Month: January 2017

Pediatric Lactate & Sepsis

Some syndicated media has “Shark Week”. We have Sepsis Week!

The current generation of sepsis care is defined not just by our quixotic quest for simplified early warning tools, but also, more than anything, by lactate levels. In someways, lactate is our friend – no more central catheter placement solely for measurement of central venous oxygenation. However, the ease of use of checking a lactate level also means we apply it indiscriminately. The lactate has become the D-dimer of infection – increasingly weakly predictive, the more we rely upon it.

This is a snapshot of the performance of lactate levels in pediatric sepsis. This is an observational registry of patients evaluated in the Emergency Department of a pediatric hospital, consisting of 1,299 patients in whom clinically suspected sepsis resulted in a lactate order. These authors hypothesized that, as in adults, a lactate level of 36mg/dL (4mmol/L) would portend increased mortality.

And, naturally, they were correct. However, its predictive value was virtually nil. There were 103 patients with lactate elevated above their cut-off and 1,196 below. Only 5 of the 103 patients elevated lactate suffered 30-day mortality. Then, of the 1,196 below the cut-off, 20 suffered 30-day mortality. A mortality of 4.8% is higher than 1.7%, but the sensitivity is only 20% – and the specificity of 92.3% with such a low prevalence of the primary outcome means over 95% of elevated lactate levels are “false positives”.

There are some limitations here, however, that could have a substantial effects on the outcomes. There is a selection bias inherent to eligibility in which lactates were likely ordered only on the most ill-appearing patients. The effect of this would be to improve the apparent performance characteristics of the test in the study population. However, then, it is likely the patients with elevated lactate levels received more aggressive treatment than if the treating clinicians were blinded to the result. The effect of this would be a mortality benefit in the population with elevated lactate, worsening the apparent test characteristics.

But, hairs split aside, these pediatric results are grossly similar to those in adults. An elevated lactate is a warning signal, but should hardly be relied upon.

“Association Between Early Lactate Levels and 30-Day Mortality in Clinically Suspected Sepsis in Children”
https://www.ncbi.nlm.nih.gov/pubmed/28068437

A qSOFA Trifecta

There’s a new sepsis in town – although, by “new” it’s not very anymore. We’re supposedly all-in on Sepsis-3, which in theory is superior to the old sepsis.

One of the most prominent and controversial aspects of the sepsis reimagining is the discarding of the flawed Systemic Inflammatory Response Syndrome criteria and its replacement with the Quick Sequential Organ Failure Assessment. In theory, qSOFA replaces the non-specific items from SIRS with physiologic variables more closely related to organ failure. However, qSOFA was never prospectively validated or compared prior to its introduction.

These three articles give us a little more insight – and, as many have voiced concern already, it appears we’ve just replaced one flawed agent with another.

The first article, from JAMA, describes the performance of qSOFA against SIRS and a 2-point increase in the full SOFA score in an ICU population. This retrospective analysis of 184,875 patients across 15 years of registry data from 182 ICUs in Australia and New Zealand showed very little difference between SIRS and qSOFA with regard to predicting in-hospital mortality. Both screening tools were also far inferior to the full SOFA score – although, in practical terms, the differences in adjusted AUC were only between ~0.69 for SIRS and qSOFA and 0.76 for SOFA. As prognostic tools, then, none of these are fantastic – and, unfortunately, qSOFA did not seem to offer any value over SIRS.

The second article, also from JAMA, is some of the first prospective data regarding qSOFA in the Emergency Department. This sample is 879 patients with suspected infection, followed for in-hospital mortality or ICU admission. The big news from this article is the AUC for qSOFA of 0.80 compared with the 0.65 for SIRS or “severe sepsis”, as defined by SIRS plus a lactate greater than 2mmol/L. However, at a cut-off of 2 or more for qSOFA, the advertised cut-off for “high risk”, the sensitivity and specificity were 70% and 79% respectively.

Finally, a third article, from Annals of Emergency Medicine, also evaluates the performance characteristics of qSOFA in an Emergency Department population. This retrospective evaluation describes the performance of qSOFA at predicting admission and mortality, but differs from the JAMA article by applying qSOFA to a cross-section of mostly high-acuity visits, both with and without suspected infection. Based on a sample of 22,350 ED visits, they found similar sensitivity and specificity of a qSOFA score of 2 or greater for predicting mortality, 71% and 74%, respectively. Performance was not meaningfully different between those with and without infection.

