Table 3 Average difference between the location of the nasogastric tube determined by magnet tracking and by chest X-ray.

From: Feasibility of a low-cost magnet tracking device in confirming nasogastric tube placement at point of care, a clinical trial

 

Sub 01

Sub 02

Sub 03

Sub 04

Sub 05

Sub 06

Sub 08

Sub 09

Sub 10

Sub 11

(a) upper sensor pair on the sternal angle

\({\mu }_{y,ic}\)

1.15

1.29

1.67

0.73

1.60

1.29

0.54

2.78

0.83

1.84

\({\mu }_{y,wc}\)

1.43

1.40

0.56

1.58

1.65

1.67

0.56

1.99

1.12

1.70

\({\mu }_{y,iw}\)

2.08

1.33

1.59

1.46

0.40

1.54

0.38

1.16

0.89

0.30

\({n}_{ic}\)

8

10

4

9

9

5

11

6

9

4

\({n}_{wc}\)

8

10

4

9

9

5

11

6

8

4

 

Sub 01

Sub 02

Sub 05

Sub 06

Sub 08

Sub 09

Sub 10

Sub 11

  

(b) upper sensor pair on the xiphisternum

  

 \({\mu }_{y,ic}\)

5.79

3.41

4.87

1.96

1.39

3.22

2.85

3.80

  

\({\mu }_{y,wc}\)

2.06

3.23

3.20

1.84

1.60

3.49

1.71

4.36

  

\({\mu }_{y,iw}\)

3.55

2.23

10.64

0.53

0.43

0.91

1.92

2.10

  

\({n}_{ic}\)

9

8

9

7

11

8

9

10

  

\({n}_{wc}\)

3

8

3

7

9

8

5

5

  
  1. Unit of measurement: cm.
  2. Sub: research participant.
  3. \({\upmu }_{{\text{y}},{\text{ic}}}\) : average absolute distance in Y-axis between the tracking result and the chest X-ray during insertion of the magnet.
  4. \({\mu }_{y,wc}\): average absolute difference in Y-axis between the tracking result and chest X-ray during withdrawal of the magnet.
  5. \({\mu }_{y,iw}\): average absolute difference in Y-axis between the tracking results of insertion and withdrawal of the magnet.
  6. \({{\text{n}}}_{{\text{ic}}}\): number of comparisons made during insertion of the magnet (spaced 2 cm apart vertically).
  7. \({{\text{n}}}_{{\text{wc}}}\): number of comparisons made during withdrawal of the magnet (spaced 2 cm apart vertically).
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