Critical Care Research and Practice

Clinical Study

Volumetric and End-Tidal Capnography for the Detection of Cardiac Output Changes in Mechanically Ventilated Patients Early after Open Heart Surgery

Table 3

Sensitivity, specificity, likelihood ratios, and predictive values set at criterion value giving maximal Youden index. The prevalence of responders and nonresponders was set to the ratio in the sample when calculating predictive values.


	AUC (95% CI)	Criterion (%)	Specificity (%)	Sensitivity (%)	+LR	−LR	PPV (%)	NPV (%)

VtCO₂ at RVP	0.68 (0.50 to 0.83)	5.2	83	56	1.9	0.3	83	56
EtCO₂ at RVP	0.80 (0.62 to 0.92)	1.7	100	56	2.3	0.0	86	100
VtCO₂ at PLR	0.50 (0.32 to 0.68)	4.2	92	44	1.7	0.19	82	67
EtCO₂ at PLR	0.64 (0.46 to 0.80)	2.2	88	56	2.0	0.23	84	63

AUC = area under the curve; +LR = positive likelihood ratio; −LR = negative likelihood ratio; PPV = positive predictive value; NPV = negative predictive value; VtCO₂ = exhaled carbon dioxide per tidal volume; EtCO₂ = end-tidal carbon dioxide; RVP = ventricular pacing; PLR = passive leg raise.