Pulmonary embolism

leosrain, BSN, RN · Jul 4, 2007

I'm not sure what the correct answer is...but wow! I would never wait for a doc's orders before giving 02 in an emergency. I'd probably be elevating the bed and administering 02 at the same time. But you're right, I can't immediately recall the correct bed positioning. I now feel the need to research it stat!

I do know that if the patient has a PE, the clot has already gone through the heart and to the lungs, so it would be hard to trap it in the heart.

Can anyone better describe the correct actions?

Daytonite, BSN, RN · Jul 4, 2007

Since you didn't specify what the two questions were, i can't make an assessment as to why one answer was correct for one question and the other answer was correct for the other question. I can tell you this, however. These questions are designed to test your ability to think critically. They involve putting together a number of pieces of information that you are supposed to call to your mind: the nursing process, the disease process and the treatment and nursing interventions that are normally given when you are presented with a scenario.

What i can tell you is this. Your very first priority would be to address the patient's physiological need for oxygen, so give oxygen. You may need a doctor's order to do that because oxygen is technically a drug. If you don't, he's going to go hypoxic on you eventually and it won't make any difference if the head of his bed is elevated or not because he is going to be dead from anoxia.

Depending on how the question was worded, however, elevating the head of the bed might be the answer choice as your first independent nursing action. You don't need a doctor's order to elevate the head of the bed. You can do that to help ease his breathing while you are running off to the phone to call the doctor for the order for oxygen.

For some questions you have to know from the wording whether they are asking about dependent (requiring a doctor's order) or independent (something a nurse can do on their own) nursing interventions. So the question may also be testing you for your knowledge of nursing law too.

Leosrain. . .the reason you position the patient in trendelenberg on their left side has to do with the normal anatomy and physiology of the circulation of blood through the heart and lungs. Deoxygenated blood is pumped from the heart through the pulmonary artery to the lung where it circulates through the lung to exchange carbon dioxide for oxygen. The oxygenated blood returns to the heart via the four pulmonary veins and goes into the left atrium and then the left ventricle. Blood is pumped out of the heart and into the general body circulation via the aorta which is kind of like a left side exit off the freeway rather than a normal right hand exit. The aorta and aortic valve are actually located more toward the central area of the heart.

Now, think about the physics of this. If you've got some kind of embolus (air, is the more likely candidate) and you want to prevent it from getting into the general body circulation, the best way you can prevent this is to: (1) get the patient into a trendelenberg position. This is where the patient's head is lower than their feet. What does that do? It now makes the left ventricle of the heart (it's apex) the highest part of the heart if you consider it's relation to the horizon. (2) turn the patient to their left side. The aortic valve and the aorta are the last places the blood travels as it makes it way out of the heart and it's your last chance to prevent an air embolism from escaping into the general circulation. Any air is either going to float to the top of the highest point of the structure it is in (not a danger in the atrium, goes to the apex of the heart if it's in the ventricle). Meanwhile, the liquid blood continues to be pumped around normally. If you make a boo-boo and put the patient in reverse trendelenberg and/or turn the patient on their right side, guess where your air bubble is going if it gets into the left ventricle? You can kiss some major organ goodbye because there's a danger of the air embolism occluding a blood vessel in one of them resulting in anoxia and tissue necrosis.

Nuieve · Jul 4, 2007

Daytonite, thanks for tuning in...

The questions in question :) were general questions about what nurse should do first when suspecting air embolism following some procedure (list of procedures given. two totally wrong, and two - one about oxygen the other one about raising bed head). Unfortunately Saunders (both book and CD) mysteriously lost the embolism related questions - I just skipped through the whole CD trying to locate any one of them, but with no success.

Anyway, what I'm trying to find out is, when is patient placed in Trendelenburg position and when Fowler... I would assume, Trendelenburg is used when embolism is suspected/expected (not yet entered pulmonary circulation), and Fowler - when embolism already occurred (stuck in one of pulmonary arteries). Although I'm curious what symptoms can lead a nurse to suspect an "incoming embolism" as opposed to the one that already occurred...

Daytonite, BSN, RN · Jul 4, 2007

Ah, i got it. You don't put a patient with a embolism (blood clot) in a trendelenburg position at all. You'll probably kill them. Air embolism (a large bubble of air) is a different story because it is life threatening. Keep in mind that air is the lightest substance we know and air rises. The last place you want air to go is into the brain. The patient will have a stroke and die.

