You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is The single most useful clinical sign of severity of in a person without underlying lung disease Is and explain in detail?
CURB65 Each risk factor scores one point, for a maximum score of 5: Confusion of new onset (defined as an AMTS of 8 or less) Blood Urea nitrogen greater than 7 mmol/l (19 mg/dL) Respiratory rate of 30 breaths per minute or greater Blood pressure less than 90 mmHg systolic or diastolic blood pressure 60 mmHg or less Age 65 or older Ref Davidson edition23rd pg 583