Cerebral oximetry values in dialyzed surgical patients: a comparison between hemodialysis and peritoneal dialysis

Figures & data

Table 1. Demographic, clinical characteristics, comorbidities and baseline rSO₂ values in the two groups.

Variables	Group A n = 23	Group B n = 9	p Value
Age, median (range)	76 (21–85)	61 (51–80)	NS
Gender (male/female)	16/7	7/2	NS
Diabetes mellitus, n	12	4	NS
Hypertension, n	13	7	NS
History CVD, n	11	5	NS
Duration of RRT (months), median (range)	8.5 (3–168)	10.5 (2–64)	NS
Preoperative Hb, (mg/dl), median, (range)	10 (7–12)	11 (9–12)	0.04
SpO2 (%), median, (min–max)	96 (88–99)	99 (93–99)	NS
MAP (mmHg), median (min–max)	98 (66–135)	96 (73–120)	NS
Baseline rSO2 L (%) median (min–max)	50 (28–63)	63 (45–69)	0.002
Baseline rSO2 L < 50 (%), n	11 (48%)	1 (11%)	0.05

Note: Values are expressed as median (range) or number (proportion) as appropriate.

Table 2. Univariate regression analysis.

	Unstandardized coefficients		Standardized coefficients
Parameter	B	Std. error	Beta	Significance
Age	−0.128	0.129	−0.178	0.330
Preoperative Hb	4.169	1.041	0.590	0.000
MAP	0.066	0.103	0.116	0.526
SpO2	1.829	0.396	0.645	0.000
CVD	−3.999	4.426	−0.175	0.382
Diabetes mellitus	−3.653	4.717	−0.159	0.447
Hypertension	−1.800	5.721	−0.065	0.756
Duration of RRT	−1.27	0.058	−0.461	0.065
Dialysis modality	−13.266	3.559	−0.563	0.001

Note: Dependent variable: baseline rSO₂.

Table 3. Multivariate hierarchical stepwise regression analysis with baseline rSO₂ as dependent variable: standardized and unstandardized coefficients.

		Unstandardized coefficients		Standardized coefficients
Model		B	Std. error	Beta	t	Significance
1	(Constant)	11.743	10.277		1.143	0.262
	Hb Preop	4.146	1.029	0.593	4.031	0.000
2	(Constant)	−103.171	34.843		−2.961	0.006
	Hb Preop	2.704	0.980	0.386	2.759	0.010
	SpO2	1.355	0.397	0.478	3.409	0.002
3	(Constant)	−60.860	35.475		−1.716	0.098
	Hb Preop	2.472	0.988	0.353	2.502	0.019
	SpO2	1.064	0.380	0.375	2.799	0.009
	Dialysis modality	−6.860	3.032	−0.291	−2.262	0.032

Note: Dependent variable: baseline rSO₂.

Table 4. Hierarchical stepwise regression, with baseline rSO₂ as dependent variable.

Model	R	R^2	Adjusted R^2	Std. error of estimate	R^2 change	F change	Sig. F. change
1	0.593^a	0.351	0.330	8.819	0.351	16.246	0.000
2	0.733^b	0.537	0.505	7.579	0.186	11.624	0.002
3	0.801^c	0.642	0.589	6.905	0.068	5.118	0.032

Notes: ^aPredictors: (Constant). Hb Preop.

^bPredictors: (Constant). Hb Preop, SpO₂.

^cPredictors: (Constant). Hb Preop, SpO₂, Dialysis modality.