Capacity planning for maternal-fetal medicine using discrete event simulation

BACKGROUND

Maternal-fetal medicine is a rapidly growing field requiring collaboration from many subspecialties. We provide an evidence-based estimate of capacity needs for our clinic, as well as demonstrate how simulation can aid in capacity planning in similar environments.

METHODS

A Discrete Event Simulation of the Center for Fetal Diagnosis and Treatment and Special Delivery Unit at The Children's Hospital of Philadelphia was designed and validated. This model was then used to determine the time until demand overwhelms inpatient bed availability under increasing capacity.

FINDINGS

No significant deviation was found between historical inpatient censuses and simulated censuses for the validation phase (p = 0.889). Prospectively increasing capacity was found to delay time to balk (the inability of the center to provide bed space for a patient in need of admission). With current capacity, the model predicts mean time to balk of 276 days. Adding three beds delays mean time to first balk to 762 days; an additional six beds to 1,335 days.

CONCLUSION

Providing sufficient access is a patient safety issue, and good planning is crucial for targeting infrastructure investments appropriately. Computer-simulated analysis can provide an evidence base for both medical and administrative decision making in a complex clinical environment.

Thoracoamniotic shunts for the management of fetal lung lesions and pleural effusions: a single-institution review and predictors of survival in 75 cases

PURPOSE

Hydrops and pulmonary hypoplasia are associated with significant morbidity and mortality in the setting of a congenital lung lesion or pleural effusion (PE). We reviewed our experience using in utero thoracoamniotic shunts (TA) to manage fetuses with these diagnoses.

METHODS

A retrospective review of fetuses diagnosed with a congenital lung lesion or pleural effusion who underwent TA shunt placement from 1998-2013 was performed.

RESULTS

Ninety-seven shunts were placed in 75 fetuses. Average gestational age (±SD) at shunt placement and birth was 25±3 and 34±5 weeks. Shunt placement resulted in a 55±21% decrease in macrocystic lung lesion volume and complete or partial drainage of the PE in 29% and 71% of fetuses. 69% of fetuses presented with hydrops, which resolved following shunt placement in 83%. Survival was 68%, which correlated with GA at birth, % reduction in lesion size, unilateral pleural effusions, and hydrops resolution. Surviving infants had prolonged NICU courses and often required either surgical resection or tube thoracostomy in the perinatal period.

CONCLUSION

TA shunts provide a therapeutic option for select fetuses with large macrocystic lung lesions or PEs at risk for hydrops and/or pulmonary hypoplasia. Survival following shunting depends on GA at birth, reduction in mass size, and hydrops resolution.

Outcomes of prenatally diagnosed lung lesions in multigestational pregnancies

BACKGROUND

The outcomes of prenatally diagnosed lung lesions in the context of multigestational pregnancies are unknown.

METHODS

Of 960 fetal lung lesion cases evaluated at a single tertiary center over 16 years, 30 occurred in multigestational pregnancies. We reviewed this series to aid in prenatal counseling of affected families and to provide prognostic information for decision making. Pre- and postnatal clinical characteristics were gathered for these pregnancies, and the morbidity and mortality were determined for both affected and normal fetuses, whether twins or triplets.

RESULTS

Mortality was found to be 3/30 (10%) for affected fetuses, and morbidity in normal co-twins was consistent with the degree of prematurity. No morbidity was seen in co-twins born at or after 36 weeks of gestation. Median gestational age at delivery was 35 5/7 weeks.

CONCLUSIONS

Outcomes for the affected fetus correlate with the size and pathophysiologic consequences of the lesion and are not worse than previously reported outcomes for similar lesions in singleton pregnancies, while morbidity in the normal co-twin is consistent with prematurity related to the fetal age of the multiple gestation at delivery, irrespective of the fetal lung lesion.

