The best replacement for hypercapnia is hypercarbia.

The best alternatives to hypercapnia are rated as following:
★★★★★  hypercarbia
★★★  hypoxia
★★  hypoxemia
★  hypocapnia
  hypercapnia

Your alternative for hypercapnia is not listed? Suggest!
Speaking about hypercapnia, one probably shouldn't forget about hypoxia.

Other search terms related to hypercapnia and their ratings are:
★★★★★ hypoxia
★★ respiratory acidosis
★ hypoxemia
You have in mind a companion for hypercapnia and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of hypercapnia in all years. Click on graph for more.
hypercapnia
hypercarbia
hypoxia