Forensics and Fiction

Clever, Intriguing, and Downright Odd Questions from Crime Writers

D. P. Lyle, M.D.

Minotaur/Thomas Dunne Books

Forensics and Fiction
Part I
Traumatic Injuries, Illnesses, Doctors, and Hospitals
What Are the Symptoms and Signs of Bleeding to Death?
Q: What would be the symptoms and visible signs of being bled to death? The situation in my story is a man being bled to death by way of blood transfusion tubes.
Marion Arnott Paisley, Scotland Author of Sleepwalkers
A: Blood is a liquid filled with various cell types, one type being the red blood cells (RBCs). These contain hemoglobin, a molecule that carries oxygen (O2) from the lungs to the tissues and removes carbon dioxide (CO2) from the tissues and transports it to the lungs, where it is exhaled with each breath. Bleeding, depending upon how rapid it is, leads to two basic derangements. One is a drop in blood pressure (BP), resulting in shock, and the other is the development of anemia, which is a low level of RBCs in the blood. The former is due to a rapid drop in the volume of the blood (think bleeding air from a tire--as you do, the pressure within the tire falls) and the latter is due to a loss of the blood cells that carry oxygen.
In your scenario, if the blood is removed rapidly, the volume of blood in the victim's body falls, which causes a drop in BP, and results in shock and, if not treated appropriately and quickly, death. This is what happens when someone exsanguinates (bleeds to death) after an auto accident, a gunshot wound (GSW), or a rapidly bleeding ulcer. Depending upon the size of the person, the body contains from 8 to 12 pints of blood. The rapid loss of 3 or 4 pints would lead to shock in most people. So, if the blood were removed from your victim rapidly, his BP would fall and he would begin to show signs of shock.These signs and symptoms include shortness of breath, weakness, dizziness, chills, thirst, and as it progresses, confusion, disorientation, sleepiness, coma, and death. This could happen over a few minutes or an hour or so, depending upon how rapidly the blood was removed.
If the bleeding is slow (your villain removing a little blood each day) the person will become progressively anemic. In anemia the RBC count is low, so the ability of the blood to transport O2 to the body is reduced. Why? Less RBCs per ounce of blood means that each ounce of blood pumped by the heart carries less O2. This means the tissues receive less O2 and the symptoms of anemia reflect this reduction. They include shortness of breath (particularly with activity), fatigue, weakness, lethargy, headache, pallor (pale appearance), and chills. If your perpetrator bled your victim to death slowly, by removing blood little by little, these symptoms and signs would develop and progress as the anemia worsened. This could occur over many hours, days, or weeks.
FORENSICS AND FICTION. Copyright © 2007 by D. P. Lyle, M.D. All rights reserved. No part of this book may be used or reproduced in any manner whatsoever without written permission except in the case of brief quotations embodied in critical articles or reviews. For information, address St. Martin's Press, 175 Fifth Avenue, New York, N.Y. 10010.