目的:部分羊水二氧化碳(CO2)吹入(PACI)用于改善可视化并促进复杂的胎儿镜手术。然而,人们担心胎儿高碳酸血症和术后胎膜炎症。我们评估是否使用加热和加湿,而不是寒冷和干燥,CO2可能降低PACI对绵羊胎儿和胎膜的影响。
方法:将12只胎龄105天(足月=145天)的胎儿羔羊部分外植体,通过中线剖腹手术和子宫切开术,通过手术插入动脉导管和流量探头。10个存活的胎儿被送回子宫,然后关闭并注入寒冷,干(22°C,0-5%湿度,n=5)或加热,加湿(湿度为40°C,湿度为100%,n=5)CO2在15mmHg下保持180min。吹入后立即收集胎膜用于组织学分析。生理数据和膜白细胞计数,提示膜炎症,对两组进行比较。
结果:吹气180分钟后,在接受PACI感冒的组中,胎儿存活率为0%,干CO2,在接受加热的组中有60%(n=3),加湿气体。当所有吹入的胎儿逐渐变得高碳酸血症(PaCO2>68mmHg)时,在那些加热的地方,使用加湿气体:吹入120分钟后,与那些接受寒冷的人相比,干燥气体(n=3),胎儿受热,湿化PACI(n=5)的CO2动脉分压较低(平均值±平均值的标准误差,加热82.7±9.1mmHg,加湿CO2vs寒冷时170.5±28.5,PACI期间的干CO2,P<0.01),较低的乳酸水平(1.4±0.4vs8.5±0.9mmol/L,P<0.01)和更高的pH(pH,7.10±0.04vs6.75±0.04,P<0.01)。PACI加热后,胎儿颈动脉压力升高的趋势也不明显,与寒冷相比加湿,干二氧化碳(30.5±1.3vs8.7±5.5mmHg,P=0.22)。此外,在接受加热的PACI的组中,绒毛膜中白细胞的中位数(四分位距)明显较低,加湿的CO2与接受寒冷的组相比,干燥CO2(每平方微米0.7×10-5(0.5×10-5)vs3.2×10-5(1.8×10-5)细胞,P=0.02)。
结论:PACI与寒冷,干燥的二氧化碳会导致高碳酸血症,酸中毒,胎儿绵羊的低血压和胎膜炎症,引起人们对其在人类中使用的潜在担忧。似乎使用加热,用于吹气的加湿CO2部分缓解了这些影响,这可能是降低胎儿酸碱紊乱风险的合适替代方法,和胎膜炎症之后,复杂的胎儿镜手术。©2018作者由JohnWiley&SonsLtd代表国际妇产科超声学会出版的妇产科超声。
OBJECTIVE: Partial amniotic carbon dioxide (CO2 ) insufflation (
PACI) is used to improve visualization and facilitate complex fetoscopic surgery. However, there are concerns about fetal hypercapnic acidosis and postoperative fetal membrane inflammation. We assessed whether using heated and humidified, rather than cold and dry, CO2 might reduce the impact of
PACI on the fetus and fetal membranes in sheep.
METHODS: Twelve fetal lambs of 105 days\' gestational age (term = 145 days) were exteriorized partially, via a midline laparotomy and hysterotomy, and arterial catheters and flow probes were inserted surgically. The 10 surviving fetuses were returned to the uterus, which was then closed and insufflated with cold, dry (22 °C at 0-5% humidity, n = 5) or heated, humidified (40 °C at 100% humidity, n = 5) CO2 at 15 mmHg for 180 min. Fetal membranes were collected immediately after insufflation for histological analysis. Physiological data and membrane leukocyte counts, suggestive of membrane inflammation, were compared between the two groups.
RESULTS: After 180 min of insufflation, fetal survival was 0% in the group which underwent
PACI with cold, dry CO2 , and 60% (n = 3) in the group which received heated, humidified gas. While all insufflated fetuses became progressively hypercapnic (PaCO2 > 68 mmHg), this was considerably less pronounced in those in which heated, humidified gas was used: after 120 min of insufflation, compared with those receiving cold, dry gas (n = 3), fetuses undergoing heated, humidified PACI (n = 5) had lower arterial partial pressure of CO2 (mean ± standard error of the mean, 82.7 ± 9.1 mmHg for heated, humidified CO2 vs 170.5 ± 28.5 for cold, dry CO2 during
PACI, P < 0.01), lower lactate levels (1.4 ± 0.4 vs 8.5 ± 0.9 mmol/L, P < 0.01) and higher pH (pH, 7.10 ± 0.04 vs 6.75 ± 0.04, P < 0.01). There was also a non-significant trend for fetal carotid artery pressure to be higher following
PACI with heated, humidified compared with cold, dry CO2 (30.5 ± 1.3 vs 8.7 ± 5.5 mmHg, P = 0.22). Additionally, the median (interquartile range) number of leukocytes in the chorion was significantly lower in the group undergoing PACI with heated, humidified CO2 compared with the group receiving cold, dry CO2 (0.7 × 10-5 (0.5 × 10-5 ) vs 3.2 × 10-5 (1.8 × 10-5 ) cells per square micron, P = 0.02).
CONCLUSIONS: PACI with cold, dry CO2 causes hypercapnia, acidosis, hypotension and fetal membrane inflammation in fetal sheep, raising potential concerns for its use in humans. It seems that using heated, humidified CO2 for insufflation partially mitigates these effects and this may be a suitable alternative for reducing the risk of fetal acid-base disturbances during, and fetal membrane inflammation following, complex fetoscopic surgery. © 2018 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.