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The impact of environmental factors in pre-hospital thermistor-based tympanic temperature measurement: a pilot field study.

Skaiaa SC, Brattebø G, Aßmus J, Thomassen Ø - Scand J Trauma Resusc Emerg Med (2015)

Bottom Line: After exposure, T tymp was recorded every 15 s for 10 min and compared with T rect .After surface cooling of head and neck, T tymp did not accurately reflect core temperature within the first 10 min of measurement.With the risk of over-triage, T tymp may at this point provide an indication of T core and also exhibit a trend.

View Article: PubMed Central - PubMed

Affiliation: Department of Anaesthesia & Intensive Care, Oslo University Hospital, N 0424, Oslo, Norway. scskaiaa@gmail.com.

ABSTRACT

Background: Few pre-hospital services have the possibility to accurately measure core temperature (T core). Non-invasive estimation of T core will improve pre-hospital decision-making regarding the triage and management of hypothermic patients. Thermistor-based tympanic temperature (T tymp) correlates well with T core in controlled studies; however, little is known about the feasibility of using T tymp under field conditions. This study assessed the impact of pre-hospital environmental factors on the accuracy of T tymp . Deep rectal temperature (T rect) was used as a substitute for T core .

Methods: Normothermic volunteers (n = 13) were exposed to four simulated field conditions producing local cooling of the head and ear canal. After exposure, T tymp was recorded every 15 s for 10 min and compared with T rect . Descriptive analysis and Bland-Altman plots were used to assess agreement.

Results: Immediately after exposure mean T tymp was low, but increased rapidly and reached an apparent steady state after 3-5 min. After 5 and 10 min, the mean temperature difference (∆T rect-tymp) ranged from 1.5-3.2 °C (SD = 0.5) and 1.2-2.0 °C, respectively. T rect remained unchanged throughout the study period.

Conclusions: After surface cooling of head and neck, T tymp did not accurately reflect core temperature within the first 10 min of measurement. The variation of ∆T rect-tymp was low after 10 min, regardless of the initial degree of cooling. With the risk of over-triage, T tymp may at this point provide an indication of T core and also exhibit a trend.

Trial registration: ClinicalTrials.gov: NCT02274597.

No MeSH data available.


Related in: MedlinePlus

(Row a): Bland-Altman plots with mean and 95 % limits of agreement for scenario a at baseline (BL), 0, 5 and 10 min. (Row b): Bland-Altman plots with mean and 95 % limits of agreement for scenario b at baseline (BL), 0, 5 and 10 min. (Row c): Bland-Altman plots with mean and 95 % limits of agreement for scenario c at baseline (BL), 0, 5 and 10 min. (Row d): Bland-Altman plots with mean and 95 % limits of agreement for scenario d at baseline (BL), 0, 5 and 10 min
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Fig4: (Row a): Bland-Altman plots with mean and 95 % limits of agreement for scenario a at baseline (BL), 0, 5 and 10 min. (Row b): Bland-Altman plots with mean and 95 % limits of agreement for scenario b at baseline (BL), 0, 5 and 10 min. (Row c): Bland-Altman plots with mean and 95 % limits of agreement for scenario c at baseline (BL), 0, 5 and 10 min. (Row d): Bland-Altman plots with mean and 95 % limits of agreement for scenario d at baseline (BL), 0, 5 and 10 min

Mentions: Bland-Altman plots were used to assess agreement between Trect and Tcore (Fig. 4). At baseline we observed a mean difference of 0.8 °C for all scenarios (P < 0.001). At 0 min an outlier is observed in scenarios A and B (recognisable as parallel lines in Fig. 1), probably representing a delay in data registration. During the 10 min measurement phase we observed a linear decrease in both the mean difference and range of agreement. After 10 min the mean difference ranged from 1.2 to 2.0 °C for scenarios B and D, respectively (P < 0.001). The concordance correlations showed a similar pattern, but were very low (≤0.063, Additional file 2).Fig. 4


The impact of environmental factors in pre-hospital thermistor-based tympanic temperature measurement: a pilot field study.

