Amniotic Fluid Embolism Clark, Steven L
Obstetrics and gynecology (New York. 1953),
2014-February, Letnik:
123, Številka:
2, PART 1
Journal Article
Recenzirano
Amniotic fluid embolism remains one of the most devastating conditions in obstetric practice with an incidence of approximately 1 in 40,000 deliveries and a reported mortality rate ranging from 20% ...to 60%. The pathophysiology appears to involve an abnormal maternal response to fetal tissue exposure associated with breaches of the maternal–fetal physiologic barrier during parturition. This response and its subsequent injury appear to involve activation of proinflammatory mediators similar to that seen with the classic systemic inflammatory response syndrome. Progress in our understanding of this syndrome continues to be hampered by a lack of universally acknowledged diagnostic criteria, the clinical similarities of this condition to other types of acute critical maternal illness, and the presence of a broad spectrum of disease severity. Clinical series based on population or administrative databases that do not include individual chart review by individuals with expertise in critical care obstetrics are likely to both overestimate the incidence and underestimate the mortality of this condition by the inclusion of women who did not have amniotic fluid embolism. Data regarding the presence of risk factors for amniotic fluid embolism are inconsistent and contradictory; at present, no putative risk factor has been identified that would justify modification of standard obstetric practice to reduce the risk of this condition. Maternal treatment is primarily supportive, whereas prompt delivery of the mother who has sustained cardiopulmonary arrest is critical for improved newborn outcome.
The evolution of continuous electronic fetal heart rate (FHR) monitoring has presented the obstetrician with a critical clinical conundrum: basic science observations suggest that such monitoring ...might be associated with improved long-term neurologic outcomes, yet, after a half century of use and millions of cesarean deliveries based on FHR monitoring, evidence for such improvement remains absent. This dichotomy appears to be related to widespread misconceptions regarding the physiology underlying various FHR patterns and the developmental origins of cerebral palsy. These misconceptions are strengthened by a reliance on anecdotal experience and tradition in lieu of evidence-based medicine, the confusing "category II" FHR designation, medical-legal considerations, and our tendency to view fetal monitoring, as originally conceptualized, as a single, indivisible entity whose concepts must be accepted or rejected en bloc. Ill-defined and largely imaginary conditions such as "depletion of fetal reserve" are particularly harmful and their use in clinical medicine uniquely not evidence based. A solution to this self-inflicted injury to our specialty will require a concerted effort involving teachers, authors, and researchers.
Abstract Background Despite intensive efforts directed at initial training in fetal heart rate interpretation, continuing medical education, board certification/recertification, team training and the ...development of specific protocols for the management of abnormal fetal heart rate patterns, the goals of consistently preventing hypoxia-induced fetal metabolic acidemia and neurologic injury remain elusive. Objective To validate a recently published algorithm for the management of category II fetal heart rate tracings , examine reasons for the birth of infants with significant metabolic acidemia despite the use of electronic fetal heart rate monitoring and critically examine the limits of EFHRM in the prevention of neonatal metabolic acidemia. Study Design The potential performance of electronic fetal heart rate monitoring (EFHRM) under ideal circumstances was evaluated in an outcomes- blinded examination FHRTs of infants with metabolic acidemia at birth (base deficit > 12) and matched controls (base deficit < 8) under the following conditions: (1) Expert primary interpretation. (2) Use of a published algorithm developed and endorsed by a large group of national experts. (3) Assumption of a 30 minute period of evaluation for non-critical category II FHRTs, followed by delivery within 30 minutes. (4) Evaluation without the need to simultaneously provide patient care. (5) Comparison of results under these circumstances with those achieved in actual clinical practice. Results During the study period, 120 infants were identified with arterial cord blood BD > 12mM/L. Matched controls were not demographically different from subjects. In actual practice, operative intervention on the basis of an abnormal FHRT occurred in 36 of 120 fetuses (30.0%) with metabolic acidemia. Based on expert , algorithm- assisted reviews, 55 of 120 acidemic patients (45.8%) were judged as needing operative intervention for abnormal FHRT. This difference was significant (p=0.016). In infants born with BD > 12mM/L in which blinded, algorithm-assisted expert review indicated the need for operative delivery the decision for delivery would have been made an average of 131 minutes prior to the actual delivery. The rate of expert intervention for FHR concerns in the non-acidemic control group (22/120 =18.3%) was similar to the actual intervention rate (23/120= 19.2%, p =1.0) Expert review did not mandate earlier delivery in 65 of 120 patients with metabolic acidemia. (Table) The primary features of these 65 cases included the occurrence of sentinel events with prolonged deceleration just prior to delivery, rapid deterioration of non-emergent category II FHRTs prior to realistic time frames for recognition and intervention, and the failure of recognized FHR patterns such as variability to identify metabolic acidemia. Conclusions Expert, algorithm-assisted FHR interpretation has the potential to improve standard clinical performance by facilitating significantly earlier recognition of some tracings associated with metabolic acidemia without increasing the rate of operative intervention. However, this improvement is modest. Of infants born with metabolic acidemia, only about one-half could be potentially identified and have delivery expedited even under ideal circumstances which are probably not realistic in current U.S. practice. This represents the limits of EFHRM performance. Additional technologies will be necessary if the goal of preventing neonatal metabolic acidemia is to be realized.
