Nevner at mild hyperkapni gir økt blodsirkulasjon.

http://www.ncbi.nlm.nih.gov/pubmed/10708167

Acute hypercapnia (Paco2 from 40+/-3 to 52+/-3 torr, p<.05) increased cardiac index (3.43+/-0.37 vs. 3.97+/-0.43 mL/min/m2, p<.05), heart rate (95+/-6 vs. 105+/-3 beats/min, p<.05), and mean pulmonary artery pressure (21+/-1 vs. 24+/-1 mm Hg, p<.05) and reduced systemic vascular resistance (992+/-98 vs. 813+/-93 dyne x sec/ cm5, p<.05) and oxygen extraction ratio (27+/-3% vs. 22+/-2%, p<.05).

In this small group of stable patients, moderate acute variations in Paco2 had a significant effect on global hemodynamics, but splanchnic perfusion, assessed by deltaPco2, did not change.