It seems pretty clear, then, this score doesn’t hold a lot of value. SIRS, obviously, has its well-documented flaws. qSOFA seems to have better discriminatory value with regards to the AUC, but its performance at the cut-off level of 2 puts it right in a no-man’s land of clinical utility. It is not sensitive enough to rely upon to capture all patients at high-risk for deterioration – but, then, its specificity is also poor enough using it to screen the general ED population will still result in a flood of false positives.

So, unfortunately, these criteria are probably a failed paradigm perpetuating all the same administrative headaches as the previous approach to sepsis – better than SIRS, but still not good enough. We should be pursuing more robust decision-support built-in to the EHR, not attempting to reinvent overly-simplified instruments without usable discriminatory value.

“Prognostic Accuracy of the SOFA Score, SIRS Criteria, and qSOFA Score for In-Hospital Mortality Among Adults With Suspected Infection Admitted to the Intensive Care Unit”

http://jamanetwork.com/journals/jama/article-abstract/2598267

“Prognostic Accuracy of Sepsis-3 Criteria for In-Hospital Mortality Among Patients With Suspected Infection Presenting to the Emergency Department”

http://jamanetwork.com/journals/jama/fullarticle/2598268

“Quick SOFA Scores Predict Mortality in Adult Emergency Department Patients With and Without Suspected Infection”

http://www.annemergmed.com/article/S0196-0644(16)31219-7/fulltext

Another Step in Antibiotics for Appendicitis

Antibiotics are unnecessary! No, antibiotics are great! No, we give too many antibiotics! It’s getting hard to keep track of which conditions we’re giving and withholding antibiotics for these days.

This article is a teaser for more evidence to come regarding strategies for managing appendicitis without surgical intervention. We’ve seen a few trials already, with essentially unconvincing results in either direction. A large trial regarding an antibiotics-first strategy in an adult population was criticized for using open surgical technique rather than laproscopic – and the one-year failure rate was still rather high. However, a pilot report in a pediatric population probably demonstrates an antibiotic-first strategy is still a reasonable option to present in shared decision-making.

This is a pilot project describing the initial results and feasibility outlook for an antibiotics-first protocol for appendicitis. In this protocol, patients randomized to an antibiotics-first strategy received an intravenous dose of ertapenem in the Emergency Department, were eligible for discharge directly from the Emergency Department, returned for a second dose of ertapenem the next day, and then completed an 8-day course of oral cefdinir and metronidazole.

In their pilot, 42 patients were screened and 30 patients consented for randomization. Of these, 15 were adults and 1 was a pediatric patient. Of the 15 adults, 14 felt well enough for discharge after initial Emergency Department observation. The pediatric protocol called for in-hospital observation regardless of symptoms at presentation.

The results are generally of lesser consequence than the effectiveness of this pilot demonstrating the feasibility of the protocol, and the yield at which patients could be enrolled for a larger trial. There were a couple instances of recurrent appendicitis in the antibiotics-first cohort, one of which was successfully treated with antibiotics a second time. There were a couple surgical complications in the surgery cohort. Costs and overall quality of life scores favored the antibiotics-only group, obviously – but, again, this sample is small enough none of these outcomes have been measured with reliable accuracy or precision.

I think it is reasonable to expect an antibiotics-first strategy to eventually take root as part of acceptable medical practice. However, I suspect this transition will be slow in coming – and more data would be quite helpful in determining any specific risks for antibiotic strategy failures.

“Antibiotics-First Versus Surgery for Appendicitis: A US Pilot Randomized Controlled Trial Allowing Outpatient Antibiotic Management”

https://www.ncbi.nlm.nih.gov/pubmed/27974169

Shenfu!

I will readily admit I am stepping outside the bounds of my expertise with this post – with respect to the “shenfu injection” and its effects on physiology. The authors describe shenfu as “originated from Shenfu decoction, a well-known traditional Chinese formulation restoring ‘Yang’ from collapse, tonifying ‘Qi’ for relieving desertion”. More specifically, from a physiologic standpoint: “Ginsenosides and aconite alkaloids are the main active ingredients in Shenfu. Ginsenosides are the determinant contributor to the vasodilator benefit of Shenfu, whereas the alkaloids play a vital role in the cardiac electrophysiological effect of Shenfu by blocking ion channels”. In China, a pharmacologic shenfu distillate is used routinely to treat sepsis and septic shock as a 100mL daily injection – and this is a placebo-controlled trial endeavoring to demonstrate its efficacy.

