Archive | December, 2012

weather dependent nasal erythema in reindeer

24 Dec

I love the fact that this review article exists:

Towards evidence based emergency medicine: best BETs from the Manchester Royal Infirmary. Weather dependent nasal erythema in reindeer (Rangifer tarandus).  Teece S, Foëx BA. Emerg Med J. 2007 Dec;24(12):848-50.

 

HIGHLIGHTS:

“There appears to be no evidence for a specific disease state in reindeer, therefore nasal erythema may be due to increased blood flow to the nose”

“The evidence suggests that in winter resting reindeer will not have a red nose, but that when frantically circumnavigating the globe their noses will glow as they try to lose heat.

A reindeer with a red nose at rest at the North Pole means either deranged temperature regulation, or the use of drugs. Neither of these conditions would inspire confidence for an arduous journey.”

 

Clinical bottom line

“A global positioning system is perhaps a more reliable navigational instrument than a reindeer with a brain at boiling point.”

 

———————-

On hiatus for the holidays, but we’ll kick up again with the new year!

Happy holidays, and happy new year!

 

References: the article; picture

atypical antipsychotic receptors: nice tiny chart

21 Dec

Nice brief chart in November’s EMN (along with an article) in November’s Emergency Medicine News:

CLICK THROUGH TO THE ARTICLE TO SEE THE CHART:

 

10-SECOND TAKEAWAY:

atypical antipsychotics include:

  • olanzapine (zyprexa)
  • quetiapine (seroquel)
  • clozapine (clozaril)
  • aripiprazole (abilify)
  • risperidone (risperidal)
  • ziprasidone (geodon)

 

these tend to have multiple receptor affinities (antagonists of:

 

BOTTOM LINE:

not all antipsychotics hit all these receptors, but in OD, likely to be:

  • tachy(cardic)
  • wacky(CNS effects)

 

  • if there’s alpha-effects, hypotension
  • worst case, as with most tox end-points: seizure/coma/death.

 

References: article; picture

want less post-LP headaches? re-insert the stylet

20 Dec

Best evidence topic report by Deibel et al. basically found one article worth its snuff:

Strupp et al:

  • 600 neurology patients getting LPs (21 gauge needle)
    • 300 to stylet replacement before needle removal
    • 300 not reinserted
  • followed-up for post-LP headache within 7 days
  • 49/300 (16%) post-LP headache when stylet NOT re-inserted
  • 15/300 (5%) when stylet reinserted.
  • Post-lumbar puncture syndrome was also less severe (2.8 v 4.5 scale of 10) if stylet reinserted

 

BOTTOM LINE:

Replacing the stylet before removal of the spinal needle may help decrease the incidence of post-lumbar puncture headaches

 

References: best evidence report; original article; picture

minor face-lift

19 Dec

playing with some different themes. this may change again, but feedback is appreciated.

 

thanks!

random review (i.e. thing i looked up again recently): narcan (drip) dosing

19 Dec
Narcan = naloxone (opoid antagonist) 
 
Onset of action:
  • I.V.: ~2 minutes
  • Endotracheal, I.M., SubQ: 2-5 minutes
  • Inhalation via nebulization: ~5 minutes
  • Intranasal: ~8-13 minutes

Duration:

  • ~30-120 minutes depending on route of administration
  • I.V. has a shorter duration of action than I.M. administration
  • shorter than that of most opioids, repeated doses are usually needed

 

DOSING:

I.V., I.M., SubQ:

  • 0.4-2 mg initial dose
  • can be IV push, but personally, I like drawing up your dose in a 10cc flush, and slow pushing (e.g. 1cc at a time), with the goal of titrating to breathing but NOT wide-awake-in-withdrawal-now-vomiting-and/or-punching-me
  • repeat PRN (probably in ~30-60 min)

Continuous infusion:

  • use two-thirds (2/3) of the initial effective naloxone bolus on an hourly basis (typically 0.25-6.25 mg/hour)
  • one-half (1/2) of the initial bolus dose should be readministered 15 minutes after initiation of infusion
  • adjust infusion rate as needed to assure adequate ventilation and prevent withdrawal symptoms

 

References: uptodate.com, picture

 

Sgarbossa and pacemakers

18 Dec

quick refresher’s HERE and HERE

WHAT’S THE BIG IDEA WITH PACEMAKERS?

