Basic HTML Version
Chapter 33 — 2
In addition to these the causes associated with
scuba diving
are:
• Hypocapnea
• Decompression sickness
• Air embolism from pulmonary barotrauma
• Nitrogen narcosis
• Carbon monoxide toxicity
• Hypoxia due to faulty equipment or gas contamination
In addition to these, causes associated with
rebreathing
or
mixed gas diving equipment
(not commonly used by recreational divers) include :
• Hypercapnea
• Oxygen toxicity
• Hypoxia due to ascent, dilution or excessive consumption.
The more
common causes
of unconsciousness are as follows:
HYPOXIA
(
SEE CHAPTER
20)
Hypoxia of the brain associated with near-drowning is the final event in many diving
accidents and is the most common cause of unconsciousness in divers. It may follow events
as diverse as breath-holding in free diving, inadequate air supply, salt water aspiration,
equipment faults or misuse, inhalation of vomit, pulmonary barotrauma, gas contamination,
etc. It is frequently associated with panic and physical exhaustion.
Case History 33.1
A diver breathing from a semi-closed breathing apparatus lost consciousness shortly after
leaving the surface. He was brought back to the surface and revived with 100% oxygen. His slightly bluish face
turned red later on when it was discovered that he had filled his cylinders with pure nitrogen.
Diagnosis:
Hypoxia due to inadequate (i.e. nil) inspired oxygen.