Agreement of in-ear temperature to core body temperature measures during invasive whole-body cooling for hypothermic circulatory arrest in aortic arch surgery (2024)

Abstract

Targeted temperature management (TTM) with therapeutic hypothermia (TH) during aortic arch surgery requires valid estimations of core body temperature. The ear canal and epitympanic region might be an easy-to-assess, noninvasive site for the read-out of supra-aortic, cerebral temperature. This observational cohort study comparatively investigated in-ear temperature and different core body temperature (cBT) measurements during TTM/TH for moderate hypothermic circulatory arrest (mHCA) in aortic arch surgery. In total 24 patients (mean age of 56.8 ± 17.5years; six females) were measured using infrared-thermography of the epitympanic region (BTtym), thermistor-based measurements at the esophagus (BTeso; gold standard), at the ear canal (BTear), at the nasopharynx (BTnas), in the bladder (BTves), and in the rectum (BTrec). The data analysis comprised absolute agreement (AA), bias, intraclass correlation coefficient (ICC), and limit of agreement (LoA). The results revealed high AAs of BTtym, BTear, BTnas in reference to BTeso (biases 0.3–0.6°C), with also excellent ICCs > 0.9. BTves and BTrec showed lower AAs, higher biases of + 2.5°C to 3.1°C with moderate ICCs during mHCA. In the phases of rapid temperature changes, the biases and LoAs were higher throughout all BT measurements. Herein, BTtym performed best of all measurement sites. The study informs about the BT dynamics at different body sites during the mHCA procedure. It supports the approach of using minimally invasive in-ear techniques to estimate core body temperature in an intrahospital TTM/TH setting of mHCA.

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Introduction

Targeted temperature management (TTM) with therapeutic hypothermia (TH) is a fundamental part of the neuroprotective strategy during aortic arch surgery1. Procedures extending into the arch per definition require circulatory arrest (CA). The vulnerability of the brain to hypoxemia determines the duration and potential harmfulness of the iatronegic CA procedures. The induction of hypothermia to a targeted core body temperature (cBT) of 22–26°C prior to CA2 enhances the ischemic tolerance of the central nervous system by multiple mechanisms3. Thus, TTM/TH with rapid change rates and moderate hypothermic circulatory arrest (mHCA) is a clinical standard procedure for aortic arch surgery. The 2021 ERC guidelines also recommend TTM/TH with a higher cBT target range of 32–34°C for neuroprotection after out-of-hospital cardiac arrest4.

TTM/TH procedures demand for continuous and accurate cBT monitoring with a desired read-out of cerebral temperature. With the rapid temperature changes during cooling and rewarming phases for mHCA, the cBT measurement procedures are supposed to show immediate and fast dynamic behavior. The most accurate methods for this purpose is the measurement of central blood temperature at the pulmonary artery, but limited by its high degree of invasity. The measurement of tissue temperature in the middle part of the esophagus is therefore regularly chosen as clinical standard method for TTM/TH monitoring in aortic arch surgery2. Monitoring of rectal or bladder cBT is less invasive. However, cBT changes recorded in the bladder or in the rectum are considered slower in response and with inferior temporal dynamics of BT4.

The external ear canal as a possible measurement site enables further potentials for body temperature (BT) monitoring. The easy accessibility of the ear canal and the development of wearable in-ear sensors, nowadays, enable a minimally invasive and continuous monitoring of epitympanic or aurical BT. The proximity of the (epi-) tympanum to intracranial arteries and the hypothalamus potentially allows the estimation of cBT5, respectively cerebral temperature6. Additionally, the minor sympathic influence of its arteries may lead to a preserved vascularization of the epitympanum and ear canal during centralization induced by hypotonia or hypothermia7.

Recent intra-hospital investigations demonstrated a satisfactory concordance between epitympanic BT and cBT (derived from the pulmonary artery) in mild TTM/TH8 and mHCA9, with no evaluation of the clinical standard of esophageal BT in either study. Nonetheless, investigations with different technical or procedural specifications have reported contradictory findings10.

To generate comparative data, this study systematically investigates cBT measurements at various sites during the whole mHCA procedure while aortic arch surgery. The primary objective is to examine the concordance and limits of agreement of different body temperature measurements in reference to the clinical gold standard of esophageal cBT. The second objective is the investigation of the temporal dynamics of different cBT measures during rapid temperature gradients in the TTM/TH procedure.

