Pooled results of several trials comparing recombinant tissue plasminogen activator with placebo in ischaemic stroke quantify the profile of benefit and harm for alteplase in broadly selected patients. Generally, alteplase appears to improve the outcome of one in three patients treated between 1 and 3 h from onset and of one in six patients treated in the 3–4·5 h window, but confers no net benefit beyond that time. Benefit may decrease exponentially (according to an accompanying editorial), so if you are a believer then get in there early.
Time to treatment with intravenous alteplase and outcome in stroke: an updated pooled analysis of ECASS, ATLANTIS, NINDS, and EPITHET trials
Lancet. 2010 May 15;375(9727):1695-703
Category Archives: Acute Med
Acute care of the medically sick adult
Thoracic electrical bioimpedance in dyspnoea
Thoracic electrical bioimpedance (TEB) was used in ED patients presenting with dyspnoea to differentiate between cardiac and non-cardiac causes.
The fundamental principle behind TEB is based on Ohm’s law. If a constant electrical current is applied to the thorax, changes in impedance (ΔZ) to flow are equal to changes in voltage drop across the circuit. As a current will always seek the path of lowest resistivity, which in the human body is blood, ΔZ of the thorax will primarily reflect the dynamic changes of blood volume in the thoracic aorta. Changes in thoracic electrical impedance are continuously recorded and processed using a computer algorithm to calculate a number of cardiohaemodynamic parameters such as stroke volume, CO, CI, SVR and systemic vascular resistance index (SVRi).
A cardiac index cut-off of 3.2 l/m/m2 had a 86.7% sensitive (95% CI 59.5% to 98.0%) and 88.9% specific (95% CI 73.9% to 96.8%) for cardiac dyspnoea in the 52 patients studies, of which 15 had cardiac-related dyspnoea.
The study has several limitations including small numbers and using the gold standard of discharge diagnosis.
Thoracic electrical bioimpedance: a tool to determine cardiac versus non-cardiac causes of acute dyspnoea in the emergency department
Emerg Med J. 2010 May;27(5):359-63
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Carotid Artery Stenting versus Endarterectomy
The Carotid Revascularization Endarterectomy vs. Stenting Trial (CREST) compared the outcomes of carotid-artery stenting with those of carotid endarterectomy among over 2500 patients with symptomatic or asymptomatic extracranial carotid stenosis.
The authors offer the following conclusions:
- Stroke was more likely after carotid artery stenting.
- Myocardial infarction was more likely after carotid endarterectomy, but the effect on the quality of life was less than the effect of stroke.
- Younger patients had slightly fewer events after carotid-artery stenting than after carotid endarterectomy; older patients had fewer events after carotid endarterectomy.
- The low absolute risk of recurrent stroke suggests that both carotid-artery stenting and carotid endarterectomy are clinically durable and may also reflect advances in medical therapy.
Stenting versus Endarterectomy for Treatment of Carotid-Artery Stenosis
NEJM May 26 2010 Published Online
Guidelines for Clostridium Difficile
Guidelines for preventing, detecting, and treating Clostridium Difficile infection from the Infectious Diseases Society of America have been published.
Clinical Practice Guidelines for Clostridium difficile Infection in Adults: 2010 Update by the Society for Healthcare Epidemiology of America (SHEA) and the Infectious Diseases Society of America (IDSA)
Infect Control Hosp Epidemiol 2010;31:431–455 Full Text
Bloodtest Not Pertinent (BNP)
Despite a lack of evidence that it’s useful, many emergency departments have introduced BNP testing. Some smart Australians decided to properly evaluate its benefit the best way possible – with a randomised controlled trial on 612 patients with acute severe dyspnoea. Guess what? Clinician knowledge of BNP values in patients who presented with shortness of breath to the emergency department did not reduce the probability of hospital admission or alter management or length of hospital stay. The study findings do not support indiscriminate BNP testing in all dyspnoea patients, but do not rule out a possible role in patients with milder dyspnoea.
B-type natriuretic peptide testing, clinical outcomes, and health services use in emergency department patients with dyspnea: a randomized trial
Ann Intern Med. 2009 Mar 17;150(6):365-71
PCI and therapeutic hypothermia
Percutaneous coronary intervention did not increase the risk of dysrhythmia, infection, coagulopathy, or hypotension associated with therapeutic hypothermia after cardiac arrest. Intensivists and cardiologists should perhaps agree that this adds to existing evidence that the two therapies are not mutually exclusive.
