External bleeding is a visible hemorrhage that can be anything from a nose bleed (Epistaxis) to bleeding from an open wound.
When examining a patient with serious external bleeding always attempt to determine the amount of blood loss. This can be difficult to do because blood can look so much different on different surfaces. It may have soaked into the patients clothing or have been diluted by water in certain environments. Regardless of the exact amount of blood loss the most important thing in your assessment is how your patient presents.
The human body cannot tolerate large amounts of blood loss that are greater than 20% of the total blood volume. An average adult weighing 175lbs (80 kg) has approximately 70 mL of blood per kilogram of body weight. This calculates out to approximately 6 L or 10 to 12 pints of blood. If an adult loses in excess of 1 L or 2 pints of blood they will have significant changes in their vital signs. Their heart & respiratory rates will increase and their blood pressure will decrease in the later stages of shock. Infants and children have less blood volume to begin with so a smaller volume of blood loss can have the same effects on them. If a 1 year old child only has a total blood volume of approximately 800 mL changes in vital signs will occur with the loss of only 100 to 100 mL of blood. This is not much blood at all when you consider that a regular sized coke can holds approximately 355 mL of liquid.
When considering how well peoples bodies can compensate for blood loss is based on how rapidly they bleed. If a healthy adult is donating blood they give approximately 500 mL of blood over a 15 to 20 minute time frame. If that same person cut an artery in their arm and lost the same 500 mL of blood in much shorter period of time they may go into hypovolemic shock very quickly. Hypovolemic shock is a serious condition caused by low blood volume, which then results in inadequate perfusion (circulation of blood to meet the needs of the body’s cells) of vital organs which can lead to death.
Bleeding should be considered serious & treated rapidly if the patient presents with any of the following conditions:
1. You cannot control the bleeding .
2. The personis rapidly losing blood.
3. You observe that the person has lost a significant amount of blood.
4. After assessing the person you note definite signs & symptoms of shock (Hypoperfusion).
5. The person has a poor general appearance and is CALM.
6. The bleeding is associated with a serious mechanism of injury such as a gun shot wound or deep laceration.
This is first post of a series on how to control external bleeding in an emergency situation. In the following posts we will cover the characteristics of external bleeding, how to stop external bleeding through the use of direct pressure, splints & tourniquets, how to apply a pressure dressing, how to determine if a person is bleeding through a capillary, artery or vein, bleeding from the nose, ears and mouth & how to diagnose & treat internal bleeding. In each post will go through WILDERNESS improvised techniques that you can use when first aid kits or definite medical care is not readily available. My hope is that you’ll learn & be ready to help when a true emergency arises.
Author: Brian Freeman EMT-B , OUTDOORSMAN