Tabbutt S, Ramamoorthy C, Montenegro L M, Durning S M, Kurth C D, Steven J M, Godinez R I, Spray T L, Wernovsky G, Nicolson S C
Department of Pediatrics, Division of Cardiology, The Children's Hospital of Philadelphia and the University of Pennsylvania School of Medicine, Philadelphia, USA.
Circulation. 2001 Sep 18;104(12 Suppl 1):I159-64. doi: 10.1161/hc37t1.094818.
Management strategies for preoperative infants with hypoplastic left heart syndrome (HLHS) include increased inspired nitrogen (hypoxia) and increased inspired carbon dioxide (hypercarbia). There are no studies directly comparing these 2 therapies in humans. This study compares the impact of hypoxia versus hypercarbia on oxygen delivery, under conditions of fixed minute ventilation.
Ten anesthetized and paralyzed preoperative infants with HLHS were evaluated in a prospective, randomized, crossover trial comparing hypoxia (17% FIO(2)) with hypercarbia (2.7% FICO(2)). Each patient was treated in a random order (10 minutes per condition) with a recovery period (15 to 20 minutes) in room air. Arterial (SaO(2)) and superior vena caval (SvO(2)) co-oximetry and cerebral oxygen saturation (ScO(2)) measurements were made at the end of each condition and recovery period. ScO(2) was measured by near infrared spectroscopy. Hypoxia significantly decreased both SaO(2) (-5.2+/-1.1%, P=0.0014) and SvO(2) (-5.6+/-1.7%, P=0.009) compared with baseline, but arteriovenous oxygen saturation (AVO(2)) difference (SaO(2)-SvO(2)) and ScO(2) remained unchanged. Hypercarbia decreased SaO(2) (-2.6+/-0.6%, P=0.002) compared with baseline but increased both ScO(2) (9.6+/-1.8%, P=0.0001) and SvO(2) (6+/-2.2%, P=0.022) and narrowed the AVO(2) difference (-8.5+/-2.3%, P=0.005). Both hypoxia and hypercarbia decreased the balance between pulmonary and systemic blood flow (Qp:Qs) compared with baseline.
In preoperative infants with HLHS, under conditions of anesthesia and paralysis, although Qp:Qs falls in both conditions, oxygen delivery is unchanged during hypoxia and increased during hypercarbia. These data cannot differentiate cerebral from systemic oxygen delivery.
对于术前患有左心发育不全综合征（HLHS）的婴儿，管理策略包括增加吸入氮气（低氧）和增加吸入二氧化碳（高碳酸血症）。尚无直接比较这两种疗法对人体影响的研究。本研究比较了在固定分钟通气量条件下，低氧与高碳酸血症对氧输送的影响。
对10例麻醉并瘫痪的术前HLHS婴儿进行了一项前瞻性、随机、交叉试验，比较低氧（吸入氧分数为17%）与高碳酸血症（吸入二氧化碳分数为2.7%）。每位患者按随机顺序接受治疗（每种情况治疗10分钟），并在室内空气中恢复期（15至20分钟）。在每种情况和恢复期结束时进行动脉血氧饱和度（SaO₂）和上腔静脉血氧饱和度（SvO₂）共血氧测定以及脑氧饱和度（ScO₂）测量。ScO₂通过近红外光谱法测量。与基线相比，低氧显著降低了SaO₂（-5.2±1.1%，P = 0.0014）和SvO₂（-5.6±1.7%，P = 0.009），但动静脉血氧饱和度（AVO₂）差值（SaO₂ - SvO₂）和ScO₂保持不变。与基线相比，高碳酸血症降低了SaO₂（-2.6±0.6%，P = 0.002），但增加了ScO₂（9.6±1.8%，P = 0.0001）和SvO₂（6±2.2%，P = 0.022），并缩小了AVO₂差值（-8.5±2.3%，P = 0.005）。与基线相比，低氧和高碳酸血症均降低了肺循环与体循环血流量之比（Qp:Qs）。
在麻醉和瘫痪状态下的术前HLHS婴儿中，尽管两种情况下Qp:Qs均下降，但低氧期间氧输送不变，高碳酸血症期间氧输送增加。这些数据无法区分脑氧输送和体循环氧输送。
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