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Table 1 Summary of carbon monoxide (CO) exposure levels and durations and corresponding carboxyhemoglobin (COHb) levels, by health status

From: A review of the experimental evidence on the toxicokinetics of carbon monoxide: the potential role of pathophysiology among susceptible groups

Exposure period

Exposure level (ppm)

Number of subjects

Meana COHb (%) among controls or during control periodb

Meana COHb (%) among exposed persons or after exposure

Mean increase in COHb with exposurec (%)

Healthy subjects

 1 min (5 exposures separated by 7 min each) [36]

7500

11

NR

NR

2.05

 3–6.65 min [42]

6683 ppm

15

2.08 (SD: 0.08)

NR

–

 2.5–3.5 min [25]

5000d

10

NR

3.95 (SD: 1.87)

–

 5 min (×  5 exposures separated by 3 min each) [36]

1500

11

NR

NR

2.08

 3–8 min [50]

3000d

12

NR

6.2 (SD: 0.3)

–

 10–30 min [45]

4000

12

NR

10

–

 30 min [49]

500d

15

1.2 (SD: 0.5)

8.5 (SD: 0.9)

7.3

 30–45 min [46]

1200

10

–

10

–

 1 h

100 [31]d

10

1.67 (SD: 0.33)

3.95 (SD: 0.49)

2.28

500 [49]d

15

1.2 (SD: 0.5)

9.4 (SD: 0.6)

8.2

500 [48]

13

1.2 (95% CI: 1.0, 1.4)

7.0 (95% CI: 6.5, 7.7)

5.8

 4 h [34]

35.7

30

1.5 (SD: 0.27)

3.03 (SD: 0.71)

1.53

74.1

30

1.3 (SD: 0.39)

5.1 (SD: 0.57)

3.80

10 days [33]

15d

15

0.5

2.4

1.90

50d

15

0.5

7.2

6.70

Susceptible groups

Subjects with cardiovascular disease

 3–120 s [51]

50,000

25

0.98

8.96

7.98

 50–70 min [61]

117 (SD: 4.4)d

63

0.6 (SD: 0.02)

2.0 (SD: 0.05)

1.4

253 (SD: 6.1)d

63

0.6 (SD: 0.02)

3.9 (SD: 0.08)

3.3

 1 h

50 [58] d

15

1.09 (SD: 0.15)

2.02 (SD: 0.16)

0.93

100 [63]d

24

1.5

3

1.5

100 [65]d

41c

1.82 (SD: 0.06)

3.93 (SD: 0.07)

2.11

100 [59]d

30c

1.7

4.1

2.4

159 (SD: 25) [68]d

33c

0.7

3.2

2.5

200 [64]d

41

1.82 (SD: 0.06)

5.91 (SD: 0.07)

4.09

292 (SD: 31) [68]d

33c

0.7

5.1

4.4

 1.5 h

53 (SD: 6) [53]d

10

1.12 (SD: 1.20)

5.08 (SD: 1.19)

3.96

100 [69]d

17

0.2–2.1

4.2 (SD: 0.3)

–

 2 h

50 [55]d

10c

1.03 (0.27)

2.68 (SD: 0.15)

1.65

50 [56]d

10

1.08

2.77

1.69

100 [69]d

17

0.64

3.91

3.27

142 ppm [39]

21

0.80 (SD: 0.20)

17.06 (SD: 1.38)

 

 4 h [54]

50d

10

1.3

2.9 (range: 1.3–3.8)

1.6

100d

10

1.3

4.5 (range: 2.8–5.4)

3.2

Subjects with chronic obstructive pulmonary disease

 1 h [71] d

100

10

1.48

4.08

2.60

Subjects with anaemia

 1 h [72]

50d

10

2.14 (SD: 0.55)

3.38 (SD: 0.83)

1.24

Subjects of older age (>  60 years)

 3 h [73]

50

36

1.30

2.77

1.47

  1. aAdditional summary statistics provided where reported, including standard deviation (SD), range, and 95% confidence intervals (CI). COHb levels reported to the number of decimal points reported in the original paper
  2. bRepresents COHb levels after exposure to fresh/filtered air, or pre-CO exposure; NR = not reported
  3. cCalculated as difference between pre (baseline) and post exposure COHb levels where values were reported. Dashed line (−-) indicates that not enough information was available for calculation. The number of decimal points are presented to match values reported in the original paper
  4. dExperimental conditions included exercise
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Environmental Health

ISSN: 1476-069X