Which condition is commonly associated with tachycardia in a neonate?

Tachycardia in neonates can be associated with a range of physiological and pathological conditions, with dehydration being one of the most common culprits. When a neonate is dehydrated, it leads to a decreased volume of circulating blood, which can trigger the heart to beat faster in an effort to maintain adequate tissue perfusion and blood pressure. This compensatory mechanism results in an increase in heart rate, manifesting as tachycardia.

Dehydration can occur due to inadequate fluid intake, excessive loss from vomiting or diarrhea, or other factors that reduce overall fluid balance. In the neonatal population, the impact of dehydration can be particularly pronounced due to their relatively higher metabolic rate and smaller body fluid reserves.

While sepsis and hypoxemia can also result in tachycardia, these conditions are typically associated with a more systemic response, which may include additional symptoms such as fever, lethargy, or respiratory distress. In contrast, dehydration represents a more straightforward and common cause of tachycardia that emphasizes the importance of fluid balance in newborns. Bradycardia is, in fact, a decreased heart rate, and does not contribute to tachycardia in neonates.