• refractory hypoxema

A 73 year old man, with a medical history of coronary artery disease, called the ambulance, because of retrosternal chest pain. When the paramedics arrived, his initial vital signs were normal and a pulse oximetry (Spo₂) was 94% on room air as he layed supine in bed. The pain persisted after sublingual nitroglycerin administration, and he was transported to hospital. While he was lying in a semi-recumbent position on the ambulance stretcher, his Spo₂ decreased to 70% and, despite receiving 100% oxygen through a face mask with an oxygen reservoir and oxygen flow of 12 l/min, it only rose to 80%. On arrival at the emergency department, the patient complained of shortness of breath, …