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Table 1 Overview of intermittent high fresh gas episodes and ensuing sevoflurane spikes

From: Agent consumption with the Zeus® in the automated closed circuit anesthesia mode with O2/air mixtures

  

High FGF episodes

Sevoflurane spikes

  

Etiology

Message

Time

Av FGF

Composition

Duration

Volume wasted

Vsevoprior to spike

Vsevoduring spike

Duration

Sevo waste

% of average usage 1–60 min (5.44 mL)

Pt

  

min

L/min

% O2

sec

L

mL/h

mL/h

sec

mL

 

#

FAsevo overshoot +

Autoflush

2

6.4

21

36

3.86

part of washin after overshoot,

N/A

 

1

CO2 sampling issue

Autoflush

7

2.1

100

31

1.10

followed by sampling issue

N/A

 

1

During calibration

Calibration

27

2.0

33

19

0.65

 

no change

 

N/A

 

2

Pressure on abdomen

Bag filling

14

14.0

38

7

1.64

7

84-198

7

0.15-0.39*

3-7

5

 

Bag filling

20

13.8

100

7

1.61

8

79-165

7

0.14-0.32 *

3-6

4

 

Bag filling

25

13.3

99

6

1.33

6

58-131

11

0.16-0.40*

3-7

5

 

Bag filling

25

13.2

21

6

1.32

4

72-172

8

0.15-0.38*

3-7

2

 

Bag filling

33

16.6

100

6

1.66

4

89

6

0.14

3

3

 

Bag filling

34

16.9

98

6

1.69

4

100-300

6

0.16-0.49*

3-9

3

FIO2 < 50%

Autoflush

45

1.9

100

27

0.87

5

6

209

0.08

2

6

 

Autoflush

51

2.3

100

26

0.98

7

21

20

0.08

1

4

 

Autoflush

52

1.9

100

33

1.07

5

7

311

0.19

3

7

 

Autoflush

55

1.7

100

37

1.04

2

4

254

0.16

3

1

Pressure on abdomen + FIO2 < 50%

Bag filling, then autoflush

36

3.1

60

32

1.68

4

13

60

0.15

3

3

  1. FAsevo = end-expired sevoflurane %; FGF = fresh gas flow; Av = average; Vsevo = sevoflurane usage; Pt = patient; N/A = not applicable.
  2. *Sevoflurane injection rate at least temporarily > 100 mL/h, thus a range is given. See text for details.