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Southern_girl29
04-08-2007, 03:50 AM
My character is stabbed in the upper arm. Could she lose enough blood with that kind of wound to need a transfusion? What kind of tests do doctors do to find out about blood loss and if the person needs a transfusion? Thanks in advance.

Vanatru
04-08-2007, 07:16 AM
What's she stabbed with? Pen knife, stick, bowie knife, pencil, tweezers?

How deep? Surface scratch, below the fatty tissue, deep down into the muscle?

Is she going pail, are her gums and fingernails going white?

-Bill

Tish Davidson
04-08-2007, 09:41 AM
Upper arm is not the greatest place for blood loss. Obvious blood loss plus very low blood pressure and difficulty stopping the bleeding would be signals for a transfusion.

Rosamund
04-08-2007, 02:35 PM
How long before she gets to medical help?

How long before pressure is put on the wound to slow down/stop the bleeding?

My flatmate broke her upper arm a few years ago. The bone pierced the skin, resulting in a stab-like wound. She lost enough blood to drench the side of her top before the bleeding was attended to (I had to soak and wash her clothes for her - they were stiff with her dried blood), but that wasn't enough to need a transfusion.

kikazaru
04-08-2007, 06:23 PM
I think you would need to sever an artery before it would be life threatening. Also if the victim raises her arm, this slows blood loss even further (hard for the blood to be pumped uphill.)

If it is a really bad wound, there is the danger of the victim going into shock - and this can be lethal.

jclarkdawe
04-08-2007, 07:15 PM
I was hoping someone with more medical knowledge might answer this. I'm a former EMT/firefighter, so I'd be more informed about the field treatment than the what happens in the hospital.

It is possible that a stab wound could cause a significant loss of blood. It would not be likely, but if someone hacked the arm almost all the way off ...

Okay, here comes the brief lesson on blood loss --

The average adult has between 10 - 12 pints of blood (weight of 150 pounds). A pint of blood is usually referred to as a 'unit.' There are four classes of blood loss. Class 1 is up to 15% (1.5 units) and has little or no effect. To see how much blood loss is involved, take your measuring cup, take some red food color, and spill three cups of water on the kitchen floor. Big mess and if you walked in on a scene like this, you'd be in a state of shock.

Class 2 is up to 30% (3 units) blood loss. Add three more cups onto the floor. You're beginning to see signs, patient would be pale, blood pressure narrows, pulse increases, breathing increases. Skin would be cool, pale and dry.

Class 3 is up to 40% (4 units) blood loss. Add two more cups onto the floor. Rapid heart rate, rapid respiration, cool, clammy extremities. Patient would be confused, restless, and anxious. Medical emergency. Lights and siren all the way to the hospital. One, probably two large bore IV's running. Supplemental oxygen. Call to ED to let them know what they're getting. Surgical team would be notified. I'm guessing there would probably be a transfusion at the hospital. By the way, your floor is a mess. Until you've walked into a scene with this amount of blood loss, you won't believe how much blood is in a human being.

Class 4 is more than 40% (4 units) of blood loss. Patient is rapidly bleeding out. Hopefully patient has a will, because more likely than not, they're going to need it. Incredible amount of blood is the person is not bleeding into themselves. Everything will be red. Patient is only marginally responsive. Blood pressure probably unreadable. This is what is called professionally, an "oh, shit" call. Like when you walk in on the scene and go, "Oh, shit."

Tests are: blood pressure, capillary refill, pulse, respiration, observation (when EMT tells the doctor "Oh my God, there was blood everywhere.").

On the hospital end, the test would be for blood type. Here's where I don't know too much. I believe that in cases involving large amount of blood losses, they put blood in before matching is done, but I'm not sure. Class 3 and 4 go through the ED and up to the operating room before the ambulance leaves the hospital (cleaning takes a while in these cases).

Other than suicide, it's hard to get the blood loss with an arm injury. You really have to know what you're doing. I'd add a couple wounds to the stomach to get up to a Class 3 blood loss. The other alternative is a lot of hacking damage to the arm, but chances of full recovery to the arm would be unlikely. Good possibility of amputation.

I hope this helps.

Jim Clark-Dawe

After reviewing this, I remembered that a unit is 1 liter of blood, not one pint. I don't remember the conversion between the two.

