Ringer Simone K, Clausen Nicola G, Spielmann Nelly, Weiss Markus
Section Anaesthesiology Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
Department of Anaesthesiology, University Children's Hospital Zurich, Zurich, Switzerland.
Paediatr Anaesth. 2019 Nov;29(11):1114-1121. doi: 10.1111/pan.13736. Epub 2019 Sep 12.
Hypocapnia is a common alteration during anesthesia in neonates.
To investigate the effects of hypocapnia and hypocapnia combined with hypotension (HCT) on cerebral perfusion and tissue oxygenation in anesthetized piglets.
Thirty anesthetized piglets were randomly allocated to groups: moderate hypocapnia (mHC), severe hypocapnia (sHC), and HCT. Cerebral monitoring comprised a tissue oxygen partial pressure and a laser Doppler probe inserted into the brain tissue as well as a near-infrared spectroscopy (NIRS) sensor placed on the skin, measuring regional oxygen saturation. Hypocapnia was induced by hyperventilation (target PaCO mHC: 3.7-4; sHC: 3.1-3.3 kPa) and hypotension by blood withdrawal and nitroprusside infusion (mean blood pressure: 35-38 mm Hg). Data were analyzed at baseline, during (Tr20, Tr40, Tr60) and after (Post20, Post40, Post60) treatment.
Compared to baseline, tissue oxygen partial pressure decreased significantly and equally during all treatments (mean [SD] at baseline: mHC 35.7 [32.45]; sHC: 28.1 [20.24]; HCT 25.4 [10.3] and at Tr60: mHC: 29.9 [27.36]; sHC: 22.2 [18.37]; HCT: 18.4 [9.5] mm Hg). Decreased laser Doppler flow was detected with all treatments at Tr20 (mHC: 0.9 [0.18]; sHC: 0.88 [0.15]; HCT: 0.97 [0.13] proportion from baseline). Independently of group, regional oxygen saturation varied only after reverting and not during treatment. Blood lactate, pH, HCO , and PaO increased during treatment with no differences between groups.
This animal model revealed reduced cerebral blood flow and brain tissue oxygenation during hypocapnia without detectable changes in regional oxygen saturation as measured by NIRS. Changes occurred as early as during moderate hypocapnia.
低碳酸血症是新生儿麻醉期间常见的一种改变。
研究低碳酸血症以及低碳酸血症合并低血压（HCT）对麻醉仔猪脑灌注和组织氧合的影响。
将30只麻醉仔猪随机分为三组：中度低碳酸血症组（mHC）、重度低碳酸血症组（sHC）和HCT组。脑监测包括插入脑组织的组织氧分压和激光多普勒探头，以及置于皮肤上用于测量局部氧饱和度的近红外光谱（NIRS）传感器。通过过度通气诱导低碳酸血症（目标PaCO mHC：3.7 - 4；sHC：3.1 - 3.3 kPa），通过放血和输注硝普钠诱导低血压（平均血压：35 - 38 mmHg）。在基线期、治疗期间（Tr20、Tr40、Tr60）和治疗后（Post20、Post40、Post60）对数据进行分析。
与基线相比，所有治疗期间组织氧分压均显著且同等程度降低（基线时平均值[标准差]：mHC 35.7 [32.45]；sHC：28.1 [20.24]；HCT 25.4 [10.3]，Tr60时：mHC：29.9 [27.36]；sHC：22.2 [18.37]；HCT：18.4 [9.5] mmHg）。在Tr20时所有治疗均检测到激光多普勒血流降低（mHC：0.9 [0.18]；sHC：0.88 [0.15]；HCT：0.97 [0.13]，相对于基线的比例）。与组别无关，局部氧饱和度仅在恢复后而非治疗期间发生变化。治疗期间血乳酸、pH、HCO 和PaO 升高，组间无差异。
该动物模型显示，低碳酸血症期间脑血流量和脑组织氧合降低，而通过NIRS测量的局部氧饱和度无明显变化。变化最早在中度低碳酸血症期间出现。
