Placenta Accreta Spectrum Treatment With Intraoperative Multivessel Embolization: the PASTIME protocol.

BACKGROUND: Multidisciplinary care of placenta accreta spectrum cases improves pregnancy outcomes, but the specific components of such a multidisciplinary collaboration varies between institutions. As experience with placenta accreta spectrum increases, it is crucial to assess new surgical techniques and protocols to help improve maternal outcomes and to advocate for hospital resources. OBJECTIVE: This study aimed to assess a novel multidisciplinary protocol for the treatment of placenta accreta spectrum that comprises cesarean delivery, multivessel uterine embolization, and hysterectomy in a single procedure within a hybrid operative suite. STUDY DESIGN: This was a matched prepost study of placenta accreta spectrum cases managed before (2010-2017) and after implementation of the Placenta Accreta Spectrum Treatment With Intraoperative Multivessel Embolization protocol (2018-2021) at a tertiary medical center. Historical cases were managed with internal iliac artery balloon placement in selected cases with the decision to inflate the balloons intraoperatively at the discretion of the primary surgeon. Intraoperative Embolization cases were compared with historical cases in a 1:2 ratio matched on the basis of placenta accreta spectrum severity and surgical urgency. The primary outcome was a requirement for transfusion with packed red blood cells. Secondary outcomes included estimated surgical blood loss, operative and postoperative complications, procedural time, length of stay, and neonatal outcomes. RESULTS: A total of 15 Placenta Accreta Spectrum Treatment With Intraoperative Multivessel Embolization cases and 30 matched historical cases were included in the analysis. There were no demographic differences noted between the groups. A median (interquartile range) of 0 units (0-2 units) of packed red blood cells were transfused in the Intraoperative Embolization group compared with 2 units (0-4.5 units) in the historical group (P=.045); 5 of 15 (33.3%) Intraoperative Embolization cases required blood transfusions compared with 19 of 30 (63.3%) cases in the historical group (P=.11). The estimated blood loss was significantly less in the Intraoperative Embolization group with a median (interquartile range) of 750 mL (450-1050 mL) compared with 1750 mL (1050-2500 mL) in the historical group (P=.003). There were no cases requiring massive transfusion (≥10 red blood cell units in 24 hours) in the Intraoperative Embolization group compared with 5 of 30 (16.7%) cases in the historical group (P=.15). There were no intraoperative deaths from hemorrhagic shock using the Intraoperative Embolization protocol, whereas this occurred in 2 of the historical cases. The mean duration of the interventional radiology procedure was longer in the Intraoperative Embolization group (67.8 vs 34.1 minutes; P=.002). Intensive care unit admission and postpartum length of stay were similar, and surgical and postoperative complications were not significantly different between the groups. The gestational age and neonatal birthweights were similar; however, the neonatal length of stay was longer in the Intraoperative Embolization group (median duration, 32 days vs 15 days; P=.02) with a trend toward low Apgar scores. Incidence of arterial umbilical cord blood pH <7.2 and respiratory distress syndrome and intubation rates were not statistically different between the groups. CONCLUSION: A multidisciplinary pathway including a single-surgery protocol with multivessel uterine embolization is associated with a decrease in blood transfusion requirements and estimated blood loss with no increase in operative complications. The Placenta Accreta Spectrum Treatment With Intraoperative Multivessel Embolization protocol provides a definitive surgical method that warrants consideration by other centers specializing in placenta accreta spectrum treatment.

Atomic-Scale Analytical Tomography.

The concept of atomic-scale tomography has been proposed in the past decade as a technique that could deliver the position of all atoms with high precision and their elemental (isotopic) identity. The technique was never intended to be limited to merely structural information and there is clearly a rich array of additional analytical information that can be brought to bear on such tomographs. In this paper, some of these types of information are considered and the implications are explored. The fuller realm of this analytical and structural information may be called atomic-scale analytical tomography.

Atomic-scale tomography: a 2020 vision.

Atomic-scale tomography (AST) is defined and its place in microscopy is considered. Arguments are made that AST, as defined, would be the ultimate microscopy. The available pathways for achieving AST are examined and we conclude that atom probe tomography (APT) may be a viable basis for AST on its own and that APT in conjunction with transmission electron microscopy is a likely path as well. Some possible configurations of instrumentation for achieving AST are described. The concept of metaimages is introduced where data from multiple techniques are melded to create synergies in a multidimensional data structure. When coupled with integrated computational materials engineering, structure-properties microscopy is envisioned. The implications of AST for science and technology are explored.

