In order for a Medical Examiner (or Forensic Pathologist) to pronounce someone dead due to “POSITIONAL ASPHYXIA” (whether or not the positional asphyxia death is restraint-related), ALL of the following THREE key elements MUST BE SUBSTANTIATED during an AUTOPSY INVESTIGATION:(2,12-15)

• ALL other causes of death – natural and unnatural, medical and traumatic – must be explored by autopsy and EXCLUDED, to within a reasonable degree of medical certainty. In other words; if the victim’s autopsy identifies a strongly-probable natural or unnatural, medical or traumatic cause of death (apart from asphyxia), THAT pathological evidence should be considered indicative of the “cause” of death – not positional asphyxia.
  In fact, it is only when there is no clearly apparent “cause of death” found at autopsy that a medical examiner is prompted (required) to more-closely examine the activities and events surrounding the actual TIME OF DEATH, in order to determine the factual CAUSE of death.(2,16-18)

• Upon investigation of the activities surrounding the time of death; AT the Time Of Death the victim must have been in a position readily-recognized as one that could have interfered with his ability to BREATHE.
  BTW: The “Time Of Death” position that the medical examiner must investigate is the position the Victim was in at the moment when his breathing or pulse was FIRST noticed to have stopped – NOT the position the Victim was in at the time that all prehospital and/or inhospital resuscitation efforts were determined to have failed, and he was “PRONOUNCED” dead.
  “ASPHYXIATING” POSITIONS RANGE FROM
  
  • a position that obstructs the mouth and nose (“upper airway”); or
    
  • a position that causes hyperflexion (extreme bending-forward) of the neck,
    so as to obstruct the trachea (the largest “lower airway” passage); or
    
  • a position that causes restriction of the chest or diaphragm –
    a position that impedes or prevents the MECHANICAL means of breathing;
    
  • OR a combination of any of the above-described asphyxiating positions.

• LASTLY: The inability of the Victim to ESCAPE the asphyxiating position must be explained.
  Clinical asphyxia studies have shown that airway obstruction causes a variable period of physically-forceful muscular hyperactivity and reposition attempts, while the CONSCIOUS Victim struggles to alleviate or escape the position that is interfering with his breathing. If the victim is unable to regain the ability to breathe, he rapidly becomes UNCONSCIOUS. Once UNCONSCIOUSNESS ensues, a portion of the Victim’s brain INVOLUNTARY cues his body to continue performing muscular activity, in an unconscious effort to alleviate or escape the position that is interfering with breathing. Thus, the Victim’s muscular “struggle” does not stop even after loss of consciousness occurs. In fact, struggle to alleviate or escape the position that is interfering with breathing does not STOP until after the Victim’s PULSE STOPS!(19)
  In positional asphyxia deaths unrelated to RESTRAINT, alcohol intoxication is the most frequent explanation of the Victim’s inability to escape from the asphyxiating position.(14)
  [Please Note: The aforementioned “alcohol intoxication” does not imply an alcohol “overdose” or “poisoning.” If alcohol “overdose” or “poisoning” occurs, the Victim’s respiratory center is deactivated. Thus, THAT would be the “cause of death” – not positional asphyxia.]

Only if ALL of the above THREE ELEMENTS are discovered during an accurate and effective autopsy investigation, can an individual’s cause of death be identified as a form of “POSITIONAL ASPHYXIA” – whether due to restraint asphyxia, or not.

Effective Respiration is entirely dependent upon a combination of three critical elements(12): An open and “patent” airway (a passageway for air to travel from the atmosphere to the lungs, that is open and not threatened – in any way), An adequate gas exchange between the lung’s tissue (alveoli) and the body’s smallest blood vessels (the capillaries), and A functional respiratory muscular pump – or “bellows” system – the ability to change the interior size of the chest, so that airflow in and out of the lungs can be accomplished.

2004 PPt Slide, C.D.Miller

An Effectively Functioning Muscular Pump or “Bellows System”
requires – at least – the FIRST and THIRD of the following three elements(2,12):

2004 PPt Slide, C.D.Miller

An appropriately functioning central nervous system control of respiratory muscle activity: an unimpaired brain “respiratory center” sending appropriate “messages” to the respiratory muscles, causing them to act in a manner that effectively produces inspiration and expiration, The ability of the ribcage to be expanded and relaxed by action of the intercostal muscles (muscles between the ribs), appropriately increasing and decreasing the size of the chest and interior lung-space. [If the diaphragm is properly functioning, ribcage expansion is not required for “normal” breathing to effectively be accomplished.(12)] AND

NEXT: Normal breathing requires both effective inspiration and expiration; the movement of air in and out of the body. But, air will ONLY move from one place to another – from the atmosphere into the lungs, or from the lungs back out to the atmosphere – if the air pressure in one of those two places has been CHANGED.