Fetal Myelomeningocele Repair: The Post-MOMS Experience at the Children's Hospital of Philadelphia

Background: Fetal myelomeningocele (fMMC) repair has become accepted as a standard of care option in selected circumstances. We reviewed our outcomes for fMMC repair from referral and evaluation through surgery, delivery and neonatal discharge. Material and Methods: All patients referred for potential fMMC repair were reviewed from January 1, 2011 through March 7, 2014. Maternal and neonatal data were collected on the 100 patients who underwent surgery. Results: 29% of those evaluated met the criteria and underwent fMMC repair (100 cases). The average gestational age was 21.9 weeks at evaluation and 23.4 weeks at fMMC repair. Complications included membrane separation (22.9%), preterm premature rupture of membranes (32.3%) and preterm labor (37.5%). Average gestational age at delivery was 34.3 weeks and 54.2% delivered at ≥35 weeks. The perinatal loss rate was 6.1% (2 intrauterine fetal demises and 4 neonatal demises); 90.8% of women delivered at the Children's Hospital of Philadelphia and 3.4% received transfusions. With regard to the neonates, 2 received ventriculoperitoneal shunts prior to discharge; 71.1% of neonates had no evidence of hindbrain herniation on MRI. Of the 80 neonates evaluated, 55% were assigned a functional level of one or more better than the prenatal anatomic level. Conclusion: In an experienced program, maternal and neonatal outcomes for patients undergoing fMMC repair are comparable to results of the MOMS trial.

Twin reversed arterial perfusion sequence: a new method of parabiotic twin mass estimation correlated with pump twin compromise

OBJECTIVES

The purpose of this study was to test the hypothesis that using the formula of a prolate ellipsoid to estimate parabiotic twin mass correlates better with findings of pump twin compromise than using the sonographic method of Moore et al (Am J Obstet Gynecol 1990; 163:907-912).

METHODS

A 10-year retrospective review was performed to identify all cases of the suspected twin reversed arterial perfusion (TRAP) sequence. Parabiotic twin mass was estimated by summing body and extremity volumes calculated using the prolate ellipsoid formula (width × height × length × 0.523). Parabiotic twin mass was also estimated using the sonographic Moore method [1.21 × length(2) - (1.66 × length)]. Parabiotic twin mass estimated by both methods was correlated with sonographic findings associated with increased risk of pump twin compromise.

RESULTS

Fifty-nine pregnancies complicated by TRAP were identified. Using the prolate ellipsoid formula, the parabiotic twin mean sizes ± SD (as a percentage of pump twin weight) were 103.0% ± 52.0% and 56.9% ± 44.3% in cases with and without pump twin compromise (P = .0005), respectively. Using the sonographic Moore method, the mean parabiotic twin sizes were 122.9% ± 54.3% and 99.6% ± 62.8% in cases with and without pump twin compromise (P = .14). The median estimated masses of the parabiotic twin were 197 ± 219 g using the prolate ellipsoid formula and 310 ± 212 g using the sonographic Moore method (P = .0001). A parabiotic twin size greater than 70% of the pump twin correlated with findings associated with increased risk of pump twin compromise when using the prolate ellipsoid formula (P = .002) but not the sonographic Moore method (P = .09).

CONCLUSIONS

Sonographic findings associated with increased risk of pump twin compromise correlate better with prolate ellipsoid estimates of parabiotic twin mass. The median estimated mass of the parabiotic twin was statistically larger when calculated by the sonographic Moore method than by the prolate ellipsoid formula.

Perinatal management of congenital oropharyngeal tumors: the ex utero intrapartum treatment (EXIT) approach

PURPOSE

To present our experience in the perinatal management of fetuses with large oropharyngeal tumors by ex utero intrapartum treatment (EXIT).

METHODS

We performed a retrospective chart review of all patients with congenital oropharyngeal tumor who underwent an EXIT procedure between May 2006 and June 2012.

RESULTS

Four patients were included in the series, three females and one male. The diagnoses were epignathus (n=2) and congenital epulis (n=2). Three EXITs were done at term and one at late preterm due to premature rupture of membranes. Median maternal time under anesthesia was 185 min (range: 166-281) and median maternal operative time was 99 min (range: 85-153). Median maternal blood loss was 550 ml (range: 350-2000); one mother required a blood transfusion. Mean maternal hospital stay was 4 days. Median hysterotomy-to-cord clamp time was 24 min (range: 18-66). Mean fetal birth weight was 2.7 kg (range: 2.4-3). The airway was successfully accessed and secured under placental circulation in all cases. In the two patients with congenital epulis the tumors were resected at the base of their pedicles and the airway accessed via direct laryngoscopy before the umbilical cord was clamped. One patient with epignathus underwent a retrograde tracheal intubation under placental circulation and had the tumor resected thereafter. The second patient with epignathus had a tracheostomy done under placental circulation and then had tumor debulking immediately after the EXIT. The maternal morbidity was minimal and there were no mortalities.

