Interventions to improve fetal heart rate patterns during open myelomeningocele repair

Abstract

Material and methods: A study with 37 fetuses submitted to intrauterine myelomeningocele repair between the 24th and 27th week of gestation was performed to evaluate FHR at specific periods: pre-anaesthesia, post-anaesthesia, during neurosurgery (early skin manipulation, spinal cord release, and synthesis), and at the end of surgery. Surgery room (SRT) and uterine surface (UST) temperatures were strictly controlled. A plastic cover was used to protect to protect uterine heat loss. We determined the mean ± standard deviation (SD) of FHR of each period, and we used analysis of variance (ANOVA) with repeated measures to assess differences among these periods. Tukey multiple comparation test was used to compare global surgery stages. Results: The mean FHR in the specific time points were: 138.6, 138.4, 132.8, 127.7, 131.4, and 132.7 bpm, respec-tively ( p < 0.001). In the comparisons between times two by two, the neurosurgery stage presents the lower frequencies, especially during release of the spinal cord, but episodes of bradycardia were no longer found. SRT and UST remained stable during the critical stages of the procedure. Conclusions: It is known that many are the factors involved in fetal cardiovascular disorders. Possibly, these changes allowed for better haemodynamic control of the fetus, improving the safety of the procedure. is an important issue in order to understand the modifications that any intervention aimed to solve the blood transfusion can determine on the surviving fetuses. Many studies have shown that in the long term, after laser coagulation (LC) of severe TTTS syndrome, cardiac function and blood pressure return to normal in the majority of surviving twins. This indicates that the preceding cardiac dysfunction regresses once LC has removed the underlying cause. However, a reported increased in the prevalence of pulmonary stenosis despite successful LC justifies the need for prenatal and postnatal cardiac surveillance. Material and methods: In our data of 28 pairs of twins complicated by TTTS and undergoing LC, we observed abnormal prenatal cardiac findings before treatment and the postnatal occurrence of some structural heart defects. One twin recipient with hydrops and functional pulmonary atresia had the same features at postnatal follow-up; another twin recipient with fetal hydrops, and mitral and tricuspid valve regurgitation presented with moderate pulmonary stenosis postnatally. Results: One fifth of all TTTS recipient twins show congenital and/or acquired diseases, i.e. right ventricle outflow tract obstruction (RVOTO), PA, or PS. Laser coagulation in severe stages can solve the blood transfusion but does not solve the acquired CHD (such as right ventricular outflow obstruction and pulmonary valve atresia). Conclusions: Laser coagulation should always be performed before cardiac function deteriorates, if possible.