CHS CHS Decompression Sickness & Diving Medicine

Question 1

What is the primary pathophysiological mechanism of decompression sickness (DCS)?

Accepted Answer

Formation of nitrogen gas bubbles in tissues and blood during rapid ascent

Answer

Rapid ascent causes dissolved nitrogen in tissues to come out of solution and form bubbles, which physically obstruct vessels, compress nerves, and trigger inflammatory cascades.

Question 2

Type II (serious) DCS most commonly affects which body system, making early treatment with HBOT critical?

Accepted Answer

Spinal cord and central nervous system

Answer

Type II DCS frequently causes spinal cord and CNS injury from venous infarction and bubble emboli, presenting with paralysis, sensory deficits, or altered consciousness.

Question 3

The US Navy Treatment Table 6 (TT6) is the standard HBOT protocol for serious DCS. At what pressure is the majority of the treatment conducted?

Accepted Answer

3.0 ATA (66 fsw)

Answer

USN TT6 is conducted primarily at 2.8 ATA (60 fsw equivalent on the oxygen schedule), but the treatment depth reached initially may be 2.8 ATA; however TT6 is conducted at 2.8 ATA with the first oxygen breathing at 60 fsw = 2.8 ATA.

Question 4

Which clinical finding is most consistent with arterial gas embolism (AGE) in a SCUBA diver?

Accepted Answer

Sudden loss of consciousness immediately upon or within minutes of surfacing

Answer

AGE causes immediate neurological catastrophe on surfacing as air bubbles enter the pulmonary veins and travel to the cerebral circulation, producing rapid loss of consciousness or stroke-like symptoms.

Question 5

When a diver with suspected AGE presents for HBOT, what is the recommended immediate positioning during transport?

Accepted Answer

Supine with head at the same level as the body

Answer

Current guidelines recommend supine positioning; head-down positioning is no longer recommended as it may increase cerebral edema without proven benefit in reducing bubble migration.

(CHS) Certified Hyperbaric Specialist Practice Test

(CHS) Certified Hyperbaric Specialist Practice Test

CHS CHS Decompression Sickness & Diving Medicine