An 80s F presents to the ED with shortness of breath x one day. There is no cough or chest pain. Her medical problems include asthma-copd, cabg-mi-chf, dvt, and diabetes. Her VS are HR 148, RR 28, BP 104/70, T 98.0. Her room air oxygen sat is 80. On exam, the patient is not in distress. She has mild bibasilar crackles on exam, no S3, no murmurs, no JVD, and no lower extremity edema. A cxr and an ekg are done. What do we do next?