A PCA is a patient care associate, AKA certified nurses aide, patient care tech, technical associate. Acute care would be an inpatient unit in a hospital where patients are acutely ill and are usually
there short-term. Medical, surgical, telemetry, neuro, anything like that. It's a step under intensive care.
I don't think you could go wrong with working as an aide or tech on any inpatient acute care unit. You will be gaining experience in dealing with different types of patients, diagnoses, equipment, emergencies. You'd learn different skills like taking vital signs and drawing blood. All of those things will come in helpful while in school and while practicing as a PA. Working as a nurses aide while in nursing school
really helped me to understand the material in class better because I could associate it with what I'd seen at work.
I'm not sure what would be out there for tech jobs in an outpatient (Dr. office or clinic) setting that would provide much for experience. What about an EMT? You'd have to take a course for that though.