Methods

Participants

Sample size calculation (MedCalc® 23.0.2) was performed with the assumptions α = 0.05, β = 0.20 and an expected mean difference of 1.0 ± 0.8°C between the different measures. The minimum number of participants for repeated measures Bland-Altmann-procedures was n = 17, for repeated measures ANOVA it was n = 24.

In total 24 patients (mean age of 56.8 ± 17.5years; 6 females) were recruited as part of the in-ear temperature and perfusion monitoring during therapeutic hypothermia study (in-ear-TEMPERATURE; DRKS-ID: DRKS00032338) at the LMU University Hospital, Ludwig Maximillian University Munich, Bavaria, Germany. Inclusion criteria were (I) an age above 18years, and (II) a planned replacement of the proximal arch of the aorta with mHCA. Exclusion criteria were (I) the presence of clinical signs of inflammation of the ear canal, (II) an auditory canal obstruction (anatomic/ foreign material), and (III) a history of tympanic plastic surgery. Each participant provided written informed consent before participation. Ethical approval for this study (Ethical Committee N° 22–0322) was provided by the Ethical Committee of the LMU University Hospital, Munich, Germany in agreement with the Declaration of Helsinki.

Study procedures and recordings

Following induction of anesthesia, thermistor probes (Ruesch Rectal/Temperature Sensor, Teleflex Medical, Ireland) were inserted into the bladder, rectum, middle esophagus (standardized placement 0.35m away from teeth row), and nasopharynx (standardized placement 0.20m away from nasal apertura). Continuous temperature data was assessed with 0.1Hz. A commercially available, medical device ear canal sensor (Cosinuss° cmed° alpha®) was inserted into the right ear without further insulation of the ear. The Cosinuss° cmed° alpha® sensor includes both a thermistor and an IR-thermography for direct mode, in-ear measurement of temperature (0.1Hz). The IR-thermography directs towards the tympanum, thus delivering BT data of epitympanic tissue. The thermistor of the Cosinuss° cmed° alpha® records BT of the external ear canal tissue. The BT measurements from the thermistor probes and the in-ear sensor were calibrated via the blackbody and water bath procedure according to the ASTM International standard11. After the surgery, the thermistor probes and the ear sensor were removed, leaving the thermistor in the bladder for clinical routine at the ICU.

Hypothermia procedure during surgery

During anesthesia induction and transport to the operation room, no standardized TTM/TH procedure was performed. A possible passive reduction of BT during this period was tolerated, when BT maintained > 35°C (Table 1, phase 1). In the following sequence, an standard procedure for mHCA at the cardiac surgery unit included a target cBT measured in the bladder < 27°C (phase 3) and a specific cooling and rewarming protocol (phases 2 and 4). It was defined by a maximum temperature difference of 6°C (for phase 2) and 3°C (for phase 4)between perfusate delivered by the heart–lung machine (HLM) and the drained venous blood temperature. The bladder was deliberately chosen as the measurement site for target cBT to ensure thorough cooling of all tissue regions of the body at the initiation of circulatory arrest. Further institutional standards of patient management during aortic arch surgery are described elsewhere12 and can be reviewed in the supplemental data. Table 1 highlights the definitions of the starting and ending time points of the mHCA procedure. Phase 1 involved the preparation at normothermic conditions; phase 2 comprised the cooling process; phase 3 included hypothermic circulatory arrest, while phase 4 entailed the rewarming process.

Full size table

Data processing and analysis

BT data was recorded with a sampling rate of 0.1Hz and resampled for 1min intervals. Herein, the mean and standard deviation (SD) of BT were calculated for the bladder (BTves), for the rectum (BTrec), for the nasopharynx (BTnas), for the esophagus (BTeso), for the epitympanic region (BTtym), and for the external ear canal (BTear).

The time stamps for the Draeger® and Cosinuss°® systems were synchronized manually by setting the system clocks of both devices with a double check via manual light tapping of the ear sensor accelerometer (related to the system clock of the Draeger® monitoring device).

