correlated with significant differences in troponin levels between the two groups (p=0.03). Conclusions Echocardiographically derived speckle-tracking strain measures correlate well with troponin biomarker of myocardial dysfunction.