Relationship between acid–base status and inflammation in the critically ill

Table 3 Results of the principal component analysis (only principal components used in analysis are shown)

	PC1	PC2	PC3
Eigenvalue	1.51	1.35	1.02
Proportion of variance	0.30	0.27	0.20
Cumulative variance	0.30	0.57	0.78
Loadings
Simplified acute physiology score 3 (SAPS3)	-0.09	0.09	0.98
Albumin	0.53	-0.70	-0.12
Strong apparent ion difference (SIDa)	0.88	0.04	0.07
Strong ion gap (SIG)	0.16	0.92	0.05
Lactate	-0.65	0.04	0.19

Note that principal component (PC)1 was largely positively determined by SIDa and albumin, and negatively determined by lactate. PC2 is positively determined by SIG and negatively determined by albumin. Both PC1 and PC2 are relatively independent of SAPS3 score. PC3 reflects mostly SAPS 3 score. PC = principal component.

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