–ventricularly paced ECGs are tough to interpret for MI, because the signal starts somewhere other than the SA node/AV node/Purkinje fiber expressway, giving it a wide QRS complex pattern similar to a bundle-branch block

WHAT IF YOU USE SOMETHING THAT WORKS IN LBBB FOR PACED ECGs?

Study by Maloy et al:

57 study patients, retrospective review

  • ventricularly paced ECG
  • elevated cardiac markers <12hrs after ED ECG
  • diagnosis of AMI

99 control patients

  • ventricular-paced ECG
  • negative cardiac markers

A blinded board certified cardiologist reviewed all ECGs for Sgarbossa criteria.

RESULTS:

“ST-segment elevation of 1 mm concordant with the QRS complex”

  • no ECG fit this criterion;

“ST-segment depression of 1 mm in lead V1, V2, or V3,”

  • sensitivity was 19% (95% CI 11-31%),
  • specificity 81% (95% CI 72-87%),
  • likelihood ratio of 1.06 (0.63-1.64);

For “ST-segment elevation >5mm discordant with the QRS complex,”

  • sensitivity was 10% (95% CI 5-21%),
  • specificity 99% (95% CI 93-99%), 
  • likelihood ratio of 5.2 (1.3 – 21).

 

BOTTOM LINE:

 “the most clinically useful Sgarbossa criterion in identifying AMI was ST-segment elevation >5mm discordant with the QRS complex. This characteristic may prove helpful in identifying patients who may ultimately benefit from early aggressive AMI treatment strategies.”

translation: if you see discordant ST elevation >5mm in a paced rhythm, worry about an MI.

interesting that the least useful rule in LBBB might be the most useful in paced rhythms.

 

 

References: article, nice review on pacers at lifeinthefastlane; picture

Sgarbossa Criteria — modified

17 Dec

QUICK REVIEW:

–Sgarbossa criteria help look for STEMIs in people with LBBB (left bundle branch block)

 

ECG CRITERIA:
5 pts – concordant (same direction as QRS complex) ST elevation >=1mm any lead
3 pts – ST depression >=1mm in anterior leads (V1, V2, V3)
2 pts – discordant (opposite direction of QRS) ST elevation >=5mm any lead

–add up the points, score >=3 is 90+ percent specific for an MI

Smith et al study:

admission ECGs for all patients with an acutely occluded coronary artery and left bundle branch block

R or S wave, whichever was most prominent, and ST segments, relative to the PR segment, were msmith-sgareasured to the nearest 0.5 mm.

ST/S ratio was calculated for each lead that has discordant ST deviation of greater than or equal to 1 mm

cutoff for proposed rule was ST/S ratio <=  -0.25  (e.g. more discordant)

The study and control groups included 33 and 129 ECGs, respectively.

 

NOTABLE:

  • (3rd sgarbossa criteria) discordant ST-segment elevation of 5 mm was present in at least one lead in 30% of ECGs in patients AMI vs 9% of the control group
  • (proposed criteria) ST/S ratio less than (i.e. more negative than; more relative discordance than) -0.25 was present in 58% versus 8%.
  • Sensitivity of the revised rule (proposed ST/S ratio rule replaces 5mm ST elevation rule): 91% versus 52%.
  • Specificity of the revised rule was lower than that of the weighted rule (P=.002) and similar to that of the unweighted rule (P=1.0): 90%  versus 98% versus 90%.
  • Positive likelihood ratio for the revised rule 9.0
  • negative liklihood ratio for the revised rule 0.1

 

THEIR CONCLUSION:

“Replacement of the absolute ST-elevation measurement of greater than or equal to 5 mm in the third component of the Sgarbossa rule with an ST/S ratio less than -0.25 greatly improves diagnostic utility of the rule for STEMI.”

 

BOTTOM LINE:

the ST/S ratio rule seems more sensitive, similar specificity of old rule.

 

HOW DO I USE THIS?:
–you’re handed an EKG, there’s a LBBB

–look for >=1mm concordant ST elevation
–look for ST depression in anterior leads

–look for discordant ST deviation; if ST segment change is > 1/4th the amplitude of the R or S-wave, be curious

 

–if you see these things, worry about an MI

 

Reference(s): old post; article; picture is from the article