Agreement of infrared ear temperature with nasopharyngeal temperature and diagnostic performance on hypothermia in general anesthetized patients

Q: What was the purpose of the study?

To evaluate how well infrared ear temperature agrees with nasopharyngeal temperature in general anesthetized patients, and to assess its diagnostic performance for intraoperative hypothermia.

Q: How were temperatures measured and compared?

Infrared ear temperature and nasopharyngeal temperature were measured simultaneously before, during, and after surgery. Agreement was assessed using ICC and Bland-Altman analysis.

Q: What diagnostic accuracy did the infrared ear thermometer show for hypothermia?

The infrared ear thermometer showed high diagnostic accuracy for hypothermia, with an ROC area under the curve of 0.95. The cutoff was 36.2°C with reported sensitivity and specificity.

Sep 29, 2026

Uploaded by James

Infrared ear thermometry is widely used clinically for noninvasive, convenient, rapid temperature sampling, but its accuracy and feasibility in anesthetized patients remain unclear. This cross-sectional study evaluated agreement between infrared ear and nasopharyngeal temperatures and assessed diagnostic performance for intraoperative hypothermia in adult female patients under general anesthesia. Agreement was quantified using ICC and Bland-Altman analysis, and hypothermia diagnostic accuracy was analyzed with ROC curves.

LanguageEnglish

CategoryHealthcare

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Pages5

Reading Time13 min

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Abstract

Background

Methods

Results

Conclusion

Introduction

J Chin MedAssoc Original article Agreement of infrared ear temperature with nasopharyngeal temperature and diagnostic performance on hypothermia in general anesthetized patients Li Wana, Pei-Ying Shena, Shu-Xian Zhanga, Li-Zhong Wangb,* aDepartment of Nursing, Jiaxing Maternity and Children Health Care Hospital, Affiliated Women and Children Hospital, Jiaxing University, Jiaxing, Zhejiang, China; bDepartment of Anesthesiology, Jiaxing Maternity and Children Health Care Hospital, Affiliated Women and Children Hospital, Jiaxing University, Jiaxing, Zhejiang, China Abstract Background: Infrared ear thermometry is widely used in clinical practice due to its noninvasive, convenient, and quick sampling. However, its accuracy and feasibility in anesthetized patients have not yet been established. Methods: We conducted this cross-sectional study to evaluate the agreement between infrared ear temperature and nasopharyngeal temperature in general anesthetized patients and its performance in intraoperative hypothermia, defined as nasopharyngeal temperature <36°C. Adult female patients who underwent gynecological surgery under general anesthesia were enrolled in this study. Infrared ear temperature by Braun ThermoScan PRO 4000 (Braun GmbH, Kronberg, Germany) and nasopharyngeal temperature were measured simultaneously before, during, and after surgery. The agreement between the two temperatures was assessed using the intraclass correlation coefficient (ICC) and Bland-Altman analysis. The diagnostic performance of the infrared ear thermometer for hypothermia was evaluated using receiver operating characteristic (ROC) curve analysis. Results: Fifty-six patients with 168 pairs of simultaneous infrared ear and nasopharyngeal temperatures were included in this analysis. The mean infrared ear temperature was consistently higher than the nasopharyngeal temperature throughout surgery, but the differences were small (0 .22, 0. 13, and 0.06°C before, during, and after surgery, respectively) . The ICC between the two temperatures before, during, and after surgery was 0.70, 0.75, and 0.80, respectively, and 93.5% of the differences fell within the 95% limits of agreement of ±0 .5°C. An infrared ear thermometer had high diagnostic accuracy for hypothermia, with an area under the ROC curve of 0.95 (95% confidence interval [CI], 0 .92-0.98) . The cutoff of infrared ear temperature for hypothermia was 36 .2°C with a sensitivity of 0.89 (95% CI, 0.71-0.98) and a specificity of 0.87 (95% CI, 0.81-0.92) . Conclusion: The infrared ear temperature is in good agreement with the nasopharyngeal temperature in general anesthetized patients without hyperthermia and has high performance for detecting hypothermia. An infrared ear thermometer can be a diagnostic tool for intraoperative hypothermia. Keywords: General anesthesia; Hypothermia; Infrared ear thermometer; Monitoring; Temperature 1. INTRODUCTION Body temperature is maintained by a thermoregulatory system that involves afferent sensing, central control, and efferent defenses.1 Anesthesia can impair central thermoregulatory control and peripheral responses to hypothermia, such as vasoconstriction and shivering, leading to thermal disturbances. The *Address correspondence. Dr. Li-Zhong Wang, Department of Anesthesiology, Jiaxing Maternity and Children Health Care Hospital, Affiliated Women and Children Hospital, Jiaxing University, 2468, Zhonghuan East Road, Jiaxing, Zhejiang, [China. E-mail address: jxlzw@sina.com](China. E-mail address: jxlzw@sina.com) (L.-Z. Wang). Conflicts of interest: The authors declare that they have no conflicts of interest related to the subject matter or materials discussed in this article. Journal of Chinese Medical Association. (2022) 85: 1093-1097. Received March 28, 2022; accepted June 9, 2022. doi: 10. 1097/JCMA.0000000000000770. Copyright © 2022, the Chinese Medical Association. This is an open access article under the CC BY-NC-ND license ([h

FAQs

What was the purpose of the study?

To evaluate how well infrared ear temperature agrees with nasopharyngeal temperature in general anesthetized patients, and to assess its diagnostic performance for intraoperative hypothermia.

How were temperatures measured and compared?

Infrared ear temperature and nasopharyngeal temperature were measured simultaneously before, during, and after surgery. Agreement was assessed using ICC and Bland-Altman analysis.

What diagnostic accuracy did the infrared ear thermometer show for hypothermia?

The infrared ear thermometer showed high diagnostic accuracy for hypothermia, with an ROC area under the curve of 0.95. The cutoff was 36.2°C with reported sensitivity and specificity.

Sep 29, 2026

Uploaded by James