Friday, December 19, 2014

New atrial fibrillation guidelines

From AHA/ACC/HRS. Free full text here.

Ileal pouch infection with C diff

From a recent article in the American Journal of Gastroenterology:

Clostridium difficile (C. difficile) infection (CDI) following total proctocolectomy and ileal pouch-anal anastomosis has been increasingly recognized over the past 5 years. CDI of the ileal pouch has been recognized in ~10% of symptomatic patients seen at a tertiary referral center for pouch dysfunction. In contrast to colonic CDI in the general population or in patients with inflammatory bowel disease, postoperative antibiotic exposure and the use of immunosuppressive agents or proton pump inhibitors do not appear to be associated with CDI of the pouch. Male gender, recent hospitalization, and presurgery antibiotic use were shown to be risk factors for ileal pouch CDI...Postcolectomy CDI likely represents a spectrum of disease processes, varying from asymptomatic colonization to severe symptomatic infection. CDI should be considered in any patient with an ileal pouch presenting with a change in “normal” symptom pattern or treatment-refractory disease.

Non convulsive seizure related altered mental status

When patients present with altered mental status of unclear etiology consider this from a recent study:

To identify the prevalence of NCS and other EEG abnormalities in ED patients with AMS…

Two hundred fifty-nine patients were enrolled (median age: 60, 54% female). Overall, 202/259 of EEGs were interpreted as abnormal (78%, 95% confidence interval [CI], 73-83%). The most common abnormality was background slowing (58%, 95% CI, 52-68%) indicating underlying encephalopathy. NCS (including non-convulsive status epilepticus [NCSE]) was detected in 5% (95% CI, 3-8%) of patients. The regression analysis predicting EEG abnormality showed a highly significant effect of age (P less than .001, adjusted odds ratio 1.66 [95% CI, 1.36-2.02] per 10-year age increment). IRA for EEG interpretations was modest (κ: 0.45, 95% CI, 0.36-0.54).

The prevalence of EEG abnormalities in ED patients with undifferentiated AMS is significant. ED physicians should consider EEG in the evaluation of patients with AMS and a high suspicion of NCS/NCSE.

Rethinking IV hydralazine

IV hydralazine is popular in hospitals because it is old, familiar and easy to use. A recent post at Emergency Medicine PharmD serves as a reminder of the potential for adverse effects. Among the downsides are unpredictable pharmacokinetics (it can hang around much longer than expected in some patients) and pharmacodynamics (unexpected and poorly tolerated hypotension can occur), activation of the sympathetic nervous system and cerebral autoregulatory failure due to its vasodilating effects.

As stated in the post, hydralazine is contraindicated in many true hypertensive emergencies and is not the drug of choice for any of them. And if it's not a hypertensive emergency (severe asymptomatic hypertension with no target organ damage) one should question whether a parenteral antihypertensive of any kind is warranted.

Thursday, December 18, 2014

Point of care blood glucose testing may soon disappear from the ICU if certain regulators have their way

No, I'm not kidding. Check this out from a recent article in Mayo Clinic Proceedings. From the article:

The CMS regulates all laboratory testing (except research) on humans in the United States through regulations established by the Clinical and Laboratory Improvement Amendments (CLIA) of 1988...
No POC BGM has ever been cleared by the FDA for critically ill patients.11 Therefore, these devices are being used “off-label” in the ICU, operating room, recovery room, and emergency department...

In contrast to the off label use of drugs, the off label use of laboratory methods is against the regulations. More from the article:

The CMS recently became aware that POC BGMs are being used in hospitals off-label and is ready to enforce the prohibition of their off-label use, according to 2 recent letters from the New York State Department of Health.

Despite the fact that virtually all hospitals have been doing this for decades and it has become a standard of care, CMS has only recently become aware of it!! Well that illustrates how profoundly out of touch they are with what really goes on at the “point of care.”

According to one of the authors in the accompanying video CMS is poised to cite or even shut down hospitals. The authors propose a moratorium on further regulatory action.

How do medical school faculty get information on line?

This recent paper from the Journal of the Medical Library Association describes how faculty members utilize information resources. A major limitation is that it is a single center study and may reflect trends that are peculiar to the culture of the institution. It is available as free full text and there is a lot to unpack. An area of particular interest to me was that of faculty members' preferences for patient care look up:

..the 180 respondents to the question rarely searched the 13 point-of-care databases listed in the survey for clinical or patient-care information. Over 90% stated that they never used 5 of the databases for clinical or patient care, and another 5 databases had between 75% and 90% of respondents never using them. For example, UpToDate was used daily by 4.8% of respondents but was never used by 64.1% of respondents for clinical or patient care purposes. MD Consult was the most used by all respondents, with 43.6% reporting using it at least a few times a year or more for clinical or patient care information.