The Kolmogorov–Smirnov test assessed the distribution of the derived parameters followed by a descriptive analysis for the absolute temperature values. A repeated measure ANOVA (rmANOVA) with Bonferroni’s post-hoc analysis was utilized to calculate the f-value (F) and p-value (p) for the independent factor “measurement site”. Additionally, Bland–Altman procedures (for repeated measures) with limits of agreement (LoA) and intraclass correlation coefficients (ICC, two-way mixed model, absolute agreement) were calculated with BTeso as the reference for all BT measures. The ICC was evaluated according to the following standards: low (< 0.39); moderate (0.40–0.59); high (0.60–0.79); and excellent (≥ 0.80)13. Results were considered significant at p < 0.05. Statistical analysis was performed using SPSS (Version 29.0; IBM Corp., Aronk, NY).

Results

Characteristics of the study cohort and surgery procedures

Demographic characteristics and health variables were computed and are presented in Table 2. The mean age of the cohort was 56.8 ± 14.8years, six of the 24 patients were female. All patients underwent mHCA according to the standard operation procedure for the replacement of the proximal arch of the aorta.

Full size table

The mean duration of the surgical procedure for participants was 225 ± 41min, with phase 1 (P1) of 55 ± 22min, phase 2 (P2) of 46 ± 12min, phase 3 (P3) of 25 ± 7min, and phase 4 (P4) of 91 ± 21min.

ANOVA model of absolute body temperature measurements

For all time sections of the study and for all measurement sites, normal distribution was evident for BT (all p > 0.05 in the Kolmogorov–Smirnov test).

The mean BTeso was 35.5 ± 0.5°C during P1 and 23.4 ± 1.1°C during P3. The mean change of BTeso was 0.4 ± 0.1°C/min for P2, respectively 0.4 ± 0.1°C/min for P4 (Table 3). The rmANOVA model revealed a significant effect of the variable “measurement site” on the detected BT during P3 (F6, 23) = 2.4, p < 0.05), on the change of BT (ΔBT) during P2 (F6, 23 = 6.4, p < 0.05), and on ΔBT during P4 (F6, 23 = 10.2, p < 0.01) (Table 3).

Full size table

For absolute BT at P3, Bonferroni posthoc tests showed significantly higher values of BTves and BTrec compared to the BTeso (p < 0.01 for both pairs). The duration of T3 did not significantly influence these positive offsets (z = −0.82, p = 0.089). There were no significant differences between BTeso, BTtym, BTear, and BTnas in pairwise comparisons.

During both dynamic phases (P2 & P4), Bonferroni posthoc tests showed significantly lower ΔBTs for BTves and BTrec in comparison to BTeso (p < 0.01 for both pairs).

Intraclass correlation coefficient (ICC), temperature differences, and Bland-Altmann plots

Significant ICC values (in reference to BTeso) were evident for all phases of the study. The ICC values ranged from -0.067 to 0.986 (p’s < 0.001) (Table 4), with lowest values for BTves and BTrec. In contrast, the ICC values for BTtym, BTear, and BTnas were consistently > 0.8 across all four phases of the study, indicating excellent correlations between these BTs (Table 4).

Full size table

The mean BT differences (biases) of BTtym and BTnas compared to BTeso were less than 0.5°C. The lowest biases were present for BTtym (here fore: biases < 0.3°C, LoAs < 2.3°C). For BTear, temperature biases were slightly higher in the static phases of P1 and P3. During the dynamic phases P2 and P4, the biases were smaller compared to BTnas (Table 5), although the rmANOVA model did not reveal significant differences for these three BT measures.

Full size table

RmANOVA with posthoc comparisons revealed significantly higher biases of BTves and BTrec compared to BTtym, BTear, and BTnas (all p < 0.01; Bonferroni posthoc analysis) (Table 5). These findings were evident for P2, P3, and P4 of the study (single patient plot: Fig.1).

Single patient comparative BT measurement results. Comparative BT data of patient #19 for all study phases. BT: body temperature; C: celsius; CA: cardiac arrest.

Full size image

Correspondingly, the LoAs of BTs at all measurement sites showed narrow ranges during normothermia, with the lowest values for BTtym and BTnas (both 0.77°C). The LoAs for BTves and BTrec were significantly larger than those of supra-aortic regions, especially during P2, P3, and P4 (all p < 0.01; according to Bonferroni post-hoc analysis). The rapid changes of BT during P2 and P4 induced higher LoAs also for BTtym, BTear, and BTnas, compared to the phases P1 and P3 (for details: Table 5, Fig.2). BTtym revealed preferable LoA values for all study phases. The BAP comprised the overall range of all measured cBT values of the cohort, where the extremities of the range mainly represent the static conditions P1 and P3.

