Please explain a copd patient's oxygen saturation!

Larry3373 · Apr 21, 2016

You have to look at each person individually to assess their baseline. Many times a patient with COPD may live with higher than normal CO2 levels in the blood and lower than normal O2 saturation. It used to be believed that some COPD patients were more dependent on their hypoxic drive to trigger respirations. This means that if you give a person with COPD too much supplementary oxygen, it might slow their breathing further and actually cause them respiratory failure. Since the normal person relies primarily on CO2 levels to trigger respirations, and the COPD patient relies more on the level of O2 in the blood to trigger respirations (it was believed), then it could actually be dangerous to give a COPD patient too much oxygen. From what I have read, this has been proven false. Look up the term "hypoxic drive" for more info. The bottom line is when dealing with patients, you have to assess what is normal for them, and if there is a sudden change from their baseline, you would address it accordingly.

mrsboots87 · Apr 21, 2016

I am curious to see your source for that info about COPD being false it is almost what is taught in school currently.

In COPD patients their body compensates for the higher than normal CO2 and lower than normal 02 levels in the blood. By giving them too much O2, their body believes it is getting enough O2 and will then slow the respiratory rate to reduce the O2 levels. This can cause further respiratory problems.

BUT, that does not mean that you want to keep every COPDer on low O2 sats. Each will be different. Some are compensating and will do great with supplemental O2 to keep data above 92%. Some need to remain in the 88-92% range. Treat the patient not the disease.

Larry3373 · Apr 22, 2016

From Medscape.com: Carbon dioxide retention from depression of hypoxic drive has been overemphasized. Despite the widely held belief that too much oxygen causes significant respiratory depression, multiple studies in the literature dispute this view. With administration of oxygen, PaCO₂ rises, but not in proportion to the very minor changes in respiratory drive. Carbon dioxide retention is more likely a consequence of ventilation-perfusion mismatching rather than respiratory center depression. While this complication is not common, it is best avoided by titrating oxygen delivery to maintain the PaO₂ at 60-65 mm Hg.

Medscape: Medscape Access

Author Zab Mosenifar, MD, FACP, FCCP Geri and Richard Brawerman Chair in Pulmonary and Critical Care Medicine, Professor and Executive Vice Chairman, Department of Medicine, Medical Director, Women's Guild Lung Institute, Cedars Sinai Medical Center, University of California, Los Angeles, David Geffen School of Medicine

sammiesmom · Apr 28, 2016

I used to work at a respiratory floor, most patients are chronic COPD and end-stage COPD. Some docs would write orders that it is ok (for end stage ones) for them to be at spO2 of 86, some even lives on spO2 of 83%. During my time there, it was believed that increased oxygenation further depresses respiratory drive but there is always new evidence and study now suggests that this is not the case.