Volume Management in ALI/ARDS in Dialysis Patients

There is often the discussion of proper volume management in patients with ALI (acute lung injury) or ARDS (acute respiratory distress syndrome). We are often called when the patients develop worsening renal function for whatever reason or issues with volume management, so I thought it best to breifly review both ALI/ARDS and volume management in respect to patients with renal failure.

ALI and ARDS are clinical syndromes characterized by the acute onset (less than 7 d) of severe hypoxemia and bilateral pulmonary infiltrates in the absence of clinical evidence for leftatrial hypertension. The severity of the hypoxemia differentiates ALI from ARDS. The American/European Consensus Conference defined patients with ALI as those who have a ratio of partial pressure of oxygen in arterial blood (Pa 02) to the inspired fraction of oxygen (FiO2) of less than 300 and patients with ARDS as those with a Pa02/FiO2) of less than 200.

So there are several studies that support keeping this patients relatively dry, specifically this study Comparison of Fluid Management Strategies from ARDS Network which supports keeping the CVP as low as possible. This study first off found no mortality difference in a conservative (CVP < 8mmHg or PAOP < 4mmHg) vs liberal strategy (CVP of 10-14 mmHg or PAOP 14-18 mmHg) at 60 days, but the conservative arm had more ventilator-free days in the first 30 days (p value <0.001) and more ICU-free days (p value <0.001). Also there was no difference in percentage of patients on dialysis at day 60, meaning that surprisingly there wasn’t any significant (non-pulmonary) organ failure from hypoperfusion from the conservative approach.

From this study we can take the following points:

• Invasive monitoring of hemodynamics with CVP maybe helpful early in these patients
• Aim for lower CVP/PAOP with volume removal with furosemide
• Dialysis when necessary for renal failure or when patients remain hypoxemic and resistant to diuretics

Diuretic use should be initiated prior to ultrafiltration, and diuretics should be optimized first with a regimen similar to that of the DOSE trial.

Now to the question of albumin and loop diuretics. Here is a good study that actually supports giving colloids and diuretics concurrently in patietnts with ALI: Albumin and Furosemide in hypoproteinemic patients with ALI. For those that might need a refresher in ALI here is a great Review of ALI for Nephrologist by Kathleen Liu.