Fluid management with a simplified conservative protocol for the acute respiratory distress syndrome

Conservative fluid management improves ventilator-free days and oxygenation in patients with the Acute Respiratory Distress Syndrome (ARDS). In the Fluid and Catheter Treatment Trial (FACTT) of the National Institutes of Health, National Heart Lung and Blood Institute, ARDS Network (NIH/NHLBI ARDS Network), patients were randomized and managed with either a conservative fluid protocol (FACTT Conservative) or a liberal fluid protocol (FACTT Liberal) (Supplemental Table 1, Supplemental Digital Content 1, http://links.lww.com/CCM/B130) (1). Both FACTT Conservative and FACTT Liberal protocols provided instructions for subjects with a mean arterial pressure greater than 60 mm Hg who had not received vasopressors for at least 12 hours. FACTT Conservative targeted a central venous pressure (CVP) of less than 4 mm Hg or a pulmonary artery occlusion pressure (PAOP) of less than 8 mm Hg, whereas FACTT Liberal targeted a CVP of 10–14 mm Hg or PAOP of 14–18 mm Hg. Management with the FACTT Conservative protocol resulted in a significantly lower cumulative fluid balance over 7 days. While there was no difference in 60-day mortality, the FACTT Conservative group had more ventilator-free days and an improved oxygenation index and lung injury score (1). The FACTT Conservative and Liberal protocols are complex. They provide instructions determined by CVP or PAOP, urinary output, and an effective or ineffective circulation (Supplemental Table 1, Supplemental Digital Content 1, http://links.lww.com/CCM/B130). For subjects not in shock, there are a total of 18 different protocol cells with instructions that include dobutamine infusion, fluid bolus, or furosemide administration. There are no protocol-directed instructions for management of shock. Fluid management was an important cointervention in the NIH/NHLBI ARDS Network studies following FACTT (2–4). The ARDS Network investigators developed a simplified conservative fluid protocol, FACTT Lite. FACTT Lite excluded instructions for ineffective circulation because the clinical examination findings of ineffective circulation did not correlate with cardiac index (5), and the instructions in the FACTT Conservative protocol for management of ineffective circulation were rarely encountered. FACTT Lite (Table 1) provides three possible instructions determined by the CVP and urine output: furosemide administration, fluid bolus, or no intervention. Similar to the original FACTT Conservative protocol, FACTT Lite contains instructions to withhold furosemide until the subject has achieved at least 12 hours of a mean arterial pressure greater than 60 mm Hg off vasopressors. Fluid management of subjects in shock was left to the discretion of the clinical team. Although the FACTT Lite protocol has been used in subsequent ARDS Network studies (2–4), its performance has never been formally evaluated. Table 1 Simplified Conservative Fluid Management Protocol (Fluid and Catheter Treatment Trial Lite) We retrospectively compared the performance of FACTT Lite with FACTT Conservative and FACTT Liberal. We hypothesized that the FACTT Lite protocol would be equivalent to FACTT Conservative, and more favorable than FACTT Liberal, with respect to cumulative fluid balance over 7 days, number of ventilator-free days, 60-day mortality, and prevalence of new onset shock and acute kidney injury.