Friday, May 15, 2015

Let’s Talk Blood!

Let’s talk about blood…the marvelous red, magical fluid that carries oxygen to our brain so we can think, pumps quickly through lungs so we can breathe and provides a quick, ready source of cash for college students.  Blood is the magical potion that British Rakes and Vampires lust after and many a folks have paid big bucks for legally and illegally to live.


Scientists estimate the volume of blood in a human body to be about 7 percent of body weight. An average adult body with a weight of 150 to 180 pounds will contain approximately 4.7 to 5.5 liters (1.2 to 1.5 gallons) of blood or about or 5 ½ pints.  The average woman has 6-7 pints of blood and the average man has about 8 pints.  Children, of course, have less blood. 


Usually, 40% or greater blood loss is considered the maximum amount of blood an adult can lose before the body can no longer compensate. In an 80 kg or 176-pound adult, this would be about 2.24 liters.


Hemorrhage is best defined as a blood loss and often occurs in traumatic injury that may be due to a car accident, gunshot wound or stabbing.  Other injuries can also facilitate serious blood loss

A Class I Hemorrhage occurs when a patient loses 15%, or less, of their blood volume. In an 80 kg person (or about 176 lbs.) this would be about 0.84 liters. At this level there are almost no signs or symptoms so in essence, your victim would be asymptomatic.

Class II Hemorrhage becomes evident when a person experiences a 15 to 30% loss of their blood volume or about 1.68 liters in a 176 lb. person. At this level of blood loss, the heart will start to beat faster, and the person will start to look pale and feel cool. When this occurs, the patient is in the beginning stage of hypovolemia shock so if action isn’t taken quickly, the patient will become worse.

Class III Hemorrhage represents a 30 to 40% loss of blood. In an 80 kg person this would be about 2.24 liters. At this level the heart will be beating very fast (tachycardia) as it works hard to keep up with the oxygen needs of the body. Remember, the heart always shuttles blood to the brain first, but the person will look very pale, and may appear confused, dizzy or may have nausea or vomit. The patient’s respirations or breathing will increased but ineffective. The lower extremities will feel very cool and may begin to discolor as will the upper extremities. The nail beds may discolor and appear a greyish-blue.  The victim is in shock and will be in severe trouble in a matter of a couple of minutes. If the patient is bleeding externally, a large amount of blood will pool around the wound onto the floor or wherever gravity takes it.

Class IV Hemorrhage occurs when there is a greater than 40% blood loss.  In an 80 kg adult this would be more than 2.24 liters. The body can no longer keep up with the blood loss and the person, without immediate care (IV fluids and wound compression) will die.

Types of Bleeding


Arterial Bleeding

With arterial bleeding, the blood is bright red and under pressure from the pumping heart. Therefore, blood is spurted from the wound in time with the heartbeat. A severed artery may produce a jet of blood several feet high and can rapidly empty the circulatory system of blood.

Venous Bleeding

With venous bleeding the blood is dark red in coloration. It is under less pressure than arterial blood, but since the vein walls are capable of great distention, blood may pool. Thus, blood from a severed major vein may gush profusely.

Capillary Bleeding

This type of bleeding can be characterized as oozing and occurs at the site of all wounds. Although capillary bleeding may at first be brisk, blood loss is generally negligible.
Need More Info About Blood

Until next time, take care and stay safe!