Thursday, May 19, 2011

Fluid resuscitation in septic shock

The title of a recent paper in Critical Care Medicine is deceptive: Fluid resuscitation in septic shock: A positive fluid balance and elevated central venous pressure are associated with increased mortality. It would seem to run contrary to what we know about treating septic shock, from both clinical and animal data. But the study's actual findings were not so simple. Keep in mind that this was not an intervention trial. From the results:

After correcting for age and Acute Physiology and Chronic Health Evaluation II score, a more positive fluid balance at both at 12 hrs and day 4 correlated significantly with increased mortality...
At 12 hrs, patients with central venous pressure less than 8 mm Hg had the lowest mortality rate followed by those with central venous pressure 8–12 mm Hg. The highest mortality rate was observed in those with central venous pressure greater than 12 mm Hg.

The CVP target for early goal directed therapy (EGDT) is 8. Does this study refute EGDT? No. This study looked at CVP and fluid balance from 12 hours into presentation to 4 days. Early goal directed therapy (emphasis on the word early) is an intervention for the first 6 hours. The original EGDT trial was premised on knowledge from studies decades ago showing that when goal directed hemodynamic resuscitation commenced relatively late in the course of septic shock, after the patient had arrived in the ICU and had a right heart cath inserted, outcomes were not improved or made worse. The whole idea was to find out the results of hemodynamic resuscitation in the first 6 hours, in the ER. That's not what this study looked at.

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