Matt Harmon

165 Chapter eight Multivariable models with all co-variables included in the analyses for hyper- and hypocapnia versus normocapnia are presented in Table 3a and b. Our main analysis revealed no statistically significant difference between the hypercapnia and the normocapnia group (OR 0.70, 95% CI 0.44 - 1.11; P = 0.13) or the hypercapnia and the non-hypercapnia group (OR 0.80, 95% CI 0.51 - 1.22; P = 0.31) in relation to poor neurological outcome. In a similar analysis the hypocapnia group was compared to the normocapnia and subsequently to the non- hypocapnia group with no significant differences (OR 0.96, 95% CI 0.64 -1.45; P = 0.85); (OR 1.04, 95% CI 0.72 - 1.49; P = 0.82). The ∆PaCO 2 analysis did not reveal a statistically significant association with poor neurological outcome, neither for the 33°C nor the 36°C subgroup (OR 1.08, 95% CI 0.9 - 1.29; P = 0.37); (OR 1.00, 95% CI 0.82 - 1.20; P = 0.96), or for the combined group (OR 1.04, 95% CI 0.91 - 1.18; P = 0.56). The PaCO 2 -AUC from admission to end of intervention time or the first four measured PaCO 2 values (early dyscarbia) were not associated with poor neurological outcome (OR 1.09, 95% CI 0.83 - 1.42; P = 0.53) and (OR 0.99, 95% CI 0.81 - 1.22; P = 0.96) respectively. Table 3a . Multivariate model of hypercapnia versus normocapnia in relation to neurological outcome. OR CI P-value Hypercapnia (normocapnia reference) 0.70 0.44 – 1.11 0.13 TTM group (33°C reference) 1.00 0.71 – 1.42 0.99 Age (per year) 1.07 1.05 – 1.08 <0.001 Sex (male reference) 1.34 0.84 – 2.15 0.22 Chronic heart failure (yes/no) 2.09 0.98 – 4.46 0.06 Asthma/COPD (yes/no) 1.32 0.72 – 2.43 0.37 Bystander witnessed arrest (yes/no) 0.61 0.35 – 1.07 0.09 Bystander CPR (yes/no) 0.87 0.57 – 1.33 0.53 Time to ROSC (per min) 1.03 1.02 – 1.04 <0.001 GCS - M (1 vs 2 – 5) 2.5 1.72 – 3.57 <0.001 Shock on admission (yes/no) 1.56 0.88 – 2.75 0.13 First rhythm shockable (yes/no) 0.19 0.11 – 0.33 <0.001 pH (per 1.0 unit increase) 0.28 0.07 – 1.17 0.08