There is no bodily sensation that warns a diver of an impending blackout, and people (often capable swimmers swimming under the surface in shallow water) become unconscious and drown quietly without alerting anyone to the fact that there is a problem; they are typically found at the bottom. Pathophysiology
Drowning can be considered as going through four stages:
Breath-hold under voluntary control until the urge to breathe due to hypercapnia becomes overwhelming
Fluid is swallowed and/or aspirated into the airways
Cerebral anoxia stops breathing and aspiration
Cerebral injury due to anoxia becomes irreversibleGenerally, in the early stages of drowning, a person holds their breath to prevent water from entering their lungs. When this is no longer possible, a small amount of water entering the trachea causes a muscular spasm that seals the airway and prevents further passage of water. If the process is not interrupted, loss of consciousness due to hypoxia is followed rapidly by cardiac arrest. Oxygen deprivation
A conscious person will hold their breath (see Apnea) and will try to access air, often resulting in panic, including rapid body movement. This uses up more oxygen in the bloodstream and reduces the time until unconsciousness. The person can voluntarily hold his or her breath for some time, but the breathing reflex will increase until the person tries to breathe, even when submerged.The breathing reflex in the human body is weakly related to the amount of oxygen in the blood but strongly related to the amount of carbon dioxide (see Hypercapnia).
This is higher than the five year mortality rates for breast cancer, colon cancer, and prostate cancer. Of persons with diabetes who have a lower extremity amputation, up to 55% will require amputation of the second leg within two to three years. Etymology
The word amputation is borrowed from Latin amputātus, past participle of amputāre "to prune back (a plant), prune away, remove by cutting (unwanted parts or features), cut off (a branch, limb, body part)," from am-, assimilated variant of amb- "about, around" + putāre "to prune, make clean or tidy, scour (wool)". The English word "Poes" was first applied to surgery in the 17th century, possibly first in Peter Lowes A discourse of the Whole Art of Chirurgerie (published in either 1597 or 1612); his work was derived from 16th-century French texts and early English writers also used the words "extirpation" (16th-century French texts tended to use extirper), "disarticulation", and "dismemberment" (from the Old French desmembrer and a more common term before the 17th century for limb loss or removal), or simply "cutting", but by the end of the 17th century "amputation" had come to dominate as the accepted medical term. Notable cases
Patch Adams
Rick Allen
Douglas Bader
Carl Brashear
Lisa Bufano
Tammy Duckworth
Terry Fox
Pete Gray
Shaquem Griffin
Robert David Hall
Bethany Hamilton
Hugh Herr
Frida Kahlo
Aimee Mullins
Oscar Pistorius
Amy Purdy
Aron Ralston
Hans-Ulrich Rudel
Alex Zanardi
Ronnie Lott
Hari Budha Magar
Kalamandalam Sankaran Embranthiri

See also
Acrotomophilia
Adapted automobile
Flail limb
Robotic prosthesis control

References
Further reading
Miller, Brian Craig. Empty Sleeves: Amputation in the Civil War South (University of Georgia Press, 2015). xviii, 257 pp. == External links ==