Hyperbaric therapeutic chambers are pressure vessels capable of accommodating one or more persons with the purpose of providing medical treatment. Therapeutic hyperbaric chambers have been in use from the mid-20(th) century, yet apparently their design has not reached their full potential and they are not compatible with current healthcare facilities design. This paper will present therapeutic hyperbaric chambers from a human-environment-machine perspective in order to highlight their specific problems and requirements, and suggest design concepts that may improve patient satisfaction, quality of treatment, and functionality of the staff. Data were collected from a literature review, a market survey, and personal observations. Main design solutions include personal space and privacy, stress- and anxiety-reducing environments, hazard mitigation, rearrangement of seating, and personalized (user-tailored) entertainment systems. It is suggested that adopting a user-centered design rather than an engineering focus will increase satisfaction and overall 'user experience' of the patients, alleviate psychological issues, and lessen workload and improve functionality of the staff. This study could be applicable and easily adapted to other confined therapeutic environments in which patients are restrained for several hours on a regular basis in receiving treatment, such as dialysis or chemotherapy rooms, and for confined nonmedical situations such as aircrafts and rapid trains.