Which of the following is NOT a typical measurement assessed on an arterial blood gas in young infants?

In the context of assessing arterial blood gases (ABGs) in young infants, pulmonary function as a measurement is not typically evaluated within the ABG itself. ABGs primarily focus on three key components: arterial pH, partial pressures of carbon dioxide (PCO2) and oxygen (PO2), bicarbonate (HCO3), and sometimes base excess.

HCO3 is important for understanding the metabolic aspect of acid-base balance; PCO2 helps evaluate respiratory function and acidosis or alkalosis; and base excess provides insights into the metabolic component of the acid-base status.

Pulmonary function tests, however, are separate evaluations that assess how well the lungs are working. They require more extensive measurements and typically involve spirometry or similar methodologies that are not part of standard ABG analysis. Thus, the correct answer highlights that of the listed measurements, pulmonary function does not fit within the typical parameters assessed by arterial blood gases in young infants.