Bland-Altmann plots of all BT measurement sites and all study phases. Bland–Altmanns plots for the different BT measurement site references to BTeso. Section A: static BT phases (normothermia and hypothermia), Section B: dynamic BT phases (cooling and rewarming). x-axis: (BT + BTeso)/2 in [°C]; y-axis: BT- BTeso. BT: body temperature; C: Celsius; HCA: hypothermic cardiac arrest; LoA: Limits of Agreement.

Full size image

Discussion

Core body temperature measurements at the middle part of the esophagus or in the pulmonary artery are the gold standards for accurate, intraoperative monitoring. Specific characteristics of the TTM/TH procedures for mHCA induce a more elaborate cBT monitoring strategy. Fast temperature gradients during HLM circulation require an immediate responsiveness of the cBT estimation2. Moreover, there is a specific interest in the monitoring of cerebral body temperature. Thus, scientific efforts have been made to evaluate non-invasive temperature estimations in supra-aortal regions14, such as the measurement of the tympanic BT15. This study delivers BT data at various body sites allowing comparisons between supra-aortal circulation regions and lower-body measurement sites.

The study’s main findings are as follows:

  1. I.

    There is a high absolute agreement for body temperature measurements of the esophagus, epitympanic region, external auditory canal, and nasopharynx during normothermia and mHCA. The body temperature measurements in the bladder and rectum exhibit significantly higher biases during mHCA.

  2. II.

    The fast temporal dynamics during the cooling and rewarming phases induce wider limits of agreement for all body temperature estimations. Best absolute agreements, intraclass coefficient correlations and limits of agreements are present for the epitympanic BT measurements.

Body temperature estimation in regions of supra-aortic circulation

All three supra-aortic measurement sites delivered BT data with good absolute agreements and biases ranging from < 0.3°C (epitympanic) to < 0.6°C (nasopharynx, ear canal). These findings suggest similar temperature homeostasis in tissues of supra-aortic circulation and the mediastinal tissues, which is in accordance with recent studies using pulmonary artery blood temperature as the gold standard8,16. Further, supra-aortic BT measurement appears to be also valid during the process of mHCA, which complements studies in procedures of mild TTM/TH after cardiac arrest17.

Only minor, non-significant, differences within the three supra-aortic BT measurement sites were present in the current study. During the phases with dynamic temperature changes (P2 and P4), the LoAs of the BTnas were slightly higher than those of BTtym and BTear. Nasopharyngeal BT is considered a suitable technique to assess core BT during the process of invasive cooling after cardiac arrest18,19. The current findings indicate that in-ear BT measures could even deliver more robust body temperature data during fast temperature changes while mHCA. Both areas, the nasopharynx and the ear, share vascularization via the external carotid artery, so the discrete variation of the BT data might originate also by procedural differences. As a possible explanation, the employed in-ear sensor with its silicone head mold putatively offers thermal insulation for the ear canal, thereby protecting it against ambient temperature changes20 and manipulation effects. In this sense, the resulting continuous ear-canal insulation could generate a local microclimate, that might improve the quality of cBT estimation at this site21.

The results of this study do not support findings of former investigations, that indicate a systematic body temperature gradient in the ear canal with the warmest point at the tympanic membrane22. We found non-significant trends towards narrower LoAs and smaller biases of the BTtym compared to BTear especially in phases of fast temperature changes. The latter might indicate a faster response of tympanic BT to changes in blood temperature due to different vascularization patterns between the ear-canal tissue and the tympanum10. Alternatively, different technical specifications (epitympanic: IR-thermography; ear canal: thermistor) of the in-ear sensor might explain the variation in the data.

Body temperature estimation in the bladder and rectum during TTM/TH and mHCA

Rectal and bladder thermistor probes are commonly utilized techniques for temperature monitoring during surgical procedures and in intensive care, primarily due to its beneficial placement options.

During TTM/TH of mHCA, high agreements and high correlations of BTves and BTrec with BTeso were found under normothermic conditions23. At mHCA and during the cooling and rewarming of the patients, the bias of both body temperature measures exceeded 3°C, with wide LoAs and only moderate ICC values.

