| PS | pacemaker syndrome; paired stimulation; paradoxical sleep; paraspinal; parasympathetic; Parkinson sy... |
|---|---|
| PSA | parasternal short axis; pleomorphic salivary gland adenoma; polyethylene sulfonic acid; polysacchari... |
| qhs | every hour of sleep [Lat. quaque hora somni] |
| QS | question screening; quiet sleep |
| REMS | rapid eye movement sleep |