Plasmonic color filtering has provided a range of new techniques for “printing” images at resolutions beyond the diffraction‐limit, significantly improving upon what can be achieved using ...traditional, dye‐based filtering methods. Here, a new approach to high‐density data encoding is demonstrated using full color, dual‐state plasmonic nanopixels, doubling the amount of information that can be stored in a unit‐area. This technique is used to encode two data sets into a single set of pixels for the first time, generating vivid, near‐full sRGB (standard Red Green Blue color space)color images and codes with polarization‐switchable information states. Using a standard optical microscope, the smallest “unit” that can be read relates to 2 × 2 nanopixels (370 nm × 370 nm). As a result, dual‐state nanopixels may prove significant for long‐term, high‐resolution optical image encoding, and counterfeit‐prevention measures.
Using nanostructured metal surfaces to separate discrete colors from white light shows tremendous promise for enabling the next generational leap in image sensors, “printing” techniques, and display technologies. Here, the use of two‐color nanopixels for optical image encoding is explored: employing them as dual‐state nanopixels to generate surfaces encoded with two sets of optical information using just one set of pixels.
Mcl-1 is a member of the Bcl-2 family of proteins that promotes cell survival by preventing induction of apoptosis in many cancers. High expression of Mcl-1 causes tumorigenesis and resistance to ...anticancer therapies highlighting the potential of Mcl-1 inhibitors as anticancer drugs. Here, we describe AZD5991, a rationally designed macrocyclic molecule with high selectivity and affinity for Mcl-1 currently in clinical development. Our studies demonstrate that AZD5991 binds directly to Mcl-1 and induces rapid apoptosis in cancer cells, most notably myeloma and acute myeloid leukemia, by activating the Bak-dependent mitochondrial apoptotic pathway. AZD5991 shows potent antitumor activity in vivo with complete tumor regression in several models of multiple myeloma and acute myeloid leukemia after a single tolerated dose as monotherapy or in combination with bortezomib or venetoclax. Based on these promising data, a Phase I clinical trial has been launched for evaluation of AZD5991 in patients with hematological malignancies (NCT03218683).
Objective The purpose of this study was to examine the efficacy of specific protocols that have been developed in response to a previous analysis of maternal deaths in a large hospital system. We ...also analyzed the theoretic impact of an ideal system of maternal triage and transport on maternal deaths and the relative performance of cause of death determination from chart review compared with a review of discharge coding data. Study Design We conducted a retrospective evaluation of maternal deaths from 2007-2012 after the introduction of disease-specific protocols that were based on 2000-2006 data. Results Our maternal mortality rate was 6.4 of 100,000 births in just >1.2 million deliveries. A policy of universal use of pneumatic compression devices for all women who underwent cesarean delivery resulted in a decrease in postoperative pulmonary embolism deaths from 7 of 458,097 cesarean births to 1 of 465,880 births ( P = .038). A policy that involved automatic and rapid antihypertensive therapy for defined blood pressure thresholds eliminated deaths from in-hospital intracranial hemorrhage and reduced overall deaths from preeclampsia from 15-3 ( P = .02.) From 1-3 deaths were related causally to cesarean delivery. Only 7% of deaths were potentially preventable with an ideal system of admission triage and transport. Cause of death analysis with the use of discharge coding data was correct in 52% of cases. Conclusion Disease-specific protocols are beneficial in the reduction of maternal death because of hypertensive disease and postoperative pulmonary embolism. From 2-6 women die annually in the United States because of cesarean delivery itself. A reduction in deaths from postpartum hemorrhage should be the priority for maternal death prevention efforts in coming years in the United States.