Feasibility and safety of combined percutaneous coronary intervention and therapeutic hypothermia following cardiac arrest
Resuscitation. 2010 Apr;81(4):398-403
Rapid discharge in AF
The Ottawa Aggressive Protocol is used to treat recent onset (< 48 hours) atrial fibrillation or flutter with procainamide and/or cardioversion to allow discharge from the emergency department.
A cohort of 660 patient visits is described in a paper in the Canadian Journal of Emergency Medicine, 95.2% involving atrial fibrillation and 4.9% involving atrial flutter. The mean age of patients enrolled was 64.5 years. In total, 96.8% were discharged home and, of those, 93.3% were in sinus rhythm. All patients were initially administered intravenous procainamide, with a 58.3% conversion rate. A total of 243 patients underwent subsequent electrical cardioversion with a 91.7% success rate. Adverse events occurred in 7.6% of cases: hypotension 6.7%, bradycardia 0.3% and 7-day relapse 8.6%. There were no cases of torsades de pointes, stroke or death. The median lengths of stay in the ED were as follows: 4.9 hours overall, 3.9 hours for those undergoing conversion with procainamide and 6.5 hours for those requiring electrical conversion.
This proactive approach by emergency physicians seems excellent for patients who in some centres probably still get admitted for this presentation. I’m not sure why they continue to use a drug with a conversion percentage in the 50’s, which the authors have demonstrated before. Many of us routinely use flecainide for recent onset AF in patients likely to have structurally normal hearts, as it has been shown to be superior to procainamide in AF.
Association of the Ottawa Aggressive Protocol with rapid discharge of emergency department patients with recent-onset atrial fibrillation or flutter
Canadian Journal of Emergency Medicine 12.3 (May 2010): p181(11)
Higher D Dimer cut-off in older patients
D-dimer levels below the conventional cut-off point of 500 µg/l combined with a “low/intermediate” or “unlikely” clinical probability can safely rule out the diagnosis in about 30% of patients with suspected pulmonary embolism.
However, the D-dimer concentration increases with age and its specificity for embolism decreases, which makes the test less useful to exclude pulmonary embolism in older patients; the test is able to rule out pulmonary embolism in 60% of patients aged <40 years, but in only 5% of patients aged >80.
A new, age dependent cut-off value was derived and then validated in two independent retrospective datasets from Belgium, France, the Netherlands, and Switzerland. They studied over 5000 patients aged >50 years.
The new D-dimer cut-off value was defined as (patient’s age x 10) µg/l in patients aged >50.
In 1331 patients in the derivation set with an “unlikely” score from clinical probability assessment, pulmonary embolism could be excluded in 42% with the new cut-off value versus 36% with the old cut-off value (<500 µg/l). In the two validation sets, the increase in the proportion of patients with a D-dimer below the new cut-off value compared with the old value was 5% and 6%. This absolute increase was largest among patients aged >70 years, ranging from 13% to 16% in the three datasets. The failure rates (all ages) were 0.2% (95% CI 0% to 1.0%) in the derivation set and 0.6% (0.3% to 1.3%) and 0.3% (0.1% to 1.1%) in the two validation sets.
Potential of an age adjusted D-dimer cut-off value to improve the exclusion of pulmonary embolism in older patients: a retrospective analysis of three large cohorts.
BMJ. 2010 Mar 30;340:c1475
TIA and stroke definitions
A quick reminder of the current defintions, as these have changed a couple of times over the last few years:
- Transient ischemic attack (TIA): a transient episode of neurological dysfunction caused by focal brain, spinal cord, or retinal ischemia, without acute infarction.
- An ischemic stroke is defined as an infarction of central nervous system tissue.
Definition and Evaluation of Transient Ischemic Attack: A Scientific Statement for Healthcare Professionals From the American Heart Association/American Stroke Association Stroke Council; Council on Cardiovascular Surgery and Anesthesia; Council on Cardiovascular Radiology and Intervention; Council on Cardiovascular Nursing; and the Interdisciplinary Council on Peripheral Vascular Disease: The American Academy of Neurology affirms the value of this statement as an educational tool for neurologists.
Stroke. 2009 Jun;40(6):2276-93 Full Text
STEMI and PCI guidelines
Lots of interesting and up to date information in this thick document from December 2009
Full text is available here
2009 Focused Updates: ACC/AHA Guidelines for the Management of Patients With ST-Elevation Myocardial Infarction (Updating the 2004 Guideline and 2007 Focused Update) and ACC/AHA/SCAI Guidelines on Percutaneous Coronary Intervention (Updating the 2005 Guideline and 2007 Focused Update)