Dysbarism - Emergency Medicine

 Hello all !

Dysbarism: 

refers to illness that is related to pressure changes in the body , that exceeds the body's capacity to adapt to these changes 

Pathophysiology of dysbariam depends on the Boyle's law : in which pressure is inversely related to volume

When you descend e.g deep water : Pressure increases and volume decreases

When you ascend : Volume increases and pressure decreases 

I will explain the main disorders of Descent and Ascent

Disorders of descent

1. Nitrogen Narcosis 

Gas we breath contains all gases : including nitrogen.

When you descend the nitrogen gas dissolves in blood and causes the symptoms of nitrogen intoxication.

Management : Ascent

2. Barotitis

Pressure damage to the ear due to squeezing secondary to the elevated pressures

Management: Ascent , supportive treatment

Disorders of Ascent

1. Arterial Gas Embolism 

Volume expansion in every air filled areas of the body e.g GIT, Alveoli 

When it occurs in the alveoli it cause the formation of an air embolus into the pulmonary vein : which can travel to the brain - causing stroke, in the heart - causing Myocardial Ischaemia

Usually acute onset : usually within minutes of ascent (e.g from diving)

Management: involves hyperbarric treatment

2. Decompression Sickness

This is caused by formation of nitrogen gas bubbles (opposite to when you descend where it dissolves)

There are two main types of decompression sickness

i. Type 1

- Usually involving the skin and joints : painful skin and joints

ii. Type 2

- Usually involving the CNS : paraesthesia, paralysis 

Management involves : Hyperbarric treatment , Oxygen, Aspirin 

NB : patient with type 1 DS : have to avoid air travel for upto one week ,those with type 2 DS : have to avoid air travel for upto 1 month 

I hope it was helpful ! For any queries feel free to contact me 

Happy reading !

Author : Mohammad Faruk Omar

Emergency Medicine Resident 

Muhimbili University of Health and Allied Sciences, Tanzania