Air embolism is almost always a complication of a central venous catheter. It somehow becomes open to atmospheric air, the patient takes a breath and negative pressure causes air to be sucked into the proximal end of the catheter. Since the distal end of these central catheters is seated in the subclavian vein, and more often the superior vena cava, guess where that bolus of air goes? The right atrium of the heart! When that kind of air embolism happens you immediately put the patient in trendelenburg because the air bubble is lighter than blood and it is going to float to the highest point within the body cavity it ends up in. If it's in the right atrium of the heart it goes toward the lateral wall; if it's in the left atrium it goes toward the septum--if the patient is in trendelenburg. If it's in the ventricle it goes as near to the apex area as it can get. The turbulence created by the pumping action of the heart will break off smaller little bubbles that can end up in the general circulation. Those don't cause any harm. See the information on air embolism on pages 140 and 141 in the saunders book. This business of air bubbles in the veins underwent some discussion as well as air embolism on this thread some time ago:

Pulmonary embolism is a different story. Did you see the information on page 738 of the saunders book? Look at the box down at the lower left side of the page. These are the progressively worsening symptoms. These patients can get really short of breath to the point where they are having a respiratory emergency. They need help breathing. Trendelenburg position will aggravate their breathing problems. Ever try to breathe tilted downward or standing on your head? Try it some time. A pulmonary embolism is not likely to move out of the lung. It's often trapped there. Now, that's not to say that it can't, but it's not likely. The network of blood vessels in the lung starts out large at the pulmonary artery but become smaller and smaller as they spread out to the capillaries in the alveoli in order for the blood to dump carbon dioxide and pick up oxygen. A clot usually ends up trapped in one of those smaller pulmonary blood vessels and can't get out. Depending how big the clot is determines where it gets stuck and how much damage it is going to do. In order to get out of the lung, it's got to get through the small capillaries of the alveoli and start making it's way to the pulmonary veins. My copy of Nurse's 5-Minute Clinical Consult: Diseases from lippincott williams & wilkins on page 646 list these complications of a pulmonary embolism:

respiratory failure
pulmonary infarction
pulmonary hypertension
embolic extension (basically, this means the clot gets bigger)
hepatic congestion and necrosis
pulmonary abscess
shock
acute respiratory distress syndrome
massive atelectasis
right-sided heart failure
ventilation-perfusion mismatch (crappy abgs)
death

Notice that nearly all of them are respiratory conditions or they bring on congestive failure conditions in the heart or liver because the clot is blocking the circulation and blood is backing up system circulation.

If you also look at page 225 of saunders they give a definition of trendelenburg position. Notice the very last thing says, "this position is contraindicated in clients with head injuries, increased intracranial pressure, spinal cord injuries, and certain respiratory disorders." (saunders comprehensive review for the nclex-rn examination, 3rd edition, by linda anne silvestri) dyspnea is a symptom of almost all respiratory disorders. If you have a patient having dyspnea don't put them in a trendelenburg position. It will compromise their ability to breathe.

Hope that helps clear this up for you. I have to tell you that my mother developed a pulmonary embolism when she was in the hospital two years ago. It was found on one of the x-rays or scans they did of her lungs when they were looking for metastasis of her cancer. The doctors were puzzled because she didn't have one symptom of it. That's why i mentioned the list of symptoms on page 738 of saunders was "progressively worsening".

By the way, when I don't have anything else to do I put that cd from saunders nclex on my computer to play around with. There are lots of errors in it. Even their explanations (if you use the study mode) will have the correct information while the correct answer choice is scored incorrect. Maybe we should ask for some of our money back from the publisher or a discount toward another one of the books they publish.

Nuieve · Jul 4, 2007

Daytonite,

Thanks for clarification and for the thread link - I just read it, very interesting... I wasn't aware that it takes that much air to do damage... Yes, I have a pretty clear picture of it now... except for one thing. The book says (page 141): "If an air embolism is suspected... place the client in left Trendelenburg".... I wonder what are the signs of suspected embolism? I can imagine if a nurse witnesses (hears) air being sucked into the CVC site... But what if it's silent, or she's not in the room? What if she comes into a room to a patient that has "suspected" embolism? What signs/symptoms make a nurse decide that the embolism occurred, but has not reached pulmonary circulation yet? I mean, if it's in the lungs and the patient is having pain, tachycardia, tachypnea etc - it's not suspected anymore, it's there and you don't place the client in Trendelenburg because embolus is already in the lungs and it won't get out of there by the use of positioning. So the only time Trendelenburg can be used is when the clot is stuck somewhere before the pulmonary artery (right side of the heart, or superior vena cava)... I wonder what are the signs of an embolus in the "pre-pulmonary" system?

