A 2-year-old with respiratory distress may have swallowed an object. What should be the next step to determine the cause?

The appropriate next step in evaluating a 2-year-old with respiratory distress who may have swallowed an object is bronchoscopy. This procedure allows healthcare providers to visualize the airways directly and identify any foreign objects that may be causing the obstruction or respiratory issues. Given the clinical suspicion of an ingested foreign body, bronchoscopy not only aids in diagnosis but can also facilitate the removal of the object if necessary, thereby alleviating the respiratory distress.

In such cases, while pulse oximetry can provide information about oxygen saturation and help assess the severity of respiratory distress, it does not identify the cause of the distress. Arterial blood gas analysis can give insight into the patient's respiratory and metabolic status, but it also does not determine the presence of a foreign body. Spirometry is a test typically used to measure lung function but is not suitable in an acute setting, especially in a young child with distress and suspected airway obstruction. Thus, bronchoscopy is the most direct and effective approach for both diagnosis and potential intervention in this scenario.