Saturday, September 3, 2011

When Does a Repeat Head CT Have Value?

Not practice-changing, but an interesting observational report regarding when these authors found value in performing a repeat head CT after minor head trauma.

Specifically, they looked at a subgroup of patients whose initial head CT was normal after blunt trauma, but received a repeat head CT an average of ~8 hours later for an abnormal neurologic examination.  These abnormal neurologic examinations were further stratified into three groups - a "persistently abnormal" exam, a "acute deterioration" in neurologic examination, and a catchall "unknown" group.  The first two groups had mean GCS of 12.4 and 14.5 - but the reason why the "unknown" group is what it is - their average GCS is 4.

They found that repeating the head CT in the 61 patients they had with persistently abnormal neurologic examinations did lead to some worsening of the initial findings - but did not change management in any cases.  However, 6 of the 21 patients who had an acute deterioration had a change in management, as well as 1 patient in the unknown group.

Small sample, but interesting, nonetheless.

"Utility of Repeat Head Computed Tomography in Patients With an Abnormal Neurologic Examination After Minimal Head Injury."
www.ncbi.nlm.nih.gov/pubmed/21857258

Thursday, September 1, 2011

When Is Blunt Chest Trauma Low-Risk?

According to this study, always - but rarely.

This is a prospective 3-center trauma study attempting to discern clinical variables that predicted the absence of serious traumatic chest injury in the setting of blunt trauma.  2,628 subjects enrolled, with 271 of them diagnosed with a serious injury - pneumothorax, hemothorax, great vessel injury, multiple rib fractures, sternal fracture, pulmonary contusion, and diaphragmatic rupture.  They do a recursive partitioning analysis and identify a combination of seven clinical findings that had a 99.3% (97.4 - 99.8) sensitivity for serious traumatic injuries.

But, I might be missing the point of this instrument a little bit.  Only 10% of their cohort had a traumatic injury - yet out of the remaining 90% without serious traumatic injury, their rule could only carve out 14% as low risk.  These low risk patients, the authors then propose, obviates any chest imaging at all.  While I am all for reducing unnecessary testing, this seems like an awfully low yield decision rule.  Yes, this study identifies young patients who are perfectly fine after a low-risk blunt trauma and do not need even an x-ray - but I'd really rather see more work preventing some of the 584 chest CTs performed in this cohort.  Additionally, their criterion standard for negative imaging is inadequate - most received CXR alone and there's no follow-up protocol to test for possible missed injuries, whether clinically significant or not.

Considering the criteria they identified, it seems they could almost get equal or greater reduction in imaging if the clinicians were simply a little more thoughtful with respect to knee-jerk imaging in trauma.

"Derivation of a Decision Instrument for Selective Chest Radiography in Blunt Trauma."
www.ncbi.nlm.nih.gov/pubmed/21045745

Wednesday, August 31, 2011

iPhone Medical Apps To The Rescue

In this study, the author and creator of "PICU Calculator" for iPhone details the superiority of a medical student with a smartphone over an attending using the pharmacy reference book.  A few entertaining tidbits from their main results:
 - Medical students don't know how a book functions - failed to correctly complete any pediatric dosing task using the British National Formulary for Children.
 - Residents and attendings managed to make the book work for them about half the time.
 - Overall across all levels of training, 35 for 35 in correct dosage and volume using the iPhone app - with a mean time savings of over 5 minutes.

So, when the author of an iPhone app choses a clinical task his app is designed to replace, it works great!  But, the larger point - as we already knew - there is a role for well-designed point-of-care electronic tools, so we shouldn't give up on our CPOE and EHR kludge so soon.

"Students prescribing emergency drug infusions utilising smartphones outperform consultants using BNFCs."
www.ncbi.nlm.nih.gov/pubmed/21787737

Monday, August 29, 2011

Who Are The Readmitted?

Now, where I trained, we were the only useful facility for hundreds of miles - so we actually had a a lot of continuity of care in the Emergency Department.  And nothing beat the continuity we saw when a patient who was discharged in the morning was back in our Emergency Department by evening - and the inevitable question of "how did they screw this up?"

This is a retrospective look at the readmissions from 11 teaching and community hospitals trying describe the readmissions as avoidable vs. unavoidable, characterize the cause for readmission, and see if there were any baseline characteristics that might predict readmission.  They found avoidable readmissions were in the minority, and there was no useful predictive clinical information regarding baseline differences between the readmitted group and the overall cohort - comorbidities, length of stay, new medications, etc.  When patients were avoidably readmitted, however, several recurring factors were noted:
 - Management error (48% of the time)
 - Surgical complications (38.5%)
 - Medication-related event (32.7%)
 - Nosocomial infection (18.3%)
 - System error (15.4%)
 - Diagnostic error (10.6%).

Considering CMS is looking closely at decreasing payments to physicians and hospitals for readmissions, this study provides a small amount of systematic insight into some of the things we've all observed anecdotally.

"Incidence of potentially avoidable urgent readmissions and their relation to all-cause urgent readmissions."
www.cmaj.ca/content/early/2011/08/22/cmaj.110400

Sunday, August 28, 2011

Good Thought, But It's Not Pertussis

A Swiss study in which only 2.5% percent of 1,049 pediatric ambulatory and hospitalized patients presenting with a cough-illness and who were tests for pertussis were culture positive for B. pertussis or parapertussis.  Probably a relatively accurate picture of the general prevalance of pertussis in a non-outbreak situation.  They additionally report that viral superinfection is rare enough to be coincidental - 0.6% - although the authors do note other studies have reported higher incidence, particularly in RSV+ hospitalized children <6 months of age.

So, this data is out the window if there's an outbreak situation, but the overall clinical take home is that, yet again, our index of suspicion may be too high for an infrequently diagnosed condition - and we should moderate testing in the lower acuity cases.

"Bordetella pertussis and Concomitant Viral Respiratory Tract Infections are Rare in Children With Cough Illness."
www.ncbi.nlm.nih.gov/pubmed/21407144