Raw data of paper entitled: "Peripheral oxygenation in heart failure patients with periodic breathing: insights from NIRS"

Background. Periodic breathing (PB) is characterized by cyclic fluctuations in ventilation and expired gases. PB is observed at rest or during exercise and is a marker of poor prognosis. In this study we investigated whether PB affects oxygen availability in peripheral muscles. Materials and Methods. This pilot, prospective, single-center study enrolled severe reduced ejection fraction heart failure (HF) patients exhibiting PB. Oxygenated (O2Hb) and deoxygenated hemoglobin (HHb) in the quadriceps femoralis were measured using near-infrared spectroscopy (NIRS), along with ventilation and expired gases. NIRS and ventilation data were collected at rest and analyzed for cyclic patterns. Clinical evaluations, including cardiopulmonary exercise test (CPET) and echocardiography, were performed. The Metabolic Exercise Combined with Cardiac Kidney Indexes (MECKI) score was used for prognosis evaluation. Results. Twenty HF patients with PB were evaluated. NIRS revealed two distinct periodic behaviors: in 7 patients, O2Hb and HHb fluctuated in-phase; in 13, they were out-of-phase. In-phase patients had higher left ventricular ejection fraction, lower LV volumes, and lower BNP and soluble interleukin 1 receptor-family member ST2 concentrations. Out-of-phase patients had more severe HF, with longer, less variable cycles and a higher MECKI score. Six of 13 out-of-phase patients died within 6 months, compared to 2 of 7 in-phase patients. Conclusion. PB is associated with distinct peripheral oxygenation patterns, potentially representing disease progression stages. In-phase O2Hb and HHb suggest blood flow cycling, while out-of-phase behavior suggests periodicity in ventilation/perfusion mismatching. These findings provide novel insights into the dynamic effects of PB on peripheral oxygenation.背景。周期性呼吸（Periodic breathing, PB）以通气量与呼出气体的周期性波动为特征。该现象可在静息状态或运动过程中被观测到，是预后不良的标志物。本研究旨在探讨周期性呼吸是否会影响外周肌肉的氧供情况。 材料与方法。本项前瞻性单中心先导研究纳入了表现出周期性呼吸的严重射血分数降低型心力衰竭（Heart Failure, HF）患者。采用近红外光谱（Near-infrared spectroscopy, NIRS）检测股四头肌的氧合血红蛋白（Oxygenated hemoglobin, O2Hb）与去氧血红蛋白（Deoxygenated hemoglobin, HHb）水平，同时同步采集通气量与呼出气体数据。静息状态下采集NIRS与通气数据，并对其周期性模式进行分析。研究开展了包括心肺运动试验（Cardiopulmonary exercise test, CPET）与超声心动图在内的临床评估，并采用代谢运动联合心肾指数（Metabolic Exercise Combined with Cardiac Kidney Indexes, MECKI）评分进行预后评估。 结果。本研究共纳入20例合并周期性呼吸的心力衰竭患者进行评估。NIRS检测显示两种截然不同的周期性表现：7例患者的O2Hb与HHb呈同相位波动，其余13例则呈异相位波动。同相位波动组患者的左心室射血分数更高、左心室容积更低，且B型钠尿肽（B-type natriuretic peptide, BNP）与可溶性白细胞介素1受体家族成员ST2的浓度也更低。异相位波动组患者的心力衰竭程度更严重，其波动周期更长、变异性更低，且MECKI评分更高。13例异相位波动患者中，有6例在6个月内死亡；而同相位波动组的7例患者中仅2例死亡。 结论。周期性呼吸与独特的外周氧合模式相关，该模式或可反映疾病进展阶段。O2Hb与HHb的同相位波动提示血流周期性循环，而异相位波动则提示通气/灌注不匹配存在周期性特征。本研究结果为周期性呼吸对外周氧合的动态影响提供了全新的研究视角。