Lock It In
Why a Vital Sign Changes Priority
A vital sign is a window into a body system under stress.
A vital sign is a window into a body system under stress. Blood pressure reflects pressure available for tissue perfusion; heart rate may rise to preserve cardiac output; respiratory rate reflects the work of ventilation and, sometimes, metabolic distress; oxygen saturation estimates haemoglobin oxygenation; temperature reflects the balance between heat production and heat loss. None of these values diagnoses a patient by itself. The patient’s appearance and the direction of change give the number meaning. A respiratory rate that has climbed from 18 to 28 may be more concerning than a chronic respiratory rate of 28 in a patient whose baseline is known. New confusion, increasing work of breathing, cool skin, reduced urine output, or an inability to speak in full sentences can signal deterioration before a dramatic blood pressure change appears. Look for a pattern rather than waiting for one perfect abnormal value. Tachycardia with hypotension and cool skin suggests impaired perfusion. Tachypnoea with restlessness or altered level of consciousness may indicate worsening oxygenation, metabolic stress, or fatigue. Bradycardia with hypotension and reduced responsiveness is not “just a low...