梅斯医学MedSci APP
医路相伴，成就大医
梅斯医学MedSci APP
医路相伴，成就大医
背景与目的 体外循环（CPB）的目的是在氧供（ḊO2）和氧耗之间保持适当的平衡。临界ḊO2是指在一定供氧量下，耗氧量依赖于供氧量。本研究旨在确定代谢率高于成人的新生儿的临界ḊO2。 方 法 在本项回顾性新生儿队列研究中，根据主动脉阻断期间记录的CPB参数计算ḊO2。主动脉开放后测得的高乳酸浓度（lactOFF）用于鉴别无氧代谢。数据分析采用混合线性比例优势回归模型。在lactOFF<2.5 mM患儿亚组中（这些患儿被认为氧供和氧耗相平衡），分析ḊO2与温度之间的关系。预估回归系数进一步用于调整假设ḊO2阈值，并且将低于阈值的ḊO2偏移量化为强度持续时间。在37℃时，提供强度持续时间的最低阈值与lactOFF增加相关，被用作最低适宜（临界）ḊO2。 结 果 本研究共对180例新生儿的22896个时间点进行了分析。40例lactOFF<2.5mM的患儿中，ḊO2变化了22.87 (0.70) ml min-1m-2℃-1。在340-380ml min-1m-2之间改变ḊO2阈值时，低于阈值的偏移与递增的lactOFF有关。低于340ml min-1m-2 ḊO2阈值的100 mlm-2的偏移使lactOFF增加1mM的风险增大了22%（OR:1.22；95%CI：1.02~1.45）。 结 论 结果发现，340ml min-1m-2 可能是新生儿在常温CPB期间维持有氧代谢所需的最低适宜（临界）ḊO2。
原始文献摘要
Bojan M, Gioia E, Di Corte F, et al. Lower limit of adequate oxygen delivery for the maintenance of aerobic metabolism during cardiopulmonary bypass in neonates.Br J Anaesth 2020,124(4):395-402.
Background: The objective of cardiopulmonary bypass (CPB) is to maintain an adequate balance between oxygen delivery (ḊO2) and consumption. The critical ḊO2 is that at which consumption becomes supply dependent. This study aimed to identify the critical ḊO2 in neonates, who have higher metabolic rates than adults.
Methods: In a retrospective cohort of neonates, ḊO2 was calculated from CPB parameters recorded during aortic cross-clamping. High lactate concentration measured after aortic unclamping (lactOFF) was used to identify anaerobic metabolism. Data were analysed using mixed linear and proportional odds regression models. The relationship between ḊO2 and temperature was analysed in a subgroup of patients with lactOFF <2.5 mM, thought to have had balanced oxygen delivery and consumption. The estimated regression coefficient was further used to adjust hypothetical ḊO2 thresholds, and ḊO2 excursions below the threshold were quantified as magnitude-durations. The lowest threshold that provided magnitude-durations and linked with an increase in lactOFF was used as the lowest suitable (critical) ḊO2 at 37℃.
Results: Overall, 22 896 time points were analysed in 180 neonates. In 40 patients with lactOFF <2.5 mM, ḊO2 varied by 22.87 (0.70) ml min-1m-2℃-1. When varying the ḊO2 threshold between 340 and 380 ml min-1m-2, excursions below the threshold were linked with incremental lactOFF. A 100 ml m-2 excursion below the 340 ml min-1m-2 ḊO2 threshold increased the risk of a 1 mM increment in lactOFF by 22% (odds ratio: 1.22; 95% confidence interval: 1.02~1.45).
Conclusions: It was found that 340 ml min-1m-2 is likely to represent the lowest suitable ḊO2 required in neonates to maintain aerobic metabolism during normothermic CPB.
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