HYPOXIC DRIVE, real of urban legend?

[MSDeltaFlt]

Pickwickian Syndrome and Obesity Hypoventilation syndrome are definitely things to look up also. One thing can lead to another which causes another and cascades into a very complex broken system whch the body tries to compensate for.

A true hypoxic drive, in my experience, is where the patient begins to hypoventilate when given supplemental oxygen. Never really saw that with my COPD patients. However, with my morbidly obese patients with chronic hypoventilation syndrome or Pickwicks who were CO2 retainers (>70torr) I have seen have a significant drop in level of consciousness
with even a simple mask... in my presence. Kind of weird to witness the first time you see it.

 

[BLS Systems Limited]

One of the patients I experienced it with was a 16 year old MS patient...very thin and one of the last people you'd expect, but when you think about it he suffered from hypoventilation for most of his life creating a COPD-like picture.

 

[JakeEMTP]

A true hypoxic drive, in my experience, is where the patient begins to hypoventilate when given supplemental oxygen. Never really saw that with my COPD patients. However, with my morbidly obese patients with chronic hypoventilation syndrome or Pickwicks who were CO2 retainers (>70torr) I have seen have a significant drop in level of consciousness
with even a simple mask... in my presence. Kind of weird to witness the first time you see it.

Since these patients are already known hypoventilators, they are a group that raises concerns and are difficult to manage. On the one hand they do need oxygen due to their co-morbidities but they may also need assisted ventilations to maintain MV as well as oxygenation. For their home CPAP or BIPAP machines, they are usually on significant pressures.

ALS and some of the other neuromuscular disesases are also in the hypoventilation group. But, for some reason it is the COPD group that is given the most attention and are probably the group with the least CO2 retainers.

 

[JakeEMTP]

Children who had pulmonary problems at birth is also another group that is not greatly considered but they are now in home care or becoming adults. Their days in the Neonatal ICU may have a lasting effect.

http://ajrccm.atsjournals.org/content/168/3/356.full#sec-54


The "Treatment" section talks about home oxygen and its controversies. It has some concerns but without it, growth and development migth be impacted. Adult O2 dependent patients who were initially qualified for the script with a resting SpO2 without any activity and this also presents a challenge in the long term.

It might also be good to know that the full articles in that journal are available from past issues.

http://ajrccm.atsjournals.org/

 

[KellyBracket]

The only thing that seems clear, as others have described, is that the old story of the hypoxic drive is faulty. There are some great studies done in the hospital on critical COPD patients that have failed to show a harmful effect of oxygen on respiratory drive, rate, depth, or CO2 levels. Check out COPD: Is EMS Killing Patients with Oxygen? (1)

Of course, in an acute COPD attack, where the carbon dioxide levels are building, oxygenation isn't going to help much either. Ventilation is the issue.