A modified SCBA facepiece for accurate metabolic data collection from firefighters

To better assess the energy expenditure and exertion of firefighters during simulated firefighting activities, a commercial firefighter self-contained breathing apparatus (SCBA) facepiece was modified to interface with a portable metabolic monitoring device (Cosmed K4b²) while still functioning as a positive pressure SCBA air supply. To validate the device, standard National Fire Protection Association 1981 SCBA function tests were conducted and 14 subjects performed variable-workload assessments using all combinations of two test devices (Cosmed K4b² and metabolic cart) and two masks (modified SCBA facepiece and stock manufacturer-supplied breath collection). Metabolic data collected with the Cosmed K4b² via the modified facepiece were found to be accurate when compared to a ParvoMedics Truemax 2400 metabolic cart (average per cent difference: 4.6%). This modified facepiece design is suitable for use in metabolic studies requiring the utilisation of an SCBA system. Furthermore, the well-established overestimation of oxygen consumption from the Cosmed K4b² system was replicated.

为更精准评估模拟灭火作业中消防员的能量消耗与运动负荷，本研究对一款商用消防员自给式呼吸器（self-contained breathing apparatus, SCBA）面罩进行改装，使其可与便携式代谢监测设备（Cosmed K4b²）对接，同时仍可作为正压式SCBA供气系统正常工作。为验证改装装置的性能，本研究开展了符合美国国家消防协会（National Fire Protection Association, NFPA）1981标准的SCBA功能测试，并招募14名受试者开展变负荷评估测试，测试组合涵盖2台测试设备（Cosmed K4b²与代谢仪）与2种面罩（改装型SCBA面罩与原厂标配呼吸采集面罩）的所有搭配方式。经与ParvoMedics Truemax 2400代谢仪的检测结果对比，通过改装面罩由Cosmed K4b²采集的代谢数据准确度达标，平均百分比偏差仅为4.6%。该改装面罩设计适用于需使用SCBA系统的代谢研究场景。此外，本研究成功复现了Cosmed K4b²系统此前已被广泛证实的氧消耗高估现象。