TABLE 1

Mean differences in oxygen saturation stratified by the oxygen saturation measured by oximetry

Ethnicity not recordedWhiteBlackAsianMixed
Overall difference(n=995)
+3.1%
(−21.6, +27.7)
(−64.1, +80.9)		(n=3946)
+3.2%
(−22.8, +29.1)
(−87.7, +80.1)		(n=151)
+5.4%
(−25.9, +36.8)
(−57.3, +73.4)		(n=246)
+5.1%
(−23.8, +34.0)
(−31.4, +74.8)		(n=36)
+6.9%
(−21.9, +35.8)
(−2.2, +68.6)
Arterial SO2 95–100%(n=355)
−2.2%
(−9.3, +4.9)
(−29.8, +3.9)		(n=1451)
−2.4%
(−10.7, +5.8)
(−38.1, +4.9)		(n=47)
−1.0%
(−6.8, +4.9)
(−11.6, +4)		(n=82)
−1.3%
(−8.2, +5.6)
(−24.1, +3.1)		(n=15)
+0.5%
(−3.7, +4.7)
(−2.2, +4.8)
Arterial SO2 90–94%(n=404)
−0.1%
(−7.2, +7.0)
(−29.8, +8.6)		(n=1436)
−0.4%
(−8.7, +7.9)
(−52.3, +10.1)		(n=62)
+0.5%
(−15.2, +16.3)
(−57.3, +8.8)		(n=103)
+1.0%
(−6.4, +8.4)
(−17, +10.3)		(n=11)
+1.7%
(−2.1, +5.4)
(−1.9, +4.4)
Arterial SO2 85–89%(n=93)
+3.4%
(−7.3, +14.1)
(−22.8, +13.9)		(n=418)
+2.4%
(−14.2, +19)
(−87.7, +15.9)		(n=17)
+3.9%
(−8.0, +15.9)
(−10.8, +15.4)		(n=23)
+5.8%
(−1.6, +13.2)
(−0.7, +14)		<5 patients
Arterial SO2 <85%(n=143)
+24.9%
(−16.1, +66.0)
(−64.1, +80.9)		(n=641)
+24.4%
(−15, +63.8)
(−73.9, +80.1)		(n=25)
+30.7%
(−16.8, +78.2)
(−28.7, +73.4)		(n=38)
+29.8%
(−18.3, +77.8)
(−31.4, +74.8)		(n=7)
+30.1%
(−12.0, +72.2)
(+5.2, +68.6)

Data are shown as mean difference in oxygen saturation (SO2) in paired arterial and pulse oximetry samples within a 30-min time window with 95% confidence intervals and range values. p<0.0001 for ethnic group (excluding unknown ethnicity), p<0.0001 for blood gas categories (two-way ANOVA of saturation difference across individual ethnic group and blood gas categories). Sensitivity analysis restricted to 10-min interval between measurements: p=0.003 for ethnic group (excluding unknown ethnicity), p<0.0001 for blood gas saturation categories (two-way ANOVA of saturation difference across individual ethnic group and blood gas categories).