Decompression Illness describes a collection of symptoms arising from decompression of the body.

DCI is caused by two different mechanisms, which result in overlapping sets of symptoms. The two mechanisms are:

• Decompression sickness
  Decompression sickness
  Decompression sickness describes a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurization...
  
   (DCS), which results from gas dissolved in body tissue under pressure precipitating out of solution and forming bubbles on decompression. It typically afflicts scuba divers on poorly managed ascent from depth or aviators flying in inadequately pressurised aircraft.
• Arterial gas embolism
  Air embolism
  An air embolism, or more generally gas embolism, is a pathological condition caused by gas bubbles in a vascular system. The most common context is a human body, in which case it refers to gas bubbles in the bloodstream...
  
   (AGE), which is gas bubbles in the bloodstream. In the context of DCI these may form either as a result of precipitation of dissolved gas into the blood on depressurisation, as for DCS above, or by gas entering the blood mechanically as a result of pulmonary barotrauma
  Barotrauma
  Barotrauma is physical damage to body tissues caused by a difference in pressure between an air space inside or beside the body and the surrounding fluid...
  
  . Pulmonary barotrauma is a rupturing of the lungs by internal over-pressurisation caused by the expansion of air held in the lungs on depressurisation such as: a scuba diver ascending while holding the breath or; the explosive decompression of an aircraft cabin or other working environment.

Mechanisms of injury

• Refer to the main article decompression sickness
  Decompression sickness
  Decompression sickness describes a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurization...
  
   for the mechanism of injury behind DCS.
• Refer to the main article arterial gas embolism for the mechanism of injury behind AGE.

Signs and symptoms

Below is a summary comparison of the signs and symptoms of DCI arising from its two components: Decompression Sickness and Arterial Gas Embolism.
A more detailed account of the signs and symptoms of Decompression Sickness can be found here.

Decompression sickness	Arterial Gas Embolism
Signs
Skin rash	Bloody froth from mouth or nose
Paralysis, muscle weakness	Paralysis or weakness
Difficulty in urinating	Convulsions
Confusion, personality changes, bizarre behaviour	Unconsciousness
Loss of memory, tremors	No breathing
Staggering	Death
Collapse or unconsciousness
Symptoms
Fatigue	Dizziness
Skin itch	Blurring of Vision
Pain in joints or muscles	Areas of decreased sensation
Dizziness, vertigo, ringing in the ears	Chest pain
Numbness, tingling and paralysis	Disorientation
Shortness of breath

First aid

First aid

First aid

First aid is the provision of initial care for an illness or injury. It is usually performed by non-expert, but trained personnel to a sick or injured person until definitive medical treatment can be accessed. Certain self-limiting illnesses or minor injuries may not require further medical care...

 is common for both DCS and AGS:

• Monitor the patient for responsiveness, airway, breathing and circulation, resuscitate if necessary.
• Treat for shock.
• Lay the patient on their back, or for drowsy, unconscious, or nauseated victims, on their side.
• Administer 100% oxygen
  Oxygen therapy
  Oxygen therapy is the administration of oxygen as a medical intervention, which can be for a variety of purposes in both chronic and acute patient care...
  
   as soon as possible.
• Seek immediate medical assistance, locate a hospital with hyperbaric facilities and plan for possible transport.
• Allow the patient to drink water
  Water
  Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
  
   or isotonic
  Isotonic
  The term isotonic may refer to;*Isotonic for the term associated with muscle contraction*An isotone in nuclear physics*Sports drinks are sometimes designed in an isotonic way to assist athletes rehydrate while balancing electrolytes...
  
   fluids only if responsive, stable, and not suffering from nausea or stomach pain. Administration of intravenous saline solution
  Saline (medicine)
  In medicine, saline is a general term referring to a sterile solution of sodium chloride in water but is only sterile when it is to be placed intravenously, otherwise, a saline solution is a salt water solution...
  
   is preferable.
• Record details of recent dives and responses to first aid treatment and provide to the treating medical specialist. The diving details should include depth and time profiles, breathing gas
  Breathing gas
  Breathing gas is a mixture of gaseous chemical elements and compounds used for respiration.Air is the most common and only natural breathing gas...
  
  es used and surface intervals.

Treatment

Treatment for the Decompression Sickness and the Arterial Gas Embolism components of DCI may differ significantly. Refer to the separate treatments under those articles.