CHT Oxygen Toxicity & Contraindications

Question 1

What is the primary mechanism by which central nervous system (CNS) oxygen toxicity occurs during hyperbaric oxygen therapy?

Accepted Answer

Formation of reactive oxygen species causing neuronal damage

Answer

CNS oxygen toxicity is primarily caused by reactive oxygen species (free radicals) that overwhelm antioxidant defenses and damage neuronal membranes.

Question 2

Which of the following is the hallmark presentation of CNS oxygen toxicity during HBO therapy?

Accepted Answer

Grand mal (tonic-clonic) convulsions

Answer

Grand mal convulsions are the hallmark of CNS oxygen toxicity; though they may be preceded by VENTID-C warning signs, they can also occur without warning.

Question 3

In the mnemonic VENTID-C used to identify early CNS oxygen toxicity symptoms, the 'V' stands for:

Accepted Answer

Vision changes such as tunnel vision

Answer

In VENTID-C, V stands for Visual disturbances (tunnel vision), which is an early warning sign of CNS oxygen toxicity preceding convulsions.

Question 4

What is the generally accepted maximum oxygen partial pressure (PO2) to minimize risk of CNS oxygen toxicity during routine HBO treatments?

Accepted Answer

1.6 ATA (1,216 mmHg)

Answer

A PO2 of 1.6 ATA (1,216 mmHg) is the generally accepted ceiling for intermittent HBO exposures to minimize CNS oxygen toxicity risk.

Question 5

Pulmonary oxygen toxicity (Lorrain Smith effect) results primarily from:

Accepted Answer

Progressive lung injury from prolonged exposure to elevated partial pressures of oxygen

Answer

The Lorrain Smith effect describes progressive pulmonary injury from prolonged high-oxygen breathing, leading to inflammation, alveolar damage, and decreased vital capacity.

(CHT) Certified Hyperbaric Technician Practice Test

(CHT) Certified Hyperbaric Technician Practice Test

CHT Oxygen Toxicity & Contraindications