Nontraumatic Subarachnoid Hemorrhage in the Setting of Negative Cranial Computed Tomography Results: External Validation of a Clinical and Imaging Prediction Rule

Nontraumatic Subarachnoid Hemorrhage in the Setting of Negative Cranial Computed Tomography Results: External Validation of a Clinical and Imaging Prediction Rule

Study objective
Clinical variables can reliably exclude a diagnosis of nontraumatic subarachnoid hemorrhage in patients with negative cranial computed tomography (CT) results. We externally validated 2 decision rules with 100% reported sensitivity for a diagnosis of subarachnoid hemorrhage, among patients undergoing lumbar puncture after a negative cranial CT result: (1) clinical rule: presence of any combination of age 40 years and older, neck pain or stiffness, loss of consciousness, or headache onset during exertion; and (2) imaging rule: cranial CT performed within 6 hours of headache onset.

Methods
This was a matched case-control study of patients presenting to 21 emergency departments between 2000 and 2011. Patients with a diagnosis of subarachnoid hemorrhage as determined by lumbar puncture after a negative cranial CT result were screened for inclusion. A matched control cohort was selected among patients with a diagnosis of headache after negative cranial CT and lumbar puncture results.

Results
Fifty-five cases of subarachnoid hemorrhage meeting inclusion criteria were identified, 34 (62%) of which were attributed to cerebral aneurysms. External validation of the clinical rule demonstrated a sensitivity of 97.1% (95% confidence interval [CI] 88.6% to 99.7%), a specificity of 22.7% (95% CI 16.6% to 29.8%), and a negative likelihood ratio of 0.13 (95% CI 0.03 to 0.61) for a diagnosis of subarachnoid hemorrhage. External validation of the imaging rule revealed that 11 of 55 subarachnoid hemorrhage cases (20%) had negative cranial CT results for tests performed within 6 hours of headache onset.

Conclusion
The clinical rule demonstrated useful Bayesian test characteristics when retrospectively validated against this patient cohort. The imaging rule, however, failed to identify 20% of subarachnoid hemorrhage patients with a negative cranial CT result.

 

2-Hour Accelerated Diagnostic Protocol to Assess Patients With Chest Pain Symptoms Using Contemporary Troponins as the Only Biomarker

2-Hour Accelerated Diagnostic Protocol to Assess Patients With Chest Pain Symptoms Using Contemporary Troponins as the Only Biomarker : The ADAPT Trial. Than, M, Cullen, L, et. al. Am Coll Cardiol. 2012 Jun 5;59(23):2091-­‐8.

In the ADAPT trial patients were enrolled between 2007 – 2011. Inclusion and exclusion criteria appear appropriate and relevant to our population with the exception one: the inability to contact the patient after follow-up. This exclusion could potentially apply to a large number of our patients. In addition the exclusion criteria included “staff considered recruitment to be inappropriate”, which could introduce bias into the study.  Of those recruited not a single person was lost to follow-up. Of those deemed low-risk only one had a MACE, which on further review had a rising trop, making it very unlikely that this patient would have been discharged from our ED. The negative likelihood ratio for the ADAPT trial was 0.01, which is very strong. Additionally it was noted that the negative likelihood ratio for TIMI 0 and non-ischemic ECG was 0.07, also very strong. This data is similar that found in other studies evaluating TIMI and low-risk ECG. While this data needs to be reproduced in additional studies a 2 hours protocol using TIMI, ECG, and high sensitivity troponin may be safe option in low-risk patients.

Overall the article was well received. It was felt that although the study was done in Australia, as we are currently using high-sensitivity troponin in our ED, this study could be applied to our patient population. In general the study receives a thumbs-up.

Zinc for the Common Cold

Zinc for the Common Cold
Singh, M., Das, R.R.  Zinc for the common cold.  Cochrane Database Syst Rev. 2011 Feb 16;(2):CD001364. doi: 10.1002/14651858.CD001364.pub3
http://www.ncbi.nlm.nih.gov/pubmed/21328251

1)      The common cold is one of the most common causes for illness, doctor visits, and missing school/work.  The average child gets eight colds per year and the average adult gets three colds per year.  This study proposed assessing zinc supplementation as beneficial for the common cold.  This was a Cochrane review that included randomized, double-blind placebo-controlled trials with zinc; both the treatment and prevention of colds were assessed.  Nine hundred sixty-six participants in 13 trials were assessed and findings showed that there was a significant reduction in the duration and severity of the colds with zinc.  In two preventative trials with 394 participants, there was decreased incidence of colds, less antibiotic use, and fewer school absences in the zinc group.  However, there was also a higher rate of nausea and bad taste in the zinc group.  Results showed that zinc should be administered within one day of symptoms at the onset of the cold to be effective and should continue for at least five days.

2)      The patients were randomized and they only included placebo-controlled trials.  This review used a total of 15 different studies that were very heterogeneous in the outcomes they measured and the type and amount of zinc that was used.  They included the best studies available to date with the best methodology, but given the variety in studies, it is hard to make clear statements on exact recommendations.  Patients may have also known what group they were in based solely on the taste of zinc and nausea associated with its use.  Treatment effects were clearly shown in some studies and not clear in others. However, overall the results showed that if zinc is taken within one day of symptoms, the patient had a two-day earlier resolution of their cold as well as decreased severity.  The patients in these studies tended to be outpatients and not ED patients.  Given that side effects are minimal and not life threatening, the benefits are worth the potential risk.

3)      Although this is not a lifesaving treatment, it is something that is safe and can provide patients with an additional way to fight off viral infections in lieu of only purchasing over- the-counter cold relievers. It has also been shown that patients who take zinc end up being prescribed fewer antibiotics, which is highly beneficial to both patients and healthcare at the national level.

Coben Thorn

A Phase 2 Randomized, Double-Blind, Placebo– Controlled Study of the Safety and Efficacy of Talactoferrin in Patients With Severe Sepsis*,

A Phase 2 Randomized, Double-Blind, Placebo–Controlled Study of the Safety and Efficacy ofTalactoferrin in Patients With Severe Sepsis*

Objectives:
Lactoferrin is a glycoprotein with anti-infective and antiinflammatory
properties found in secretions and immune cells. Talactoferrin
alfa, a recombinant form of human lactoferrin, has similar
properties and plays an important role in maintaining the gastrointestinal
mucosal barrier integrity. In experimental animal models, administration
of talactoferrin reduces translocation of bacteria from the gut
into the systemic circulation and mortality from sepsis. Our objective
was to determine if talactoferrin could reduce 28-day all-cause mortality
in patients with severe sepsis and to assess its safety.