Temperature change rates were significantly lower in BTves/ BTrec compared to BTeso, implying slower response dynamics during TTM/TH. In the hypothermic phase, bladder and rectal BT exhibit significant biases of + 3 to + 4°C. This disparity constantly persisted over P3 without an obvious tendency to approach the body temperature estimations of the esophagus or the supra-aortic measurements. Therefore, this effect is probably not solely a result of a slower dynamic of BTves/ BTrec after the cooling process. Differences in tissue vascularization patterns and the ‘reservoir’ function of the bladder/rectum may account for this bias. Although not directly examined, the production of urine and its intraoperative drainage protocol influenced the bladder BT during our study procedures (data not shown).

Blood and tissue temperatures of the supra-aortic regions were significantly lower than those of the bladder and rectum during mHCA. On a single-patient basis, bladder/rectal BT was systematically higher and slower in response in comparison to supra-aortic BTs during all phases except for normothermia.

Former studies provide evidence for a good agreement of BTves and other cBT measurements in the context of mild TTM/TH (32–34°C)8. This agreement putatively diminishes for mHCA with its fast BT gradients.

Clinical applicability and generalizability of non-invasive cBT measurements

This study indicates a highly accurate core body temperature estimation at the epi-tympanum, the ear canal, and the nasopharynx during moderate hypothermia and rapid temperature changes in an intraoperative, well-controlled setting. Considering the minor invasivity of the in-ear measurement and its direct vascularization via carotid arteries, in-ear BT measurement procedures appear to be a useful adjunct in patient management during mHCA24. Epitympanic BT estimations with a preserved insulation of the ear canal might have beneficial effects on the quality of the estimation.

Conclusions regarding the generalizability of supra-aortic BT estimation procedures to monitor body temperature in other forms of hypothermia are limited. The fast temperature changes of the used TTM/TH protocol are normally higher than those during accidental hypothermia, although case reports of patients with accidental hypothermia (especially when extricated from avalanches or water), have already reported fast temperature drops up to 0.5°C per minute25. Moreover, vasoregulation between TTM/TH and accidental, external hypothermia might be considerably different: TTM/TH originates by direct perfusion of cold blood through cannulated, central arteries. As a result, the BT derived from the local tissue depends on the temperature of the perfusate. In contrast, hypothermia caused by external cooling might induce significant differences in vasoregulation and local thermohomeostasis that can influence the BT estimations in the ear. There is evidence for effects on thermoregulation and perfusion dynamics of the ear induced by a decline of facial skin temperature26. In this line, studies in prehospital settings have highlighted the IR-thermography to produce unreliable results27. This could be a result of a high vulnerability to ambient and skin temperature changes28.

Limitations of the study

The employed in-ear sensor provides a dual temperature estimation using IR-thermography (epitympanic) and thermistor (ear canal) technology, which might induce technical variation in the data. This limitation, however, was mitigated through direct warm-water calibration of the systems as described in the method section with an offset < 0.1°C between the different BT measurement techniques.

Moreover, the findings have to be interpreted in the context of an optimally fitted ear/head ambiance and the induction of hypothermia via an internal stream of cold blood through cannulation and selected perfusion of central arteries. Herewith, HLM delivered blood flow to the ear canal with a targeted temperature with unclear consequences on vasoregulation of the supra-aortic circulation. Especially the effects of a trigeminovascular regulation, e.g. induced by changes of the skin temperature of the face, have to be further evaluated to increase the generalizability of in-ear BT measurements in the context of cBT monitoring during other clinical scenarios.

Conclusions

This study supports the approach of using minimally invasive in-ear techniques to estimate core body temperature in an intrahospital TTM/TH setting of mHCA. Due to the common blood supply of the carotid arteries and the proximity of the ear to brain temperature, an estimation of brain temperature may be assumed, though this was not directly examined in our study.

Data availability

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

References

  1. Taccone, F. S., Picetti, E. & Vincent, J.-L. High quality targeted temperature management (TTM) after cardiac arrest. Crit. Care Lond. Engl. 24, 6 (2020).

    Article Google Scholar

  2. Polderman, K. H. & Herold, I. Therapeutic hypothermia and controlled normothermia in the intensive care unit: practical considerations, side effects, and cooling methods. Crit. Care Med. 37, 1101–1120 (2009).

    Article PubMed Google Scholar

  3. Gonzalez, D. et al. Post cardiac arrest care in the cardiac intensive care unit. Curr. Cardiol. Rep. 26, 35–49 (2024).

