Shock, Sepsis, Sirs, Mods Flashcards
What a shock?
Not enough oxygen for tissue perfusion.
That is really the essence of shock one so when you watch TV and you watched all of the medical dramas, and the patients are in shock, what are they treating them with?
Fluids. which is the exact second thing to do. The first thing to do is oxygen. Always remember that.
So there is a few things that I want to review, tissue and oxygen perfusion is directly related to mean arterial pressure, and there are three factors that influence mean arterial pressure.
The first factor is total employment volume. Second factor is cardiac output, and the third factor is the size of the vascular bed.
So if total blood volume and cardiac output are low, mean arterial pressure will be low.
If cardiac output and total blood volume are high, the mean arterial pressure will be high.
What is the required for minimum mean arterial pressure to perfuse the heart?
- So any time that the mean arterial pressure drops below 60, we should start to get nervous.
if your heart rate is higher than your systolic pressure…
you need to be calling somebody.
Now, in terms of the size of the vascular bed, if it becomes larger, the mean arterial pressure drops.
So when I say that the vascular bed becomes larger, what am I really saying? Vasodilation. Exactly.
So if we had vasoconstriction, and all of a sudden the vascular bed is smaller,…
the mean arterial pressure goes up. We get faster flow.
What controls vascular bed size ?
sympathetic Stimulation. So if you have an increased sympathetic nervous system stimulation, you are going to increase mean arterial pressure.
Any issue that impairs oxygen delivery to tissues and organs can start the syndrome of shock.
Any issue that impairs oxygen delivery to tissues and organs can start the syndrome of shock.
Shock is a syndrome because
it occurs in a predictable sequence and pattern.
Additionally shock is a metabolic condition, because
oxygen delivery is not adequate to meet tissue demand. It represents a whole body response. Everybody’s system is affected by shock.
now there are some common cellular changes that occur in all of the types of shock. The first one is…..
decreased energy production. So decreased ATP
With that decreased energy production comes decreased aerobic metabolism, and increased in aerobic metabolism. What is the outcome of increased anaerobic metabolism?
Lactic acid. Which results in what type of acidosis? Metabolic.
You have decreased cell function, so whatever the cell is supposed to do, it’s not working right.
So if it is a pancreatic cell, you have insulin issues. If it is a heart cell, you have rhythm issues. If it is a lung cell, you may have diffusion issues. So it could be an issue with oxygenation, or what is the other part? Ventilation.
You will have altered integrity of the cell membrane. If the cell membrane alters itself, what happens inside the cell?
It is going to be “Bad”. The cell is going to explode. We call this process apoptosis. because it is what the cell is doing. It is popping open. With those changes in the cellular environment, you will have an acidosis, electrolyte changes, rupture of the lysosome and then apoptosis.
hypovolemic shock. What is really going on here?
too little circulating blood volume.What is important here is that in this extracellular fluid, a quarter of this is plasma, and three quarters of this is interstitial.
in hypovolemic shock when there is too little circulating blood volume are issue is decreased intravascular volume.. Because of that decreased intravascular volume, we had decreased venous return. What does that sound like?
CHF.
decreased intravascular volume leads to…
decreased venous return…
decreased venous return leads to….
decreased ventricular filling…
decreased ventricular filling…leads to…
results in a decreased stroke volume….
results in a decreased stroke volume leads to….
a decreased cardiac output..
a decreased cardiac output leads to…
decreased tissue perfusion, which takes us to cellular changes….
those cellular changes are those that I just mentioned where you have decreased ATP production,
where you have decreased cell function, where you have changes in the cellular environment, and then the cell gets mad and it blows itself up. Suicidal cells.
cellular changes are where you have decreased ATP production, where you have decreased cell function, where you have changes in the cellular environment, and then the cell gets mad and it blows itself up. Suicidal cells. So how do we see this in the patient?
Decreased MAP
Now what are some causes of hypovolemic shock?
