Friday, November 30, 2012

Dabigatran: Hidden Danger in the Home

The flaws with dabigatran have been well-described on this blog – mostly focusing on its lack of realistic reversal options.  However, less obvious are the unanticipated ways patients end up in situations requiring such reversal.

This case report from the Rocky Mountain Poison Center describes an elderly male on dabigatran who does something commonly seen in the elderly: he suffers acute renal failure from a minor medical illness.  Unlike warfarin, dabigatran is renally excreted, and should not be used by patients with reduced glomerular filtration rates – these patients were excluded from the Phase III trials.  In the presence of renal failure, the half-life increases from 12-17 hours to 18-27 hours, depending on the severity of the renal dysfunction.  This leads to supratherapeutic levels.

This patient was noted to have a dabigatran plasma concentration nearly triple the therapeutic mean and developed spontaneous, unremitting gastrointestinal hemorrhage.  Despite resuscitation, blood products, and emergency dialysis – which halved the dabigatran concentration within four hours – the patient expired. 

Clinicians using dabigatran, therefore, need be acutely aware of any clinical changes in their patients that may reduce renal function.

"Fatal dabigatran toxicity secondary to acute renal failure" 
www.ncbi.nlm.nih.gov/pubmed/23158612

Wednesday, November 28, 2012

Make Ketamine Work For You

Along with droperidol and dexamethasone, ketamine is on my short list of favorite medications for use in the Emergency Department.  As this correspondence from authors at Highland Hospital summarizes, it's a floor wax and a dessert topping:
 - Use as peri-procedural pain control/anxiolytic to assist with subcutaneous infiltrative local anesthesia.
 - Use as adjunctive pain control in patients who are failing high-dose narcotics.
 - Use as pain control/anxiolytic in patients with significant supratentorial comorbidities.

These authors state "In clinical practice, chronic pain, psychologic distress, and behavioral disorders frequently overlap", and I couldn't agree more.  Sub-disassociative doses of ketamine (0.1 to 0.3 mg/kg) have an excellent safety profile and represent an ideal option for multiple common clinical situations in the ED.

If your ED restricts the use of ketamine, you need to make that stop.

"Emerging applications of low-dose ketamine for pain management in the ED"
www.ncbi.nlm.nih.gov/pubmed/23159425

Monday, November 26, 2012

Ultrasound – For Long Bone Fracture

I have to say, I'm a little confused by all the new SonoSite television ads – direct-to-consumer marketing for sports medicine ultrasonography?  Or for zero-complication central line placement?  Weird.

But, I digress.  A little.  This is a pediatric study of lightly trained ultrasonographers with varying levels of expertise using ultrasound to diagnose long-bone fractures.  They performed 98 ultrasound examinations that were followed up by plain radiography, and they picked up 41 of the 43 fractures present, with 8 false positives:  95% sensitivity and 85% specificity.  Six required reduction, all of which were identified as meeting criteria for reduction on ultrasound – as well as one additional false positive from a distal radius fracture.


As a feasibility study, it's a nice little pilot.  As a practice-changing strategy, it needs larger sample sizes and external validity.  However, it does seem as though it will soon become reasonable to use bedside ultrasound to quickly rule-out fracture in patients with a low pre-test probability, while plain radiography will continue to play a role in advanced orthopedics management.


"Emergency Ultrasound in the Detection of Pediatric Long-Bone Fractures"
www.ncbi.nlm.nih.gov/pubmed/23114237