Fetal Anesthesia Research Articles

Ex utero intrapartum procedure for delivery of a fetus with a large cervical mass

Ex utero intrapartum procedure for delivery of a fetus with a large cervical mass

Anestesia para correção intra-útero de mielomeningocele: relato de caso

Fetal surgery is the treatment of choices for prenatal malformations that are not adequately corrected after birth and aims at treating or preventing the progression of the abnormalities. This report describes a case of anesthesia for intrauterine correction of a myelomeningocele.Pregnant patient, 19 years old, 23 weeks of gestational age, without previous anesthetic history, physical status ASA I, submitted to intrauterine fetal surgery under general anesthesia associated to continuous epidural continuous anesthesia. The patient was premedicated with rectal indomethacin (50 mg), intravenous metoclopramide (10 mg) and cimetidine (50 mg), in addition to intravenous midazolam (2 mg). The patient received 0.25% bupivacaine with epinephrine (25 mg) associated to fentanyl (100 microg) epidurally, followed by cephalic catheter insertion for postoperative analgesia. The uterus was left-displace with a Crawford's wedge. Rapid sequence anesthesia was induced with fentanyl, propofol and rocuronium, and was maintained with 2.5% - 3% isoflurane in O2 and N2O. After stapling hysterectomy to promote homeostasis, fetal operative site was exposed and fetal analgesia and immobility was obtained with the association of fentanyl (10 microg.kg-1) and pancuronium (0.1 mg.kg-1) administered on fetal gluteus muscle. Maternal systolic blood pressure was maintained above 100 mmHg with bolus ephedrine (5 mg), colloids and crystalloids. Lost amniotic fluid was replaced with warm saline. After correction of the fetal defect, both uterus and amniotic membrane were closed in two planes with vicryl suture and fibrin glue. Afterwards, isoflurane concentration was gradually decreased and bolus magnesium sulfate (4 g/20 minutes) followed by continuous infusion was administered to maintain uterine relaxation (2 g/hour). Morphine (2 mg) was administered via epidural catheter at the end of surgery for postoperative analgesia.Anesthesia for fetal surgery involves two individuals the mother and the fetus, an anesthetic management requires: maternal-fetal safety, fetal anesthesia and immobility, uterine relaxation, prevention of premature labor and postoperative analgesia.

Fetal surgery, anaesthesiological considerations

Refined techniques and skills have enabled sophisticated prenatal diagnosis in utero and resulted in the newly evolving specialty of fetal surgery in a few centres worldwide. Most of the procedures performed today have been preceded by extensive experimental research in animals, whereas fetal anaesthesia is mainly based on clinical experience and a few studies performed in pregnant sheep. Major limitations of fetal surgery include the high frequency of preterm labour and delivery which may offset any fetal benefit of the surgical procedure. The development of more potent tocolytic drugs than the drugs currently available may thus be compared to the meaning of potent immunosuppressive agents in organ transplantation. Fetal mortality and maternal morbidity consequently lead to a more cautious way of treatment, as with the development of endoscopic fetal surgery. The invasive fetal surgery is still considered as being in a research stage in most cases. Therefore most procedures are performed as minimally invasive, avoiding substantial risks by accessing the uterus through minimal openings. Some new devices are under investigation for monitoring the myometrial electrical activity and mechanical contractility and the fetal electroencephalogram, the continuous monitoring of the fetal arterial oxygen saturation, PO2 and PCO2, and for monitoring fetal cerebral oxygenation, blood volume and blood flow by near infrared spectroscopy.

Prenatal therapy for thoracic and mediastinal lesions.

Most prenatally diagnosed lung lesions can be managed successfully during the neonatal period. Prenatal imaging and experimental models have provided a comprehensive understanding of the pathophysiology, natural history, and prognosis of intrathoracic and mediastinal lesions. Clinical experience has demonstrated that progression to nonimmune hydrops fetalis and pulmonary hypoplasia is a harbinger of fetal or neonatal demise. Advances in fetal anesthesia, tocolysis, and surgical techniques have made fetal surgery a viable in utero option to ameliorate life-threatening masses. Congenital cystic adenomatoid malformation, bronchopulmonary sequestration, and congenital hydrothorax are the most common abnormalities amenable to surgical intervention. The natural history, evaluation, and treatment of intrathoracic and mediastinal lesions are discussed.

