Figure 1
Sampling strategies from 1999 to 2019. a – SkyPost Gas; b– Bravo M Plus pump; c– Lp-2,4-DNPH-S10 coated cartridge; d – GilAir-3 pump; e– FFA-PDMS/DVB SPME fibre; f– diffusive sampling fibre holder; g– Sep-Pak XpoSure sampler plus short DNPH-coated cartridge; h– GilAir Plus; i– Formaldemeter™ htV-M; j– GasCheck Basic; k – NEMo XT; l – Gasera One; m – ergonomic armchair (a) headrest with two NEMo XT and a Gascheck (b)
Figure 2
Box plot of the gross room FA monitoring results from 1999 to 2019. Mean, median, and quartile distribution of TWA and short-term concentrations (μg/m3)
Figure 3
Box plot of the specimen reception FA monitoring results from 1999 to 2019. Mean, median, and quartile distribution of TWA and short-term concentrations (μg/m3)
Figure 4
Box plot of the operating theatre FA monitoring results from 1999 to 2019. Mean, median, and quartile distribution of short-term concentrations (μg/m3)
Table 1
Trends in FA concentrations (μg/m3) at the Careggi Hospital operating theatres and pathology lab over three periods that saw improvements in handling and measuring FA exposure. Decreases are relative to the previous time interval
| Time interval | |||
|---|---|---|---|
| 1999–2007 | 2008–2015 | 2016–2019 | |
| Operating theatre | |||
| Short-term exposure (15 min) | |||
| Median range (μg/m3) (no. of monitoring campaigns) | 158–200 (9) | 61–108 (8) | 20–28 (4) |
| Mean decrease (%) | 182 (-) | 99 (46) | 24 (76) |
| Pathology laboratory – gross room | |||
| Short-term exposure (15 min) | |||
| Median range (μg/m3) (no. of monitoring campaigns) | 269–613 (9) | 71–161 (8) | 15–44 (4) |
| Mean decrease (%) | 410 (-) | 121 (71) | 29 (76) |
| TWA | |||
| Median range (μg/m3) (no. of FA campaigns) | 706–875 (9) | 115–180 (8) | 16–37 (4) |
| Mean decrease (%) | 301 (-) | 145 (52) | 32 (78) |
| Pathology laboratory – specimen reception | |||
| Short-term exposure (15 min) | |||
| Median range (μg/m3) (no. of monitoring campaigns) | 180–300 (9) | 85–90 (8) | 15–37 (4) |
| Mean decrease (%) | 211 (-) | 89 (58) | 28 (69) |
| TWA | |||
| Median range (μg/m3) (no. of monitoring campaigns) | 127–200 (9) | 44–73 (8) | 10–33 (4) |
| Mean decrease (%) | 160 (-) | 59 (63) | 25 (58) |
[i] FA– formaldehyde; TWA – time-weighted average
Table 2
2019 FA monitoring campaign overall measurements for all three work units (operating theatres, Pathology Lab gross room, and Pathology Lab specimen reception). The Wilcoxon rank-sum test was using whole data from the three work units. Probability (p) and z score values are reported for each comparison of methods. There is no evidence to reject the null hypothesis (p<0.05) for any of the tests
| 2019 FA monitoring campaign overall measurements for operating theatres and Pathology Lab specimen reception and gross room (μg/m3) | ||||||
|---|---|---|---|---|---|---|
| Active-sampling | Active-sampling | Active-sampling | Active-sampling | Direct-reading | Direct-reading | |
| DNPH cartridge | DNPH cartridge | DNPH cartridge | DNPH cartridge | NEMO Monitor | GASERA Monitor | |
| GilAir Plus | GilAir Plus | GasCheck | GasCheck | |||
| Personal sampling | Ergonomic armchair | Area sampling | ||||
| Short-term | TWA | Short-term | TWA | TWA | TWA | |
| No. samplings of | 103 | 76 | 103 | 76 | 76 | 76 |
| Mean (μg/m3) | 33 | 18 | 29 | 17 | 18 | 14 |
| Median (μg/m3) | 27 | 14 | 27 | 13 | 14 | 11 |
| Range (μg/m3) | 5–192 | 6–61 | 5–192 | 5–65 | 7–55 | 5–47 |
| Wilcoxon rank-sum test | ||||||
| Method comparison | p value (z) | |||||
| Active DNPH-cartridge personal short-term sampling vs Active DNPH-cartridge GasCheck Basic automatic collector sampling | 0.595 (0.532) | |||||
| Active DNPH-cartridge personal TWA sampling vs Active DNPH-cartridge GasCheck Basic automatic collector sampling | 0.252 (1.144) | |||||
| Active DNPH-cartridge personal sampling vs Direct-reading NEMO monitor sampling | 0.816 (-0.233) | |||||
| Active DNPH-cartridge GasCheck Basic automatic collector sampling vs Direct-reading Gasera monitor sampling | 0.195 (1.296) | |||||
Table 3
Calibration data for the analytical method and direct readings in lab setting
| Expected FA concentrations of gaseous standards (atmospheres) | Active-sampling DNPH cartridge | Direct-reading GASERA monitor |
|---|---|---|
| (μg/m3) | Mean ± SD (μg/m3) | Mean ± SD (μg/m3) |
| 20 | 24±7 | 17±8 |
| 40 | 44±8 | 63±6 |
| 80 | 83±7 | 98±12 |
| 160 | 166±15 | 144±23 |
| 320 | 323±13 | 337±25 |
| Simple linear regression estimation y=α+βx | ||
| R2 | 0.992 | 0.964 |
| β | 0.993 | 0.960 |
| (SE) | (0.017) | (0.038) |
| α | -3.151 | -2.675 |
| (SE) | (3.008) | (6.600) |
| p value of F test | ||
| H0: α=0 | 0.149 | 0.131 |
| β=1 | ||
| Method parameters | ||
| LOD (μg/m3) | 1 | - |
| LOQ (μg/m3) | 3 | 1* |
| Within session accuracy (%) | 4 | 6 |
| Within session repeatability (%) | 7 | 9 |
| Inter session repeatability (%) | 8 | 9 |
[i] SD – standard deviation; R2 – regression estimation parameters (α, β); SE – standard error of simple linear regression; LOD – limit of detection; LOQ – limit of quantification; * LOQ defined by the manufacturer