CONCLUSIONS

We conclude that the EXIT procedure is the ideal delivery strategy for fetuses with prenatally diagnosed oropharyngeal tumors and potential airway obstruction at birth. Patients with prenatally diagnosed oropharyngeal tumors should be promptly referred to a fetal treatment center with a dedicated multidisciplinary team and EXIT capabilities.

Sonographic features of rare posterior fetal neck masses of vascular origin

The purpose of this series is to describe the grayscale and color Doppler sonographic characteristics as well as the histopathologic features of rare solid posterior neck masses identified on prenatal sonography in pregnant patients. We conducted a retrospective review of detailed fetal sonographic examinations of second- and third-trimester pregnancies referred to the Center for Fetal Diagnosis and Treatment at the Children's Hospital of Philadelphia for suspected fetal neck masses from June 1998 to December 2011. Eight predominately solid posterior neck masses were identified on 139 studies performed during the study period. Of the 7 cases in which follow-up was available, 6 were confirmed as hemangiomas, and 1 was confirmed as a kaposiform hemangioendothelioma with Kasabach-Merritt syndrome. The most common sonographic features were hypervascularity (7) and calcifications (5). Posterior solid fetal neck masses are rare anomalies. Hemangioma is the most common etiology and should be suggested as the likely diagnosis rather than teratoma, even in the presence of calcifications.

The Garbose Family Special Delivery Unit: a new paradigm for maternal-fetal and neonatal care

Birth defects remain the leading cause of infant mortality in the United States according to the Centers for Disease Control. For many anomalies, etiology remains unknown, management and outcome vary widely, and treatment is costly. Great strides have been made in prenatal diagnosis, yet standardized prenatal care and delivery protocols are needed for women carrying fetuses with specific birth defects such as diaphragmatic hernia, lung lesions, abdominal wall defects, congenital heart disease and so forth. In an effort to standardize and improve the overall care for mother and baby with a known birth defect, the Garbose Family Special Delivery Unit was opened at the Children's Hospital of Philadelphia in June 2008. This paper describes an innovative healthcare delivery model focusing on the rationale for developing a specialized delivery unit, the facility design and development process, care model, team and services, and the types of fetal diagnoses and maternal admission criteria for the SDU.

Ex utero intrapartum treatment in the management of giant cervical teratomas

PURPOSE

The purpose of this study is to present the outcome and technical details of the Ex Utero Intrapartum Treatment (EXIT) procedure performed in the management of the fetus with a giant cervical teratoma.

METHODS

A retrospective review of the medical records of patients undergoing the EXIT procedure between September 1995 and September 2010 was performed.

RESULTS

Eighty-seven EXIT procedures were performed. In 20% of cases (17/87), the indication was giant cervical teratoma. There were 10 females and 7 males. Polyhydramnios was present in 82%. Median gestational age at EXIT was 35 weeks (range, 30-39 weeks). Median birth weight was 2.5 kg (range, 1.7-3.7 kg). Access to the airway under placental support was established in all cases via direct laryngoscopy/bronchoscopy in 8 patients (47%) and via surgical exploration (tracheostomy or retrograde intubation) in 9 patients (53%). The mortality rate under placental support was zero. Seven patients had the tumors resected immediately after the EXIT, 6 patients had the resection later, and 4 patients died before resection. The neonatal mortality rate was 23% (4/17 patients). Patients who died had severe pulmonary hypoplasia that resulted from the upward traction by the giant cervical mass on the airway and compression of the lungs against the thoracic apex.

CONCLUSIONS

We conclude that the EXIT procedure continues to be the optimal delivery strategy for patients with prenatally diagnosed giant cervical teratomas and potential airway obstruction at birth. A thorough evaluation of the prenatal images and an experienced multidisciplinary team are key factors for an effective approach to the obstructed fetal airway.

A randomized trial of prenatal versus postnatal repair of myelomeningocele

BACKGROUND

Prenatal repair of myelomeningocele, the most common form of spina bifida, may result in better neurologic function than repair deferred until after delivery. We compared outcomes of in utero repair with standard postnatal repair.