    Article PubMed Google Scholar

  4. Zweifler, R. M., Voorhees, M. E., Mahmood, M. A. & Parnell, M. Rectal temperature reflects tympanic temperature during mild induced hypothermia in nonintubated subjects. J. Neurosurg. Anesthesiol. 16, 232–235 (2004).

    Article PubMed Google Scholar

  5. Basak, T., Aciksoz, S., Tosun, B., Akyuz, A. & Acikel, C. Comparison of three different thermometers in evaluating the body temperature of healthy young adult individuals. Int. J. Nurs. Pract. 19, 471–478 (2013).

    PubMed Google Scholar

  6. Mariak, Z., White, M. D., Lyson, T. & Lewko, J. Tympanic temperature reflects intracranial temperature changes in humans. Pflüg. Arch. 446, 279–284 (2003).

    Article CAS Google Scholar

  7. Budidha, K. & Kyriacou, P. A. The human ear canal: investigation of its suitability for monitoring photoplethysmographs and arterial oxygen saturation. Physiol. Meas. 35, 111–128 (2014).

    Article CAS PubMed Google Scholar

  8. Shin, J., Kim, J., Song, K. & Kwak, Y. Core temperature measurement in therapeutic hypothermia according to different phases: comparison of bladder, rectal, and tympanic versus pulmonary artery methods. Resuscitation 84, 810–817 (2013).

    Article PubMed Google Scholar

  9. Göbölös, L. et al. Reliability of different body temperature measurement sites during aortic surgery. Perfusion 29, 75–81 (2014).

    Article PubMed Google Scholar

  10. Masè, M., Micarelli, A., Falla, M., Regli, I. B. & Strapazzon, G. Insight into the use of tympanic temperature during target temperature management in emergency and critical care: a scoping review. J. Intensive Care 9, 43 (2021).

    Article PubMed PubMed Central Google Scholar

  11. Standard Specification for Infrared Thermometers for Intermittent Determination of Patient Temperature. https://www.astm.org/e1965-98r23.html.

  12. Peterss, S. et al. Patient management in aortic arch surgery. Eur. J. Cardiothorac. Surg. 51, i4–i14 (2017).

    Article PubMed Google Scholar

  13. Cicchetti, D. V. Guidelines, criteria, and rules of thumb for evaluating normed and standardized assessment instruments in psychology. Psychol. Assess. 6, 284–290 (1994).

    Article Google Scholar

  14. Abou-Chebl, A., Sung, G., Barbut, D. & Torbey, M. Local brain temperature reduction through intranasal cooling with the RhinoChill device: preliminary safety data in brain-injured patients. Stroke 42, 2164–2169 (2011).

    Article PubMed Google Scholar

  15. Poli, S. et al. Induction of cooling with a passive head and neck cooling device: effects on brain temperature after stroke. Stroke 44, 708–713 (2013).

    Article PubMed Google Scholar

  16. Krizanac, D. et al. Femoro-iliacal artery versus pulmonary artery core temperature measurement during therapeutic hypothermia: an observational study. Resuscitation 84, 805–809 (2013).

    Article PubMed Google Scholar

  17. Hasper, D., Nee, J., Schefold, J. C., Krueger, A. & Storm, C. Tympanic temperature during therapeutic hypothermia. Emerg. Med. J. 28, 483–485 (2011).

    Article CAS PubMed Google Scholar

  18. Hine, K. et al. Nasopharynx is well-suited for core temperature measurement during hypothermia therapy. Pediatr. Int. Off. J. Jpn. Pediatr. Soc. 59, 29–33 (2017).

    Google Scholar

  19. Knapik, P. et al. Relationship between blood, nasopharyngeal and urinary bladder temperature during intravascular cooling for therapeutic hypothermia after cardiac arrest. Resuscitation 83, 208–212 (2012).

    Article PubMed Google Scholar

  20. Masè, M., Micarelli, A. & Strapazzon, G. Hearables: new perspectives and pitfalls of in-ear devices for physiological monitoring. A scoping review. Front. Physiol. 11, 568886 (2020).

    Article PubMed PubMed Central Google Scholar

  21. Nagano, C. et al. Technique for continuously monitoring core body temperatures to prevent heat stress disorders in workers engaged in physical labor. J. Occup. Health 52, 167–175 (2010).

