Which of the following is a vital sign often monitored during triage?

Respiratory rate is a critical vital sign monitored during triage because it provides essential information about a patient's respiratory function and overall health status. In emergency situations, assessing how well a patient is breathing can help identify conditions such as respiratory distress, airway obstruction, or other life-threatening issues. A normal respiratory rate varies between individuals, and deviations from this range can indicate serious medical concerns that require immediate attention.

Monitoring respiratory rate, in combination with other vital signs like heart rate and blood pressure, helps healthcare providers prioritize patients based on the severity of their conditions. For instance, an increased respiratory rate may suggest that a patient is experiencing hypoxia or an acute asthma exacerbation, requiring urgent intervention.

In contrast, blood type is important for compatibility during transfusions but is not considered a vital sign that would be routinely monitored during triage. Base metabolic rate is more associated with long-term metabolic health rather than immediate clinical assessment and allergy history, although significant, does not provide urgent information about a patient's current physiological status. Thus, respiratory rate stands out as a vital sign that is both critical for immediate evaluation and effective triage.