Certified Hyperbaric Technologist Test CHT Decompression Sickness and Gas Embolism Treatment 1 — Questions and Answers
Question 1: The standard US Navy treatment table for serious decompression sickness (Type II) or arterial gas embolism is:
- USN Treatment Table 6 (Correct answer)
- USN Treatment Table 5
- USN Treatment Table 3
- USN Treatment Table 9
Correct answer: USN Treatment Table 6
USN Table 6 is the standard treatment for serious DCS and AGE, using 60 fsw at 2.8 ATA with oxygen breathing and structured decompression stops.
Question 2: Type I decompression sickness (DCS) is characterized by:
- Joint pain, skin mottling, or lymphatic symptoms without neurological involvement (Correct answer)
- Paralysis, unconsciousness, or cardiopulmonary compromise
- Arterial gas embolism with retinal involvement
- Pulmonary over-inflation and pneumothorax only
Correct answer: Joint pain, skin mottling, or lymphatic symptoms without neurological involvement
Type I DCS involves musculoskeletal, skin, and lymphatic symptoms; Type II involves more serious neurological or cardiopulmonary manifestations.
Question 3: Arterial gas embolism (AGE) most commonly occurs as a result of:
- Pulmonary over-inflation with gas entering pulmonary veins during ascent (Correct answer)
- Nitrogen saturation exceeding tissue absorption limits
- Oxygen toxicity damaging pulmonary capillaries
- Mechanical trauma to a joint space at depth
Correct answer: Pulmonary over-inflation with gas entering pulmonary veins during ascent
AGE results from pulmonary barotrauma during ascent; ruptured alveoli allow gas to enter pulmonary veins and reach the arterial circulation.
Question 4: First aid for a suspected DCS or AGE victim before reaching a recompression chamber includes:
- 100% normobaric oxygen, IV fluids, and supine positioning (Correct answer)
- Immediate cold water immersion to slow bubble expansion
- Oral aspirin to prevent clotting around gas bubbles
- Rebreathing into a paper bag to raise CO2
Correct answer: 100% normobaric oxygen, IV fluids, and supine positioning
High-flow 100% oxygen accelerates nitrogen washout from bubbles; fluids support circulation; supine positioning prevents orthostatic hypotension.
Question 5: The 'chokes' in decompression sickness refers to:
- Pulmonary DCS with chest pain, coughing, and respiratory distress from venous gas emboli in the lungs (Correct answer)
- Laryngospasm caused by aspiration during rapid ascent
- CNS DCS affecting the brainstem respiratory center
- Pneumothorax following pulmonary over-inflation
Correct answer: Pulmonary DCS with chest pain, coughing, and respiratory distress from venous gas emboli in the lungs
'Chokes' describes pulmonary venous gas embolism causing impaired gas exchange; it is a serious form of DCS requiring urgent recompression.
Question 6: If a patient's neurological DCS symptoms worsen during USN Table 6, the recommended action is:
- Extend the table by adding oxygen periods at 60 fsw and consult the diving medical officer (Correct answer)
- Immediately abort the table and surface the patient
- Switch to Table 5 as a shorter alternative
- Increase pressure beyond 60 fsw to 165 fsw
Correct answer: Extend the table by adding oxygen periods at 60 fsw and consult the diving medical officer
Table 6 allows for extensions at 60 fsw; worsening symptoms warrant table extension and expert consultation rather than premature surfacing.
Certified Hyperbaric Technologist Test CHT Decompression Sickness and Gas Embolism Treatment 1
The standard US Navy treatment table for serious decompression sickness (Type II) or arterial gas embolism is: