Till Holger, Yeung Chung Kwong, Bower Wendy, Shi Yimin, Tian Q, Chu W, Yip H Y, Tse J
Department of Pediatric Surgery, University of Leipzig, Childrens' Hospital, 04317 Leipzig, Germany.
J Pediatr Surg. 2007 Jul;42(7):1255-8. doi: 10.1016/j.jpedsurg.2007.02.026.
Recently, gas amniodistension has been advocated for fetoscopic surgery to employ ergonomics similar to laparoscopy. However, neither the optimal type of gas nor its physiological influence on the fetus have been clearly outlined yet. This study investigates the impact of helium (HE) vs nitrous oxide (N2O) on fetal goats during fetoscopy.
We insufflated either HE or N2O in 12 pregnant goats (15 fetuses; HE = 7, N2O = 8), then increased the pressures from 0, 4, 7, to 10 mm Hg in 30-minute intervals and recorded the fetal and maternal vital parameters. Finally, whole-body computed tomography to asses for intracorporeal gas was performed.
All fetuses survived. Mean fetal vital signs showed no significant differences between HE or N2O at specific pressure levels. In detail, HE/N2O at 0 vs 10 mm Hg caused a fetal temperature decrease (32.9 degrees C/33.2 degrees C vs 32 degrees C/32.5 degrees C), heart rate increase in the N2O group (100/102 vs 102/121 beats per minute), and no significant change in arterial pressure (45.8/48.3 vs 53.7/46.7 mm Hg). The PO2 was adequate (3.7/3.3 vs 3.7/2.9 kPa), whereas the pH remained unchanged (7.4/7.3 vs 7.3/7.3). However, fetal pCO2 was elevated in the N2O group before insufflation (5.5/7.2 vs 6.8/8.0 kPa) owing to maternal hypoventilation (maternal PCO2: 4.9/5.8 vs 5.0/5.4 kPa), correction of which was slower in the fetus than in the maternal animal. Computed tomography ruled out intracorporeal gas accumulation.
Neither HE nor N2O impose significant physiological harm for the fetus. Heating of the gas and maternal anesthesia seem essential. Considering the potential teratogenicity of N2O, however, HE could be the favorable environment for fetoscopic procedures under gas amniodistension.
最近，有人主张在胎儿镜手术中采用气体羊水扩张法，以实现类似于腹腔镜检查的人体工程学效果。然而，目前尚未明确最佳的气体类型及其对胎儿的生理影响。本研究调查了氦气（HE）与一氧化二氮（N2O）在胎儿镜检查期间对胎羊的影响。
我们对12只怀孕山羊（15只胎儿；HE组 = 7只，N2O组 = 8只）分别注入HE或N2O，然后每隔30分钟将压力从0、4、7升高到10毫米汞柱，并记录胎儿和母体的生命参数。最后，进行全身计算机断层扫描以评估体内气体情况。
所有胎儿均存活。在特定压力水平下，HE组和N2O组的平均胎儿生命体征无显著差异。具体而言，0毫米汞柱与10毫米汞柱时，HE/N2O导致胎儿体温下降（32.9摄氏度/33.2摄氏度对32摄氏度/32.5摄氏度），N2O组心率增加（100/102对102/121次/分钟），动脉压无显著变化（45.8/48.3对53.7/46.7毫米汞柱）。氧分压充足（3.7/3.3对3.7/2.9千帕），而pH值保持不变（7.4/7.3对7.3/7.3）。然而，由于母体通气不足（母体二氧化碳分压：4.9/5.8对5.0/5.4千帕），N2O组胎儿在注入前二氧化碳分压升高（5.5/7.2对6.8/8.0千帕），胎儿的这种情况纠正速度比母体动物慢。计算机断层扫描排除了体内气体积聚。
HE和N2O对胎儿均未造成显著的生理损害。气体加热和母体麻醉似乎至关重要。然而，考虑到N2O的潜在致畸性，在气体羊水扩张下进行胎儿镜检查时，HE可能是更有利的环境。