At face value, the trial appears reasonable – a targeted enrollment of 160 patients with a goal of detecting a 20% difference in mortality at 28-days, based on an expected overall mortality of 40%. Their primary outcome, however, were the co-primary outcomes of “length of ICU stay, the duration of vasopressor use, illness severity, and the degree of organ dysfunction.” A proper study, of course, has a single primary outcome – and, considering the study was powered for a mortality difference, this patient-oriented outcome probably ought to have been made primary.

Regardless, from the results presented here, it is reasonable to suggest this is promising and worthy of additional evaluation. Several outcomes – ICU LOS, APACHE II score, and duration of vasopressor us – reached statistical significance favoring the intervention. The mortality outcome did not meet statistical significance with the intervention at 20.5% and the placebo at 27.8%. However, an absolute mortality improvement of 7.3% is nothing to sneeze at – and I would be happy to see more work performed to replicate or generalize these results.

“Shenfu injection for improving cellular immunity and clinical outcome in patients with sepsis or septic shock”

https://www.ncbi.nlm.nih.gov/pubmed/28029485

More CLEAR!

Ah, the CLEAR trial – a trial evaluating the efficacy of intraventricular injections of alteplase for intracerebral hemorrhage with acute obstructive hydrocephalus. In other words, treating brain bleeds with an agent responsible for brain bleeds. It is not quite as nonsensical as it seems, however, as improved resolution of the intraventricular blood is linked to improved outcomes.

This trial, however, performed over the course of six years and enrolling 500 patients, fails to find anything reliable in favor of alteplase – a rather inconsequential end to a decade’s worth of build-up from the initial and phase II trial. At the end of the day, there was no significant difference between either treatment with regard to the primary outcome, patients attaining a mRS of 0-3.

It should also be noted the preliminary results from this trial were presented last year at the International Stroke Conference with breathless coverage:
“CLEAR III: tPA Clot Removal Hope for Intraventricular Hemorrhage”

Along with the lead author stating “This treatment saves lives. Our results suggest that physicians should begin to think about using it for stable hemorrhagic stroke patients.”

Which, now that we can all review the results together, is obviously not the case – nor is it their conclusion in the published article. These results do raise some questions – mortality was lower in the intervention group, and patients with improve clot evacuation also tended to do better – regarding potential subgroups for benefit. However, without further prospective data to confirm these signals, this intervention should continue to be reserved for controlled trials.

“Thrombolytic removal of intraventricular haemorrhage in treatment of severe stroke: results of the randomised, multicentre, multiregion, placebo-controlled CLEAR III trial”
https://www.ncbi.nlm.nih.gov/pubmed/28081952

Some Old News About Thrombolysis Before Endovascular Therapy

We’ve spent a little bit of energy on this blog teasing out the appropriate indications for endovascular therapy, and and we’ve used a few of those words to discuss whether thrombolysis prior to is necessary. I am of the opinion: probably not.

It turns out, there are many other prominent neurologists who share that same opinion. Unfortunately, this article is just a rehash of prior data without any new specific insight. Of course, the lay medical press does their typical job of creating definitive, misleading headlines:
“Stroke: No Benefit from Adding tPA to Thrombectomy”
“No Benefit for IV tPA Before Mechanical Thrombectomy in Ischemic Stroke”

This is a small post-hoc analysis of the 291 patients undergoing treatment in the SWIFT and STAR trials. Of these, 131 did not receive thrombolysis prior to intervention, with the most common exclusion being either presence of an elevated INR and oral anticoagulation or symptom onset being >4 hours prior to hospital arrival. Other, less common exclusions included blood pressure exclusions, hypoglycemia, and prior strokes. Some patients also received bridging tPA or reduced-dose tPA, as determined appropriate by the interventionalist.

In such a small analysis such as this, little reliable can be made of the results – except to generally say there was no obvious signal confirming nor refuting the appropriateness of thrombolysis prior to intervention. Hemorrhagic complications were similar between groups, as were patient-oriented outcomes. At the least, they offer the appropriate weak conclusion supported by these data: prospective trials are reasonable.

“Combined Intravenous Thrombolysis and Thrombectomy vs Thrombectomy Alone for Acute Ischemic Stroke: A Pooled Analysis of the SWIFT and STAR Studies”
http://jamanetwork.com/journals/jamaneurology/article-abstract/2596239

Does FEIBA Work for NOACs?

“Maybe”?

