Certified Hyperbaric Technologist Test CHT Hyperbaric Contraindications and Complications 2 — Questions and Answers
Question 1: A patient experiences a tonic-clonic seizure at 2.4 ATA during HBO. The immediate action is to:
- Remove the oxygen mask and protect the airway (Correct answer)
- Immediately decompress the chamber
- Administer anticonvulsants through the chamber port
- Increase pressure to abort the seizure
Correct answer: Remove the oxygen mask and protect the airway
Removing the oxygen mask stops further O2 delivery; the seizure typically self-terminates, and rapid decompression during a seizure risks pulmonary barotrauma.
Question 2: Sinus squeeze (sinus barotrauma) is best prevented by:
- Ensuring the patient is free of upper respiratory congestion before treatment (Correct answer)
- Compressing more rapidly to reduce exposure time
- Having the patient hold their breath during descent
- Administering supplemental nitrogen
Correct answer: Ensuring the patient is free of upper respiratory congestion before treatment
Sinus barotrauma occurs when blocked sinuses cannot equalize; treating or deferring patients with congestion prevents this complication.
Question 3: Visual changes (myopia) experienced by patients after multiple HBO treatments are:
- Usually reversible within weeks to months after completing therapy (Correct answer)
- Permanent and require corrective lens prescription
- A sign of immediate CNS oxygen toxicity
- Caused by retinal barotrauma
Correct answer: Usually reversible within weeks to months after completing therapy
HBO-induced myopia results from temporary lens changes and typically resolves within 6–8 weeks after completing treatments.
Question 4: Which relative contraindication requires special precaution because trapped gas may expand on ascent?
- History of thoracic surgery with blebs or bullae (Correct answer)
- Well-controlled type 2 diabetes
- Stable angina on medication
- History of closed head injury over 1 year ago
Correct answer: History of thoracic surgery with blebs or bullae
Pulmonary blebs or bullae can rupture during decompression as trapped gas expands, risking pneumothorax or arterial gas embolism.
Question 5: Confinement anxiety (claustrophobia) in a hyperbaric patient is classified as:
- A relative contraindication that can often be managed with anxiolytics (Correct answer)
- An absolute contraindication requiring treatment refusal
- A physiological complication requiring decompression
- A contraindication only in monoplace chambers
Correct answer: A relative contraindication that can often be managed with anxiolytics
Claustrophobia is a relative contraindication that can frequently be managed with anxiolytics, patient education, and acclimation tours of the chamber.
Question 6: Nitrogen narcosis is NOT a concern in HBO therapy primarily because:
- Patients breathe 100% oxygen, eliminating nitrogen narcosis risk (Correct answer)
- Treatment pressures never exceed 1.5 ATA
- Nitrogen is added to prevent narcosis
- Patients are premedicated against narcosis
Correct answer: Patients breathe 100% oxygen, eliminating nitrogen narcosis risk
Since patients breathe 100% oxygen during HBO (not air), there is no nitrogen present to cause narcosis.
Certified Hyperbaric Technologist Test CHT Hyperbaric Contraindications and Complications 2
A patient experiences a tonic-clonic seizure at 2.4 ATA during HBO.
The immediate action is to: