February 11, 2016

Background: Headache accounts for approximately 2% of all ED visits. One of the most serious etiologies of headache is aneurysmal subarachnoid hemorrhage (SAH), which accounts for 4 – 12% of ED patients with thunderclap headache. There have been several studies in the past few years suggesting that in neurologically intact patients, the sensitivity of modern CT scanners for SAH approaches 100% if performed within 6 hours of headache onset and interpreted by qualified radiologists. If true this data suggests that an LP may not be necessary to rule out SAH and an initial negative CT can be considered a rule-out test.

February 8, 2016

Background: Tracheal intubation is a procedure that is often performed in the ED on patients in critical condition. Because of this, there is the potential for complications such as hypoxemia, hypotension, dysrhythmias, aspiration, and cardiac arrest. Apneic Oxygenation (ApOx) is a concept first explored decades ago in the anesthesia literature and more recently, has gained acceptance in the ED. Studies in the operating room (OR) show that delivery of oxygen through the use of nasal cannula during periods of apnea significantly delays the onset of oxygen desaturation. These studies however, were in controlled settings with elective surgical patients who were not in critical condition. Physiologically, ApOx makes sense, its low cost, and low complexity and could improve the safety of RSI in the ED, by extending the safe apnea time. To date there have been no RCTs on ApOx in the ED. The recently published Fellow Trial questioned the use of ApOx in critically ill patients, but had some significant issues with 2/3 of the usual care arm not being apneic (i.e. Bag Valve Mask Ventilation or Non-Invasive Ventilation) prior to intubation.

February 4, 2016

Background: The electrocardiogram (ECG) is one of the most useful diagnostic studies for identification of acute coronary syndrome (ACS) and acute myocardial infarction (AMI). The classic teaching is ST-segment elevation myocardial infarction (STEMI) is defined as symptoms consistent with acute coronary syndrome (ACS) + new ST-segment elevation at the J point in at least 2 anatomically contiguous leads of at least 2mm (0.2mV) in men or at least 1.5mm in women in leads V2 – V3 and/or at least 1mm (0.1mV) in other contiguous leads or the limb leads, in the absence of a left bundle branch block, left ventricular hypertrophy, or other non-acute MI ST-segment elevation presentations. Unfortunately, the ECG may be non-diagnostic in nearly half of all patients who initially present with AMI. There are also STEMI equivalent patterns that are caused by occlusion of the coronary arteries that place a significant portion of the left ventricle at jeopardy and result in poor outcomes. This review article focused on 5 under recognized high-risk ECG patterns in the ACS patient that result in poor outcomes including malignant dysrhythmias, higher rates of cardiogenic shock, and death.

January 21, 2016

One of the major reasons contributing to dismal survival rates in out-of-hospital cardiac arrest (OHCA) is the lack of bystander initiated cardiopulmonary resuscitation (CPR). Even though the majority of OHCA is witnessed, only 1 in 5 patients will receive bystander initiated CPR [1].  Survey studies have shown that bystanders are not wanting to do mouth-to-mouth resuscitation on strangers. Outside of early defibrillation, only early bystander initiated CPR has consistently been shown to improve neurologically intact survival in OHCA. So what about  Cardiocerebral Resuscitation, also known as "Hands-Only" CPR?

January 11, 2016

Background: Left Bundle Branch Block (LBBB) on the ECG makes accurate recognition of ST-Elevation Myocardial Infarction (STEMI) rather difficult. The 1996 and 2004 American College of Cardiology/American Heart Association (ACC/AHA) STEMI guidelines recommended immediate reperfusion therapy for patients with potentially ischemic symptoms and new, or presumed new, LBBB. In 2013, this recommendation was removed from the guidelines. Historically, reperfusion decisions in LBBB have been determined by the original Sgarbossa criteria published in 1996, but there are three key limitations to the original study by Sgarbossa et al:
  1. The original Sgarbossa criteria (i.e. the “weighted” Sgarbossa criteria) depends on a point system that rely on 3 findings, only 2 of which would provide enough points (i.e. 3) to make the diagnosis of AMI. Using the Sgarbossa criteria without the point system (i.e. the “unweighted” Sgarbossa criteria) increases sensitivity but decreases specificity.
  2. Sgarbossa et al diagnosed AMI by creatine kinase MB (CK-MB) elevations instead of angiographic evidence of acute coronary occlusion (ACO), which limits the sensitivity of the rule because it combines NSTEMI and STEMI patients in the outcome definition
  3. Finally, Sgarbossa et al used an absolute criterion (5mm) rather than a proportional criterion for excessively discordant ST elevation lowering the sensitivity of the criteria.
The modified Sgarbossa criteria replaces the absolute 5mm discordant ST elevation with a proportion (ST elevation/S-wave amplitude ≤ -0.25). In other words, the modified Sgarbossa criteria only changes the last of the original Sgarbossa criteria with the first two criteria staying intact. Now, if any of these criteria are met, the cardiac catheterization lab should be activated. We have written on REBEL EM before about the modified Sgarbossa criteria and one of our conclusions was this rule looked very promising, but needed an external validation study. Well that study is now here and for full disclosure I am one of the authors on the paper.