<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 72-year-old man presents to the emergency department with severe respiratory distress. He was diagnosed with metastatic pancreatic cancer 6 months ago and underwent 2 rounds of chemotherapy. He says that he has had a cough and flu-like symptoms for the past week. During the interview, he is having progressive difficulty answering questions and suddenly becomes obtunded with decreased motor reflexes. His temperature is 38.8C 102.0F, blood pressure is 9060 mm Hg, pulse is 94min, and respirations are 22min. Pulse oximetry is 82 on room air. The patients medical record contains an advanced directive stating that he would like all interventions except for cardiopulmonary resuscitation. Which of the following is the most appropriate next step in management?? A: Observe and monitor vital signs for improvement., B: Administer intravenous fluids., C: Intubate and administer intravenous antibiotics., D: Administer intravenous antibiotics and draw blood for testing., E: Intubate only.,  <response>: This is a clinical vignette about a 72-year-old man with metastatic pancreatic cancer presenting with respiratory distress and altered mental status. The key findings are severe respiratory distress, history of metastatic pancreatic cancer, cough and flu-like symptoms for 1 week, high fever, hypotension, tachycardia, hypoxemia, and decreased mental status. He has an advanced directive stating he does not want CPR. The differential diagnosis includes pneumonia, sepsis, pulmonary embolism, and progression of cancer. However, his respiratory failure and altered mental status require urgent airway protection and ventilation. IV antibiotics should be started empirically for presumed pneumoniasepsis. Fluids may help temporarily but airway and breathing are the priorities. He does not want CPR, but intubation is not considered CPR.C: Intubate and administer intravenous antibiotics. 