Pereira Carina Barbosa, Yu Xinchi, Czaplik Michael, Rossaint Rolf, Blazek Vladimir, Leonhardt Steffen
Chair for Medical Information Technology, Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany.
Department of Anesthesiology, University Hospital RWTH Aachen, Aachen, Germany.
Biomed Opt Express. 2015 Oct 16;6(11):4378-94. doi: 10.1364/BOE.6.004378. eCollection 2015 Nov 1.
An atypical or irregular respiratory frequency is considered to be one of the earliest markers of physiological distress. In addition, monitoring of this vital parameter plays a major role in diagnosis of respiratory disorders, as well as in early detection of sudden infant death syndrome. Nevertheless, the current measurement modalities require attachment of sensors to the patient's body, leading to discomfort and stress. The current paper presents a new robust algorithm to remotely monitor breathing rate (BR) by using thermal imaging. This approach permits to detect and to track the region of interest (nose) as well as to estimate BR. In order to study the performance of the algorithm, and its robustness against motion and breathing disorders, three different thermal recordings of 11 healthy volunteers were acquired (sequence 1: normal breathing; sequence 2: normal breathing plus arbitrary head movements; and sequence 3: sequence of specific breathing patterns). Thoracic effort (piezoplethysmography) served as "gold standard" for validation of our results. An excellent agreement between estimated BR and ground truth was achieved. Whereas the mean correlation for sequence 1-3 were 0.968, 0.940 and 0.974, the mean absolute BR errors reached 0.33, 0.55 and 0.96 bpm (breaths per minute), respectively. In brief, this work demonstrates that infrared thermography is a promising, clinically relevant alternative for the currently available measuring modalities due to its performance and diverse remarkable advantages.
非典型或不规则呼吸频率被认为是生理窘迫最早的指标之一。此外，监测这一重要参数在呼吸系统疾病的诊断以及婴儿猝死综合征的早期检测中发挥着重要作用。然而，目前的测量方式需要将传感器附着在患者身体上，这会导致不适和压力。本文提出了一种新的稳健算法，通过热成像远程监测呼吸频率（BR）。这种方法能够检测和跟踪感兴趣区域（鼻子）以及估计呼吸频率。为了研究该算法的性能及其对运动和呼吸障碍的鲁棒性，采集了11名健康志愿者的三种不同热成像记录（序列1：正常呼吸；序列2：正常呼吸加任意头部运动；序列3：特定呼吸模式序列）。胸部用力（压力容积描记法）作为验证我们结果的“金标准”。估计的呼吸频率与实际值之间达成了极佳的一致性。序列1 - 3的平均相关性分别为0.968、0.940和0.974，平均绝对呼吸频率误差分别达到0.33、0.55和0.96次/分钟。简而言之，这项工作表明，由于其性能和多种显著优势，红外热成像对于当前可用的测量方式来说是一种有前景的、与临床相关的替代方法。
