Table 3.

Logistic regression analyses

Variable (unit)	Univariate					Multivariable
	P-value	Wald	OR	CI low	CI high	P-value	Wald	OR	CI low	CI high
Predisposing factors
Age (years)	0.092	2.84	1.07	0.99	1.16
Gender (female)	0.22	1.49	0.65	0.32	1.30
Weight (kg)	0.009	6.76	1.04	1.01	1.06
NRS pain (0–10)	0.030	4.69	1.21	1.02	1.43	0.042	4.12	1.20	1.01	1.44
Diabetes (yes)	0.052	3.79	2.69	0.99	7.31	0.029	4.78	3.24	1.13	9.32
Gastritis/peptic ulcer (yes)	0.067	3.36	3.00	0.93	9.71
Oxygen saturation peripheral (%)	0.053	3.74	0.83	0.70	1.00	0.045	4.03	0.82	0.67	1.00
Platelet count (109/l)	0.096	2.76	0.99	0.99	1.00
Combined surgical procedure (yes)	0.038	4.31	2.58	1.05	6.30	0.024	5.08	2.98	1.15	7.70
Precipitating factors
At operation
Operation time (h)	0.020	5.39	1.68	1.08	2.59
Lowest oxygen saturation (%)	0.079	3.08	0.85	0.72	1.02
Insulin infusion required (yes)	0.045	4.03	2.78	1.02	7.57
Blood loss (l)	0.079	3.09	2.85	0.89	9.17
Volume load (blood excluded) (l)	0.003	8.81	2.08	1.28	3.39	0.003	8.78	2.19	1.30	3.67
In the ICU
Ventilator time (h)	0.005	8.04	1.23	1.07	1.42	0.027	4.92	1.20	1.02	1.41
Lowest oxygen saturation (%)	0.021	5.31	0.82	0.69	0.97
Highest temperature recorded (°C)	0.068	3.32	1.88	0.95	3.73
Sodium concentration (mmol/l)	0.033	4.55	1.17	1.01	1.35	0.043	4.09	1.17	1.00	1.37
Combined predisposing and precipitating factors
Age (years)						0.036	4.39	1.10	1.01	1.21
Diabetes (yes)						0.032	4.58	3.49	1.11	10.99
Gastritis/peptic ulcer (yes)						0.050	3.83	4.00	1.00	16.06
Volume load during operating theatre (blood excluded) (l)						0.001	10.71	2.77	1.51	5.11
Ventilator time in ICU (h)						0.042	4.14	1.20	1.01	1.42
Highest temperature recorded in ICU (°C)						0.044	4.06	2.23	1.02	4.85
Sodium concentration in ICU (mmol/l)						0.038	4.30	1.19	1.01	1.41

NRS: numeric rating scale of pain; ICU: intensive care unit; OR: odds ratio; CI: confidence interval ± 95%.