The Successful Use of Nitroglycerin for Uterine Hyperstimulation with Fetal Heart Rate Abnormality Caused by a Controlled-Release Dinoprostone Vaginal Delivery System (PROPESS): A Case Report

The PROPESS, a controlled-release dinoprostone vaginal delivery system, is a pharmacological cervical ripening intervention and promotes cervical change causing uterine contraction. During insertion of the PROPESS, uterine hyperstimulation could occur and result in fetal heart rate (FHR) abnormality. We report a case of uterine hyperstimulation accompanied with FHR abnormality caused by the PROPESS in a pregnant woman. Postural change, oxygenation, fluid infusion, and the immediate PROPESS removal were ineffective to address the adverse event, so we administered nitroglycerin for acute uterine relaxation. The nitroglycerin resulted in uterine relaxation, and the FHR abnormality was resolved immediately, thereby preventing an emergency cesarean section. Therefore, nitroglycerin could be considered an effective option for uterine hyperstimulation accompanied with FHR abnormality caused by the PROPESS.

“En Caul” Cesarean Delivery for Extremely Premature Fetuses: Surgical Technique and Anesthetic Options

The risks and technical difficulties at the cesarean delivery for extremely premature infant under 1,000g are as follows: (1) a premature infant is very weak for pressure of uterine wall or human hands, (2) skin of infant is really premature and weak, (3) uterine wall is thick and difficult to incise at lower segment of uterus, (4) classical vertical incision or reverse T-shape incision are at risk for future uterine rupture, and (5) at the timing of rupture of membrane, uterine wall may contract drastically and the infant is trapped the uterine wall, so called “hug-me-tight-uterus”.To resolve the problems, we use the technique of “En Caul” cesarean delivery with nitroglycerin. Intravenous injection of nitroglycerin just before uterine incision made the rapid and sufficient relaxation of uterine muscle. After getting adequate uterine relaxation, U- or J-shaped incision is made to lower segment of the uterus; however, we never incise the membrane before the infant was delivered. The baby is delivered with wrapped amniotic fluid and the membrane, which protect the infant against the pressure of uterine wall or surgeon’s hands. The infant is gently handled to neonatologist by “En Caul” with the placenta. Neonatologist can make the membrane ruptured and resuscitation. Own blood transfusion can be made through the umbilical cord and placenta, if the infant was anemic or hypovolemic.

The role of potassium channels and calcium in the relaxation mechanism of magnesium sulfate on the isolated rat uterus

MgSO4 is used as a tocolytic agent. It is considered to be a calcium channel antagonist, but a different mechanism of its action might be involved. The aim of this study was to examine the contribution of calcium concentrations and potassium channels in the mechanism of MgSO4-mediated uterine relaxation. Isolated uteri from female Wister rats were treated with increasing MgSO4 concentrations (0.1-30 mM). MgSO4 induced dose-dependent inhibition of spontaneous activity. Addition of Ca2+ (6 mM and 12 mM) stimulated uterine contractile activity and attenuated the inhibitory activity of MgSO4. In order to analyze the role of different subtypes of potassium channels, Ca2+-stimulated uteri were pretreated with glibenclamide (Glib), a selective ATP-sensitive potassium channel inhibitor (KATP), tetraethylammonium (TEA), a non-specific inhibitor of large conductance calcium-activated potassium channels (BKCa), and 4-aminopyridine (4-AP), a voltage-sensitive potassium channel inhibitor (Kv), at concentrations that had no effect per se. Pretreatment with 4-AP had no effect on MgSO4-mediated relaxation of Ca2+-stimulated uteri. The relaxing effect of MgSO4 was potentiated by pretreatment with glibenclamide. Pretreatment with TEA attenuated the MgSO4-mediated decrease in frequency. Our results suggest that MgSO4 acts as a general calcium antagonist that influences Ca2+-mediated potassium channels. Furthermore, it seems that MgSO4 uterine relaxation activity is partially mediated by selective ATP-sensitive potassium channels, suggesting an ATP-dependent role.

Myelomeningocele Repair

Myelomeningocele (MMC) is a spinal birth defect associated with significant morbidity directly related to the exposure of meninges and neural structures. Further neurological dysfunction may occur secondary to Chiari II malformation and hydrocephalus. MMC repair is typically performed postnatally within the first 24 to 48 hours of life due to the concern for infection. Prenatal MMC correction is performed in select cases after studies showed improved neurological outcomes. Anesthesia for MMC repairs can be challenging, and appropriate screening should be performed preoperatively. During postnatal repair, care must be taken when positioning the infant to avoid any pressure on the MMC sac. Anesthesia can be maintained with a combination of inhalational agents and intravenous opioids. Prenatal MMC repairs must consider both fetal and maternal safety outcomes. They can be performed through both open and fetoscopic routes, with anesthesia focused on maintaining maternal blood pressure, optimizing uterine relaxation, and adequate pain control.

Novel multidisciplinary approach to monitor and treat fetuses with gastroschisis using the Svetliza Reducibility Index and the EXIT-like procedure

ABSTRACT Objective: To describe our initial experience with a novel approach to follow-up and treat gastroschisis in “zero minute” using the EXITlike procedure. Methods: Eleven fetuses with prenatal diagnosis of gastroschisis were evaluated. The Svetliza Reductibility Index was used to prospectively evaluate five cases, and six cases were used as historical controls. The Svetliza Reductibility Index consisted in dividing the real abdominal wall defect diameter by the larger intestinal loop to be fitted in such space. The EXIT-like procedure consists in planned cesarean section, fetal analgesia and return of the herniated viscera to the abdominal cavity before the baby can fill the intestines with air. No general anesthesia or uterine relaxation is needed. Exteriorized viscera reduction is performed while umbilical cord circulation is maintained. Results: Four of the five cases were performed with the EXIT-like procedure. Successful complete closure was achieved in three infants. The other cases were planned deliveries at term and treated by construction of a Silo. The average time to return the viscera in EXIT-like Group was 5.0 minutes, and, in all cases, oximetry was maintained within normal ranges. In the perinatal period, there were significant statistical differences in ventilation days required (p = 0.0169), duration of parenteral nutrition (p=0.0104) and duration of enteral feed (p=0.0294). Conclusion: The Svetliza Reductibility Index and EXIT-like procedure could be new options to follow and treat gastroschisis, with significantly improved neonatal outcome in our unit. Further randomized studies are needed to evaluate this novel approach.

EPINEPHRINE

The most common complication of spinal anesthesia for cesarean section ishypotension. Ephedrine is the most commonly used vasopressor that increases blood pressurewith minimal impact on uteroplacental blood flow. An alpha-1 adrenergic receptor agonist mayneed to be administrated when ephedrine is ineffective. Unavailability of alpha-1 receptoragonists in a period of time in our center leads to administration of epinephrine as the seconddrug. In the present study, the data of 14 patients with ephedrine resistant hypotension duringspinal anesthesia for cesarean section were reviewed. Increase in maternal blood pressurewas recorded one minute after epinephrine administration in all patients. Surprisingly, thismedication also causes uterine relaxation after one to five minutes. Ease of fetal extractionwas noticed in 13 patients. All patients achieved adequate uterine contraction after delivery.Epinephrine helped regulate blood pressure and surprisingly facilitate uterine relaxation inpatients with emergency cesarean section with spinal anesthesia.