Division of Anesthesiology, Department of Anesthesiology, Intensive Care and Pain Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
Department of Neurosurgery, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
J Clin Monit Comput. 2019 Oct;33(5):917-923. doi: 10.1007/s10877-018-0227-z. Epub 2018 Nov 22.
In the noninvasive zero-heat-flux (ZHF) method, deep body temperature is brought to the skin surface when an insulated temperature probe with servo-controlled heating on the skin creates a region of ZHF from the core to the skin. The sensor of the commercial Bair-Hugger ZHF device is placed on the forehead. According to the manufacturer, the sensor reaches a depth of 1-2 cm below the skin. In this observational study, the anatomical focus of the Bair-Hugger ZHF sensor was assessed in pre- and postoperative CT or MRI images of 29 patients undergoing elective craniotomy. Assuming the 2-cm depth from the forehead skin surface, the temperature measurement point preoperatively reached the brain cortex in all except one patient. Assuming the 1-cm depth, the preoperative temperature measurement point did not reach the brain parenchyma in any of the patients and was at the cortical surface in two patients. Corresponding results were obtained postoperatively, although either sub-arachnoid fluid or air was observed in all CT/MRI images. Craniotomy did not have a detectable effect on the course of the ZHF temperatures. In Bland-Altman analysis, the agreement of ZHF temperature with the nasopharyngeal temperature was 0.11 (95% confidence interval - 0.54 to 0.75) °C and with the bladder temperature - 0.14 (- 0.81 to 0.52) °C. As conclusions, within the reported range of the Bair-Hugger ZHF measurement depth, the anatomical focus of the sensor cannot be determined. Craniotomy did not have a detectable effect on the course of the ZHF temperatures that showed good agreement with the nasopharyngeal and bladder temperatures.
在无创零热通量 (ZHF) 方法中，当带有皮肤表面伺服控制加热的绝缘温度探头从核心到皮肤创建 ZHF 区域时，深部体温被带到皮肤表面。商业 Bair-Hugger ZHF 设备的传感器放置在前额。根据制造商的说法，传感器在皮肤下 1-2 厘米的深度达到。在这项观察性研究中，评估了 29 名接受择期开颅手术的患者的术前和术后 CT 或 MRI 图像中 Bair-Hugger ZHF 传感器的解剖焦点。假设从额部皮肤表面深度 2 厘米，除了一名患者外，所有患者的术前温度测量点都达到大脑皮层。假设深度为 1 厘米，所有患者的术前温度测量点均未到达脑实质，两名患者的温度测量点位于皮质表面。术后获得了相应的结果，尽管所有 CT/MRI 图像中均观察到蛛网膜下腔积液或空气。开颅术对 ZHF 温度的过程没有可检测的影响。在 Bland-Altman 分析中，ZHF 温度与鼻咽温度的一致性为 0.11（95%置信区间-0.54 至 0.75）℃，与膀胱温度的一致性为-0.14（-0.81 至 0.52）℃。总之，在报告的 Bair-Hugger ZHF 测量深度范围内，无法确定传感器的解剖焦点。开颅术对 ZHF 温度的过程没有可检测的影响，ZHF 温度与鼻咽温度和膀胱温度具有良好的一致性。
