Which device measures the temperature within the pulmonary artery and is considered the most accurate for this site?

• A. PA catheter
• B. Tympanic
• C. Esophageal
• D. Oral

Answer: (A)

Measuring temperature at its most accurate core level comes from sampling blood in the central circulation. A PA catheter has a thermistor at its distal tip inside the pulmonary artery, where it reads the temperature of mixed venous blood. That temperature closely reflects the body's true core temperature and remains reliable despite changes in environment or airway/ventilation. In contrast, surface or mucosal sites like the tympanic, esophageal, or oral temperatures are more susceptible to external heat exchange, ventilation effects, recent intake, or positioning, making them less consistently accurate for core temperature. So the pulmonary artery temperature measurement provides the most accurate core temperature reading.