Early Restrictive Fluid Resuscitation has no Clinical Advantage in Experimental Severe Pediatric Acute Respiratory Distress Syndrome.

BACKGROUND: Intravenous fluids are widely used to treat circulatory deterioration in pediatric acute respiratory distress syndrome (PARDS). However, the accumulation of fluids in the first days of PARDS is associated with adverse outcome. As such, early fluid restriction may prove beneficial, yet the effects of such a fluid strategy on the cardio-pulmonary physiology in PARDS is unclear. In this study, we compared the effect of a restrictive to a liberal fluid strategy on hemodynamic response and the formation of pulmonary edema in an animal model of PARDS.

METHODS: Sixteen mechanically ventilated lambs (2-6 weeks) received oleic acid infusion to induce PARDS and were randomized to a restrictive or liberal fluid strategy during a 6-hour period of mechanical ventilation. Transpulmonary thermodilution determined extravascular lung water (EVLW) and cardiac output (CO) Post-mortem lung wet-to-dry weight ratios were obtained by gravimetry.

RESULTS: Restricting fluids significantly reduced fluid intake, but increased use of vasopressors among animals with PARDS. Arterial blood pressure was similar between groups, yet CO declined significantly in animals receiving restrictive fluids (p=0.005). There was no difference in EVLW over time (p=0.111) and lung wet-to-dry weight ratio (6.1 IQR 6.0-7.3 vs. 7.1 IQR 6.6-9.4 restrictive vs. liberal, p=0.725) between fluid strategies.

CONCLUSIONS: Both fluid strategies stabilized blood pressure in this model, yet early fluid restriction abated CO. Early fluid restriction did not limit the formation of pulmonary edema, therefore this study suggests that in the early phase of PARDS a restrictive fluid strategy is not beneficial in terms of immediate cardio-pulmonary effects.