METHODS

We randomly assigned eligible women to undergo either prenatal surgery before 26 weeks of gestation or standard postnatal repair. One primary outcome was a composite of fetal or neonatal death or the need for placement of a cerebrospinal fluid shunt by the age of 12 months. Another primary outcome at 30 months was a composite of mental development and motor function.

RESULTS

The trial was stopped for efficacy of prenatal surgery after the recruitment of 183 of a planned 200 patients. This report is based on results in 158 patients whose children were evaluated at 12 months. The first primary outcome occurred in 68% of the infants in the prenatal-surgery group and in 98% of those in the postnatal-surgery group (relative risk, 0.70; 97.7% confidence interval [CI], 0.58 to 0.84; P<0.001). Actual rates of shunt placement were 40% in the prenatal-surgery group and 82% in the postnatal-surgery group (relative risk, 0.48; 97.7% CI, 0.36 to 0.64; P<0.001). Prenatal surgery also resulted in improvement in the composite score for mental development and motor function at 30 months (P=0.007) and in improvement in several secondary outcomes, including hindbrain herniation by 12 months and ambulation by 30 months. However, prenatal surgery was associated with an increased risk of preterm delivery and uterine dehiscence at delivery.

CONCLUSIONS

Prenatal surgery for myelomeningocele reduced the need for shunting and improved motor outcomes at 30 months but was associated with maternal and fetal risks. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT00060606.).

The effects of fetal surgery on retinopathy of prematurity development

Background

Fetal surgery is selectively offered for severe or life-threatening fetal malformations. These infants are often born prematurely and are thus at risk for retinopathy of prematurity (ROP). It is not known whether fetal surgery confers an increased risk of developing severe ROP relative to published rates in standard premature populations ≤37 weeks of age grouped by birth weight (<1500 grams or ≥1500 grams).

Design

This is a retrospective chart review.

Methods

We reviewed the charts of 137 patients who underwent open fetal/fetoscopic surgery from 1996–2004. Surgical indications included twin-twin transfusion syndrome (TTTS), myelomeningocele (MMC), congenital diaphragmatic hernia (CDH), sacrococcygeal teratoma (SCT), cystic adenomatoid malformation of the lung (CCAM), and twin reversed arterial perfusion sequence (TRAP). Of these, 17 patients had local ROP examination data. Binomial tests were performed to assess whether rates of ROP in our fetal/fetoscopic surgery cohort were significantly different from published rates.

Results

There were 5 patients each with an underlying diagnosis of TTTS and MMC, 2 patients each with CDH and TRAP, and 1 patient each with SCT, CCAM, and mediastinal teratoma. The mean gestational age at surgery was 23⁴/₇ ± 2³/₇ weeks, mean gestational age at birth was 30 ± 2⁵/₇ weeks, and mean birth weight was 1449 ± 510 grams (610–2485). Compared to published rates of ROP and threshold ROP, our fetal surgery patients had significantly higher rates of ROP and threshold ROP in both the <1500 grams and the ≥1500 grams group (all p-values < 0.05).

Conclusions

Fetal/fetoscopic surgery appears to significantly increase the rate of ROP and threshold ROP development. Greater numbers are needed to confirm these observations.

The response of chickens to experimental infection 'em ovo' with Mycoplasma synoviae

Embryonated chicken eggs were inoculated at 18 days of incubation with a broth culture of Mycoplasma synoviae and the infected chicks were hatched and reared in isolation. Control chicks were hatched following inoculation of eggs with sterile mycoplasma broth. Both groups were closely observed for clinical signs and, at intervals up to 6 weeks infected and control chicks were killed and examined for gross lesions and for isolation of M. synoviae. Four of the 35 infected chicks developed synovitis but there were no other clinical signs. Airsacculitis was encountered in 44% of birds at postmortem examination but M. synoviae was not consistently isolated from affected air sacs. The organism was recovered most frequently from the trachea and lung but sporadic isolations were made from other sites including infraorbital sinus, heart, kidney, liver, spleen and blood. M. synoviae was also isolated consistently from the tracheas of 10 live infected birds until the end of the experiment at 23 weeks. However, the serum plate agglutination test, using a commercial antigen was positive for only half these birds up to ten weeks, and it was not until 15 and 23 weeks that 90% to 100% of the samples were positive.

