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Table 2 Association between variables and 90-day postoperative mortality

From: The cumulative duration of bispectral index less than 40 concurrent with hypotension is associated with 90-day postoperative mortality: a retrospective study

Variables

Univariable association

Multivariable association

OR

95% CI

P-valuea

OR

95% CI

P-valueb

Age (year)

1.02

0.99–1.06

.146

  

.438

Male sexb

2.64

1.07–6.55

.036

3.22

1.24–8.36

.017

Body mass index (kg/m2)

0.97

0.87–1.08

.539

   

Category of surgery (vs. Stomach)

  

.239

   

 Colorectal

1.84

0.72–4.75

.205

   

 Hepatic

1.07

0.21–5.34

.938

   

 Biliary-pancreas

0.66

0.18–2.34

.518

   

Volatile agent compared with TIVA

1.00

0.47–2.12

.998

   

Duration of anesthesia (min)

1.00

0.99–1.00

.774

   

bis40_dur (min)

1.00

0.99–1.01

.876

   

bis40_5min

2.58

0.35–19.12

.353

   

bis20_dur (min)

0.57

0.14–2.33

.432

   

bis20_5min

< 0.01

 

.998

   

eegsup_dur (min)

0.95

0.82–1.10

.483

   

eegsup_5min

0.47

0.06–3.51

.465

   

bis40map50_durb (min)

1.38

1.16–1.65

<.001

1.26

1.04–1.53

.019

bis20map50_dur (min)

1.89

0.44–8.08

.393

   

map50_dur* (min)

1.12

1.00–1.26

.057

   

Past medical history

 Aortic stenosis

< 0.01

 

.999

   

 Congestive heart failure

< 0.01

 

.999

   

 Coronary artery disease

1.39

0.33–5.95

.655

   

 Hypertension

0.91

0.42–1.98

.809

   

 Peripheral vascular occlusive disease

< 0.01

 

.999

   

 Dysrhythmiab

5.20

1.75–15.47

.003

4.26

1.24–14.59

.021

 Chronic obstructive pulmonary disease

3.13

0.72–13.60

.128

  

.805

 Pulmonary hypertension

11.28

1.31–96.95

.027

  

.200

 Stroke

< 0.01

 

.997

   

 Malignancy

4.77

1.13–20.16

.034

  

.219

 Diabetes

2.07

0.95–4.52

.068

  

.618

 Sleep apnea

< 0.01

 

.999

   

Current smoker

1.74

0.70–4.32

.236

   

Regular alcohol ingestion

0.86

0.35–2.13

.738

   

ASA (compared with ASA I)

  

.012

  

.539

 II

7.04

0.94–52.91

.058

  

.986

 III

19.32

2.43–153.44

.005

  

.335

 IV

< 0.01

 

.999

  

.795

Hemoglobinb level (g/dL)

0.56

0.46–0.69

<.001

0.70

0.55–0.89

.004

Albuminb level (g/dL)

0.11

0.05–0.21

<.001

0.21

0.09–0.47

<.001

  1. aAfter binary logistic regression in ‘enter’ method, variables yielding P-values under 0.2 were regarded to be potential risk factors. bIn the final multivariable logistic regression analysis in ‘backward LR’ method, variables remaining in final model were regarded as significant risk factors. *BIS or MAP derived variables not yielding P-values under 0.05 in the first step of multivariable analysis were excluded from final analysis
  2. Abbreviations: OR Odds ratio; CI Confidence interval; TIVA Total intravenous anesthesia; BIS Bispectral index; bis40_dur, cumulative time in which BIS < 40; bis40_5min, incidence in which cumulative time of BIS < 40 lasted > 5 min; bis20_dur, cumulative time in which BIS < 20; bis20_5min, incidence in which cumulative time of BIS < 20 lasted > 5 min; EEG Electroencephalogram; eegsup_dur, cumulative time in which patient’s EEG was suppressed; eegsup_5min, incidence in which cumulative time of EEG suppression lasted > 5 min; MAP Mean arterial pressure; bis40map50_dur, cumulative time that BIS < 40 and MAP < 50 mmHg simultaneously; bis20map50_dur, cumulative time that BIS < 20 and MAP < 50 mmHg simultaneously; map50_dur, cumulative time that MAP < 50 mmHg; ASA The American Society of Anesthesiologists physical status