Mild Hypercapnia or Normocapnia after Out-of-Hospital Cardiac Arrest

This randomized, controlled trial (TAME) investigated whether mild hypercapnia (PaCO₂ 50–55 mm Hg) improves neurologic outcomes in comatose adults resuscitated from out-of-hospital cardiac arrest compared to normocapnia (PaCO₂ 35–45 mm Hg). Across 1700 patients from 63 ICUs in 17 countries, no significant difference was found in favorable 6-month neurologic outcomes (43.5% hypercapnia vs. 44.6% normocapnia; RR 0.98; P=0.76) or death within 6 months (48.2% vs. 45.9%; RR 1.05). Secondary outcomes, including functional disability (Rankin score 4–6) and health-related quality of life, were similar between groups. Mild hypercapnia increased cerebral blood flow but did not translate to clinical benefit, and adverse event rates were comparable. The findings support guideline-directed normocapnia and do not endorse mild hypercapnia as a therapeutic strategy post-cardiac arrest.

This randomized, controlled trial (TAME) investigated whether mild hypercapnia (PaCO₂ 50–55 mm Hg) improves neurologic outcomes in comatose adults resuscitated from out-of-hospital cardiac arrest compared to normocapnia (PaCO₂ 35–45 mm Hg). Across 1700 patients from 63 ICUs in 17 countries, no significant difference was found in favorable 6-month neurologic outcomes (43.5% hypercapnia vs. 44.6% normocapnia; RR 0.98; P=0.76) or death within 6 months (48.2% vs. 45.9%; RR 1.05). Secondary outcomes, including functional disability (Rankin score 4–6) and health-related quality of life, were similar between groups. Mild hypercapnia increased cerebral blood flow but did not translate to clinical benefit, and adverse event rates were comparable. The findings support guideline-directed normocapnia and do not endorse mild hypercapnia as a therapeutic strategy post-cardiac arrest.