Outcomes after postnatal resection of prenatally diagnosed asymptomatic cystic lung lesions

BACKGROUND

Symptomatic congenital lung lesions require surgical resection, but the management of asymptomatic lung lesions is controversial. Some surgeons advocate observation because of concerns about potential operative morbidity and mortality, as well as a lack of long-term follow-up information. On the other hand, malignant degeneration, pneumonia, and pneumothorax are known consequences of cystic lung lesions. This study aims to assess the safety of resection for asymptomatic lung lesions that were diagnosed before birth.

METHODS

A retrospective review of all patients with prenatally diagnosed lung lesions at Children's Hospital of Philadelphia (Philadelphia, Penn) was performed from 1996 to 2005. The perioperative course of patients who were asymptomatic was analyzed.

RESULTS

One hundred five complete records of children with asymptomatic lesions were reviewed. Overall mortality was 0% and morbidity was 6.7% including 2.9% significant postoperative air leak and 3.8% transfusion requirement. Nine patients had a pathologic diagnosis that differed from preoperative radiological findings, and 9 patients had additional pathologic findings.

CONCLUSION

This series demonstrates that surgery can be performed safely on patients who were asymptomatic with congenital cystic adenomatoid malformation of the lung and other types of lung lesions with no mortality and minimal morbidity. The frequency of disparate pathologic diagnoses and the potential for development of malignancy and other complications support the argument for early resection.

Liver position and lung-to-head ratio for prediction of extracorporeal membrane oxygenation and survival in isolated left congenital diaphragmatic hernia

OBJECTIVE

The purpose of this study was to determine the ability of liver position and lung-to-head ratio to predict outcome in isolated left congenital diaphragmatic hernia.

STUDY DESIGN

We reviewed prenatal studies and postnatal outcomes of congenital diaphragmatic hernia between January 1996 and January 2006.

RESULTS

Eighty-nine patients received prenatal and postnatal care at 1 institution. In fetuses with liver up, extracorporeal membrane oxygenation was required in 39 of 49 fetuses (80%), compared with 10 of 40 fetuses (25%) for those with liver down (P < .0001). Overall survival rate was 45%, compared with 93% for those with liver down (P < .00005). Low lung-to-head ratio (<1.0) predicted increased incidence of extracorporeal membrane oxygenation (75%; P = .036) and lower survival (35%; P = .0003). However, when measured at <24 weeks of gestation, lung-to-head ratio was not predictive of outcome (extracorporeal membrane oxygenation, P = .108; survival, P = .150); liver position remained highly predictive (extracorporeal membrane oxygenation, P = .006; survival, P = .001).

CONCLUSION

Liver position is the best prenatal predictor of outcome in isolated left congenital diaphragmatic hernia. Lung-to-head ratio alone should not be used to counsel families regarding mid gestational management choices.

Prenatal Diagnosis and Postnatal Management of Diffuse Congenital Hyperinsulinism: A Case Report

We present the first case of the prenatal diagnosis of congenital hyperinsulinism based on the genetic analysis of known family mutations in the SUR1 gene. An amniocentesis was performed at 16 weeks gestation at which time two mutations in the SUR1 gene were identified consistent with the diagnosis of diffuse hyperinsulinism. The mother was transported to our facility and underwent an elective caesarian section at 38 weeks gestation. The diagnosis was confirmed and treatment was initiated within the first minutes of life. After a short course of failed medical management, the patient underwent a 98% pancreatectomy with subsequent good glycemic control. This case highlights the benefits of the timely in utero diagnosis of hyperinsulinism by mutational analysis.

Diagnosis and characterization of fetal sacrococcygeal teratoma with prenatal MRI

OBJECTIVE

The purpose of this study was to determine whether prenatal MRI provides additional information about fetal sacrococcygeal teratoma compared with prenatal sonography.

MATERIALS AND METHODS

Twenty-two pregnant women with fetal sacrococcygeal teratoma underwent prenatal MRI (mean gestational age, 23 weeks). The size, location, mass characteristics, and compressive effects of the tumors were determined and correlated with sonography and postnatal findings.

