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leahzero
03-31-2010, 01:04 PM
Quick med question:

I have a person who has just arrived in a trauma center and has lost a lot of blood. However, it's important that her blood gets tested immediately.

Would it make sense for a doctor to order the nurses to collect seepage from the wounds to test? (For reference, it is being tested for viral infection.)

shaldna
03-31-2010, 01:32 PM
Quick med question:

I have a person who has just arrived in a trauma center and has lost a lot of blood. However, it's important that her blood gets tested immediately.


Why?

In my experience that is secondary to getting blood into her. They would not need to test the blood prior to infusion as they would use a universal type.



Would it make sense for a doctor to order the nurses to collect seepage from the wounds to test? (For reference, it is being tested for viral infection.)

Only if testing for specific infection. However, bear in mind that surface blood is 'contaminated' blood and so they may not get an accurate result.

Wiskel
03-31-2010, 03:01 PM
Think practicalities.

In a trauma centre, or A&E, the equipment we need to take blood is right there, it takes seconds to get it and it takes an experienced doctor or nurse under a minute to take the blood samples, and so if the centre is adequately staffed they'll be done without any fuss and won't delay anything else happening.

Secondly, the tubes for collecting blood are sealed. There is no way to get blood from an open wound into them. They're designed to be punctured by the other end of the needle that's in the vein. http://en.wikipedia.org/wiki/Vacutainer Plus if you don't treat the blood sample with care it can haemolyse and the blood tests can't tell you everything you need to know and need repeating. An averge adult has about 8 pints of blood. Blood tests take a few millilitres. They'll be done from the vein no matter how much blood is seeping from wounds. Swabs might be taken from the wounds themselves, but they're different from blood tests.

Thirdly, if your patient is suspected of having a viral infection, especially a dangerous or contagious one, the staff working on them do not want to spread infected blood everywhere by messing around collecting blood from seeping wounds. They'd be doing their best to minimise the spread of infected blood and won't want it all over their gloves if they can help it. Contact with the wounds will be the minimum needed to stop the bleeding and treat them. A venous blood sample is cleaner and safer.

Craig

Tsu Dho Nimh
03-31-2010, 04:26 PM
Quick med question:

I have a person who has just arrived in a trauma center and has lost a lot of blood. However, it's important that her blood gets tested immediately.

Would it make sense for a doctor to order the nurses to collect seepage from the wounds to test? (For reference, it is being tested for viral infection.)

No ... seeping wounds are contaminated and will not give accurate results. The lab techs will collect blood in the appropriate vacuum vials from the usual spots, using the usual request slips. There are "standing orders" ... in case of ___, collect ___ and test for ___. It usually has a couple of spare vials in case the doc wants something extra on pre-transfusion or pre-treatment blood.

One thing that DOES happen: Nurse or doc inserts the IV start kit needle, lab tech uses the convenient opening to collect the needed blood by popping off the tops and letting it run into the vials, then the nurse connects the IV bag ... one less puncture if the patient has few decent veins

Any vials of blood for crossmatching the transfusions MUST be collected and labelled according to AABB procedures or it will be tossed into the trash by the blood bank. Patient and vials have special tags that cannot be removed (transfusion mix-ups can KILL your patient - it's a very touchy area)

They might collect and hold a sample for the viral testing, or collect it and hand it to the virology testers, but no trauma center (or its lab) is going to give a darn about a virus when she's still bleeding out. And the number of viruses one can test for is quite limited, and takes a long time ... several days for most of them. Testing for antibodies a few weeks after an infection is faster.

QUESTION: Which virus? Few hospitals actually test for the uncommon viruses. They ship them to a central lab that specializes in it, often the CDC.

NOTE: After a few units of blood, lots of lab values to go hell for quite a while because you are testing the accumulated donor units and glucose-based preservatives ... so collecting quickly for things like identifying/culturing blood infections and transfusion crossmatching is essential.

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ADDING: At the very least, blood bank will want a blood type (ABO Rh) so they can give "type specific" blood. The "universal donor" blood is O Neg, and they like to keep it for those who truly need it (other ONegs, and infants). If the patient is APos, for example, they can get OPos, APos, and Aneg ... the truly lucky trauma victim is ABPos ... they can receive any blood type packed cells.

GeorgeK
03-31-2010, 08:42 PM
Universal donor blood is sometimes not universally receivable due to Bombay phenotype and sub typings beyond the ABO/Rh bloodtypes such as P and Lewis etc. The bloodbank is still going to want to do a crossmatch even if there is O negative on the shelf. Yes, sometimes they are in too much of a hurry and might skip it now and then, but most of the time they will crossmatch.

In a major trauma it is also common to put in a central line and draw blood from that. Periperal lines are hard to get when someone is already in hypovolemic shock.

They wouldn't test for viruses on a trauma patient (except for maybe hepatitis and HIV since those pose a possible threat to the healthcare workers) but they would have drawn a cbc which can give you a good idea that someone might be infected with some sort of virus, but as others have said, viral cultures are expensive and very time consuming. Most likely that would be something to follow up on about 6 weeks after the patient goes home to make sure that the possible viral infection isn't one of the various leukemias.

veinglory
04-01-2010, 01:03 AM
I also have trouble seeing how with would be necessary. Even is someone is bleeding a few mls won't make a big difference, especially as they will be getting transfused with that much in very short order. And the collection happening right then versus half an hour later is unlikely to even effect how quickly the results come back. I think they would collect the blood the usual way.

leahzero
04-01-2010, 02:42 AM
Thanks for all the answers. I was wondering if contamination would make it pointless to collect blood from outside of the body.

