Fig. 5

Patients with higher CO-Hb more likely to die. a Increase in CO-Hb values from day one to day five. Wilcoxon matched-pairs signed rank test. Contingency diagrams showing distribution of alive/deceased between patient groups of high/low b CO-Hb max (Fisher’s exact test: p = 0.0102, Koopman asymptotic score: RR = 2.186, 95%-CI 1.300–3.502, Baptista-Pike: OR = 12.86 95%-CI 1.947–146.9, Cut-off: 3%) and c CO-Hb mean (Fisher’s exact test: p = 0.0079, Koopman asymptotic score: RR = 2.186, 95%-CI 1.295–3.686, Baptista-Pike: OR = 8.708 95%-CI 1.700–42.61, Cut-off: 2%). ****p < 0.0001. CO-Hb carboxyhemoglobin