Targeted Therapeutic Mild Hypercapnia after Resuscitated Cardiac Arrest (TAME)

Current guidelines recommend normocapnia for out-of-hospital cardiac arrest (OHCA), the TAME Study asked is mild hypercapnia better?

• Smaller previous studies have shown some benefits for hypercapnia including some improved outcomes:
  • Increased likelihood of discharge home and better 12 month neurologic outcomes
• The TAME study enrolled adults with OHCA with presumed cardiac or unknown cause within 3 hours of ROSC who were unconcious
• Unwitnessed, asystolic, hypothermic, pregnant, or ICH patients were excluded.
  • ECMO and Severe COPD patients on home O2 also excluded
• Randomization to either 24 hours of PaCO2:
  • Intervention arm:  50-55 mmHg
  • Control: 35-45 mmHg
• Strong design with strong methodology, adequate power, and good protocol adherence (>65% of measurements in group limitations) 
• Protocol violations in 8% of hypercapnia and 3% of normocapnia groups
• Missing primary outcome data in 7% of patients.
• Note: concurrent TTM trial (TTM2) was allowed to cross-enroll. Addressed with adequate statistical methodology

• Primary outcome (Favorable neurological outcome (GOSE ≥ 5)
  • 43.5% (mild hypercapnia) vs 44.6% (normocapnia)
    • ARR 0.98 (95% CI 0.87 to 1.11)
• Secondary outcomes: no differences

Conclusion: "In patients with coma who were resuscitated after out-of-hospital cardiac arrest, targeted mild hypercapnia did not lead to better neurologic outcomes at 6 months than targeted normocapnia."

References

https://www.nejm.org/doi/full/10.1056/NEJMoa2214552

https://clinicaltrials.gov/study/NCT03114033

https://www.thebottomline.org.uk/blog/ebm/tame/