A patient is undergoing oxygen therapy through a nasal cannula.If the patient inquires about the reason for having oxygen tubing in their nose, what explanation about the cannula should the nurse provide?

Choice A rationale
Slough, which is a layer of yellowish, dead tissue that can develop on the surface of a wound, is not a defining characteristic of a stage 3 pressure ulcer.
Choice B rationale
Persistent reddening of the skin is typically associated with a stage 1 pressure ulcer, not a stage 3. In a stage 1 pressure ulcer, the skin remains intact but may be red and may not blanch (lose color briefly) when you press your finger on it.
Choice C rationale
A stage 3 pressure ulcer involves full-thickness skin loss that appears as a deep crater. The ulcer may extend into the subcutaneous tissue layer, but not through it to the underlying

muscle or bone. This description matches the statement in Choice C, making it the correct answer.
Choice D rationale
A fluid-filled area under the skin could potentially indicate a blister or a stage 2 pressure ulcer, not a stage 3. In a stage 2 pressure ulcer, the outer layer of skin (epidermis) and part of the underlying layer of skin (dermis) are damaged or lost.

Choice A rationale
Rapid respirations that are unusually deep and regular are not indicative of Cheyne-Stokes respirations. Cheyne-Stokes respirations are characterized by periods of apnea followed by gradually increasing then decreasing tidal volumes until another period of apnea.
Choice B rationale
An inability to breathe without dyspnea unless sitting upright is not indicative of Cheyne- Stokes respirations. This is more characteristic of orthopnea, which is commonly seen in conditions like heart failure.
Choice C rationale
Breathing ranging from very deep to very shallow with periods of apnea is indicative of Cheyne-Stokes respirations. This pattern of breathing is often seen in conditions such as heart failure, stroke, or brain damage.
Choice D rationale

Shallow breathing alternating with periods of apnea is not indicative of Cheyne-Stokes respirations. In Cheyne-Stokes respirations, the pattern of breathing includes periods of apnea followed by a gradual increase and then decrease in the depth of respirations.