Anaesthesia for fetal surgery.

*Department of Anesthesia, Children’s Hospital, Harvard Medical School, Boston, MA,**Department of Anesthesiology and Critical Care, The Children’s Hospital of Philadelphia,University of Pennsylvania School of Medicine, Philadelphia and †Department of Anesthesia andCritical Care, The Hospital of the University of Pennsylvania, University of Pennsylvania Schoolof Medicine, Philadelphia, PA, USA

Anesthesia for Fetal Minimal Access Surgery

Fetal surgery, whether minimal access or not, involves intervention on two patients. Issues of maternal safety, teratogenicity of anesthetic agents, fetal asphyxia and monitoring, and uterine relaxation must be addressed for optimal outcomes. Prevention of preterm labor remains a major challenge and should be started before leaving the operating room. Surgical approach, i.e. whether a laparotomy is required to achieve adequate access to the fetus, will guide the anesthesiologist in the choice of anesthetic plan. Fetal anesthesia needs to be considered for those procedures that involve direct intervention on the fetus, as opposed to placental or umbilical manipulations.

Anesthetic management of the exit ( Ex Utero intrapartum treatment) procedure

The EXIT (ex utero intrapartum treatment) procedure is used to maintain fetal-placental circulation during partial delivery of a fetus with a potentially life-threatening upper airway obstruction. We performed the EXIT procedure on a fetus with a large intra-oral cyst. Sevoflurane was used as the anesthetic because of its rapid titratability. Sevoflurane provided excellent maternal and fetal anesthesia. Modifications to previously described monitoring techniques for the EXIT procedure were also used.

Pain and stress in the human fetus

Invasive diagnostic and therapeutic techniques are increasingly applied to the fetus. It is not known if the fetus feels pain during such procedures, but the fetus does mount significant stress hormonal and circulatory changes in response to these from 18–20 weeks. Perinatal stress may have long-term neurodevelopmental implications. During open fetal surgery, maternal general anaesthesia provides fetal anaesthesia. However, in closed procedures, fetal analgesia presents difficulties. The optimal drug, dose, and route of administration remain to be determined.

Fetal surgery: general or regional anaesthesia?

Major improvements in the diagnosis and treatment of fetal malformations, including in-utero surgical repair, have occurred in the past decade. As opposed to anaesthesia for caesarean sections, a high placental drug transfer is warranted to provide adequate fetal anaesthesia and immobility, strongly favouring the use of general anaesthesia for these cases. Even though the question of fetal pain perception is still debated, studies suggest that attenuation of the fetal stress response can improve outcome. Other major concerns include the maintenance of uterine blood flow and uterine relaxation, as premature labour and delivery severely limit fetal benefits from surgery. When performing these procedures, physicians have a special responsibility to weigh maternal risks against fetal benefits and should not jeopardize the life of the mother for procedures with questionable fetal outcome.

Anesthetic considerations for fetal surgery

This article outlines the perioperative management of the parturient who presents for fetal surgery. Anesthetic considerations include the physiological changes of pregnancy, preterm labor, the consequences of tocolytic drugs, maternal and fetal anesthesia, and postoperative analgesia.

