Newborn Medicine, Department of Pediatrics, Tufts University School of Medicine, Boston, MA.
Division of Neonatology, Department of Pediatrics, Oishei Children's Hospital of Buffalo, University at Buffalo, Buffalo, NY.
Pediatr Crit Care Med. 2019 Feb;20(2):166-171. doi: 10.1097/PCC.0000000000001799.
Therapeutic hypothermia is standard of care in management of moderate/severe hypoxic-ischemic encephalopathy. Persistent pulmonary hypertension of the newborn is associated with hypoxic-ischemic encephalopathy and is exacerbated by hypoxemia and hypercarbia. Gas exchange is assessed by arterial blood gas analysis (with/without correction for body temperature), pulse oximetry, and end-tidal CO2.
A retrospective chart review.
Regional perinatal center in Western New York.
Fifty-eight ventilated neonates with indwelling arterial catheter on therapeutic hypothermia.
None.
We compared pulse oximetry, PaO2, end-tidal CO2, and PaCO2 during hypothermia and normothermia in neonates with hypoxic-ischemic encephalopathy using 1,240 arterial blood gases with simultaneously documented pulse oximetry. During hypothermia, pulse oximetry 92-98% was associated with significantly lower temperature-corrected PaO2 (51 mmHg; interquartile range, 43-51) compared with normothermia (71 mmHg; interquartile range, 61-85). Throughout the range of pulse oximetry values, geometric mean PaO2 was about 23% (95% CI, 19-27%) lower during hypothermia compared with normothermia. In contrast, end-tidal CO2 accurately assessed temperature-corrected PaCO2 during normothermia and hypothermia.
Hypothermia shifts oxygen-hemoglobin dissociation curve to the left resulting in lower PaO2 for pulse oximetry. Monitoring oxygenation with arterial blood gas uncorrected for body temperature and pulse oximetry may underestimate hypoxemia in hypoxic-ischemic encephalopathy infants during whole-body hypothermia, while end-tidal CO2 reliably correlates with temperature-corrected PaCO2.
治疗性低温是中重度缺氧缺血性脑病管理的标准治疗方法。新生儿持续性肺动脉高压与缺氧缺血性脑病有关，并因低氧血症和高碳酸血症而加重。气体交换通过动脉血气分析（是否校正体温）、脉搏血氧饱和度和呼气末二氧化碳进行评估。
回顾性图表审查。
纽约西部的区域围产中心。
58 例在治疗性低温下进行有创动脉置管的通气新生儿。
无。
我们比较了 58 例缺氧缺血性脑病新生儿在低温和常温下的脉搏血氧饱和度、PaO2、呼气末 CO2 和 PaCO2，使用了 1240 次同时记录脉搏血氧饱和度的动脉血气。在低温时，92-98%的脉搏血氧饱和度与校正体温后的 PaO2（51mmHg；四分位间距，43-51）显著降低相比常温（71mmHg；四分位间距，61-85）。在整个脉搏血氧饱和度范围内，低温时几何平均 PaO2 比常温时低约 23%（95%置信区间，19-27%）。相比之下，在常温和低温时，呼气末 CO2 可准确评估校正体温后的 PaCO2。
低温会使氧合血红蛋白解离曲线向左移动，导致脉搏血氧饱和度下的 PaO2 降低。不校正体温的动脉血气监测和脉搏血氧饱和度可能会低估全身低温期间缺氧缺血性脑病婴儿的低氧血症，而呼气末 CO2 与校正体温后的 PaCO2 可靠相关。