Objective The objective of the study was to compare visually estimated blood loss (vEBL) with calculated estimated blood loss (cEBL) according to mode of delivery and degree of perineal laceration. ...Study Design Pre- and postdelivery hematocrit (HCT) and other variables including vEBL were prospectively recorded into an obstetrical database between January and September 2005. The cEBL was derived by multiplying the calculated pregnancy blood volume (0.75 × {maternal height (inches) × 50 + maternal weight in pounds × 25}) by percent of blood volume lost ({predelivery HCT − postdelivery HCT}/predelivery HCT). cEBL and vEBL were compared according to mode of delivery and degree of perineal laceration. Results There were 677 subjects with complete data. vEBL was statistically different from cEBL between each degree of laceration and between all modes of delivery, demonstrating an underestimation of vEBL with increasing cEBL. Conclusion Improved methods for calculating blood loss include the use of a modified version of the formula used for pregnancy blood volume calculation.
Nonobstetric Surgery During Pregnancy Tolcher, Mary Catherine; Fisher, William E; Clark, Steven L
Obstetrics and gynecology (New York. 1953),
2018-August, Letnik:
132, Številka:
2
Journal Article
Recenzirano
One percent to 2% of pregnant women undergo nonobstetric surgery during pregnancy. Historically, there has been a reluctance to operate on pregnant women based on concerns for teratogenesis, ...pregnancy loss, or preterm birth. However, a careful review of published data suggests four major flaws affecting much of the available literature. Many studies contain outcomes data from past years in which diagnostic testing, surgical technique, and perioperative maternal–fetal care were so different from current experience as to make these data of limited utility today. This issue is further compounded by a tendency to combine experience from vastly disparate types of surgery into a single report. In addition, reports in nonobstetric journals often focus on maternal outcomes and contain insufficient detail regarding perinatal outcomes to allow distinction between complications associated with surgical disease and those attributable to surgery itself. Finally, most series are either uncontrolled or use the general population of pregnant women as controls rather than women with surgical disease who are managed nonsurgically. Consideration of these factors as well as our own extensive experience suggests that when the risks of maternal hypotension or hypoxia are minimal, or can be adequately mitigated, indicated surgery during any trimester does not appear to subject either the mother or fetus to risks significantly beyond those associated with the disease itself or the complications of surgery in nonpregnant individuals. In some cases, reluctance to operate during pregnancy becomes a self-fulfilling prophecy in which delay in surgery contributes to adverse perinatal outcomes traditionally attributed to surgery itself.
Obstetrical hemorrhage remains a leading cause of maternal mortality worldwide. New concepts involving the pathophysiology of hemorrhage have been described and include early activation of both the ...protein C and fibrinolytic pathways. New strategies in hemorrhage treatment include the use of hemostatic resuscitation, although the optimal ratio to administer the various blood products is still unknown. Massive transfusion protocols involve the early utilization of blood products and limit the traditional approach of early massive crystalloid-based resuscitation. The evidence behind hemostatic resuscitation has changed in the last few years, and debate is ongoing regarding optimal transfusion strategies. The use of tranexamic acid, fibrinogen concentrates, and prothrombin complex concentrates has emerged as new potential alternative treatment strategies with improved safety profiles.
Objective We sought to examine etiology and preventability of maternal death and the causal relationship of cesarean delivery to maternal death in a series of approximately 1.5 million deliveries ...between 2000 and 2006. Study Design This was a retrospective medical records extraction of data from all maternal deaths in this time period, augmented when necessary by interviews with involved health care providers. Cause of death, preventability, and causal relationship to mode of delivery were examined. Results Ninety-five maternal deaths occurred in 1,461,270 pregnancies (6.5 per 100,000 pregnancies.) Leading causes of death were complications of preeclampsia, pulmonary thromboembolism, amniotic fluid embolism, obstetric hemorrhage, and cardiac disease. Only 1 death was seen from placenta accreta. Twenty-seven deaths (28%) were deemed preventable (17 by actions of health care personnel and 10 by actions of non-health care personnel). The rate of maternal death causally related to mode of delivery was 0.2 per 100,000 for vaginal birth and 2.2 per 100,0000 for cesarean delivery, suggesting that the number of annual deaths resulting causally from cesarean delivery in the United States is about 20. Conclusion Most maternal deaths are not preventable. Preventable deaths are equally likely to result from actions by nonmedical persons as from provider error. Given the diversity of causes of maternal death, no systematic reduction in maternal death rate in the United States can be expected unless all women undergoing cesarean delivery receive thromboembolism prophylaxis. Such a policy would be expected to eliminate any statistical difference in death rates caused by cesarean and vaginal delivery.
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