Fetal stabilization for antenatally diagnosed diaphragmatic hernia

Background/Purpose: Infants with congenital diaphragmatic hernia have pulmonary hypoplasia resulting in persistent pulmonary hypertension of neonates (PPHN), which is the main contributor to both high mortality and morbidity. The pulmonary artery bed in patients with congenital diaphragmatic hernia (CDH) is underdeveloped and is very sensitive to slight stimuli. It is, therefore, vital to avoid any factors that might increase pulmonary vascular resistance during the perinatal treatment of these patients. Recently, fetal anesthesia for perinatal stabilization in patients with CDH has been reported. However, the efficacy of this method remains controversial. The aim of this study is to analyze the benefits of fetal stabilization using fetal anesthesia in patients with CDH. Methods: The authors have seen 9 cases of antenatally diagnosed CDH and attempted fetal stabilization. The indication for fetal stabilization was a lung thoracic ratio of less than 0.2, without any severe associated anomalies. The protocol for fetal stabilization was (1) monitoring the fetal respiratory movement and heart beat by ultrasonography, (2) the administration of morphine (20 to 30 mg) and diazepam (5 mg) to the mother, (3) the confirmation of any interruptions in fetal movement followed by a cesarean section, (4) pancuronimum (0.5 mg) was given through the umbilical vessels, (5) intubation before clamping of the umbilical cord, and (6) high-frequency oscillatory ventilation (HFO) without bagging. Results: The lung-thratic ratio (LTR) was between 0.06 to 0.17 (average, 0.10±0.04). Operation was performed in 7 of 9 patients at between 2.5 and 27 hours after birth. The overall survival rate was 66.7% (6 of 9). All of the patients who underwent operation within 5 hours after birth survived. Conclusions: Perinatal stabilization using fetal anesthesia was found to be effective in preventing PPHN and shortening the period of preoperative stabilization. It also improved the survival rate of patients with severe CDH.

The Cesarean Delivery of a Twin Gestation Under 2 Minimum Alveolar Anesthetic Concentration Isoflurane

The Cesarean Delivery of a Twin Gestation Under 2 Minimum Alveolar Anesthetic Concentration Isoflurane

Successful fetal surgery for spina bifida

Spina bifida occurs in one of 2000 livebirths and leads to lifelong and devastating physical disabilities including paraplegia, hydrocephalus, incontinence, sexual dysfunction, skeletal deformations, and mental impairment.1Copp AJ Neural tube defects.Trends Neurosci. 1993; 16: 381-383Summary Full Text PDF PubMed Scopus (29) Google Scholar Compelling experimental evidence shows that the neurological deficit associated with open spina bifida is not entirely caused by the primary defect of neurulation, but rather is due to chronic mechanical injury and amniotic fluid-induced chemical trauma that progressively damages the exposed unprotected fetal neural tissue during gestation. Timely in-utero repair of spina bifida in fetal sheep stops the ongoing spinal cord destruction and “rescues” neurological function by the time of birth.2Meuli M Meuli-Simmen C Hutchins GM et al.In utero surgery rescues neurological function at birth in sheep with spina bifida.Nat Med. 1995; 1: 342-347Crossref PubMed Scopus (293) Google Scholar In late-gestation human fetuses and in neonates with spina bifida, the neural tissue elements show severe traumatic and degenerative alterations, or there is almost complete loss of neural tissue.3Meuli M Meuli-Simmen C Hutchins GM Sellar MJ Harrison MR Adzick NS The spinal cord lesion in human fetuses with myelomeningocele: implications for fetal surgery.J Pediatr Surg. 1997; 32: 448-452Summary Full Text PDF PubMed Scopus (167) Google Scholar Sonographic reports of human fetuses with very large spina bifida lesions and normal leg movements early in gestation imply that motor function is present initially and lost only later in gestation.4Korenromp MJ Van Good JD Bruinse HW Kriek R Early fetal leg movements in myelomeningocele.Lancet. 1986; i: 917-918Abstract Scopus (123) Google Scholar We report the first successful in-utero surgical repair of open spina bifida in an early-gestation fetus. A 27-year-old woman was referred for assessment of a 23-week gestation fetus with thoracolumbosacral spina bifida. The lesion was detected on a 20-week ultrasound done because of a raised maternal serum α-fetoprotein. Serial ultrasounds showed good leg movements, and karyotype by amniocentesis was normal. Ultrafast fetal magnetic resonance imaging revealed a spina bifida lesion extending from thoracic level 11 to sacral level 1, Arnold-Chiari type II malformation, and borderline hydrocephalus (the fetal lateral ventricles measured 10 mm). The mother declined pregnancy termination and consented to surgery. Maternal general anaesthesia provided fetal anaesthesia and uterine relaxation for open fetal surgery. A low transverse maternal laparotomy and vertical hysterotomy were performed.5Adzick NS Harrison MR Fetal surgical therapy.Lancet. 1994; 343: 897-902Abstract PubMed Scopus (133) Google Scholar The cystic membrane of the spina bifida lesion was excised, and skin flaps were developed laterally to close the defect and protect the developing spinal cord (figure). Because we were concerned about possible secondary hydrocephalus after the lesion was closed, cerebrospinal fluid shunt tubing was threaded up alongside the proximal spinal cord and the slit-valve end was brought out via a separate skin wound. Amniotic fluid was replaced with warmed lactated Ringer's solution and the uterine and laparotomy wounds were closed. Postoperatively, tocolysis was maintained with magnesium sulphate intravenous infusion and indometacin rectal suppositories, followed by terbutaline given by a subcutaneous pump. The mother was discharged from hospital 5 days postoperatively. At 30 weeks' gestation, preterm labour led to the delivery by caesarean section of a 1·3 kg baby boy who required a short period of ventilatory support. The mother recovered uneventfully. The shunt tubing was removed immediately after birth. The baby showed excellent left leg function except for absent plantar flexion of the foot (L5 level). A right club foot was present, but the baby had right hip and knee flexion and extension (L4 level). Postnatal magnetic resonance imaging confirmed that the repaired spina bifida lesion extended from T11 to S1 and revealed that the Arnold-Chiari type II malformation was no longer present and there was no hydrocephalus. He has met all developmental milestones at age 6 months, but long-term follow-up is needed. Neonates with thoracolumbar spina bifida are almost invariably paraplegic and have associated hydrocephalus that requires a lifelong shunt. This case shows that early gestation fetal surgical repair of severe spina bifida can save neurological function. By arresting the neural destruction, prenatal repair may also allow rearrangements of function due to the plasticity of the developing nervous system. In addition, the resolution of the Arnold-Chiari malformation after in-utero repair suggests that this brain malformation is a secondary consequence of spina bifida. In-utero spina bifida repair may thus obviate the complications of Arnold-Chiari malformation including the need for shunt procedures after birth.

