The most appropriate next step in treatment is to discontinue intravenous maintenance fluids and perhaps start a trial of diuretics. This patient is well past the window (within the first several hours after diagnosis) in which early aggressive fluid resuscitation is known to be beneficial in septic shock. Although individual markers of volume status are imperfect, the combination of a normalized lactic acid level, substantial positive fluid balance, improved blood pressure, and elevated central venous pressure suggest that the patient is euvolemic if not hypervolemic. Additional fluid resuscitation is unlikely to improve kidney function, may make it worse, and could exacerbate this patient's hypoxemia given his acute respiratory distress syndrome and pleural effusions.

Albumin is unlikely to be beneficial and may cause harm in a patient who is in the recovery phase of septic shock and has evidence of intravascular volume overload. Administration of colloids offers no advantage over crystalloids in resuscitating critically ill patients in general; however, sepsis guidelines note that albumin may be advantageous in patients with refractory shock not responding to crystalloids.

Hemodialysis is not clearly indicated at this time. Some concern exists that this patient is developing intravascular volume overload, but reducing intravenous fluids, avoiding nephrotoxins, and perhaps starting a trial of diuretics would be appropriate first steps. This patient does not have other indications for dialysis such as hyperkalemia, uremia, or severe acidosis. His declining kidney function is likely from the residual effect of acute tubular necrosis and may improve in the next few days now that his septic shock is resolving.

Studies of stress-dose glucocorticoids have not consistently shown benefit in patients with septic shock. Their use is generally reserved for patients with persistent shock despite fluid resuscitation and vasopressor support.