Table 2 Comparisons between non-invasive and invasive Hb

 Highest Hb (g/L)

144 (142–145)

138 (132–144)

123 (113–136)

129 (116–140)

138 (132–149)

 Lowest Hb (g/L)

127 (124–130)

128 (122–134)

114 (104–121)

107 (97–113)

134 (126–136)

 Highest – lowest Hb (g/L)

16 (16–19)

10 (9–11)

11 (9–14)

24 (16–28)

5 (5–6)

 Maximum change (%)

13 (13–15)

8 (7–9)

10 (7–12)

22 (14–27)

4 (3–5)

 Patient mean dilution (%)

7.0 (5.2–7.8)

3.9 (2.9–5.4)

4.2 (3.4–6.7)

11.5 (6.7–14.3)

2.9 (1.4–2.7)

 Highest SpHb (g/L)

139 (131–149)

134 (130–141)

126 (111–137)

123 (117–136)

134 (130–150)

 Lowest SpHb (g/L)

118 (109–126)

117 (111–122)

108 (99–120)

112 (96–124)

126 (123–139)

 Perfusion index (%)

5.2 (3.0–7.5)

7.9 (5.7–8.9)

5.0 (2.5–5.7)

3.2 (2.1–3.5)

4.1 (2.6–6.4)

 Highest – lowest Hb (g/L)

21 (19–25)

19 (14–20)

15 (11–19)

13 (7–23)

10 (8–11)

 Maximum change (%))

17 (15–24)

15 (12–18)

13 (9–16)

11 (6–21)

8 (7–8)

 Patient mean dilution (%)

8.6 (6.5–10.8)

5.3 (2.0–7.8)

2.4 (0.4–5.2)

4.3 (3.5–8.9)

0.2 ((−0.8)–0.7)

 Scatter (r²) Hb values

0.43 (0.22–0.61)

0.40 (0.25–0.63)

0.20 (0.05–0.44)

0.72 (0.48–0.81)

0.20 (0.07–0.37)

 Slope Hb values

0.95 (0.79–1.12)

1.04 (0.90–1.39)

0.46 (0.37–0.77)

0.49 (0.36–0.72)

0.16 ((−0.72)–0.70)

 Slope Hb dilution

0.96 (0.75–1.14)

1.06 (0.72–1.73)

0.43 (0.32–0.78)

0.38 (0.29–0.81)

0.16 ((−0.72)–0.49)

 Difference Hb dilution Invasive - non-invasive

−1.1 ((−3.6)–0.2)

−1.1 ((3.4)–1.9)

1.2 ((− 0.1)–6.0)

6.0 (2.4–9.7)

1.6 ((− 0.1)–3.6)