Question

An adult male patient has a Carboxyhemoglobin level of 26% and is exhibiting intermittent confusion and disorientation. You, as the respiratory therapist are recommending HBO therapy. The physician, being unfamiliar with the treatment, asks what your rationale is for recommending HBO. How would you explain it to her?

Answer 1

Hyperbaric oxygen therapy

Hyperbaric oxygen therapy (HBOT) involves breathing almost pure oxygen in a special room or small chamber.

Hyperbaric oxygen therapy (HBO) involves exposing patients to 100 percent oxygen under supra-atmospheric conditions. Hyperbaric oxygen therapy can be used in cases of severe carbon monoxide poisoning. It helps protect heart and brain tissue. This results in a decrease in the half-life of carboxyhemoglobin (COHb), from approximately 90 minutes on 100 percent normobaric oxygen to approximately 30 minutes during HBO. The amount of oxygen dissolved in the blood also rises from approximately 0.3 to 6.0 mL per dL, which substantially increases the delivery of non-hemoglobin-bound oxygen to the tissues. This speeds the replacement of Carbon monoxide in blood.

Increased oxygen delivery — Henry's Law states that the amount of an ideal gas dissolved in solution is directly proportional to its partial pressure. Thus, the dissolved plasma oxygen concentration of 0.3 mL/dL at sea level (1.0 atm) increases to 1.5 mL/dL upon administration of 100 percent oxygen, while hyperbaric oxygen delivered at 3.0 atm yields a dissolved oxygen content of 6 mL/dL. The body’s tissues need oxygen to function, and additional oxygen can help damaged tissue heal. Oxygen at high pressure can enhance tissue function and fight infection under certain conditions.

The ambient pressure inside the chamber is 3 times higher than the air pressure that people normally breathe. Breathing almost pure oxygen at this pressure can increase the concentration of oxygen available to the lungs by up to three times.