What should be done if a newborn requires epinephrine but peripheral venous access is unsuccessful?

In the scenario where a newborn requires epinephrine and peripheral venous access is unsuccessful, cannulating the umbilical vein is the most appropriate action. The umbilical vein provides a reliable route for medication delivery, especially in an emergent situation where the newborn's condition may be critical.

The umbilical vein is a central venous access point, allowing for rapid administration of medications like epinephrine directly into the systemic circulation. This is particularly vital in neonatal resuscitation, as prompt intervention can be life-saving. Cannulating the umbilical vein is generally preferred over peripheral access in neonates due to their small size and the difficulty often encountered in establishing peripheral venous access.

While intubation may ultimately be necessary for airway management, it does not directly address the immediate need for medication. Injecting the drug directly into a peripheral vein, assuming access could be achieved, is less effective than central access in critical situations. Deferment of drug therapy would not be suitable under the circumstances where immediate medication administration is crucial for the newborn's survival. Therefore, utilizing the umbilical vein stands out as the best course of action in this scenario.