Thomas Lisha, Flores Saul, Wong Joshua, Loomba Rohit
Cardiology, Advocate Children's Hospital, Chicago, USA.
Cardiology, Texas Children's Hospital, Houston, USA.
Cureus. 2019 Sep 18;11(9):e5693. doi: 10.7759/cureus.5693.
Introduction Oxygen delivery in patients with functionally univentricular hearts awaiting Norwood palliation depends on a balance between systemic blood flow (Qs) and pulmonary blood flow (Qp). Modulations of pulmonary vascular resistance and systemic vascular resistance are utilized to maintain balanced Qp:Qs in a circulation prone to pulmonary overcirculation at the expense of systemic perfusion. This study aimed to characterize changes in Qp:Qs and regional (cerebral and renal) oxygen delivery in patients awaiting Norwood palliation receiving hypoxic gas admixture therapy. Methods Patients who received care prior to Norwood palliation were identified from 2014 to 2018. Of these patients, those with cerebral and renal near-infrared spectroscopy were identified (NIRS). Arterial oxygen saturation by pulse oximetry, renal NIRS, and cerebral NIRS prior to hypoxic gas admixture initiation were compared to values six hours, 12 hours, and 24 hours after initiation. Results A total of 28 patients were eligible for inclusion in the study. Arterial saturation by pulse oximetry was 91% prior to initiation and decreased to 86% 24 hours after initiation (p<0.001). Cerebral NIRS were a mean of 60 prior to initiation compared to 58 at 24 hours (p=0.187). Renal NIRS were a mean of 60 prior to initiation compared to 57 at 24 hours (p=0.120). Calculated Qp:Qs was 9.6 at baseline compared to 2.5 at 24 hours (p=0.006). Arteriovenous difference and lactate did not significantly change with hypoxic gas admixture administration. Conclusion Administration of hypoxic gas admixture to patients with functionally univentricular hearts awaiting Norwood palliation decreases the ratio of Qp and Qs but does not improve regional oxygenation delivery.
等待诺伍德姑息手术的功能性单心室心脏患者的氧输送取决于体循环血流量（Qs）和肺循环血流量（Qp）之间的平衡。肺血管阻力和体循环血管阻力的调节被用于在一个容易出现肺循环过度灌注而牺牲体循环灌注的循环中维持平衡的Qp:Qs。本研究旨在描述接受低氧气体混合疗法等待诺伍德姑息手术的患者中Qp:Qs和区域（脑和肾）氧输送的变化。方法：从2014年至2018年确定在诺伍德姑息手术前接受治疗的患者。在这些患者中，确定有脑和肾近红外光谱检查（NIRS）的患者。将低氧气体混合开始前的脉搏血氧饱和度、肾NIRS和脑NIRS与开始后6小时、12小时和24小时的值进行比较。结果：共有28名患者符合纳入本研究的条件。开始前脉搏血氧饱和度为91%，开始后24小时降至86%（p<0.001）。开始前脑NIRS平均为60，24小时时为58（p=0.187）。开始前肾NIRS平均为60，24小时时为57（p=0.120）。计算得出的Qp:Qs在基线时为9.6，24小时时为2.5（p=0.006）。动静脉差值和乳酸水平在给予低氧气体混合后没有显著变化。结论：对等待诺伍德姑息手术的功能性单心室心脏患者给予低氧气体混合可降低Qp与Qs的比值，但不能改善区域氧输送。
