Department of Biomedical Engineering, Istituti Clinici Scientifici Maugeri IRCCS, Pavia, Italy.
Department of Cardiology, Istituti Clinici Scientifici Maugeri IRCCS, Pavia, Italy; Department of Pneumology, Istituti Clinici Scientifici Maugeri IRCCS, Pavia, Italy.
Sleep Med. 2019 Mar;55:6-13. doi: 10.1016/j.sleep.2018.10.043. Epub 2018 Dec 14.
Despite the fact that the ear is the site to monitor arterial oxygen saturation by pulse oximetry (SpO2) closest to carotid chemoreceptors, sleep studies almost invariably use finger probes. This study aimed to assess the timing and morphological differences between SpO2 signals at the ear and finger during Cheyne-Stokes respiration (CSR) in heart failure (HF) patients.
We studied 21 HF patients with CSR during a 40-min in-laboratory resting recording. SpO2 was recorded by: (1) two identical bedside pulse-oximeters with an ear (SpO2_Ear) and a finger probe (SpO2_Finger), and (2) a standard polysomnograph with a finger probe (SpO2_PSG). We estimated the delays between signals and, for each signal, computed the mean and minimum SpO2, the magnitude of cyclic desaturations and the overall time spent with SpO2<90% (T90%).
The SpO2_Finger signal was significantly delayed [bias: 12.7 s (95% limits of agreement: 2.2, 23.0 s)] and slightly but not significantly downward-shifted with respect to SpO2_Ear. SpO2_PSG was almost synchronous with SpO2_Finger; however, a further significant downward shift was observed relative to the latter. In particular, minimum SpO2_PSG was significantly lower [-2.1% (- 4.8, 0.6%)], and desaturations and T90% were significantly higher than SpO2_Finger [1.2% (-1.3, 3.7%), and 13.9% (-12.3, 40.0%), respectively].
During CSR in HF patients, the marked delay between SpO2_Ear and SpO2_Finger makes the interpretation of the timing relationship between peripheral chemoreceptor stimulation and ventilatory events rather difficult. The observed discrepancies between SpO2_PSG and SpO2_Finger, which may be due to differences in the processing of raw SpO2 signals, call for a standardization of processing algorithms.
尽管耳朵是通过脉搏血氧饱和度（SpO2）监测动脉血氧饱和度最接近颈动脉化学感受器的部位，但睡眠研究几乎无一例外地使用手指探头。本研究旨在评估心力衰竭（HF）患者 Cheyne-Stokes 呼吸（CSR）期间耳和手指 SpO2 信号之间的时间和形态差异。
我们研究了 21 例 CSR 心力衰竭患者在实验室休息记录 40 分钟期间的 SpO2。通过以下两种方式记录 SpO2：（1）使用两个相同的床边脉搏血氧仪，一个带有耳探头（SpO2_Ear），一个带有手指探头（SpO2_Finger）；（2）使用标准多导睡眠图和手指探头（SpO2_PSG）。我们估计了信号之间的延迟，并为每个信号计算了平均 SpO2 和最小 SpO2、周期性去饱和的幅度以及 SpO2<90%的总时间（T90%）。
SpO2_Finger 信号明显延迟[偏差：12.7 s（95%置信区间：2.2，23.0 s）]，并且相对于 SpO2_Ear 略有向下偏移，但无统计学意义。SpO2_PSG 与 SpO2_Finger 几乎同步；然而，相对于后者，观察到进一步的显著向下偏移。特别是，SpO2_PSG 的最小 SpO2 明显更低[-2.1%（-4.8，0.6%）]，去饱和和 T90%明显高于 SpO2_Finger[1.2%（-1.3，3.7%）和 13.9%（-12.3，40.0%）]。
在 HF 患者的 CSR 期间，SpO2_Ear 和 SpO2_Finger 之间的明显延迟使得解释外周化学感受器刺激与通气事件之间的时间关系变得相当困难。SpO2_PSG 和 SpO2_Finger 之间观察到的差异可能是由于原始 SpO2 信号处理方式的差异所致，这需要对处理算法进行标准化。