ColoradoGuy
04-08-2007, 09:05 PM
The blood volume of the average adult is 5-6 liters. Normal blood hemglobin (hgb) value is 12-14 grams/100mL of blood. We use that (or its cousin, the hematocrit) to gauge how much blood someone has lost. Remember that blood has two important components: the actual red cells, which carry the oxygen, and the volume of the fluid itself. In a bleeding patient, the volume is usually replaced with IV fluid alone and the patient observed to see if he/she fits transfusion criteria. There are not absolute parameters about when someone needs a transfusion (folks argue about this a lot), but here are some guidelines for transfusion in acutely ill people:

Transfuse if hgb is less than 10 and the person is expected to continue to lose blood.
Transfuse if hgb is less than 10 and the person has a significant need for oxygen therapy, or if it less than 12 and the person has a very high need for oxygen.
Transfuse at any value of hgb if the person is in clinical shock from known blood loss (this is because the hgb value takes a few hours to adust itself and an actively bleeding person may be in shock with a normal hgb value if this adjustment has not happened).
Transfuse if hgb is less than 8 (some say 6) no matter what -- this corresponds to loss of about half your blood volume.
Transfuse for hgb less than 10 and the person shows symtoms of anemia (typically fast heart rate) after the volume loss itself has been replaced with IV fluid.
I doubt your character would need a transfusion unless a major artery in the upper arm got severed (axillary or brachial arteries) and then only if nothing was done about it or the person trying to help was especially inept -- as others have noted, usually elevation of the arm with direct pressure slows things down enough to clot.


I hope this helps you. (I do this for a living, BTW.)

Southern_girl29
04-09-2007, 03:33 AM
Thanks everyone. I decided against the blood transfusion. She needed stitches and was taken to a hospital not too long after it happened, so I don't think realistically she would have needed one. Thanks again.

Parkinsonsd
04-09-2007, 03:41 AM
I'm glad it wasn't that serious. Hopefully, she'll be up on her feet again in no time.

Kentuk
04-09-2007, 06:57 AM
Couldn't you just have her bleed a pint, it would make a wonderful mess.

Tsu Dho Nimh
04-09-2007, 03:55 PM
"My character is stabbed in the upper arm. Could she lose enough blood with that kind of wound to need a transfusion?"

Does she NEED a transfustion for plot purposes? If so, it can happen.

Yes, if the stab wound involves one of the arm's arteries (which, BTW, are pretty well protected against injury). But probably not. And it's easy to apply pressure to those wounds.

"What kind of tests do doctors do to find out about blood loss and if the person needs a transfusion?"

A CBC (Complete blood count) or H&H (Hemoglobin and Hematocrit), followed by a transfusion. HOWEVER, current practice is to not do transfusions unless the patient is dangerously low on blood, like losing at least 2 pints. That's a LOT OF BLOOD when it's all over your clothes, bedding, and furniture ... a blood donor regularly loses about a pint with every donation. The theory is that it's safer to grow your own than get someone else's.

A ski accident last year - skier sliced his knee on someone else's snowboard - was a 1.5 inch cut that soaked his pants leg from the knee down and took 22 stitches to close up the artery and laceration. He was found by the ski patrol on slope with a ski hat and scarf wrapped around the knee to stop the bleeding. They made sure there were no other injuries, wrapped it a bit better, and hauled him downhill in a toboggan to the aid station. He walked out of the aid station with a clean pressure bandage on his knee to go to the doctor in town, and walked out of the doctor's office (I stopped at the office for some reason just as he was leaving). No transfusion needed. He probably lost 200cc of blood.

Tsu Dho Nimh
04-09-2007, 04:04 PM
On the hospital end, the test would be for blood type. Here's where I don't know too much. I believe that in cases involving large amount of blood losses, they put blood in before matching is done, but I'm not sure. Class 3 and 4 go through the ED and up to the operating room before the ambulance leaves the hospital (cleaning takes a while in these cases).

If the patient is bleeding THAT much, the blood bank takes the SIGNED "release uncrossmatched" form from the physician and hurls a couple of units of Oneg out the door to keep the patient alive.

Then they do a fast typing (ABO and Rh check), and switch to "type compatible" blood. It may not be the same as the patients type, but it won't hurt them.

After the dust settles, the technicians go back and run a proper crossmatch on everything the patient received.


After reviewing this, I remembered that a unit is 1 liter of blood, not one pint. I don't remember the conversion between the two.

Unit is actually 450-500CC ... about a pint.