Respiratory Therapy Engineering
Oxygen concentrator sieve-bed operation and degradation, humidifier infection control, and jet vs. mesh nebulizer failure modes.
Respiratory therapy equipment overlaps with ventilation equipment (Chapter 21) but covers a distinct set of devices - oxygen concentrators, humidifiers, nebulizers - with their own real failure patterns, and a meaningful share of this equipment sees home-care use, which changes the service model as well as the hardware.
Oxygen concentrator sieve beds
Oxygen concentrators separate O2 from room air using zeolite sieve beds in a pressure-swing adsorption cycle - the zeolite material selectively adsorbs nitrogen from compressed air, leaving concentrated oxygen behind, then releases the nitrogen during the pressure-swing portion of the cycle to regenerate the bed for the next cycle. Sieve-bed degradation over years of operation is a real, gradual failure mode that shows up as slowly declining output purity rather than an abrupt fault, which is why periodic O2 purity/concentration verification matters even when the unit "sounds fine" and shows no error codes - the degradation is chemical, not mechanical, and produces no obvious external symptom until purity has already dropped meaningfully.
Humidifier infection control
Humidifiers are a genuine infection-control point, not just a comfort feature - standing water in a humidifier reservoir is a real bacterial growth risk (Pseudomonas and other waterborne organisms are a documented concern in humidified respiratory circuits), and water-change and reservoir-cleaning intervals are an infection-control requirement, not just a performance one. This is a case where the equipment can function perfectly from a mechanical standpoint while still posing a real clinical risk if the water-management schedule lapses.
Jet vs. mesh nebulizers
Nebulizers split into two real designs with different failure modes: jet (pneumatic) nebulizers use compressed gas to aerosolize medication and fail mostly at the gas-orifice or compressor level - a clogged or worn orifice produces a coarser, less effective aerosol even when the unit still "runs." Mesh (vibrating-mesh) nebulizers are more efficient and typically portable/battery-powered, and they fail mostly at the mesh membrane itself - clogging from incompletely-dissolved medication or from inadequate cleaning, or fatigue failure of the vibrating element after extended use. Knowing which design is in front of you changes where you look first.
Home-care equipment considerations
Home-care respiratory equipment (often patient-owned rather than facility-owned) follows a different service model - the patient or a home-health company, not facility biomed staff, is typically responsible for routine cleaning and basic maintenance, which means equipment returning for service may have a much less predictable maintenance history than a hospital-floor unit, and incoming inspection (Chapter 03) deserves extra weight for exactly that reason.