MSS09: EARLY PHASE EFFECTS OF RESUSCITATION STRATEGY ON EXTRAVASCULAR LUNG WATER AND THE DEVELOPMENT OF ACUTE LUNG INJURY IN A PORCINE HEMORRHAGE-REPERFUSION MODEL
Joseph J Ganshert, MD1, Robert J Conrad, MD1, Catherine Uyehara, PhD2; 1Department of General Surgery, Tripler Army Medical Center, 2Department of Clinical Investigation, Tripler Army Medical Center
Hemorrhage causes the great majority of survivable combat injuries, leading to increased forward deployment of medical assets and focus on hemorrhage control and resuscitation during the “golden hour.” Complications relating to resuscitation include acute lung injury (ALI), carrying up to a 30% mortality rate. This pathogenesis begins early, and there is strong evidence to support restrictive fluid strategies to prevent ALI. Early administration of blood products is favored for multiple reasons in trauma, but this study aims to determine if crystalloid and whole blood will have differential effects on the development of ALI during the early phase of resuscitation.
Pigs (N=11) were anesthetized, intubated, and catheterized with a Swan-Ganz and PulsioFlex PiCCO system. They were hemorrhaged to goal of 30ml/kg (3ml/kg/min for 7 minutes then 1ml/kg/min) then resuscitated with shed volumes equal to the amount hemorrhaged of whole blood (WB, N=5) or normal saline (NS, N=6). Hourly measurements included parameters of hemodynamics and oxygenation, cytokines, and extravascular lung water (EVLW) via thermo-dilutional technique using the PiCCO system.
Hemorrhage induced a significant 38% drop in MAP, 27% decrease in cardiac output, increase in pulmonary resistance, and significant oxygen debt supporting the efficacy of our model. These values were successfully reversed with resuscitation, however the number of sheds required for WB was 1.00 vs 2.17 for NS. The hemodynamic effects were also more robust and durable with WB. Cytokines known to be prognostic markers of ALI showed significant increase from baseline but without difference between WB and NS. In our preliminary data there is an obvious but nonsignificant tendency for increasing EVLW with NS vs WB.
This study supports restrictive fluid resuscitation in the early phase of resuscitation. WB and NS both adequately restore blood pressure, improve cardiac output, and recover oxygen debt without causing significant lung dysfunction. WB was able to achieve this with less volume meaning it may be favored in order to minimize total fluid. An early tendency was found for NS to increase EVLW; with longer follow up or with larger sample size this difference may become significant. Pro-inflammatory cytokines were raised in both the NS and WB, suggesting the rise seen in the acute phase is caused by the hemorrhage and reperfusion rather than fluid type. Building on this model, we plan to investigate the development of EVLW after early phase, other fluids such as freed dried plasma and artificial blood, and with concomitant pulmonary contusion.