I like getting questions and here is a recent one:
I had an EMS call once where a man left the roadway in his vehicle and hit a fence. The accident itself wasn't that bad. A witness said she saw him slumped over before he left the road so we were thinking that he probably had a heart attack which caused the accident. He had a laceration across his chest and several on his arms but none of them were bleeding. Fatty tissue was visible and all lacerations that I have seen like his would normally have been bleeding. There was no other apparent trauma.

My question -- if someone suffers a cardiac arrest and is then externally injured immediately afterwards, say a laceration, will the laceration still bleed? Will the lack of circulation keep the wound from bleeding?


In my estimation, there might be a little bit of blood just from it purely being present in the vessels. However, if the heart has stopped beating before the lacerations occur, the bleeding would probably be minimal due to the drop in blood pressure. Also, if the heart attack was a ruptured MI, then there would have been a lot of blood loss from the hole in the heart, and not enough to bleed out of the lacerations. The other scenario is that the blunt force trauma caused the aorta to tear before the external lacerations causing massive internal bleeding and not leaving enough blood to bleed into the external environment. This reminds me of a homicide case we had this summer. A man was shot twice, once in the neck and once in the abdomen. How did the doctor know that the neck shot came first? Well there was no blood in the abdomen. The abdomen shot tore through the vena cava and if it had been the first shot there would have been a ton of blood in the abdominal cavity. The first bullet actually tore through the carotid arteries that literally created a fountain of blood. The crime scene investigators said that the blood shot from the driver's seat of a car, out of the sunroof and down the passenger side of the car. There was so much blood loss from the first shot that there was not any left to bleed into the abdominal cavity.

I think its sort of interesting how such subtle clues can explain a whole lot in an autopsy report.

There was a comment to the previous post that raised a good point. The Medical Examiner is in business (not really a business - taxes and federal mandates provide the capital) for other reasons besides those that are purely legal. Sure, a big responsibility of the ME is to investigate homicides or any other type of death that may lead to a trial (whether criminal or civil), but the Medical Examiner also provides closure to families. Some families readily object to having autopsies done on loved ones. These objections can be religious or they can be due to other reasons. One common reason is that they fear that the autopsy is intrusive and destructive. They don't like the thought of having a tangible representation of a loved one destroyed. In a more practical reason for objection, they fear that it might interfere with a viewing or the funeral (which it doesn't). However, many people do welcome the autopsy because it tells them why. It gives them closure and makes them understand the death better. The doctor may also be able to provide comfort to the family by assuring that no suffering was involved or that the decedent did not experience too much pain. The autopsy also provides information to the family. Some diseases and conditions are genetic and it may be useful for family members to know that a certain disorder runs in the family. This can allow family members to seek ways to prevent the disease. In conclusion the medical examiner has more uses than the obvious legal ones.

After a week of being sick and having allergic reactions to antibiotics I am now starting classes. However, I wanted to revisit something that I wanted to talk about a number of times. I spent an entire summer writing about death and the various ways to achieve it. But what exactly is death?

When we think of death one way we may think of it is as a candle flame being extinguished. Life is the flame and then it is suddenly gone. Well thats not a very good analogy. Death is not an event; it is a process. Most states define death as when the heart stops beating at respiration ceases. However, some cells may continue living and relying on anaerobic respiration (without oxygen) for hours and even days afterwords. Muscle cells are an example of this. This explains rigor mortis. The rigor ceases as the muscle cells die (Although it is a bit more complicated than that). There is also the concept of brain death. Your cerebrum may be totally dead, but as long as your cerebellum keeps on trucking then your essential body processes can continue. This can easily lead into a legal, philosophical, or ethical debate. The law does not declare you legally brain dead until ALL brain activity stops. This can be detected with an EEG or some other technique that measures activity in the brain. Even after someone is brain dead though, the heart will continue to beat for a little while because it has its own pacemaker.

The thing that is kind of interesting is the legal aspect of death. There literally is a law in the state law books that defines death. It kind of reminds me of the notion of insanity. Insanity is not a term used by psychologists in academia. It is a legal term used to describe someone's competency either when committing a crime or standing trial. This is where the forensic psychologists and psychiatrists come in and give their expert opinion as to the mental state of a defendent. The best example of an actual mental disease that could fall under the legal definition of insanity would be schizophrenia.