Bleeding, hemorrhage is the number one cause. can be external- Gunshot wounds, stabbings,can be internal- gastric ulcers, varicies, Also causes of hypovolemic shock include– dehydration from heat exhaustion or vomiting/diarrhea. - elderly- don’t drink enough- burns- DKA/DKI with excess UOP
If uncorrected, hypovolemic shock will go through 4 predictable stages. The first of those is the early stage…..
where the baseline mean arterial pressure drops by about 10 mmHg. unfortunately we don’t tend to see that because the blood pressure usually rises in this phase, as a compensatory mechanism because we have adaptive mechanisms that are working and that is a good thing.***** we had an increased heart rate and respiratory rate, and a slight increase in our diastolic blood pressure. All of this is due to increased vascular tone, from the sympathetic activity. The body is saying “I don’t have enough cardiac output, so I’m going to squeeze the vessel a little bit, and I’m going to increase the heart rate. Because I am attempting to affect heart rate times stroke volume equals cardiac output.”
Stage 2 Hypovolemic Shock-non-progressive compensatory stage
where the base mean arterial pressure has dropped about 15 mmHg. The adaptive mechanisms are effective for vital organs. So we had good blood flow to the kidney. We have good blood flow to the heart and brain, but the stomach not so much. This is all driven by renal and barrowreceptor response located in the kidney, and hormonal compensation. **Slight increase in diastolic blood pressure and increase in heart rate and respiratory rate, but you are also going to see an acidosis. Subjectively the patient is going to be anxious. objectively, they are going to be restless, they are going to have tachycardia, tachypnea, a decreasing urinary output, their systolic blood pressure will be dropping, diastolic blood pressure will be rising.They will have cool extremities, and you will begin to notice a 2 to 5% decrease in their stats. Their oxygen saturation’s… so if they were at 100%, they are now at 95%. If they were at 90%, they are now at about 86%.
In the progressive stage, or stage three hypovolemic shock…
the mean arterial pressure has now dropped about 20 mmHg. The adaptive mechanisms are less effective but still functional that there is not enough oxygen to the vital organs. So we had poor oxygenation. Because of this, we have a buildup of toxic metabolites, and cellular death. So the vital organs are hypoxic, and the non-vital organs are anoxic. The vital organs are hypoxic, so there is some oxygen there but not enough, the nonvital organs are a anoxic, there is no oxygen there. Skin, G.I. tract. Subjectively is severe thirst, deeper anxiety with impending doom. I am going to die. Objectively, they will have a rapid but weak pulse, a low blood pressure… We are now systolic less than 90, possibly even less than 80…, They will be pale to cyanotic, cool and moist skin and anuric. you will now notice up to a 20% drop in their sats. So if they were at 100% they are now at 80%. They will have a low blood pH. They will have an increased lactic acid level and an increased potassium. When you see these symptoms, you have about one hour to save this patient’s life, or we will end up in the refractory or irreversible stage.
Stage 4 refractory or irreversible stage Hypovolemic Shock…
At this point, it doesn’t matter what you do there has been too much tissue damage. Even if the shock is corrected and the mean arterial pressure returns to normal, there is too much cellular damage for the organism to survive. Signs and symptoms of the refractory stage is a rapid loss of consciousness, non palpable pulse, , cold and dusky extremities… Like the patient will look grey, slow and shallow respirations, almost like guppy breathing. Their sats will be not measurable anymore. You will not be able to pick up a waveform. Once we have widespread release of toxins, they will develop what is called mods. Multiple organ dysfunction syndrome. And once it starts it is a cycle. And it just gets worse, and we can’t reverse it.
Here is what you should always remember, for every body system that you lose, mortality increases by 10%
So if you have lost your liver function, your heart function, kidneys, now your moms, now your pancreas is gone…. That right there is a 50% mortality rate. So if I go in and have some condition that already has my mortality rate at 80% or 20% and I start losing organ function on top of that it starts to multiply. So as you are watching patients, remember that the skin is also considered a organ system, they can have decubitus ulcers, if they are intubated, those are two systems that are not functioning on their own. If they have some type of inotrope or vasopressor being used, that is three systems that we are controlling. If they are also on bedside dialysis, thats 4. If they are being fed with the NG tube thats 4 or TPN or liquids we are now up to five. So my mortality rate is up to 70 or 80%. Those patients require constant supervision by you the nurse.
