Case Series on Hypoxia


  • Practice CXR and ABG interpretation
  • Practice evaluation of different causes of hypoxemic respiratory failure
  • Recognize indications for non-invasive positive pressure ventilation in the management of respiratory failure


45 year old man admitted for AKI and management of back pain after recently diagnosed renal cell carcinoma, develops increased shortness of breath on POD2. He reports pleuritic bilateral chest pain and denies fevers, chills or cough. Vitals are notable for T 36.7, HR 125, BP 125/75, RR 24, 96% on 3L NC. On exam, he is tachypneic and uncomfortable but able to speak in full sentences. Lungs are clear to auscultation and JVD is 9 cm H2O.

What additional work-up do you want right now?

How would you interpret his ABG? 

What is your differential for his hypoxemic respiratory failure? How would you further evaluate your differential? 

Final Diagnosis and Teaching Points 


64 year old man with HFrEF of 40% and severe COPD (FEV1 0.9L) presents to the ED with increased cough and SOB over the past three days. He denies fever or chest pain but reports sore throat, increased sputum production and “chest congestion”. He has been using his inhalers around the clock and he doubled his dose of diuretics for the past three days without improvement in his symptoms. On exam, he is afebrile, RR 32, has poor air movement on auscultation of his lungs but no appreciable wheezing.

What additional work-up would you want?

How would you interpret this ABG? 

What is the most likely diagnosis? 

How would you manage this patient?

Take Home Points 


A 20 yo female with a history of developmental delay was admitted for acute hypoxemic respiratory failure requiring intubation for parainfluenza infection. She was extubated 3 days ago and has been stably on 3-4L NC. She has had thick secretions and weak cough but has not been aggressively suctioned because of agitation. She was found to be acutely hypoxic to 80% FiO2 with moderately increased work of breathing. On exam, her RR is ~ 25-30 with no accessory muscle use. She was placed on 100% NRB with improvement in her saturations to 90%. A CXR showed:


What is the differential for this finding? 

Final Diagnosis and Take Home Points: 


75 year old woman with a history of mitral stenosis and atrial fibrillation is POD1 from cystoscopic resection of a bladder mass. Intraoperatively, she recieved 1U pRBCs and 3L of IVF for atrial fibrillation with rapid ventricular response (RVR) with heart rates in 150s. Immediately post-operatively, she continued to have heart rates in the 120s and was started on metoprolol. Over the past few hours, she has reported increasing shortness of breath and has had an increase in oxygen requirement from 1L NC to 60% high flow nasal cannula.  She reports some mild chest tightness but no fevers, cough, or pleurisy.

What additional evaluation and work-up do you want? 

What is the most likely diagnosis? 

How do you want to manage the patient? 

Take Home Points:


68 yo woman with metastatic breast cancer admitted for cancer-related back pain was found to be acutely hypoxemic to 70% FiO2 and RR in the 30s. She was placed on 100% NRB with improvement in her saturations to 85%. On exam, she has wet upper airway sounds that are transmitted throughout all lung fields. There is little airway movement at the L base. She is unable to respond to any questions because of respiratory distress. She is DNR/DNI.

What is your differential diagnosis?

What additional evaluation would you want?

Final Diagnosis and Take Home Points: