Of course the refractory stage is the stage where you have irreversible damage where you have multiple organ dysfunction syndrome. And when that happens of course you have the profound changes that can occur with the heart, the lungs, that you can’t get back and that patient may end up with ARDs and a cardiac output so low, we are not able to really treat them. Hypovolemic shock what can I say here that I haven’t said, I guess I will refer back to just know the importance of that is where your lactic acid really starts to build up and hopefully you will catch that sooner rather than later. Again if you can see that lactic acid starting to build up, we will treat them just as they are shocked, give them the volume replacement sooner than later. Those changes that occur however, must be kind of captured in that 1-2 hours after the initiation where they start to be compromised so that we do have the opportunity to reverse those things that have happened instead allowing them to go on to the later stages of shock. Again those things that really are the underlying causes of hypovolemic shock are going to be hemorrhage and that of course can be external or internal and of course external we are going to be more apt to pick up on it, going to be able to see that opposed to internal where you really have to depend on your assessment skills. Dehydration which can be relative to a lot of things not just N&V, heat exhaustion things such as that. Cardiogenic shock of course is from the actual heart muscle is unhealthy and pumping is directly impaired. The person has a problem and this person likely has left ventricular hypertrophy where the left ventricle is essentially the workhorse of your heart. It does all the work, and a lot of times when you persons with cardiomyopathy or LVH where that muscle has been dilated so bad, it’s been stretched so much that the pump is not effective anymore. An MI is the most common cause of direct pump failure where they actually have the coronary arteries depending where the occlusion or blockage is or lesion in the coronary artery is, is where that part of the myocardium is impaired or effected. So if the coronary
artery that wraps around the left ventricle has a blockage or occlusion, then the left ventricle is going to be stretched and stressed the most. It could have necrotic tissue that is not recoverable. Necrotic tissue is dead tissue, it doesn’t work anymore, it will not work anymore so they may have hypokenesis of a wall that doesn’t move that volume like it is supposed to, so if a pump is bad, the cause of the shock rests or resides in the heart. That is going to be the premise of cardiogenic shock; that is going to be where that actually happens at. Let’s see on the slides you have myocardial infarction as the most common cause of direct pump failure. But you know you can have indirect pump failure from things such as pulmonary hypertension, a PE can cause cardiogenic shock because of that volume again, not being able to return and increases intrathoracic pressure. There’s a chart in your textbook for me to refer you to as far as
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- Winter '16
- hypovolemic shock, Sepsis