GREATER THAN ONE MAC OF ISOFLURANE IN OXYGEN

S367 Introduction: Surgery to correct fetal anomalies during gestation remains in the investigational stage. The anesthetic approach to these patients must consider maternal safety, tocolysis, and fetal anesthesia. A technique involving greater than one MAC of isoflurane in 100% oxygen is presented. Isoflurane provides uterine relaxation [1], maternal anesthesia [2], and fetal anesthesia [3]. Methods: After IRB approval, the charts of parturients who underwent surgery to correct fetal anomalies were reviewed. Gestational age of the fetus, the time from induction to extubation, the time from uterine incision to closure, the estimated blood loss, the amount of ephedrine administered, the highest end-tidal concentration of isoflurane, and the intraoperative fetal oxygenation were recorded. The anesthetic technique consisted of rapid sequence induction with thiopental and succinylcholine; maintenance consisted of isoflurane in oxygen. Maternal arterial pressure was maintained with ephedrine. Results: Seven parturients underwent fetal surgery. The anomalies were: 2 diaphragmatic hernias, 2 cystic adenoid malformation of the lung, 1 sacrococcygeal teratoma, and 2 twin-twin transfusions. Mean +/- standard deviation is presented. (Table 1)Table 1No fetus required supplemental narcotics or muscle relaxants for movement. Discussion: Greater than 1 MAC of isoflurane in 100% oxygen was well tolerated by the mother. Blood loss was not excessive. Ephedrine was required to maintain maternal blood pressure at baseline. Uterine relaxation and fetal anesthesia were achieved. This is the first report of oxygen saturation in a 22-24 week fetus. Despite the high concentration of isoflurane, oxygenation was maintained in the fetus. Although fetal blood pressure was not directly measured, a fetal pulse oximetry reading was able to be obtained, suggesting adequate perfusion pressure. The use of greater than 1 MAC isoflurane for surgery during pregnancy is well tolerated by the mother and fetus.

