Dysbarism

Multiple systems of classification of decompression sickness have been proposed, some of which are described in the Classification. 

Middle-ear barotrauma[34]Teed, RW. Factors producing obstruction of the auditory tube in submarine personnel. US Naval Med Bull. 1944;42:293-306.

In its current form, middle ear barotrauma contains six grades:

• Grade 0: no visible damage

• Grade 1: injection of the tympanic membrane, especially along the handle of the malleus

• Grade 2: diffuse injection plus slight haemorrhage within the substance of the tympanic membrane

• Grade 3: gross haemorrhage within the substance of the tympanic membrane

• Grade 4: gross haemorrhage in the middle ear, as evidenced by free blood and bubbles behind the tympanic membrane

• Grade 5: perforation of the tympanic membrane.