There's a lot of scatter here but a few patterns are suggested. Filtered resources such as DynaMed and UpToDate, wildly popular among residents and private physicians, were hardly used at all by faculty, who tended to prefer repositories of books and journals such as MD Consult and Access Medicine. The filtered resources are more geared for focused clinical questions whereas the repositories are better suited for background reading and that may be more suitable for the teaching objectives of faculty.

Evidence based medicine (EBM) has evolved concerning information retrieval. Original teaching held that a Medline search and critical appraisal (a phrase coined for this use by the founders of EBM) should be done by the user at the point of care. That teaching has given way to a shift toward the use of filtered resources (secondary sources) which deliver information that has been searched and critically appraised by others. Proponents of filtered resources argue that primary searching and critical appraisal is too time consuming for clinicians. Purists decry this practice as capitulation to laziness. I discussed this trend in greater detail in a recent post on the history of EBM:

Dr. Brian Haynes was asked whether EBM was too much work for the busy clinician. When one considers the steps involved in searching, critical appraisal and application it does seem a daunting task. Certainly it would have been too time consuming before the era of computer searching. On line searching was available in the 1980s (you had to go to considerable trouble to set it up) but had not yet reached prime time even by the time EBM was announced to the world in 1992.

Haynes said that he and his colleagues were working from the beginning to make the process user friendly in everyday practice. They have been exploring ways to put best evidence into secondary sources, including even textbooks (some EBM purists decry the use of textbooks) so that doctors will not have to do primary literature searches and critical appraisal. Currently available secondary resources, said Haynes, may not be where they need to be yet but are improving.

As Guyatt pointed out the leaders realized early on that getting all clinicians to search and critically appraise the literature individually was an unattainable ideal. The best that could be done was to educate clinicians in the principles of EBM so they could then make more intelligent and effective use of secondary sources. Evidence derived from such sources has already been critically appraised and has been referred to as “pre-processed” evidence. Some EBM purists, taking a negative view of this approach, consider it an unfortunate compromise and have called it “evidence based capitulation.”

Overdoses with new generation anticonvulsants

From a recently published observational study:

There were 116 gabapentin, 67 lamotrigine, 15 levetiracetam, 15 tiagabine, 56 topiramate, 23 pregabalin, and 55 oxcarbazepine cases. Overdose of newer anticonvulsants frequently results in altered mental status. Seizures may be more common with tiagabine, lamotrigine, and oxcarbazepine. There was one death reported from intentional overdose of topiramate..the risk of a more severe outcome score was significantly increased with tiagabine relative to other drugs (β = 2.8, p = 0.001). Lamotrigine ranked highest in terms of toxicity (HT = 1.66) and number of interventions performed (HI = 1.17), and levetiracetam the lowest (HT = 0.98; HI = 0.88). We could not identify a dose-effect in these data which likely reflects the limitations of self-reported doses. Despite limitations of these data, the risk of more severe outcome scores appear to be higher with tiagabine overdose while lamotrigine overdose appears to result in more reported signs, symptoms, and interventions.

A clinical score to help exclude Legionella in community acquired pneumonia

From the American Journal of Medicine:

Currently used antigen tests and culture have limited sensitivity with important time delays, making empirical broad-spectrum coverage necessary. Therefore, a score with 6 variables recently has been proposed. We sought to validate these parameters in an independent cohort...
Of 1939 included patients, the infectious cause was known in 594 (28.9%), including Streptococcus pneumoniae in 264 (13.6%) and Legionella sp. in 37 (1.9%). The proposed clinical predictors fever, cough, hyponatremia, lactate dehydrogenase, C-reactive protein, and platelet count were all associated or tended to be associated with Legionella cause. A logistic regression analysis including all these predictors showed excellent discrimination with an AUC of 0.91 (95% confidence interval, 0.87-0.94). The original dichotomized score showed good discrimination (AUC, 0.73; 95% confidence interval, 0.65-0.81) and a high negative predictive value of 99% for patients with less than 2 parameters present.
With the use of a large independent patient sample from an international database, this analysis validates previously proposed clinical variables to accurately rule out Legionella sp., which may help to optimize initial empiric therapy.

Wednesday, December 17, 2014

Inappropriate cath lab activation due to pseudoSTEMI

Inappropriate treatment of patients presenting with chest pain is an increasingly recognized consequence of the performance driven STEMI versus non-STEMI designation. The most widely discussed examples of this take the form of missed coronary occlusion due to over reliance on simple ST segment criteria. Another aspect of the problem was illustrated in this recent paper: inappropriate cath lab activation due to STMI mimics. From the article:

There were a total of 139 activations with 77 having a STEMI diagnosis confirmed and 62 activations where there was no STEMI. The inappropriate activations resulted from a combination of atypical symptoms and misinterpretation of the ECG (45% due to anterior ST-segment elevation) on patient presentation.

The fact that almost half the cath lab activations were inappropriate is concerning enough. Worse, though, was the fact that this occurred at an academic medical center.

STEMI versus pericarditis: new criteria proposed

From a recent article in the American Journal of Medicine:

..This study aims to assess whether QRS and QT duration permit distinguishing acute pericarditis and acute transmural myocardial ischemia.