Skaiaa SC, Brattebø G, Aßmus J, Thomassen Ø - Scand J Trauma Resusc Emerg Med (2015)

(Row a): Bland-Altman plots with mean and 95 % limits of agreement for scenario a at baseline (BL), 0, 5 and 10 min. (Row b): Bland-Altman plots with mean and 95 % limits of agreement for scenario b at baseline (BL), 0, 5 and 10 min. (Row c): Bland-Altman plots with mean and 95 % limits of agreement for scenario c at baseline (BL), 0, 5 and 10 min. (Row d): Bland-Altman plots with mean and 95 % limits of agreement for scenario d at baseline (BL), 0, 5 and 10 min
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4581419&req=5

Fig4: (Row a): Bland-Altman plots with mean and 95 % limits of agreement for scenario a at baseline (BL), 0, 5 and 10 min. (Row b): Bland-Altman plots with mean and 95 % limits of agreement for scenario b at baseline (BL), 0, 5 and 10 min. (Row c): Bland-Altman plots with mean and 95 % limits of agreement for scenario c at baseline (BL), 0, 5 and 10 min. (Row d): Bland-Altman plots with mean and 95 % limits of agreement for scenario d at baseline (BL), 0, 5 and 10 min
Mentions: Bland-Altman plots were used to assess agreement between Trect and Tcore (Fig. 4). At baseline we observed a mean difference of 0.8 °C for all scenarios (P < 0.001). At 0 min an outlier is observed in scenarios A and B (recognisable as parallel lines in Fig. 1), probably representing a delay in data registration. During the 10 min measurement phase we observed a linear decrease in both the mean difference and range of agreement. After 10 min the mean difference ranged from 1.2 to 2.0 °C for scenarios B and D, respectively (P < 0.001). The concordance correlations showed a similar pattern, but were very low (≤0.063, Additional file 2).Fig. 4

Bottom Line: After exposure, T tymp was recorded every 15 s for 10 min and compared with T rect .After surface cooling of head and neck, T tymp did not accurately reflect core temperature within the first 10 min of measurement.With the risk of over-triage, T tymp may at this point provide an indication of T core and also exhibit a trend.

View Article: PubMed Central - PubMed

Affiliation: Department of Anaesthesia & Intensive Care, Oslo University Hospital, N 0424, Oslo, Norway. scskaiaa@gmail.com.

ABSTRACT

Background: Few pre-hospital services have the possibility to accurately measure core temperature (T core). Non-invasive estimation of T core will improve pre-hospital decision-making regarding the triage and management of hypothermic patients. Thermistor-based tympanic temperature (T tymp) correlates well with T core in controlled studies; however, little is known about the feasibility of using T tymp under field conditions. This study assessed the impact of pre-hospital environmental factors on the accuracy of T tymp . Deep rectal temperature (T rect) was used as a substitute for T core .

Methods: Normothermic volunteers (n = 13) were exposed to four simulated field conditions producing local cooling of the head and ear canal. After exposure, T tymp was recorded every 15 s for 10 min and compared with T rect . Descriptive analysis and Bland-Altman plots were used to assess agreement.

Results: Immediately after exposure mean T tymp was low, but increased rapidly and reached an apparent steady state after 3-5 min. After 5 and 10 min, the mean temperature difference (∆T rect-tymp) ranged from 1.5-3.2 °C (SD = 0.5) and 1.2-2.0 °C, respectively. T rect remained unchanged throughout the study period.

Conclusions: After surface cooling of head and neck, T tymp did not accurately reflect core temperature within the first 10 min of measurement. The variation of ∆T rect-tymp was low after 10 min, regardless of the initial degree of cooling. With the risk of over-triage, T tymp may at this point provide an indication of T core and also exhibit a trend.

Trial registration: ClinicalTrials.gov: NCT02274597.

No MeSH data available.


Related in: MedlinePlus