In cases where people have stacked up on each other in a human pile, it has been estimated that those at the bottom are subjected to around 380 kg (840 lbs) of compressive weight. "Positional" or "restraint" asphyxia is when a person is restrained and left alone prone, such as in a police vehicle, and is unable to reposition themself in order to breathe. The death can be in the vehicle, or following loss of consciousness to be followed by death while in a coma, having presented with anoxic brain damage. The asphyxia can be caused by facial compression, neck compression, or chest compression. This occurs mostly during restraint and handcuffing situations by law enforcement, including psychiatric incidents. The weight of the restraint(s) doing the compression may contribute to what is attributed to positional asphyxia. Therefore, passive deaths following custody restraint that are presumed to be the result of positional asphyxia may actually be examples of asphyxia occurring during the restraint process. Chest compression is a technique used in various grappling combat sports, where it is sometimes called wringing, either to tire the opponent or as complementary or distractive moves in combination with pinning holds, or sometimes even as submission holds.
The Fontaine stages, were introduced by René Fontaine in 1954 to define severity of chronic limb ischemia:
Stage I: asymptomatic
Stage IIa: intermittent claudication after walking a distance of more than 200 meters
Stage IIb: intermittent claudication after walking a distance of less than 200 meters
Stage III: rest pain
Stage IV: ulcers or gangrene of the limbThe Rutherford classification was created by the Society for Vascular Surgery and International Society of Cardiovascular Surgery, introduced in 1986 and revised in 1997 (and known as the Rutherford classification after the lead author, Robert B. Rutherford). This classification system consists of four grades and seven categories (categories 0–6):
Grade 0, Category 0: asymptomatic
Grade I, Category 1: mild claudication
Grade I, Category 2: moderate claudication
Grade I, Category 3: severe claudication
Grade II, Category 4: rest pain
Grade III, Category 5: minor tissue loss; ischemic ulceration not exceeding ulcer of the digits of the foot
Grade IV, Category 6: major tissue loss; severe ischemic ulcers or frank gangreneModerate to severe PAD classified by Fontaines stages III to IV or Rutherfords categories 4 to 5, presents limb threat (risk of limb loss) in the form of critical limb ischemia.Recently, the Society for Vascular Surgery came out with a classification system based on "wound, ischemia and foot Infection" (WIfI). This classification system, published in 2013 was created to account for the demographic changes that have occurred over the past forty years including increased incidence of high blood sugar and evolving techniques and ability for revascularization.