    Article PubMed Google Scholar

  22. Twerenbold, R. et al. Limitations of infrared ear temperature measurement in clinical practice. Swiss Med. Wkly. 140, w13131 (2010).

    PubMed Google Scholar

  23. Basset, F. A., Cahill, F., Handrigan, G., DuCharme, M. B. & Cheung, S. S. The effect of lower body cooling on the changes in three core temperature indices. Physiol. Meas. 32, 385 (2011).

    Article CAS PubMed Google Scholar

  24. Daanen, H. A. M. Infrared tympanic temperature and ear canal morphology. J. Med. Eng. Technol. 30, 224–234 (2006).

    Article CAS PubMed Google Scholar

  25. Proulx, C. I., Ducharme, M. B. & Kenny, G. P. Effect of water temperature on cooling efficiency during hyperthermia in humans. J. Appl. Physiol. Bethesda Md 1985(94), 1317–1323 (2003).

    Google Scholar

  26. Thomas, K. A., Savage, M. V. & Brengelmann, G. L. Effect of facial cooling on tympanic temperature. Am. J. Crit. Care Off. Publ. Am. Assoc. Crit.-Care Nurses 6, 46–51 (1997).

  27. Strapazzon, G., Procter, E., Paal, P. & Brugger, H. Pre-hospital core temperature measurement in accidental and therapeutic hypothermia. High Alt. Med. Biol. 15, 104–111 (2014).

    Article PubMed Google Scholar

  28. Yamakoshi, T. et al. A novel method to detect heat illness under severe conditions by monitoring tympanic temperature. Aviat. Space Environ. Med. 84, 692–700 (2013).

    Article PubMed Google Scholar

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Author notes

  1. Aaron Benkert

    Present address: Institut für Notfallmedizin und Medizinmanagement, (INM), LMU Klinikum, LMU München, Germany

Authors and Affiliations

  1. Institut für Notfallmedizin und Medizinmanagement, (INM), LMU Klinikum, LMU München, Germany

    Jonas Langenhorst,Andreas Bayer,Stephan Prueckner&Roman Schniepp

  2. Department of Neurology, LMU Klinikum, LMU München, Germany

    Jonas Langenhorst,Aaron Benkert,Aaron Benkert&Roman Schniepp

  3. Department of Anesthesiology, LMU Klinikum, LMU München, Germany

    Matthias Feuerecker,Tatjana Scheiermann,Patrick Scheiermann&Matthias Witte

  4. Department for Cardiac Surgery, LMU University Hospital, LMU Klinikum, LMU München, Germany

    Sven Peterss&Maximilian Pichlmaier

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Conceptualization: R.S., J.L., P.S., S.P., M.P., T.S.; Methodology: R.S., J.L., A.B., A.B., M.F.; Data acquisition: J.L., R.S., M.F., T.S., Formal analysis and investigation: R.S., J.L., T.S.; Manuscript draft: R.S., J.L., S.P, P.S., S.P., M.P.; Manuscript revision: all authors; Funding acquisition: R.S., Resources: R.S., P.S., M.P., T.S. The manuscript fulfills the prerequisites and quality indicators established by the checklist of STROBE (Strengthening the Reporting of Observational studies in Epidemiology).

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Correspondence to Roman Schniepp.

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The study protocol was approved by the local Ethics Committee of the Ludwig-Maximilians University of Munich, (Nr. 22-0322) and was conducted according to the Declaration of Helsinki.

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All participants gave their informed written consent prior to the experiments.

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The authors declare no competing interests.

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Agreement of in-ear temperature to core body temperature measures during invasive whole-body cooling for hypothermic circulatory arrest in aortic arch surgery (6)

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Langenhorst, J., Benkert, A., Peterss, S. et al. Agreement of in-ear temperature to core body temperature measures during invasive whole-body cooling for hypothermic circulatory arrest in aortic arch surgery. Sci Rep 14, 27607 (2024). https://doi.org/10.1038/s41598-024-77237-5

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  • DOI: https://doi.org/10.1038/s41598-024-77237-5

Keywords

  • Circulatory arrest
  • Therapeutic hypothermia
  • Core body temperature
  • In-ear temperature
  • Aortic arch
Agreement of in-ear temperature to core body temperature measures during invasive whole-body cooling for hypothermic circulatory arrest in aortic arch surgery (2024)

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