BP, pulse, temperature. Three vitals. What about the fourth?

Respiratory rate is the single most sensitive early warning sign of clinical deterioration — more predictive of ICU admission, sepsis, and death than any blood test. Yet in most OPDs, it is glanced at, assumed normal, and never counted. A quietly tachypnoeic patient breathing 28 times a minute at rest is sicker than the anxious patient with a pulse of 110.

This pearl teaches you how to read the whisper before it becomes a crisis.