Chandrasekharan Praveen, Rawat Munmun, Lakshminrusimha Satyan
Division of Neonatology, Department of Pediatrics, University at Buffalo, Buffalo, NY 14260, USA.
Division of Neonatology, Department of Pediatrics, University of California Davis, Davis, CA 95616, USA.
Children (Basel). 2020 Oct 13;7(10):180. doi: 10.3390/children7100180.
Oxygen is a pulmonary vasodilator and plays an important role in mediating circulatory transition from fetal to postnatal period. Oxygen tension (PO) in the alveolus (PAO) and pulmonary artery (PaO) are the main factors that influence hypoxic pulmonary vasoconstriction (HPV). Inability to achieve adequate pulmonary vasodilation at birth leads to persistent pulmonary hypertension of the newborn (PPHN). Supplemental oxygen therapy is the mainstay of PPHN management. However, optimal monitoring and targeting of oxygenation to achieve low pulmonary vascular resistance (PVR) and optimizing oxygen delivery to vital organs remains unknown. Noninvasive pulse oximetry measures peripheral saturations (SpO) and a target range of 91-95% are recommended during acute PPHN management. However, for a given SpO, there is wide variability in arterial PaO, especially with variations in hemoglobin type (HbF or HbA due to transfusions), pH and body temperature. This review evaluates the role of alveolar, preductal, postductal, mixed venous PO, and SpO in the management of PPHN. Translational and clinical studies suggest maintaining a PaO of 50-80 mmHg decreases PVR and augments pulmonary vasodilator management. Nevertheless, there are no randomized clinical trials evaluating outcomes in PPHN targeting SpO or PO. Also, most critically ill patients have umbilical arterial catheters and postductal PaO may not be an accurate assessment of oxygen delivery to vital organs or factors influencing HPV. The mixed venous oxygen tension from umbilical venous catheter blood gas may assess pulmonary arterial PO and potentially predict HPV. It is crucial to conduct randomized controlled studies with different PO/SpO target ranges for the management of PPHN and compare outcomes.
氧气是一种肺血管扩张剂，在介导从胎儿期到出生后循环转变过程中发挥重要作用。肺泡（PAO）和肺动脉（PaO）中的氧分压（PO）是影响缺氧性肺血管收缩（HPV）的主要因素。出生时无法实现充分的肺血管扩张会导致新生儿持续性肺动脉高压（PPHN）。补充氧气疗法是PPHN治疗的主要手段。然而，如何进行最佳监测以及将氧合目标设定为实现低肺血管阻力（PVR）并优化向重要器官的氧输送仍不明确。在急性PPHN治疗期间，无创脉搏血氧饱和度测定法测量外周血氧饱和度（SpO），推荐的目标范围是91 - 95%。然而，对于给定的SpO，动脉PaO存在很大差异，尤其是随着血红蛋白类型（由于输血导致的HbF或HbA）、pH值和体温的变化。本综述评估了肺泡、导管前、导管后、混合静脉PO以及SpO在PPHN治疗中的作用。转化研究和临床研究表明，维持PaO在50 - 80 mmHg可降低PVR并增强肺血管扩张剂治疗效果。然而，尚无针对以SpO或PO为目标的PPHN结局评估的随机临床试验。此外，大多数危重症患者都有脐动脉导管，导管后PaO可能无法准确评估向重要器官的氧输送或影响HPV的因素。脐静脉导管血气分析得出的混合静脉氧分压可能评估肺动脉PO并潜在预测HPV。开展针对不同PO/SpO目标范围的PPHN治疗随机对照研究并比较结局至关重要。
