Field comparison of nitrous oxide concentrations measured using thermal desorption tubes, passive dosimeter badges, and a Miran Sapphire infrared analyzer in Indian Health Service dental clinics
Creators: name: Joplin, Dustin
name: Benchoff, Edward
name: Woodlee, Charles
name: Schaal, Nicholas
name: Stubner, Alex
name: Olsen, Cara
Publisher: name: F1000 Research Limited
Year: 2019

description: Objective: The objective of this study was to determine the agreement between a Miran SapphIRe infrared ambient analyzer, traditional passive dosimeter badges (badges), and thermal desorption tubes (TD tubes) during nitrous oxide (N<sub>2</sub>O) sampling in Indian Health Service (IHS) dental clinics.  Agreement acceptable to IHS would be ± 15% of the Miran SapphIRe and could offer evidence for the TD tubes as being a potential alternative for future passive sampling of N<sub>2</sub>O exposures in IHS clinics.  A secondary objective of the study was to determine if there was a statistically significant difference in the sample means of each device due to the placement on the dominant and non-dominant side.<br><br>Methods: Passive sampling and direct-reading measurements were taken in the breathing zone of six dentists at three separate IHS dental clinic regions during dental procedures where N<sub>2</sub>O was used as the anesthetic.  Twenty-four sample sets were collected, each consisting of one TWA Miran SapphIRe, two badges, and three TD tubes.  A repeated measures Analysis of Variance test was performed to identify statistically significant differences between the three sampling devices.  A paired t-test was used to compare measurements taken on dominant vs. non-dominant sides.  The Bland-Altman method was used to investigate the level of agreement between the methods.<br><br>Results: The measurement means of all devices proved to be significantly different for the dominant side of the dentist (<i>p&lt;.05)</i>.  However, when the Miran SapphIRe was compared to the non-dominant side the badge was found to not be statistically different (<i>p=</i>.969).  Additional results suggest a statistically significant difference in measurement due to placement (dominant vs. non-dominant) for the badges on (<i>p=.003)</i>, but no significant difference for the TD tubes (<i>p=.807)</i>.  When plotted using the Bland-Altman method, both the badge and the tube failed to meet terms set forth for good agreement ±15%.<br><br>Conclusion: Despite neither of the passive samplers meeting the level of agreement (±15%) satisfactory to IHS, the data suggest that TD tubes are closer in agreement with the Miran SapphIRe reference method than the badges.  The data also indicate that the Miran SapphIRe may report concentrations up to 13 times and 2.5 times higher than measurements obtained with the badges and TD tubes, respectively.  In addition, the Miran SapphIRe showed a tendency to report higher concentrations than the badges in 50% (non-dominant) and 76% (dominant) of the 24 procedures sampled.  This indicates that the badges may be underestimating the actual exposure more than 50% of the time.  The Miran SapphIRe reported higher concentrations than the TD tubes for 17% (non-dominant) and 25% (dominant) of the 24 procedures sampled.  Though more investigation is needed to better understand the relationship between the devices, the data in this study suggests that TD tubes may offer a more conservative estimate of the N<sub>2</sub>O exposure to dental personnel.