A Patient With COPD Presents With Worsening Respiration.

You are seeing a 65-year-old male in the emergency department (ED) where he presented with
complaint of increasing shortness of breath. He has obvious difficulty breathing and cannot speak in
full sentences. However, you are able to elicit that he has been having increasing respiratory problems
over the last 3–4 days. He has known COPD with FEV1 of “less than one” (normal FEV1 is about
4 L for a 50-year-old male and 3 L for a 50-year old female.) He has
been using his inhalers much more than usual but with minimal improvement. He has smoked one pack per day since age 18 (but proudly points out he quit 2 days ago), He has a past medical history of high cholesterol, obesity, and hypertension.
On exam, he has a respiratory rate of 26–28, heart rate of 100, blood pressure of 130/90, and temperature of 37.7. His O2 saturation is 84% on room air.
On auscultation, you do not appreciate much due to his body habitus but you still manage to hear some wheezing. He has a normal cardiac exam and no lower extremity edema.

What is the next best step to help this patient?
A) Perform emergent endotracheal intubation.
B) Administer supplemental O2 via nasal cannula.
C) Administer Solu-Medrol, 1 g IV.
D) Start antibiotics IV.
E) Obtain a chest x-ray.

Answer And Discussion

The correct answer is “B.” Administer supplemental O2 via nasal cannula.

This patient is hypoxic, and your first priority should be to improve his oxygenation. There exists a theory that oxygenating patients with COPD will suppress their respiratory drive. The classical teaching (mostly incorrect) is that COPD causes a switch from carbon dioxide levels driving respiration to oxygen levels driving respiration. While this may be partly true, further study has suggested that the main reason COPD patients are at risk of worsening hypercapnia is due to loss of hypoxic pulmonary vasoconstriction and worsening ventilation– perfusion mismatch that occurs with excess oxygen delivery. Regardless of that, you need to first worry about this patient’s oxygenation.

“A” is incorrect. The patient is protecting his airway and you have not attempted at improving his
oxygenation with less invasive methods yet.
Administering steroids, IV or PO, will have no immediate effect on his respiratory status. In fact, IV steroids might be worse than PO steroids (question of whether higher IV doses cause immunosuppression and subclinical myopathy).
Antibiotics and a chest x-ray may be reasonable, but with low O2 saturations, your priority is to quickly improve your patient’s oxygen status.

When initiating supplemental oxygen by nasal cannula, you instruct the nurse to keep the patient’s
oxygen saturation:

A) Between 96% and 100%.
B) Between 90% and 95%.
C) Between 85% and 89%.
D) At whatever saturation he looks most comfortable.

Answer And Discussion
The correct answer is “B.” Between 90% and 95%

The primary goal of supplemental oxygen is to reduce the risk of tissue hypoxia. Maintaining oxygen saturations above 90% (or PaO2 60–65 mm) will ensure tissue oxygenation. Higher oxygen saturations may result in CO2 retention and hypercapnia, as noted earlier. Also, aiming at 100% with excessive levels of O2 supplementation takes away an important patient assessment parameter because now you cannot tell easily whether his O2 needs are going up or down.
“D” is of special note. Patients with COPD who look comfortable may be becoming hypercapnic and developing CO2 narcosis. Thus, while comfort is a goal, it may not be the best judge of clinical status in patients with COPD exacerbations. To assess CO2 levels, you will need an ABG or VBG.