Table 4.

Multivariate model of hypocapnia versus normocapnia in relation to neurological outcome

	OR	95% CI	P value
Hypocapnia (normocapnia reference)	0.96	0.64–1.45	0.85
TTM group (33 °C reference)	1.00	0.69–1.46	0.99
Age (per year)	1.06	1.04–1.08	< 0.001
Sex (male reference)	1.58	0.95–2.63	0.08
Chronic heart failure (yes/no)	1.95	0.87–4.37	0.10
Asthma/COPD (yes/no)	1.41	0.74–2.66	0.29
Bystander witnessed arrest (yes/no)	0.55	0.29–1.05	0.07
Bystander CPR (yes/no)	0.97	0.62–1.53	0.91
Time to ROSC (per min)	1.03	1.02–1.05	< 0.001
GCS-Motor score (1 vs 2–5)	1.92	1.32–2.86	0.001
Shock on admission (yes/no)	2.4	1.33–4.34	0.004
First rhythm shockable (yes/no)	0.16	0.09–0.29	< 0.001
pH (per 1.0 unit increase)	0.22	0.05–0.89	0.03

Hypercapnia = PaCO₂ > 6.0 kPa, normocapnia = PaCO₂ 4.5–6.0 kPa, hypocapnia = PaCO₂ < 4.5 kPa

OR < 1 indicates better outcome

OR odds ratio, CI confidence interval, TTM Target Temperature Management, COPD chronic obstructive pulmonary disease, CPR cardiopulmonary resuscitation, ROSC return of spontaneous circulation, GCS Glasgow Coma Scale, PaCO₂ arterial carbon dioxide pressure