Okay, so they'll take blood from a vein even if the patient is bleeding--got it.

As for why, it's important that the patient gets tested because of plot reasons.


One thing that DOES happen: Nurse or doc inserts the IV start kit needle, lab tech uses the convenient opening to collect the needed blood by popping off the tops and letting it run into the vials, then the nurse connects the IV bag ... one less puncture if the patient has few decent veins

Perfect--thanks for this tidbit of info!

Tsu Dho Nimh
04-01-2010, 07:39 PM
Universal donor blood is sometimes not universally receivable due to Bombay phenotype and sub typings beyond the ABO/Rh bloodtypes such as P and Lewis etc. The bloodbank is still going to want to do a crossmatch even if there is O negative on the shelf. Yes, sometimes they are in too much of a hurry and might skip it now and then, but most of the time they will crossmatch.

I have worked in US trauma center blood banks ... they ALWAYS do the crossmatch, whether it's after the fact, or even post mortem, for any unit of blood that was partly or completely transfused. It is required by the AABB and if you don't follow AABB procedures, they shut your blood bank.

Here's the way AABB procedures work.

Screaming Emergency: The patient is going to die within a few minutes if they don't get volume, including RBC. ER/OR calls BB, lets them know how many units they need.

The doc signs a release for n units of uncrossmatched blood, stating that the medical need for the blood is severe enough that the patient will not survive unless they get blood immediately. This absolves the lab of any responsibility beyond accurately handing over ONeg or type-compatible blood. "N" typically has an upper limit, to keep docs from tying up the entire supply of blood in their OR ... ours was 6 at a time, maximum.

Maximum number of uncrossmatched units I have personally handed over for one patient, over the period of under an hour, was 27 ... by that time she had no blood of her own left. We had cops using lights and sirens to bring ONeg from nearby hospitals.

Someone hand-carries that paper to the blood bank and waits for the blood. No signed paper, no blood for you.

In the brief time it takes for the paper to arrive, one BB tech has selected n units,snipped off a couple of the already labelled sample segments from the tubing on each unit, inserted them into test tubes, and started a "crossmatch sheet" for that patient and the blood they are getting. Until the emergency is over, no other tech touches that sheet or those segments ... if it's still screaming an hour before you are scheduled to leave, a second tech starts their own sheet and tracks "their" units and you finish the crossmatching and the paperwork for "your" units ... provided you have a sample from the patient. Techs cannot hand off an unfinished crossmatch - if they drop dead, the replacement tech has to start from scratch.

The blood bank labels and throws that number of ONeg units over the counter at the person with the request (actually, puts it into a labeled cooler with refrigerant). They also send someone from the lab to tag the patient with the matching transfusion band (bright orange, can only be removed by cutting) and if at all possible, grab a few vials of blood to start screening, crossmatching, and shift to type-specific uncrossmatched if possible to preserve ONeg for the next trauma.

We're not worrying about the oddball blood types like Bombay or the possibility of a private antigen in these cases. These are the cases where blood is dripping off the gurney or OR table onto the floor.

Routine Emergency: In the absence of a release form, the blood bank does an immediate blood type for ABO and Rh so that type-compatible blood can be issued if a release form lands on them, starts screening the patient's blood for unusual antibodies using the "panel" (a commercial collection of human blood cells made from donors with convenient types that make it easy to spot the uncommon stuff that wrecks transfusions), and simultaneously crossmatching the requested number of units.

If the doc calls demanding blood before the crossmatches are completed, the blood bank tech reminds him that the only way blood leaves without a completed crossmatch is with a signed release form, would he like to sign for it or not? Usually not, because the release forms would always get reviewed by the chief of ER or OB/GYN or whatever.

A common emergency room order is "Type, screen and hold" ... meaning to get the patient's ABO and Rh, screen patient for antibodies to make sure there aren't any, and wait for further orders.

We had a set protocol for some emergencies: gunshot wounds to the torso or thigh automatically got a certain number of units set aside just in case they were needed, until the patient was out of surgery.

Impossible Transfusions: It has happened that a patient has an antibody that caused agglutination or hemolysis in every ABO and RH matched unit we tried, but was not identifiable with any of the cell panels we had.

When that happens, the blood bank will not issue any blood for transfusion, no matter what the doctors sign or threaten ... yes, they will die from blood loss, but killing them by transfusion reaction isn't any better. One idiot of a doc asked "what if I just come down and take some ONeg" ... my reply was "I'll testify at your homicide trial that I told you it would probably kill the patient and you transfused it anyway."

We would send samples off to the major antibody research centers, with all our results and the cell panels we used, screen blood relatives for potential donors, and hope we got lucky.

More often than not, the patient dies and their antibody is added to the long list of rare ones provoked by "private" antigens. Usually it's a woman with multiple pregancies, and her husband has the antigen. Less often it's someone who got multiple transfusions previously and we could check their earlier donors to see who had the antigen (for research purposes).