Arterial oxygen tension increase 2-3 h after hyperbaric oxygen therapy: a prospective observational study

Area of Science:

• Critical care medicine
• Pulmonary physiology
• Hyperbaric medicine

Background:

• Hyperbaric oxygen (HBO) therapy may transiently decrease arterial oxygen tension (PaO2) post-exposure.
• Understanding these effects is crucial for mechanically ventilated intensive care unit (ICU) patients.

Purpose of the Study:

• To evaluate the impact of HBO therapy on arterial blood gases in mechanically ventilated ICU patients.
• To determine the extent and duration of changes in PaO2 and other parameters within 6 hours post-HBO.

Main Methods:

• Arterial blood gases were measured in 11 mechanically ventilated patients undergoing HBO therapy.
• Measurements were taken at baseline, during isopression, post-decompression, and at 1, 2, 3, and 6 hours after exposure.
• Ventilator settings were maintained, and the hyperbaric protocol involved 222.9 kPa with a 50-min isopression phase.

Main Results:

• Arterial oxygen tension (PaO2) decreased by 19.7% at 1 hour post-HBO (P < 0.01).
• PaO2 levels subsequently increased by 9.3% above baseline at 3 hours (P < 0.05).
• Oxygen saturation (SaO2), alveolar-arterial oxygen tension difference, and PaO2/FiO2 ratio showed similar trends; acid-base status and carbon dioxide tension remained unaffected.

Conclusions:

• Arterial oxygen tension experiences a transient decline followed by improvement above baseline in mechanically ventilated ICU patients after HBO therapy.
• Further research is needed to assess the effects of different ventilation modes and recruitment maneuvers.