What initial treatment should be provided to a 7-year-old boy in marked respiratory distress with a heart rate that is rapid?

Administering oxygen as tolerated while auscultating lung sounds is the appropriate initial treatment for a 7-year-old boy in marked respiratory distress with a rapid heart rate. In cases of respiratory distress, the priority is to ensure that the child has adequate oxygenation.

Oxygen therapy helps improve oxygen saturation levels, which can be critical in combating hypoxia. By administering oxygen, you provide the child with immediate assistance to relieve respiratory distress. Additionally, auscultating lung sounds is crucial to assess the nature of the respiratory distress. It can help identify whether there are wheezes indicative of an asthma attack, crackles potentially suggesting pneumonia, or other abnormal sounds that could indicate different underlying issues. This step is essential for determining subsequent interventions and guiding treatment effectively.

The other options are essential as part of a comprehensive approach, but they do not address the immediate need for ensuring adequate oxygenation while simultaneously gathering information about the child's condition. For instance, assisting ventilations with a bag-mask device might be necessary if the child cannot maintain adequate breathing on his own, and preparing for intubation is critical in cases of severe respiratory failure, but those interventions may not be the first step for a child still able to breathe with assistance. Conducting a thorough history