RESULTS

Based on the MRI findings, the following American Academy of Pediatrics, Surgical Section classifications were assigned: type I in six patients, type II in 12, and type III in four. No type IV tumors were found. The sacrococcygeal teratoma appeared entirely cystic in five fetuses, microcystic in one, mixed cystic and solid in 12, and solid in four. The diagnosis of sacrococcygeal teratoma was accurate in all cases assessed at our center using both MRI and sonography. Two additional patients initially referred with the diagnosis of sacrococcygeal teratoma had a different diagnosis at reevaluation at our institution (healthy, n = 1; myelomeningocele, n = 1). MRI was superior to sonography for detecting displacement of the colon (n = 11), urinary tract dilatation (n = 9), hip dislocation (n = 4), intraspinal extension (n = 2), and vaginal dilation (n = 1). In fetuses with sacrococcygeal teratoma types II and III, MRI better showed the cephalic extent of the tumor compared with sonography. MRI findings were confirmed at surgery or autopsy in all patients. Three fetuses with high output cardiac physiology underwent open fetal resection of the tumor at 21-, 24-, and 26-weeks' gestational age with two surviving.

CONCLUSION

Our results show that ultrafast fetal MRI is a useful adjunct to the prenatal evaluation of fetal sacrococcygeal teratoma. Compared with sonography, MRI more accurately characterized the intrapelvic and abdominal extent of the tumors and provided more information on compression of adjacent organs. The additional anatomic resolution provided by MRI resulted in more accurate prenatal counseling and improved preoperative planning for surgical resection.

Severe pulmonary hypoplasia associated with giant cervical teratomas

BACKGROUND

The use of the ex utero intrapartum treatment (EXIT) procedure has salvaged many fetuses with giant neck masses. Despite an adequate airway, a subset of these patients die from an inability to achieve adequate gas exchange.

METHODS

We reviewed our experience with the EXIT procedure from 1996 to 2004. The EXIT was used to deliver 23 fetuses with giant neck masses.

RESULTS

Three fetuses with giant cervical teratomas died of severe pulmonary hypoplasia. On postmortem, these patients had severe airway distortion by the mass. The carina was retracted superiorly to the first or second rib resulting in compression of the lungs in the apices of the chest and pulmonary hypoplasia. Hypoplasia was reflected in the lung weights of 24 vs 38 g and 17 vs 34 g for age-matched normal lung.

CONCLUSIONS

Unsuspected obstructive fetal neck masses can be fatal because of an inability to secure an airway. Prenatal ultrasonography can identify fetuses at risk, allowing the fetus to be salvaged using the EXIT procedure. Despite obtaining airway control, a subset of these patients will die because of pulmonary hypoplasia. When counseling patients with large cervical masses it is important to discuss potential pulmonary hypoplasia in these patients.

Impact of Continuous Intraoperative Monitoring on Outcomes in Open Fetal Surgery

OBJECTIVES

There are shifts in fetal hemodynamics during open fetal surgery that were not appreciated until the use of intraoperative fetal echocardiography. We have developed an intraoperative monitoring strategy to continuously assess fetal hemodynamics. We hypothesized that this approach would enhance intraoperative management and survival.

METHODS

Medical records of open fetal surgery patients were reviewed since the implementation of this approach. Intraoperative fetal monitoring was accomplished by continuous echocardiography, pulse oximetry, establishment of intravenous access, and arterial blood gas and hemoglobin measurement. Overall survival was compared to fetal surgeries performed prior implementation of this monitoring strategy.

RESULTS

Resections of a congenital cystic adenomatoid malformation or a sacrococcygeal teratoma in nine hydropic fetuses were performed while using this monitoring strategy. Intraoperative echocardiography resulted in a change of management in 7 of 9 fetuses. The main observations on fetal echocardiography resulting in intraoperative intervention were decreased ventricular filling, bradycardia, and decreased ventricular contractility. Therapy included administration of volume expanders and/or inotropic agents. Overall fetal survival was 78% compared to a survival of 42% prior to the implementation of this approach.

CONCLUSION

Continuous intraoperative fetal monitoring provides real time assessment of fetal hemodynamics which results in changes in intraoperative management. The overall outcomes in these critically ill fetuses have been improved.