If a person’s airway was open, but his lung-size was in a fixed, unchanging position, the air-pressure INSIDE his lungs would be the SAME as the air-pressure OUTSIDE his body.

2004 PPt Slide, C.D.Miller

An EQUAL air-pressure inside and outside of the body results in
NO AIR MOVEMENT between these two spaces. NO “breathing.”

Graphic © 2001, C.D.Miller

When respiratory muscles are appropriately activated by messages from the brain’s respiratory center, the muscles between the ribs contract to make the ribcage expand, and the diaphragm contracts to descend into the abdomen (pushing the abdominal contents out of the way). This INCREASES the SIZE of internal lung-space. Ribcage expansion only slightly increases the size of the chest and internal lung-space. The greatest internal lung-space size increase occurs when the diaphragm contracts and travels down into the abdomen.(12)

When the internal lung-space size is increased, the air pressure inside the lungs becomes “stretched,” decreasing the internal air pressure, and creating a “negative intrathoracic air pressure” (relative to atmospheric air pressure). In other words, increasing the space and size of the lungs creates a “vacuum” within the lungs.
When the airway opens, air moves from the area of higher pressure (the atmosphere) to the area of lesser pressure (the lungs) = air rushes into the lungs, producing INSPIRATION. Air keeps moving into the lungs, continuing inspiration, until the air pressure inside the lungs becomes the SAME as the air pressure in the atmosphere. Once the internal and external air pressures equalize, all air movement stops, and all inspiration stops.
[Since “active” movement (energy-expenditure) is required to make the internal lung-space LARGER, inspiration is also called the “Active Phase” of respiration.]

Once full inspiration has been accomplished, the brain’s respiratory center automatically stops sending “contraction” messages to the respiratory muscles. When that happens, the respiratory muscles automatically relax and return to their normal state. Relaxation of the ribcage’s intercostal muscles only slightly decreases the size of the chest and its internal lung-space. The greatest lung-space size decrease occurs when the diaphragm relaxes and moves back up out of the abdomen.

Graphic © 2001, C.D.Miller

Reducing the interior lung-space size causes “compaction” of the internal air pressure, increasing the internal air pressure, and creating a “positive intrathoracic air pressure” (relative to atmospheric air pressure). When the airway opens, air moves out of the lungs (now an area of higher pressure than that of the atmosphere), producing EXPIRATION.
Air keeps moving out of the lungs and into the atmosphere until the air pressure inside the lungs becomes the SAME as the air pressure outside the lungs. Once the internal and external air pressures equalize, all air movement stops, and all expiration stops.
[Since only relaxation – and no “energy-expenditure” – is required to make the intrathoracic space smaller, expiration is also called the “Passive Phase” of respiration.

When breathing becomes difficult (for whatever reason), “accessory” muscles are automatically employed to assist the intercostal muscles and diaphragm in creating the lung-space-size changes (the air pressure changes) required for inspiration and expiration to occur.(11,19)
The muscles used to assist lung-space-size changes when breathing has become difficult include: the muscles between the ribs, neck and shoulder muscles, lateral abdominal muscles, and even the muscles of the arms and legs.
In fact, it is practically impossible for Restrainers to tell the difference between a Victim struggling to “escape restraint,” and a Victim desperately struggling to BREATHE!

2004 PPt Slide, C.D.Miller

Once someone is entirely prevented from physically changing their internal lung-size and space, entirely prevented from changing the air pressure inside their lungs, breathing cannot occur. When breathing cannot occur, that condition is called, “RESPIRATORY ARREST.”

Restraint asphyxia researchers have been warning Restrainers against the use of prone-hogtie and forceful-prone-restraint since the late 1980’s.(1,3,11,12,16,17,20) In recent years, however, restraint asphyxia researchers have come to the relatively-universal agreement that, restraint – by itself – is not solely responsible for asphyxia that occurs while a Victim is being actively restrained by others.(1,4,5,12,17,18,21-25)
Restraint asphyxia only occurs when an asphyxiating form of restraint is preceded by and associated with lethally-exhausting and body-chemical-unbalancing activities.
But, the lethally-exhausting and body-chemical-unbalancing activities preceding restraint application – by themselves – do not cause death, either. So, the asphyxiating form of restraint remains the ultimate “cause” of death.

2 to 3 “PHASES” of PHYSICALLY-EXERTIVE ACTIVITY have consistently been associated with restraint asphyxia deaths. PART TWO of this article describes these PHASES, and explains why they place a Victim at risk for restraint asphyxia.

2004 PPt Slide, C.D.Miller