A midwifery-led in-hospital birth center within an academic medical center: successes and challenges.

The University of California San Diego Community Women's Health Program (CWHP) has emerged as a successful and sustainable coexistence model of women's healthcare. The cornerstone of this midwifery practice is California's only in-hospital birth center. Located within the medical center, this unique and physically separate birth center has been the site for more than 4000 births. With 10% cesarean delivery and 98% breast-feeding rates, it is an exceptional example of low-intervention care. Integrating this previously freestanding birth center into an academic center has brought trials of mistrust and ineffectual communication. Education, consistent leadership, and development of multidisciplinary guidelines aided in overcoming these challenges. This collaborative model provides a structure in which residents learn to be respectful consultants and appreciate differences in medical practice. The CWHP and its Birth Center illustrates that through persistence and flexibility a collaborative model of maternity services can flourish and not only positively influence new families but also future generations of providers.

Chemical mapping of mammalian cells by atom probe tomography.

In atom probe tomography (APT), a technique that has been used to determine 3D maps of ion compositions of metals and semiconductors at sub-nanometer resolutions, controlled emissions of ions can be induced from needle-shaped specimens in the vicinity of a strong electric field. Detection of these ions in the plane of a position sensitive detector provides two-dimensional compositional information while the sequence of ion arrival at the detector provides information in the third dimension. Here we explore the use of APT technology for imaging biological specimens. We demonstrate that it is possible to obtain 3D spatial distributions of cellular ions and metabolites from unstained, freeze-dried mammalian cells. Multiple peaks were reliably obtained in the mass spectrum from tips with diameters of ~50 nm and heights of ~200 nm, with mass-to-charge ratios (m/z) ranging from 1 to 80. Peaks at m/z 12, 23, 28 and 39, corresponding to carbon, sodium, carbonyl and potassium ions respectively, showed distinct patterns of spatial distribution within the cell. Our studies establish that APT could become a powerful tool for mapping the sub-cellular distribution of atomic species, such as labeled metabolites, at 3D spatial resolutions as high as ~1 nm.

On the use of simulated field-evaporated specimen apex shapes in atom probe tomography data reconstruction.

The ability to accurately reconstruct original spatial positions of field-evaporated ions emitted from a surface is fundamental to the success of atom probe tomography. As such, a clear understanding of the evolution of specimen shape and the resultant ions' trajectories during field evaporation plays an important role in improving reconstruction accuracy. To further this understanding, field-evaporation simulations of a bilayer specimen composed of two materials having an evaporation field difference of 20% were performed. The simulated field-evaporation patterns qualitatively compare favorably with experimental data, which provides confidence in the accuracy of specimen shapes predicted by the simulation. Correlations of known original atom positions with detector hit positions as a function of lateral detector position and evaporated depth were derived from the simulation. These correlations are contrasted with the current state-of-the-art reconstruction method thus outlining limitations of the current methodology. A pair of transformations are defined that take into account field-evaporated specimen shapes, and the resulting radial magnifications, to relate recorded ion positions in detector space to reconstructed atomic positions in specimen space. This novel process, when applied to simulated data, results in approximately a factor of 2 improvement in accuracy for reconstructions of interfaces with unequal fields (most general interfaces). This method is not constrained by the fundamental assumption of a hemispherical specimen shape.

Exploration of atom probe tomography at sub-10K.

The operating temperature is a critical parameter in atom probe tomography experiments. It affects the spatial precision, mass resolving power and other key aspects of the field-evaporation process. Current commercially available atom probes operate at a minimum temperature of ∼25 K when measured at the specimen. In this paper, we explore and implement changes to the mechanical design of both the LEAPⓇ and EIKOS™ atom probe microscope systems manufactured by CAMECAⓇ to enable a specimen temperature in the sub-10 K regime. We use these modified instruments to analyze four materials systems: pure Al (in both pulsed-voltage and pulsed-laser mode), pure W (pulsed-voltage mode only), doped Si, and GaN (pulsed-laser mode only). The effects of conducting atom probe experiments in the sub-10 K regime were assessed with reference to a range of quantitative analysis metrics related to spatial precision, mass resolving power, stoichiometry and charge-state ratio. We demonstrate that the spatial precision is significantly improved with decreasing temperature, whilst the effect on mass resolving power is relatively minor. The enhanced spatial precision is significant insofar as it enables lattice planes from the doped Si samples to be resolved. Furthermore, mass spectral analysis, lower noise floors and changes in the field evaporation process enabled more accurate GaN compositional measurements. We discuss the significance of these findings for the semiconductor and metallurgical industries and the potential opportunities for further investigations of this parameter space.

