Remember that Oxygen Delivery is composed of two parts:
What is Shock?
[Oxygen Delivery] = [Oxygen Content] [Cardiac Output]
In the first video, let’s go over problems with that second part: cardiac output.
How can cardiac output go wrong? All of these can lead to decreased cardiac output.
- Cardiac: problems with the PUMP. The heart won’t push blood forward.
- Blood vessels: problems with the PIPES. The blood vessels are causing either obstruction to flow or are so massively dilated that blood just pools within or leaks out.
- Fluid volume: problems with the TANK. There’s not enough fluid to pump around.
The commonly taught categories of causes of cardiogenic, obstructive, distributive and hypovolemic fit into the above three physiologic groups.
How do you diagnose shock?
You can recognize shock by hypoperfusion of organ systems. So you’ll find measured blood pressure is low. Also, decreased blood flow to the
- kidneys leads to decreased urine output
- brain leads to altered mental status
- skin leads to cyanosis.
Remember that H&P are the best diagnostic tools we have. So search for potential signs and symptoms for diseases of the pump, pipes or tank. Ultrasound (the RUSH protocol) is very helpful as well. Treatment depends on identifying the cause.
How do you treat shock?
Treatment depends on the cause of hypoperfusion.
- PUMP problem? Maybe you need an inotrope or other cardiac support
- TANK problem? Then fill up the tank. Use whatever fluid you need, but remember crystalloid doesn’t carry oxygen.
- PIPE problem? Then, assuming you have a full tank, you need a pressor.
SAEM’s Clerkship Directors in Emergency Medicine (CDEM) and EMRA released a training video for medical students that demonstrates how to tell a compelling story when presenting a patient’s case. This brief video offers handy do’s and don’ts that will help medical students understand how best to efficiently and effectively communicate in the ED.
The ten-minute video features EMRA resident and student members and CDEM leaders: Aditi Mitra, Michael Yip, Zach Jarou, David Gordon with help from Cathey Wise (EMRA) and Melissa McMillan (SAEM), with yours truly playing Mr. Ferguson.
Odds ratios and risk ratios always confused me. I never really understood the reason behind having an odds ratio. It is so unintuitive to me, even still.
There’s a great article from the Southern Medical Journal that explains it all! Watch the video then read the article.
Viera AJ. Odds ratios and risk ratios: what’s the difference and why does it matter? South Med J. 2008 Jul;101(7):730-4. PMID: 18580722
Systematic reviews sit atop the evidence-based medicine pyramid as the strongest form of evidence we have. This is so because it incorporates more data than individual studies. To avoid bias in making reviews, the authors need to follow a systematic process. In this video we look at this process the authors would follow and you should note when reading such reviews.
The Patient Protection and Affordable Care Act, also known as the Affordable Care Act or ObamaCare, is the biggest change in health care policy since Medicare in 1965. Despite its importance, very few understand it. This is not surprising given its complexity. Popular news outlets and politicians (on both sides) capitalize on our ignorance by exaggerating, distorting or misrepresenting pieces of it. As health care providers and citizens, love it or hate it, we have a duty to understand it.
Diabetics often present to the Emergency Room with high blood sugar. Sometimes it’s just high and nothing else is wrong. Lower the sugar and send them on their way. Sometimes this represents something more ominous. In the next two videos we review the hyperglycemic emergencies of diabetic ketoacidosis and hyperglycemic hyperosmolar syndrome.
Here is an application of the method we use to approach trauma, namely penetrating trauma to the neck. Here are some important questions to ask yourself while watching these videos:
- What are the boundaries of the zones of the neck and why do they matter?
- Do all patients need to be intubated?
- Do all patients need to be put in a cervical collar?
- What are the “hard signs” of neck trauma and why do they matter?