Oh, and btw, yes, Saunders is full of errors, badly worded question/answers, and just illogical rationales. I even started a thread in the NCLEX forum about it, registering all the errors I could find but eventually I just got tired... :) It's still a nice book nonetheless...

VickyRN, MSN, DNP, RN · Jul 4, 2007

Great discussion! Wonderful posts and explanations, Daytonite ? You may also find this website useful (it explains the difference between a regular clot-type embolus and an air embolus):

http://www.icufaqs.org/PulmonaryEmbolism.doc

Clot-type embolus (PE) have them sitting up high-Fowler's to expand the lung tissue, facilitate lung aeration and reduce "dead space" as much as possible. Air embolus: left Trendelenburg to trap air in right atrium.

Daytonite, BSN, RN · Jul 4, 2007

Keep in mind that air embolism is usually a complication of a procedure or a device; a pulmonary embolism is a disease process. The patient doesn't have any symptoms that i can think of except the symptoms of the damage that the air embolism would have already done--anywhere from a stroke in the brain, an mi in the heart, an infarction in another organ such as the kidney or mesentery to death. So, you'd investigate the symptoms the patient is exhibiting or complaining about and take appropriate action for that. So, you would be assessing the patency of the device. If you discover evidence of device failure that would be likely to lead to an air embolism, then you take immediate action to protect the patient from air entering the general circulation through the faulty device (clamp the tube and I would have them turn to their left side) and notify the doctor immediately. If an air embolism is suspected to have entered the vascular system during a procedure, and the practitioners doing these procedures are trained to be aware and watch for this, get the patient's body tilted down into trendelenburg position and turn him to the left because that air bubble is probably right in the heart. You are not going to see air embolism very often on a general medical unit unless the patient has a central vascular access line.

I was an iv therapist for many years. I can't tell you the number of patients that managed to sever their hickman lines (i'm talking about tore the distal end off!) and they never got air embolisms. We would find patients walking around with the end caps gone from the ports of their triple lumen catheters, picc lines and hickman lines and no air embolism. I can't tell you why it didn't happen. I have my suspicions that it was either because the lumens can only accommodate a small volume of air that is not enough to cause problems during an inspiration or the fibrin sheath flaps that tend to develop and cover the distal openings of these devices within 24 hours after insertion may have had something to do with protecting them from sucking air through them (sometimes nothing will flow into these lines except under the pressure of an iv pump and the groshong access is always closed and only opens when iv pump pressure is applied to it, so many central vascular lines are now made with groshong tips for safety reasons), but I can't prove that to you. I can tell you that my shock and fear was very real whenever one of these devices was found like this and the line was clamped off immediately.

Daytonite, BSN, RN · Jul 4, 2007

VickyRN said:
Great discussion! Wonderful posts and explanations, Daytonite ? You may also find this website useful (it explains the difference between a regular clot-type embolus and an air embolus):
http://www.icufaqs.org/PulmonaryEmbolism.doc
Clot-type embolus (PE) have them sitting up high-Fowler's to expand the lung tissue, facilitate lung aeration and reduce "dead space" as much as possible. Air embolus: left Trendelenburg to trap air in right atrium.

I couldn't stop reading this article. Had me smiling all the way through, especially when she mentioned preload. Nuieve. . .make sure you read all the way to the bottom since she also addresses air embolism. I was not an ICU nurse so I never saw this kind of stuff related to the hemodynamic monitoring lines, but I'm sure the ICU nurses have. Loved the pictures. Especially the one of the brain with the air embolism. Yikes!

emtb2rn, BSN, RN, EMT-B · Jul 5, 2007

Yeah, Mark's site (http://www.icufaqs.org/) is great. I find myself out there a lot. Mark's has a superb writing style, informative yet highly enjoyable to read.

Do you find yourself talking outloud when reading the articles? As Joe Pesci said in "My Cousin Vinny", "Shout 'em out if ya know 'em."

Nuieve · Jul 5, 2007

Ok, now it's all clear. Thanks! :)

queenjean · Jul 6, 2007

I think I'm in love with Mark......

Pulmonary embolism - nurse's actions

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