Ask Mark …


Mark Mangus, RRT EFFORTS Board

Yet once again, we hear the story of a lady using oxygen, who was breathless and in extreme distress and whose lips were blue from severe lack of oxygen (hypoxia). Understand that in order for hypoxia to cause blue lips, your saturation has to be around or below 80 percent. When asked why she hadn’t increased her oxygen flow (her portable oxygen system was capable of delivering more oxygen than the setting of 2 that was on), she declared that her doctor and supplier had scolded her not to increase her oxygen or it would cause her to stop breathing from a build-up of carbon dioxide.

Once again, the “Hypoxic Drive” theory developed in the 1950s, was taught to an oxygen user, who then went around with dangerously low oxygen levels, fearful of increasing her oxygen flow. I would like to try to put a sensible perspective on this practice once and for all and to help oxygen users understand what they should know and practice themselves. Using adequate oxygen will not cause people who do not retain carbon dioxide to start to retain it.

image039-7The drive to breathe in people who do retain carbon dioxide normally, who are stable and functioning and able to engage in their normal daily activities, will not be suppressed by keeping their oxygen saturation in the 90 percent to 94 percent range – the recommended range by many current guidelines. The only documented cases in the literature attributed to using too much oxygen are all confined to those who presented to the Emergency Department with acute respiratory failure because of an exacerbation of their disease. Their condition was arguably driven by the infection or other reason that caused the exacerbation, not the oxygen level being used.

While using enough oxygen to maintain saturation in the 90 percent to 94 percent range has been shown to increase carbon dioxide levels in people who have COPD and who also retain carbon dioxide, it has been repeatedly shown in any study to be short lived in those who are in a stable condition. Further, it has never been shown to cause someone to stop breathing in any study. The recommendation in guidelines by the American Thoracic Society and American College of Chest Physicians is that it is more import- ant to ensure adequate oxygenation than to withhold oxygen for fear of what ‘could’ happen to a person’s breathing.

Oxygen users should never be forced to function with low oxygen levels. Adequate and safe oxygenation must be the goal of supplemental oxygen use.