Lactate – Is There Any Death It Doesn’t Predict?

Turns out – apparently, no!

Continuing the run on pulmonary embolism articles, we find that – in addition to all the things we know prognosticates increased mortality in PE patients – elevated plasma lactate levels also predict poor outcomes.  This is generally unsurprising, because elevated lactate levels are associated with increased mortality, even in unselected ED patients.  What is interesting, however, is that lactate levels >2 mmol/L were more associated with 30-day mortality than shock/hypotension, hypoxia, or right-ventricular dysfunction.  It’s a small cohort, but it’s a reasonable finding, regardless.

However, what’s sort of odd regarding the Editor’s Summary for this article is that it specifically mentions the lactate level does not outperform a simplified pulmonary embolism severity index clinical tool.  The “truth” is that an AUC of 0.84 is better than an AUC of 0.71 – but that (0.72 to 0.95) and (0.60 to 0.83) overlap.  Rather than trash the lactic acid level compared with the PESI, it might have been more accurate to simply state the current study was underpowered to confirm the advantage of lactic acid over PESI, and further research is necessary.

Can you buy stock in lactate level assays?  It’s clearly the new favorite all-purposes prognostication tool.