Chronic myelocytic leukemia in pregnancy: a case report describing successful treatment using multimodal therapy.

Leukemia during pregnancy is rare, posing a complex series of questions, including appropriate therapy and maternal counseling. Management of chronic myelocytic leukemia (CML) during pregnancy is limited. Our patient presented at 30 weeks' gestation with anemia, leukocytosis, and a non-productive cough. Polymerase chain reaction performed on a peripheral blood sample confirmed presence of the breakpoint cluster region-Abl1 chromosomal translocation and the diagnosis of CML. Therapy included acute leukocytapheresis, followed by α-interferon and imatinib mesylate. The patient responded to treatment and delivered a viable female infant at term weighing 2613 g. Continued imatinib mesylate chemotherapy post-delivery resulted in complete clinical remission. Successful antepartum management of newly diagnosed CML is possible utilizing leukocytapheresis, α-interferon and, more recently, imatinib mesylate. Definitive treatment should not be delayed due to pregnancy.

Kinetic-energy discrimination for atom probe tomography.

The benefits of using kinetic-energy information to aid ion discrimination in atom probe tomography (APT) are explored. Ion peak interferences in time-of-flight (TOF) mass spectra are categorized by difficulty of discrimination using TOF and kinetic-energy information. Several of these categories, which are intractable interferences when only TOF information is available, may be discriminated when kinetic-energy information also is available. Furthermore, many opportunities for removing noise from composition determinations and three-dimensional images are enabled. Modest kinetic-energy resolving powers (KRPs) of 10 or so should be sufficient to have a major impact on APT. With KRP of about 100, the energy deficits in voltage pulsing may be resolved to enable peak discrimination in straight-flight-path instruments. Real examples and simulated mass spectra are used to illustrate the benefits of kinetic-energy discrimination. Many of the conclusions are applicable generally in TOF spectroscopy. Current detectors do not provide the kinetic energy of incoming ions, but there are realistic prospects for building such detectors and these are discussed. A program to develop these detectors should be pursued.

Atomic-scale phase composition through multivariate statistical analysis of atom probe tomography data.

We demonstrate for the first time that multivariate statistical analysis techniques can be applied to atom probe tomography data to estimate the chemical composition of a sample at the full spatial resolution of the atom probe in three dimensions. Whereas the raw atom probe data provide the specific identity of an atom at a precise location, the multivariate results can be interpreted in terms of the probabilities that an atom representing a particular chemical phase is situated there. When aggregated to the size scale of a single atom (∼0.2 nm), atom probe spectral-image datasets are huge and extremely sparse. In fact, the average spectrum will have somewhat less than one total count per spectrum due to imperfect detection efficiency. These conditions, under which the variance in the data is completely dominated by counting noise, test the limits of multivariate analysis, and an extensive discussion of how to extract the chemical information is presented. Efficient numerical approaches to performing principal component analysis (PCA) on these datasets, which may number hundreds of millions of individual spectra, are put forward, and it is shown that PCA can be computed in a few seconds on a typical laptop computer.

The Laplace Project: An integrated suite for preparing and transferring atom probe samples under cryogenic and UHV conditions.

We present sample transfer instrumentation and integrated protocols for the preparation and atom probe characterization of environmentally-sensitive materials. Ultra-high vacuum cryogenic suitcases allow specimen transfer between preparation, processing and several imaging platforms without exposure to atmospheric contamination. For expedient transfers, we installed a fast-docking station equipped with a cryogenic pump upon three systems; two atom probes, a scanning electron microscope / Xe-plasma focused ion beam and a N2-atmosphere glovebox. We also installed a plasma FIB with a solid-state cooling stage to reduce beam damage and contamination, through reducing chemical activity and with the cryogenic components as passive cryogenic traps. We demonstrate the efficacy of the new laboratory protocols by the successful preparation and transfer of two highly contamination- and temperature-sensitive samples-water and ice. Analysing pure magnesium atom probe data, we show that surface oxidation can be effectively suppressed using an entirely cryogenic protocol (during specimen preparation and during transfer). Starting with the cryogenically-cooled plasma FIB, we also prepared and transferred frozen ice samples while avoiding significant melting or sublimation, suggesting that we may be able to measure the nanostructure of other normally-liquid or soft materials. Isolated cryogenic protocols within the N2 glove box demonstrate the absence of ice condensation suggesting that environmental control can commence from fabrication until atom probe analysis.