Anesthetic Management of Cesarean Delivery Complicated by Ex Utero Intrapartum Treatment of the Fetus

Anesthetic Management of Cesarean Delivery Complicated by Ex Utero Intrapartum Treatment of the Fetus

Fetal anaesthesia for intrauterine treatment

SummaryFetal anaesthesia was performed 5 times in 1 patient to treat pleural effusions, obtain fetal blood sampling, provide albumin infusion, and establish and replace a pleuro‐amniotic indwelling shunt catheter under ultrasound guidance. A maternal epidural catheter was placed and used for epidural anaesthesia for the first 4 anaesthetics. Fetal administration of pancuronium 0.15 mg·kg−1 via the umbilical vein or 0.25 mg·kg−1 intramuscularly was enough to produce immobilization without maternal effect. However, maternal pretreatment with intravenous diazepam and fentanyl was required for fetal sedation and analgesia, which was necessary for accurate and safe injection, and for suppression of fetal stress.

Protein synthesis during hypoxia in fetal lambs.

The goal of this study was to test the hypothesis that the rate of fetal protein synthesis decreases during fetal hypoxia. Catheters were inserted into 13 sheep fetuses under maternal spinal and local fetal anesthesia. Five days after surgery, an infusion of L-[1-14C]tyrosine (0.05-0.25 muCi/min) was begun. Measurements were first made when tyrosine-specific activity reached steady state at 3 h and then again 3 h after fetal oxygen delivery was reduced by lowering the maternal inspired oxygen concentration. Fetal tyrosine uptake across the umbilical circulation was 1.34 +/- 0.20 mumol X kg-1 X min-1 during normoxia and decreased to 0.72 +/- 0.12 mumol X kg-1 X min-1 during hypoxia (P = 0.017). Tyrosine use from the plasma compartment was 1.25 +/- 0.18 mumol X kg-1 X min-1 during normoxia and decreased to 0.64 +/- 0.12 mumol X kg-1 X min-1 (P = 0.0005) during hypoxia. Fetal tyrosine use decreased during reduced oxygen delivery because the rate of tyrosine use for fetal protein synthesis decreased from 0.97 +/- 0.17 to 0.38 +/- 0.09 mumol X kg-1 X min-1 (P = 0.0004). Fetal oxygen consumption decreased by 40 mumol X kg-1 X min-1 during hypoxia. Decreased protein synthesis reduced the energy needed for protein synthesis and explained 28 mumol X kg-1 X min-1 of this reduction.

Feasibility of intracranial surgery in the primate fetus. Model and surgical principles.

A research model for intracranial surgery in the primate fetus was developed and tested in 10 timed-pregnant rhesus monkeys. With general anesthesia and sterile surgical technique, a laparotomy followed by a lower uterine segment hysterotomy was performed at a site avoiding the placenta. The amnion was opened carefully by use of the operative microscope and the fetal head was exposed. A scalp incision was made over the frontal region and a small craniectomy and cortical incision were carried out. In three of the fetuses, ventricular shunts were also placed. A layered closure was performed and the uterus was returned to the peritoneal cavity. Placental integrity and fetal viability were assessed before surgery and 1 week postoperatively by ultrasonography. The survival rates were 100% for the mothers and 80% for the fetuses. One fetus died in utero after an overdose of a sedative to the mother, and another was stillborn. Postmortem examination revealed no intracranial or systemic abnormalities in either case, and the cause of death was attributed to drug overdose and a naturally occurring stillbirth, respectively. Newborns were maintained either with their mothers or in a nursery, where they were observed and evaluated for 3 weeks. Weight, crown-rump length, and occipitofrontal head circumference were measured. General patterns of behavior and neurological assessments were recorded weekly. The eight surviving neonates were normal with respect to all parameters evaluated. Several principles of fetal intracranial surgery are emphasized as important: uterine relaxation by prostaglandin inhibition; low-dose halothane anesthesia supplemented by nitrous oxide in oxygen; perioperative ultrasonography and intraoperative transillumination of the uterus for placental localization; lower uterine segment opening; controlled exposure of the fetal cranium; minimization of amniotic fluid loss; enhancement of fetal anesthesia by injection of a local anesthetic agent at the fetal operative site; and multilayered watertight closure.