Month: March 2015

Flights of the Minimally Injured

Helicopter transport of trauma patients is a controversial topic.  Most agree there is a cohort of severely and specifically injured patients who receive important benefits from HEMS versus ground transportation.  However, it is reasonably suggested from registry studies those patients are rather few.  And, if only a subset of seriously injured patients benefit from HEMS, then, certainly the minimally injured patient does not.

But, unfortunately, flights of the minimally injured are hardly infrequent.

This is a retrospective review of all trauma transports at a single academic center in Arizona.  “Minimally injured” was defined as an ISS of 5 or lower, and who did not require intensive care or operative intervention.  Over the six years of the study period, this center received 3,992 ground transports, 39% of which were minimally injured.  They also received 981 HEMS arrivals – 27% of which were minimally injured.

Or, approximately $4.8 million burned for no benefit on just pre-hospital transportation by helicopter.

The authors’ title says it all:

“Overuse of helicopter transport in the minimally injured: A health care system problem that should be corrected”
http://www.ncbi.nlm.nih.gov/pubmed/25710420

Hi Ur Pt Has AKI For Totes

Do you enjoy receiving pop-up alerts from your electronic health record?  Have you instinctively memorized the fastest series of clicks to “Ignore”?  “Not Clinically Significant”?  “Benefit Outweighs Risk”?  “Not Sepsis”?

How would you like your EHR to call you at home with more of the same?

Acute kidney injury, to be certain, is associated with poorer outcomes in the hospital – mortality, dialysis-dependence, and other morbidities.  Therefore, it makes sense – if an automated monitoring system can easily detect changes and trends, why not alert clinicians to such changes, and nephrotoxic therapies could be avoided.

Interestingly – for both good and bad – the outcomes measured were patient-oriented, randomizing 2393 patients to either “usual care” or text message alerts for changes in serum creatinine.  The goal, overall, was detection of reductions in death, dialysis, or progressive AKI.  While patient-oriented outcomes are, after all, the most important outcomes in medicine – it’s only plausible to improve outcomes if clinicians improve care.  Therefore, measuring the most direct consequence of the intervention might be a better outcome – renal-protective changes in clinician behavior.

Because, unfortunately, despite sending text messages and e-mails directly to responsible clinicians and pharmacists – the only notable change in behavior between the “alert” group and “usual care group” was increased monitoring of serum creatinine.  Chart documentation of AKI, avoidance of intravenous contrast, avoidance of NSAIDs, and other renal-protective behaviors were unchanged, excepting a non-significant trend towards decreased aminoglycoside use.

No change in behavior, no change in outcomes.  Text messages and e-mails alerts!  Can shock collars be far behind?

“Automated, electronic alerts for acute kidney injury: a single-blind, parallel-group, randomised controlled trial”
http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(15)60266-5/fulltext

Using CTA to Predict tPA Failures

tPA, the “proven” therapy foisted inappropriately on Emergency Medicine and our patients, doesn’t work.

Rather – as I’ve said before – it simply doesn’t work the way we’ve been taught.

The core concepts of the theoretical utility of tPA for ischemic stroke are demonstrated nicely in the new endovascular trials.  Patients do well, better than the natural course of their disease if:

  • There is significant viable brain distal to the vascular occlusion as a result of collateral circulation.
  • The vessel is rapidly and reliably opened.

Both these criteria were met in the new endovascular trials, requiring imaging evidence of a small infarct core and use of modern retrieval devices.  However, the broad population being pushed as candidates for tPA are not as fortunate – the key feature being the abysmal recanalization rate of tPA, only 46% in a meta-analysis of tiny case series from mostly the ‘90s.  Comparatively, in the same report, early spontaneous recanalization was present in 24%.  So, obviously, there’s only even a 1 in 5 chance a patient will receive an additive benefit from tPA for recanalization – which, with some heterogeneity, means our NNT has a maximum upper bound if we treat an unselected population of all-comers.

This study is a small case series from the ongoing PRove-IT study, looking specifically at, essentially, the permeability of intracranial thrombi.  These authors hypothesized this might be an important predictor of recanalization because, after all, if there’s no flow through an impermeable occlusion, tPA can never fully contact the substrate of interest.  These authors used CT angiography to estimate occult anterograde flow versus retrograde flow, and followed-up recanalization following tPA.

There are only 66 patients in this small observational study, but the results are rather compelling.  They estimated 17 (25.8%) of patients had some minimal anterograde flow through the occluded vessel.  These patients, with some detectable flow, had a 66.7% recanalization rate.  Conversely, the 49 patients without any residual anterograde flow had a recanalization rate of only 29.7% – a rate not dissimilar to spontaneous.  And, outcomes followed recanalization – logically, considering detectable anterograde flow and effective destruction of the occlusion are highly favorable features.

The moral of the story?  It’s quite clear there are promising venues for determining which patients have the best chance to benefit from tPA – and those for whom the harms exceed those chances.  The perpetual “tPA for all!” call being added to guidelines and quality measures is a product of conflict-of-interest and corporate sponsorship, not good medicine – and we can do better, if we simply cared to investigate.

“Occult Anterograde Flow Is an Under-Recognized But Crucial Predictor of Early Recanalization With Intravenous Tissue-Type Plasminogen Activator”
http://www.ncbi.nlm.nih.gov/pubmed/25700286