A preliminary study on the monitoring of mixed venous oxygen saturation through the left main bronchus

Table 3 Between-method statistical comparisons for the oxygen saturation measurement (SpO_2trachea versus SvO_2blood)

Intracuff pressure (cmH₂O)	n	MD (%)	SD	SEM	LOA	SEL
0	20	4.87	3.10	0.73	-1.33 to 11.07	1.201
10	20	0.25	0.97	0.21	-1.69 to 2.19	0.376
20	20	0.22	0.89	0.19	-1.56 to 2.00	0.345
40	20	0.31	0.66	0.14	-1.01 to 1.63	0.256
60	20	0.17	0.74	0.18	-1.31 to 1.65	0.287
Overall	100	1.26	2.39	0.25	-3.52 to 6.04	0.414
Overall excluding 0 cmH₂O	80	0.24	0.68	0.17	-1.12 to 1.6	0.132

LOA, limits of agreement (MD ± 1.96SD); MD, mean difference; SD, standard deviation of the difference; SEL, standard error of limit; SEM, standard error of the mean difference; SpO_2trachea, mixed venous oxygen saturation measured through the left main bronchus; SvO_2blood, oxygen saturation from pulmonary artery samples.

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