Which of the following is a treatment for hypercapnia?

Increasing helmet and lung ventilation is an effective treatment for hypercapnia, which is the condition characterized by elevated levels of carbon dioxide (CO2) in the blood. When ventilation is increased, it facilitates more effective gas exchange in the lungs, allowing for enhanced removal of CO2 and intake of oxygen. This is crucial in managing hypercapnia since the primary issue is an excess of carbon dioxide; thus, improving ventilation directly addresses the underlying cause.

In contrast, decreasing oxygen levels would worsen the patient's condition by potentially leading to oxygen deprivation, while immediate recompression is typically associated with treating decompression sickness rather than hypercapnia. The administration of sedatives is generally not indicated as they might depress respiratory function further, exacerbating hypercapnia rather than alleviating it. Therefore, increasing ventilation is the appropriate and effective approach to managing this respiratory concern.