Techniques to comprehensively evaluate pulmonary function carry a variety of limitations, including the ability to continuously record intrathoracic pressures (ITP), acutely and chronically, in a natural state of freely behaving animals. Measurement of ITP can be used to derive other respiratory parameters, which provide insight to lung health. Our aim was to develop a surgical approach for the placement of a telemetry pressure sensor to measure ITP, providing the ability to chronically measure peak pressure, breath frequency, and timing of the respiratory cycle to facilitate circadian analyses related to breathing patterns. Applications of this technique are shown using a moderate hypoxic challenge. Male C57Bl6 mice were implanted with radio-telemetry devices to record heart rate, temperature, activity, and ITP during 24 h normoxia, 24 h hypoxia (F_IO₂ = 0.15), and return to 48 h normoxia. Radio-telemetry of ITP permitted the detection of hypoxia-induced increases in 'the ITP-equivalent' of ventilation, which were driven by increases in breathing frequency and ITP on a short-term timescale. Respiratory frequency, derived from pressure waveforms, was increased by a decrease in expiratory time without changes in inspiratory time. Chronically, telemetric recording allowed for circadian analyses of respiratory drive, as assessed by inspiratory pressure divided by inspiratory time, which was increased by hypoxia and remained elevated for 48 h of recovery. Further, respiratory frequency demonstrated a circadian rhythm, which was disrupted through the recovery period. Radio telemetry of ITP is a viable, long-term, chronic methodology that extends traditional methods to evaluate respiratory function in mice.

中文翻译：

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一种新型无线电遥测方法在自由行为小鼠胸腔内压力和生理节律测量中的应用。

综合评估肺功能的技术具有多种局限性，包括在自由活动的动物的自然状态下连续记录急性和慢性胸腔内压 (ITP) 的能力。ITP 的测量可用于推导出其他呼吸参数，从而提供对肺部健康的洞察。我们的目标是开发一种外科手术方法，用于放置遥测压力传感器来测量 ITP，提供长期测量峰值压力、呼吸频率和呼吸周期时间的能力，以促进与呼吸模式相关的昼夜节律分析。使用适度缺氧挑战显示了该技术的应用。雄性 C57Bl6 小鼠被植入无线电遥测装置以记录 24 小时常氧期间的心率、温度、活动和 ITP，_我Ø ₂= 0.15)，并恢复到 48 小时常氧。ITP 的无线电遥测允许检测缺氧引起的通气“ITP 等效值”的增加，这是由短期时间尺度上呼吸频率和 ITP 的增加驱动的。来自压力波形的呼吸频率随着呼气时间的减少而增加，而吸气时间没有变化。从长期来看，遥测记录允许对呼吸驱动进行昼夜节律分析，通过吸气压力除以吸气时间进行评估，吸气时间因缺氧而增加，并在恢复 48 小时内保持升高。此外，呼吸频率表现出昼夜节律，在恢复期被打乱。ITP 的无线电遥测是一种可行的、长期的、