Clinical records and 12-lead electrocardiogram (ECG) at ×2 magnification were analyzed in 79 patients with acute pericarditis and in 71 with acute ST-segment elevation myocardial infarction (STEMI).

ECG leads with maximal ST-segment elevation showed longer QRS complex and shorter QT interval than leads with isoelectric ST segment in patients with STEMI (QRS: 85.9 ± 13.6 ms vs 81.3 ± 10.4 ms, P = .01; QT: 364.4 ± 38.6 vs 370.9 ± 37.0 ms, P = .04), but not in patients with pericarditis (QRS: 81.5 ± 12.5 ms vs 81.0 ± 7.9 ms, P = .69; QT: 347.9 ± 32.4 vs 347.3 ± 35.1 ms, P = .83). QT interval dispersion among the 12-ECG leads was greater in STEMI than in patients with pericarditis (69.8 ± 20.8 ms vs 50.6 ± 20.2 ms, P less than .001). The diagnostic yield of classical ECG criteria (PR deviation and J point level in lead aVR and the number of leads with ST-segment elevation, ST-segment depression, and PR-segment depression) increased significantly (P = .012) when the QRS and QT changes were added to the diagnostic algorithm.

Patients with acute STEMI, but not those with acute pericarditis, show prolongation of QRS complex and shortening of QT interval in ECG leads with ST-segment elevation.

Update on social media as medical education tools

This is a nice compilation of medical education social media resources. Coming from an emergency medicine journal it is biased toward that field but, after all, emergency medicine is where it's mostly happening right now.  

Monday, December 15, 2014

Non cardiac surgery after PCI

This is one of the most vexing perioperative issues for hospitalists and was the topic of a recent review article in the American Journal of Cardiology. Surgery post PCI is a difficult situation because it is the interface of two pro-thrombotic conditions, a local one (the recently manipulated artery which has not had time to endothelialize) and a systemic pro-thrombotic state resulting from the surgery.

The review offers a summary of current guidelines and more recent evidence along with a suggested approach. From the review, concerning the guidelines:

Current consensus multisociety guidelines suggest delaying elective surgery for greater than or equal to 1 year after DES implantation and for greater than or equal to 4 to 6 weeks after BMS implantation. If surgery is warranted before that period, it should be performed while on DAPT if safe. Minimums of 6 to 12 months and 4 to 6 weeks of DAPT, respectively, after DES and BMS implantation before NCS are recommended in national guidelines. If surgery is anticipated within 30 days of revascularization or if DAPT is not feasible, balloon angioplasty without stenting may be a reasonable strategy if NCS is anticipated. These recommendations are based largely on expert opinion in conjunction with limited and variable evidence based on first-generation DESs.

The authors note that newer generation drug eluging stents may be safer and thus allow earlier interruption of DAPT. In the suggested approach that follows, however, they emphasize that this remains unproven:

We propose the following simplified approach to such patients. (1) It is reasonable to postpone elective surgical procedures for greater than or equal to 6 weeks after BMS implantation and for greater than or equal to1 year after first-generation DES implantation. Second-generation DESs have a more favorable thrombogenicity profile, and emerging data suggest that it may be safe to discontinue DAPT as early as 3 months after stent implantation. Consequently, it may be feasible to safely perform NCS 3 to 6 months after second-generation DES implantation, but this remains unproved. (2) Urgent or unplanned surgery should be performed on DAPT if feasible, but this is the exception.

Sunday, December 14, 2014

What is subacute kidney injury?

From a recent paper:

Background and objectives The epidemiology of AKI and CKD has been described. However, the epidemiology of progressively worsening kidney function (subacute kidney injury [s-AKI]) developing over a longer time frame than defined for AKI (7 days), but shorter than defined for CKD (90 days), is completely unknown...
Conclusions Close to 1% of hospitalized patients develop s-AKI. This condition is independently associated with increased hospital mortality, and the risk for death increases with s-AKI severity. Patients with s-AKI had a better outcome and were less likely to require renal replacement therapy than patients with AKI.

Via Hospital Medicine Virtual Journal Club.

Saturday, December 13, 2014

Prevention of recurrent kidney stones

New guidelines are out from the ACP available as free full text here.

From the guideline document:

Recommendation 1: ACP recommends management with increased fluid intake spread throughout the day to achieve at least 2 L of urine per day to prevent recurrent nephrolithiasis. (Grade: weak recommendation, low-quality evidence)
Recommendation 2: ACP recommends pharmacologic monotherapy with a thiazide diuretic, citrate, or allopurinol to prevent recurrent nephrolithiasis in patients with active disease in which increased fluid intake fails to reduce the formation of stones. (Grade: weak recommendation, moderate-quality evidence)

The evidence for dietary interventions was mixed and not strong enough for the authors to include a recommendation. Also, the guideline states that the evidence was insufficient to support pre-treatment or on-treatment stone analysis or determination of urine composition.