You are taking care of a 5 yr old with known asthma admitted…

You are taking care of a 5 yr old with known asthma admitted to the PICU for acute exacerbation. She is NPO with IVF on continuous albuterol, IV Methylprednisone and 24 hrs of atrovent. She continues to have wheezing and respiratory distress with intercostal retractions. What is the next Best treatment strategy?