Invited review article: Atom probe tomography.

The technique of atom probe tomography (APT) is reviewed with an emphasis on illustrating what is possible with the technique both now and in the future. APT delivers the highest spatial resolution (sub-0.3-nm) three-dimensional compositional information of any microscopy technique. Recently, APT has changed dramatically with new hardware configurations that greatly simplify the technique and improve the rate of data acquisition. In addition, new methods have been developed to fabricate suitable specimens from new classes of materials. Applications of APT have expanded from structural metals and alloys to thin multilayer films on planar substrates, dielectric films, semiconducting structures and devices, and ceramic materials. This trend toward a broader range of materials and applications is likely to continue.

Incidence of wound complications after cesarean delivery: is suture closure better?

BACKGROUND: Wound complications (WC) following cesarean delivery (CD) result in significant morbidity. A randomized trial in 2013, which demonstrated lower WC rates with suture closure compared to staple closure, resulted in a practice change within our academic institution. OBJECTIVE: To determine the impact of this practice change on WC rates and identify other modifiable risk factors for WC. STUDY DESIGN: This is a retrospective cohort study of all women undergoing CD at the University of California, San Diego between 1 March 2011 and 28 February 2012 (primarily staple) and 1 March 2013 and 28 February 2014 (primarily suture). WC rates were compared between the two time intervals using Chi-square and Student's t-tests. Risk factors (OR, 95%CI) for WC were assessed using multiple logistic regression modeling. RESULTS: Of 1580 women delivered by CD, rates of WC were higher with staple closure compared to sutures (10.1% versus 4.5%; OR 2.4, 1.4-4.1). Additionally, WC were more likely with vertical skin incisions (OR 3.6, 1.6-8.1), CD for failed labor (OR 2.9, 1.1-7.4) and diabetes (OR 2.1, 1.4-3.9). CONCLUSIONS: After adjusting for confounders, there were over twofold increased odds of WC with staple closure. Vertical incisions, failed labor and diabetes also contributed to WC. Suture closure appears to decrease the risks of WC post CD.

Effect of predelivery diagnosis in 99 consecutive cases of placenta accreta.

OBJECTIVE: To estimate the effects of prenatal diagnosis and delivery planning on outcomes in patients with placenta accreta. METHODS: A review was performed of all patients with pathologically confirmed placenta accreta at the University of California, San Diego Medical Center from January 1990 to April 2008. Cases were divided into those with and without predelivery diagnosis of placenta accreta. Patients with prenatal diagnosis of placenta accreta were scheduled for planned en bloc hysterectomy without removal of the placenta at 34-35 weeks of gestation after betamethasone administration. Maternal and neonatal outcomes were assessed. RESULTS: Ninety-nine women with placenta accreta were identified, of whom 62 were diagnosed before delivery and 37 were diagnosed intrapartum. Comparing women with predelivery diagnosis with those diagnosed at the time of delivery, there were fewer units of packed red blood cells transfused (4.7+/-2.2 compared with 6.9+/-1.8 units, P=.02) and a lower estimated blood loss (2,344+/-1.7 compared with 2,951+/-1.8 mL, P=.053), although this trend did not reach statistical significance. Comparison of neonatal outcomes demonstrated a higher rate of steroid administration (65% compared with 16%, P

Advances in pulsed-laser atom probe: instrument and specimen design for optimum performance.

The performance of the pulsed-laser atom probe can be limited by both instrument and specimen factors. The experiments described in this article were designed to identify these factors so as to provide direction for further instrument and specimen development. Good agreement between voltage-pulsed and laser-pulsed data is found when the effective pulse fraction is less than 0.2 for pulsed-laser mode. Under the conditions reported in this article, the thermal tails of the peaks in the mass spectra did not show any significant change when produced with either a 10-ps or a 120-fs pulsed-laser source. Mass resolving power generally improves as the laser spot size and laser wavelength are decreased and as the specimen tip radius, specimen taper angle, and thermal diffusivity of the specimen material are increased. However, it is shown that two of the materials used in this study, aluminum and stainless steel, depend on these factors differently. A one-dimensional heat flow model is explored to explain these differences. The model correctly predicts the behavior of the aluminum samples, but breaks down for the stainless steel samples when the tip radius is large. A more accurate three-dimensional model is needed to overcome these discrepancies.