A nurse is collecting data from an infant whose guardian reports worsening symptoms.The infant has a cough productive of very thick white mucus.Upon auscultation, wheezes are heard bilaterally on inspiration and expiration.Moderate substernal and subcostal retractions are noted.Mucous membranes are pink, and a large amount of clear to white nasal discharge is noted.Capillary refill is 2 to 3 seconds.The guardian states the infant has difficulty feeding, often vomits, and has not had a wet diaper for 8 hours.During coughing episodes, mucous membranes are cyanotic, and oxygen saturation decreases.Which of the following actions should the nurse take first?