RDOS, or the Respiratory Distress Observation Scale, is an observer-rated clinical scale used to assess respiratory distress or dyspnea in patients who cannot reliably describe their symptoms themselves. It was developed for patients unable to self-report dyspnea, especially in palliative and end-of-life settings.

It uses 8 observable signs:
heart rate, respiratory rate, restlessness, paradoxical breathing pattern, accessory muscle use, grunting at end-expiration, nasal flaring, and a look of fear. The total score ranges from 0 to 16, with higher scores meaning worse respiratory distress.

A common interpretation is:

• 0–2: none or little distress
• 3: mild distress
• 4–6: moderate distress
• 7 or more: severe distress

Clinically, RDOS is useful because it helps staff measure and trend respiratory distress over time and assess response to treatment in patients who are nonverbal, cognitively impaired, or too ill to answer symptom questions.

It is an assessment scale, not a prognosis calculator. It does not predict survival or complications; it quantifies how much observable respiratory distress a patient appears to have at that moment.