Which physiological response is NOT a manifestation of acute pain in a neonate?

• A. Increased SaO2
• B. Increased heart rate
• C. Increased blood pressure
• D. Diaphoresis

Answer: (A)

In neonates, acute pain typically triggers sympathetic nervous system arousal, leading to physiological signs like a faster heart rate, higher blood pressure, and sweating as the body responds to distress. These changes reflect increased metabolic demand and effort to cope with the painful stimulus. Oxygen saturation, however, is not a direct pain response; it depends on how well the lungs are exchanging gases and how well oxygen is being delivered to tissues. Pain does not inherently cause an increase in SaO2, and in fact, saturation may stay the same or even decrease if breathing becomes irregular or compromised during distress. So, an increase in oxygen saturation is not a usual manifestation of acute pain in a neonate, whereas the other signs—tachycardia, hypertension, and diaphoresis—fit typical pain responses.