This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
[{'content': 'The most sensitive indicator of depletion of intravascular volume in an infant is – \nSelect and explain. \nA. Cardiac output, B. Stroke volume, C. Heart rate, D. Blood pressure', 'role': 'user'}, {'content': 'Answer: C \nExplanation: An increase in heart rate is the earliest and the most sensitive indicator to any reduction in intravascular volume.\nCardiac output and blood pressure are preserved initially because of compensatory mechanisms such as increase in heart rate and peripheral vasoconstriction.\nStroke volume is usually preserved in infants and compensatory increased in cardiac output is primarily achieved by increasing heart rate.', 'role': 'assistant'}]