The novel oral anticoagulants – dabigatran, rivaroxaban, apixaban, edoxaban – have spread in use quite rapidly. There is weak evidence supporting the use of idarucizumab for emergency reversal of dabigatran, and even weaker evidence regarding the use of adenxanet alfa. Prothrombin concentrate complexes seem to be efficacious for the Factor Xa inhibitors – but what about factor eight inhibitor bypassing agent?

This small case series from Pittsburgh addresses this question in the least helpful fashion: 11 patients and no comparison group. These 11 patients, most of whom were on rivaroxaban, received 20mg/kg of FEIBA for emergency reversal of anticoagulation in the setting of traumatic intracranial hemorrhage. The authors report 6 of these 11 had stable ICH on repeat CT following initial diagnosis, and, therefore, FEIBA is a potentially safe reversal option.

Of course, the full accounting requires us to mention the remainder of patients had radiographic progression of their injuries despite FEIBA. Most injuries were minor and not expected to have elevated 30-day mortality – and, unsurprisingly then, most survived. In the patients demonstrating substantial derangement of laboratory measures of coagulation, most showed profound improvement of the PT following FEIBA administration. Two patients also suffered subsequent thromboembolic events.

So, yes, FEIBA may be a treatment option for the Factor Xa inhibitors – but this hardly supports routine use outside a study setting as these authors seem to be doing.

“Factor Eight Inhibitor Bypassing Agent (FEIBA) for Reversal of Target-Specific Oral Anticoagulants in Life-Threatening Intracranial Bleeding”

https://www.ncbi.nlm.nih.gov/pubmed/28007364

Insight Is Insufficient

In this depressing trial, we witness a disheartening truth – physicians won’t necessarily do better, even if they know they’re not doing well.

This study tested a mixed educational and peer comparison intervention on primary care physicians in Switzerland, with an end goal of improving antibiotic stewardship for common ambulatory complaints. The “worst-performing” 2,900 physicians with respect to antibiotic prescribing rates were enrolled and randomized to the study intervention or none. The study intervention consisted of materials regarding appropriate prescribing, along with personalized feedback regarding where their prescribing rate ranked compared to the entire national cohort. The core of their hypothesis involved whether just this passive knowledge regarding their peer performance would exert normalizing influence over their practice.

Unfortunately, despite providing these physicians with this insight, as well as tools for improvement, the net effect of their intervention was effectively zero. There were some observations regarding changes in prescribing rates for certain age groups, and for certain types of antibiotics, but dredging through these secondary outcomes leads to only unreliable conclusions.

This is not particularly surprising data. These sorts of passive feedback mechanisms unhitched from material consequences have never previously been shown to be effective. There are other, more effective mechanisms – focused education, decision-support interventions, and shared decision-making – but, for a fragmented, national health system, this represented a relatively inexpensive model to test.

Try again!

“Personalized Prescription Feedback Using Routinely Collected Data to Reduce Antibiotic Use in Primary Care”

https://www.ncbi.nlm.nih.gov/pubmed/28027333

No Mandate for Hyperbaric Therapy in CO Poisoning

The new year – actually, the end of the old year – brings us a new update on the management of carbon monoxide poisoning, as distilled into an ACEP Clinical Policy statement. There are three elements to their update, addressing specific management questions in the context of carbon monoxide toxicity:

  • Don’t rely exclusively on non-invasive means for CO measurement.
  • Hyperbaric oxygen therapy is neither proven nor disproven of benefit.
  • Cardiac testing provides useful prognostic information.

The most impactful recommendation of the three is the one for HBO therapy, which is either dismissed out-of-hand or pursued with such zealotry that eligible patients are airlifted to far-flung dive chambers for treatment. In theory, HBO therapy helps reduce the delayed neuropathology and cognitive burden related to lipid peroxidation and other toxic metabolites. However, these authors appropriately synthesize the low-quality evidence into a conclusion that HBO therapy has no proven advantage to high-flow oxygen.

As with any therapy for which the evidence is poor, there are proponents on both sides and substantial practice variation. This Clinical Policy does not state HBO is inappropriate or not beneficial for carbon monoxide poisoning, merely the evidence is inconclusive. Sometimes, when the evidence is insufficient to provide an answer, the magnitude of benefit is small or clinically unimportant. In this case, I’m not even sure such a conclusion regarding the scope of benefit can be made – the foundational evidence is simply too unreliable to make any practice-influencing recommendations.

“Clinical Policy: Critical Issues in the Evaluation and Management of Adult Patients Presenting to the Emergency Department With Acute Carbon Monoxide Poisoning”
https://www.ncbi.nlm.nih.gov/pubmed/27993310