A nurse is caring for an infant admitted with RSV who exhibits nasal flaring grunting and intercostal retractions. After completing the initial observational respiratory assessment, which action should the nurse take next to best evaluate the infant's respiratory status?

Perform a deep palpation of the chest to assess for tenderness or abnormalities

Measure orthostatic blood pressure to evaluate cardiovascular stability

Auscultate the lungs bilaterally using the diaphragm of the stethoscope to identify abnormal breath sounds

Immediately administer a bronchodilator without completing further assessment