Final answer:
An increase in respirations from 18 to 36/min during an exercise stress test is the most significant indicator that an adult patient is experiencing distress, as it represents a substantial change from the normal respiratory rate and may point to issues with oxygen demand and cardiovascular or pulmonary function.
Step-by-step explanation:
The question asks which vital sign change during an exercise stress test should indicate to an EKG technician that an adult patient is experiencing distress. Out of the options provided, an increase in respirations from 18 to 36/min is the most indicative of distress. During exercise, it is normal for the pulse rate and blood pressure to increase, and a slight decrease in body temperature may not be significant. However, a doubling of the respiratory rate suggests that the body's demand for oxygen is not being met, which could be due to cardiac impairment, pulmonary issues, or other forms of physiological stress.
Under normal circumstances, an adult's respiratory rate is between 12-18 breaths per minute, and a significant increase to 36/min warrants attention. While exercise increases demand for oxygen and therefore increases respiration, an excessive increase can be a sign of abnormal function or distress. The EKG technician should be aware of this and be prepared to take action if the patient shows other symptoms of distress or if the change in respiratory rate is rapid and sustained.