Certified Hyperbaric Technologist Test CHT Decompression Sickness and Gas Embolism Treatment 2 — Questions and Answers
Question 1: USN Treatment Table 5 is used for:
- Mild DCS (Type I) with complete relief within 10 minutes at 60 fsw (Correct answer)
- All neurological DCS cases
- AGE when Table 6 is unavailable
- CO poisoning with mild symptoms
Correct answer: Mild DCS (Type I) with complete relief within 10 minutes at 60 fsw
Table 5 is a shorter table appropriate only when symptoms fully resolve quickly at 60 fsw and the presentation is Type I (non-neurological) DCS.
Question 2: In a multiplace chamber treating DCS, the inside tender breathes air while the patient breathes 100% oxygen at 60 fsw. The tender must be aware of:
- Their own decompression obligation acquired from the air exposure at 2.8 ATA (Correct answer)
- Oxygen toxicity from ambient chamber oxygen
- Risk of CO poisoning from the chamber hull off-gassing
- Nitrogen narcosis incapacitating them at this shallow depth
Correct answer: Their own decompression obligation acquired from the air exposure at 2.8 ATA
Air-breathing tenders acquire nitrogen saturation at treatment pressure and must follow appropriate decompression schedules when surfacing.
Question 3: Recompression therapy for AGE is most effective when initiated:
- As quickly as possible, ideally within hours of symptom onset (Correct answer)
- Only after complete neurological assessment over 24 hours
- After MRI confirmation of cerebral emboli
- Once the patient is stabilized in the ICU for 48 hours
Correct answer: As quickly as possible, ideally within hours of symptom onset
Early recompression reduces bubble size and restores tissue perfusion; delays significantly worsen neurological outcomes in AGE.
Question 4: The 'bend' (limb-bend) in DCS most commonly affects which joint?
- The shoulder and elbow in divers (Correct answer)
- The knee only in all DCS cases
- The hip in flying DCS only
- The wrist in all recreational dive DCS
Correct answer: The shoulder and elbow in divers
Shoulder and elbow joint pain (limb bends) are classically described in scuba divers; the specific joint varies by the type of diving activity performed.
Question 5: What is 'flying DCS' (altitude DCS)?
- DCS triggered by reduced atmospheric pressure during air travel after diving (Correct answer)
- DCS caused by breathing pressurized cabin air at altitude
- Any DCS occurring aboard a pressurized aircraft
- DCS limited to military aviators flying combat missions
Correct answer: DCS triggered by reduced atmospheric pressure during air travel after diving
Flying after diving reduces ambient pressure, decreasing nitrogen solubility and precipitating bubble formation from residual dissolved nitrogen.
Question 6: Hydration is recommended as an adjunct in DCS treatment primarily because:
- It reduces blood viscosity and supports tissue perfusion impaired by gas bubbles (Correct answer)
- It dilutes dissolved nitrogen in the bloodstream directly
- It counteracts oxygen toxicity at cellular level
- It prevents post-recompression seizures
Correct answer: It reduces blood viscosity and supports tissue perfusion impaired by gas bubbles
Adequate hydration combats the hemoconcentration and impaired microcirculation caused by gas bubble-induced vascular injury.
Certified Hyperbaric Technologist Test CHT Decompression Sickness and Gas Embolism Treatment 2
USN Treatment Table 5 is used for: