Friday, November 2, 2012

PCA in the ED is Brilliant and Horrible

Management of acute pain in the Emergency Department is frequently inadequate.  Considering the practice environment, the ebb and flow of workload, and the heterogenous presentations, this is not surprising.  On the inpatient side of things, many patients with acute, severe pain receive patient-controlled analgesia.  So, this is a randomized, controlled trial of PCA vs. conventional, untitrated boluses in the ED.

And, they were successful in demonstrating significant trends towards better, faster pain control and increased patient satisfaction with the PCA.  Both groups received the same total amount of morphine, but the dynamics by which patients were able to self-titrate their pain control resulted in improved pain relief.

Unfortunately, there are some flaws with this study.  This multi-center study only managed to enroll 96 patients in a one-year timeframe – probably the number we could aggressively enroll at my institution in a week.  There is no mention of adverse events – which is significant, because PCA medication variances are renowned on the inpatient side as significant sources of morbidity.  And, finally, they don't measure any of the other operational variables that are important – cost, time to set up, etc.

Patient-controlled analgesia may yet have a role in the ED – and studies like this help keep the flame alive – but significant hurdles remain.

"A Randomized Controlled Trial of Patient-Controlled Analgesia Compared with Boluses of Analgesia for the Control of Acute Traumatic Pain in the Emergency Department"

Wednesday, October 31, 2012

Arrhythmogenic Right Ventricular Dysplasia

In young Emergency Department patients with syncope, most of the time, testing is minimal.  Generally, the only universal testing is a pregnancy test and/or an electrocardiogram.

We've gotten pretty good at understanding the "life-threatening" causes of syncope in young adults diagnosed by electrocardiography, including:
 - Wolff-Parkinson-White Syndrome
 - Hypertrophic Obstructive Cardiomyopathy
 - Brugada Syndrome
 - Congenital Long QT

But there's always more, and Arrhythmogenic Right Ventricular Dysplasia is one of those "more" that seems not to be on everyone's lists.  ARVD is a genetically-inherited abnormality in cardiac desmosomes that leads to fibrofatty deposition in the right ventricle.  It is currently estimated to result in ~5% of the sudden cardiac deaths in adults under age 65, secondary to sustained monomorphic ventricular tachycardia.  The characteristic EKG finding to look out for is, unfortunately, quite subtle – the "epsilon wave".  These waves are most prominent in V1-V3, and manifest as sharp upward deflections from baseline at the conclusion of the QRS complex.

Very few Emergency Department presentations mix the high-risk needle-in-the-haystack with the low-risk like young adults with syncope, so it's important to stay alert for these rare ECG findings.

"Impact of new electrocardiographic criteria in arrhythmogenic cardiomyopathy"

Monday, October 29, 2012

Still Overpromising Benefit of PCI After Cardiac Arrest

The folks in France have been promoting PCI universally after cardiac arrest for quite some time.  It's an appealing concept – when you look at subgroups of out-of-hospital cardiac arrest, there's a significant portion of folks who clearly have a primary cardiac cause, and clearly will benefit from emergency or early PCI.

However, this study inappropriately tries to make the case for all patients to receive PCI and therapeutic hypothermia after out-of-hospital cardiac arrest.  This is a retrospective, cohort study spanning eight years of resuscitation, coordinated between Paris, France and Seattle, Washington.  They used vital records follow-up to determine patient status for each OHCA patient surviving to hospital discharge, and then looked for associations between survival and whether they received PCI or hypothermia in-house.  The most absurd statement is as follows:
"A beneficial survival association was evident among those with and without ST-elevation MI. This finding is provocative given the current debate about whether patients without evidence of ST elevation following resuscitation can benefit from PCI and should undergo early and routine coronary catheterization."
Retrospective studies such as this suffer from substantial selection bias, in which the patients who are selected for particular therapies have interactions and confounders that simply cannot be controlled or adjusted.  Patients benefit from PCI when they have a disease process amenable to intervention – and this is clearly not every cardiac arrest patient. The patients in this study who received PCI – and hypothermia – likely had specific features that identified them to treating physicians as candidates to benefit from these therapies.

The reasonable conclusion from the data presented is exactly that – cardiac arrest patients that have specific features that make them candidate for these therapies will benefit.  PCI following cardiac arrest should not be considered to be "routine".

"Long-Term Prognosis Following Resuscitation From Out of Hospital Cardiac Arrest - Role of Percutaneous Coronary Intervention and Therapeutic Hypothermia"