So what are we doing to prevent Hypovolemic Shock?
Well, we are going to teach patients about adequate fluid intake during exercise and hot and dry environments. Because you can lose a large amount of fluid without having knowledge of it. We are going to use proper safety equipment and seatbelts to prevent trauma and hemorrhaging. And we’re going to be aware of hazards in the home or workplace.
Risk Factors For Hypovolemic Shock..
Being in the HospitalSo ID those at risk for dehydration, you can find these things on pages 175-176 but specifically I am speaking about **reduced cognition, reduced mobility, and in order to be NPO. So if I can’t move and I can’t tell you that I’m thirsty and you are not letting me drink anything…. You need to be thinking that I have a risk for hypovolemia.
Assessments for Hypovolemic Shock…
Assess post invasive procedures for obvious and occult bleeding, compare pulse quality and effectiveness with the baseline. Compare urinary output to fluid intake. Check the vital signs if the patient complains of a severe thirst. ***If in the outpatient setting, watch for obvious heavy bleeding, persistent thirst, decreased urinary output, lightheadedness, and a sense of impending doom. Why are they lightheaded? Not enough oxygen, because there isn’t enough fluid to get up there, so those things that I have just said, I want you to keep in mind, is that you can lose a large amount of fluid without knowing it. Especially in hot dry environments. **And in the outpatient setting, you really need to teach patients to let you know if they have a decreased urinary output or if they get lightheaded and dizzy when they standup.
Class I Hypovolemic Shock
they have lost about 15% of their bodily fluid, less than a liter. Not much we’re going to do about that, the body will probably take care of itself. Might give them some PO fluids.
Class 2 Hypovolemic Shock
they have lost about 15 to 30% so we are going to give them IV fluids. Lactated ringers is what our choice is. But before you get the fluids, our priority intervention is oxygen. Then we will get to the fluids. So one exam I may say to you that the patient has oxygen on, what is your next priority. What will the next priority be? Fluids…. Not setting them upright in the bed. this is not an issue of ventilation, this is an issue of oxygenation. And they have to have fluids to move the oxygen through.
Class 3 Hypovolemic Shock
we are not only going to be giving IV fluids, because the patient has lost about 2 L, we are going to start getting some blood products as well. If I give too many IV fluids and not enough blood to go with it, then I hyper dilute the patient. So essentially artificially dropping their hematocrit.
Class 4 Hypovolemic Shock
we are going to have to move beyond fluids and blood, and we are going to have to use volume expanders and vasoactive drips which we will come to more detail about those later. But… Specifically I want you to know dopamine. And what is dopamine really supposed to do? Increases cardiac output. **oxygen, ringers lactate which is a crystalloid , and dopamine…
cardiogenic shockPathophysiologically, you have myocardial insult. ….
And with that you have loss of critical mass. Well, what does that mean? That means the ventricle is broke and it don’t work no more. Then from that you have impaired ventricular function and from there we are here… Where you have decreased stroke volume, decreased cardiac output, decreased tissue perfusion, cellular changes. But if you have decreased cardiac output and decreased blood pressure what goes along with that for the heart? Decreased perfusion pressure. So you have decreased coronary perfusion. You end up with myocardial ischemia and necrosis, so you have an unhealthy heart muscle that has an impaired pump action and really what is going on here with this impaired off action is reduced systolic emptying. So when I pump I don’t get as good as squeeze and I don’t get as good as output as I want. I don’t get as good of squeeze, I don’t get as good of output.
The most common cause of cardiogenic shock is…..
heart failure from MI. We call that coronary cardiogenic shock. It is associated with coronary artery disease, and as a result in MI and cumulative necrosis of 40% or more of the left ventricle.
