Five ECG Patterns You Must Know

ECG PatternsBackground: 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. Continue reading

Xanthochromia Detection: Visual Inspection vs. Spectrophotometry

XanthochromiaBackground: Although non-contrast head CT (NCHCT) has near perfect sensitivity (98-100%) in detecting aneurysmal subarachnoid hemorrhage (SAH) when performed within 6 hours of headache onset, sensitivity declines after 6 hours. As a result of declining sensitivity, lumbar puncture (LP) continues to be part of the workup in suspected SAH. An LP gives providers the ability to perform CSF analysis for red blood cells and detect xanthochromia by visual inspection or spectrophotometry. In most of the world, including the United States, the predominant approach to identifying xanthochromia is visual detection. However, this technique is subjective and considered unreliable by many. Spectrophotometry is a more objective test but, has lower specificity, carries a higher cost and is unavailable in the majority of hospitals.

In patients with SAH diagnosed by NCHCT or suspected based on LP results, angiography (CTA or MRA) is typically performed to investigate for an aneurysm that requires neurosurgical intervention. Angiography is considered to be the “gold standard” test for looking for aneurysmal SAH although it is not without it’s own limitations (a small minority of the population will have benign aneurysms and these increase with age). Continue reading

Cardiocerebral Resuscitation: Hands-Only CPR

Cardiocerebral ResuscitationOne 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? Continue reading

Clinical Decision Instruments in Minor Head Trauma – New Orleans + Canadian Decision Instruments

Clinical Decision InstrumentsBackground: CT scans are frequently done after minor head injury to evaluate for intracranial hemorrhage. While CT scans are an excellent tool for diagnosing or ruling out this disorder, they are not without harms including radiation exposure, cost and department delays. Much of the time, CTs are negative, or find injuries for which no intervention is ever done and do not clinically affect the patient. Clinical Decision Instruments may aid clinicians in determining which patients are higher risk and require imaging and which do not. Continue reading

Classic Journal Review: The OPALS Study

OPALS

The Ontario Prehospital Advanced Life Support (OPALS) Study

Background: Sudden cardiac arrest is common and, obviously, very bad. In the US, there are about 500,000 cardiac arrests each year. About half of these cardiac arrests are OHCA and the survival rate is pretty poor. The most recent survival estimates put it at 7 – 9.5% in most communities. About 10-12 years ago, the American Heart Association built the 4-step “chain-of-survival.”

  • Step One – Early access to emergency care
  • Step Two – Early CPR
  • Step Three – Early defibrillation

There is little debate about these three steps as the sum of the data supports that they lead to better outcomes.

The 4th step in the chain, however, is slightly more controversial; early advanced care. This basically means rapid access to ACLS type resuscitation skills (intubation and intravenous drug therapy). Despite it being the 4th step, ACLS has little evidence to defend it.  Continue reading