"We felt it was important that the public understand some specifics of the investigation. We felt it was important that the public understand the magnitude of this investigation and that some of the blood was Ayla's," he said. -Stephen McCausland
The blood evidence; it has been talked about and debated. Is it relevant to the disappearance of Ayla?
Blood in a body varies based on age, weight, sex, etcetera. An average amount of blood in a human weighing about 180 lbs. is 5.5 Liters or 23.3 cups. In a child weighing 80 lbs., the average amount of blood is 2.75 Liters or 11.6 cups and in an infant weighing 8 lbs. the average amount of blood is 8 oz or 1 cup. Based on these values, with Ayla weighing 30 lbs she would have an average of about 1 Liter of blood or about 4.2 cups.
*For people to visualize how much blood is in a Liter, I converted to cups.
A healthy person can lose about 10-15% of the total blood volume without serious medical difficulties. There are different classifications of blood loss:
Hemorrhaging is broken down into four classes by the American College of Surgeons' Advanced Trauma Life Support (ATLS).
- Class I Hemorrhage involves up to 15% of blood volume. There is typically no change in vital signs and fluid resuscitation is not usually necessary.
- Class II Hemorrhage involves 15-30% of total blood volume. A patient is often tachycardic (rapid heart beat) with a narrowing of the difference between the systolic and diastolic blood pressures. The body attempts to compensate with peripheral vasoconstriction Skin may start to look pale and be cool to the touch. The patient may exhibit slight changes in behavior. Volume resuscitation with crystalloids (saline solution or Lactated Ringer‘s Solution) is all that is typically required. Blood transfusion is not typically required.
- Class III Hemorrhage involves loss of 30-40% of circulating blood volume. The patient's blood pressure drops, the heart rate increases, peripheral hypoperfusion (shock), such as capillary refill worsens, and the mental status worsens. Fluid resuscitation with crystalloid and blood transfusion are usually necessary.
- Class IV Hemorrhage involves loss of >40% of circulating blood volume. The limit of the body's compensation is reached and aggressive resuscitation is required to prevent death.
So we can say that a child like Ayla could safely lose 0.15 Liters or 0.6 cups of blood without any life threatening symptoms. Something a little bigger than a small cut, as in a class II hemorrhage, would be a loss of 0.30 Liters of blood or 1.2 cups. The amount of blood loss to cause death would be more than 0.40 Liters or 1.7 cups.
The police would not confirm how much blood was found but told Trista that it was “more than a small cut would produce.” I’m not a doctor or a forensic scientist so I could not tell you what one would classify as a small cut.
For the police to use words like “troubling” and “magnitude of this investigation”, I believe that there are other factors that play into the blood evidence. Maybe it is that someone else’s blood was found along with Ayla’s. Maybe it’s that some was visible to the naked eye while other areas had to be illuminated with luminol, which means some of it was cleaned up.
Since it is nearly impossible to clean up every trace of blood at a crime scene, luminol is especially effective at detecting minute traces of blood that may not be visible to the naked eye.I found this article (page 4-6) that explains the finding of blood at a crime scene, how luminol is used and how they can tell it is blood instead of another substance.
When I take in account that Ayla’s blood was found both visibly and with the help of luminol, it is more than a small cut would produce, and they had the 2 DA’s come look at the home on Violette Ave., it offers me little hope that this evidence isn’t relevant to Ayla’s disappearance.
Blood is the most common, well-known and perhaps most important evidence in the world of criminal justice today.
There's no substitute for it, whether for medical or forensic purposes. Its presence always links suspect and victim to one another and the scene of violence. Bloodstain patterns tell a lot about position and movement during the crime, who struck whom first, in what manner, and how many times.
This destroys most alibi and self-defense arguments for crime, and at the very least, trips most suspects up in their explanation of what happened. Over the years, criminals have tried many ingenious ways to hide, clean up, and remove blood evidence, but it's an area where criminal justice technology has always stayed one step ahead of them.
In forensic law, blood has always been considered class evidence, but the potential exists for individualized blood typing, and even today, forensic serologists can provide testimony with some strong probability estimates linking a single individual, and that individual only, to a bloodstain. Consider that identical twins may have the same DNA profile but completely different antibody profiles, and you begin to see how promising the field of forensic serology really is. Forensic Serology