Diagnostic accuracy of a rapid diagnostic test for the early detection of COVID-19.

OBJECTIVES: This study was undertaken to evaluate the diagnostic performance of the BinaxNOW COVID-19 Ag Card rapid antigen assay (Abbott; Chicago, IL, USA) in the detection of COVID-19 infection compared to the reference standard of PCR testing. METHODS: We evaluated the BinaxNOW COVID-19 Ag Card rapid antigen assay relative to a standard reference PCR test. We tested 3810 nasal swabs from symptomatic and asymptomatic adults undergoing surveillance COVID-19 testing at Howard University using one swab for each nostril. One swab was tested using the rapid antigen assay and the other using the PCR test. RESULTS: The sensitivity of the BinaxNOW COVID-19 Ag Card rapid antigen assay was 91.84% (95% confidence interval (CI): 80.40-97.73%) and the specificity was 99.95% (95% CI: 99.81-99.99%). The range of Ct values for the N gene was 10.74-34.90 (M = 26.88, SD=4.86). Fourteen (28.6%) samples had an N gene Ct value > 30. The average N gene Ct value for rapid test negative (i.e. false negative) samples was 31.92. CONCLUSIONS: The sensitivity of the test in our symptomatic and asymptomatic cohort was lower than the manufacturer's reported sensitivity in a symptomatic cohort (97.1%). Despite their relatively lower sensitivity (especially in asymptomatic individuals), rapid tests have undeniable benefits (i.e., ease of use and rapid results) that make them a helpful tool in the control of the SARS-CoV-2 pandemic. Given the diagnostic accuracy of these tests as evidenced by this study, rapid tests can be thoughtfully employed in situations where swift results are critical.

Acute respiratory failure in pregnancy.

The maternal respiratory tract undergoes significant anatomic and physiologic changes during pregnancy, which increase maternal susceptibility to respiratory failure. Respiratory failure in pregnancy is relatively rare, but it remains one of the leading conditions requiring intensive care unit admission in pregnancy and carries a high risk of maternal and fetal morbidity and mortality. Acute respiratory failure can result from a variety of conditions, most of which are not pulmonary in origin. Early diagnosis of underlying disease is critical, as it will guide the management approach. Treatment goals during respiratory failure in the pregnant woman are similar to those outside of pregnancy-to maintain adequate ventilation and to provide hemodynamic and nutritional support. Additionally, the obstetrician will need to monitor fetal status and help to determine the best timing for delivery.

Chronic hypoxia differentially increases glutathione content and gamma-glutamyl cysteine synthetase expression in fetal guinea pig organs.

OBJECTIVE: Glutathione is a natural antioxidant in the fetus and adult. We sought to determine whether maternal hypoxia alters glutathione levels in fetal organs as an adaptive response to the reduced oxygenation. STUDY DESIGN: Timed pregnant guinea pigs were housed in either a Plexiglas chamber containing 10.5% O(2) from 46 to 60 days gestation (HPX, n=6) or in room air, as the normoxic control (NMX, n=5). Pregnant guinea pigs were anesthetized at near term ( approximately 60 days, term=65 days) and liver, lungand kidney were excised from anesthetized fetuses and stored frozen (-80 degrees C) prior to sample processing. Using the hypoxia marker, pimonidazole, we measured a hypoxia-induced increase in stained cells of fetal liver compared to no change in either the lung or kidney. To measure the effect of hypoxia among different organs, total glutathione (GSH) content and protein levels of gamma-glutamyl cysteine synthetase (gamma-GCS) were measured from the same organs. RESULTS: Maternal hypoxia increased (P<0.05) total glutathione levels by 121% in the fetal liver but had no effect in either fetal lung or kidney. Chronic hypoxia increased (P<0.05) gamma-GCS protein levels in all three fetal organs studied. CONCLUSION: These results demonstrate that the fetal response to maternal hypoxia may be organ specific. The increase in fetal liver glutathione via upregulation of gamma-GCS may be an important adaptive response to prolonged hypoxic stress.

Analysis of disease in the obstetric intensive care unit at a university referral center: a 24-month review of prospective data.

OBJECTIVE: To determine the current spectrum of disease in an obstetric population resulting in admission to the intensive care unit (ICU) at a tertiary care hospital. STUDY DESIGN: Analysis of data from obstetric patients admitted for critical care management at the University of Maryland Medical Center over a 24-month period. RESULTS: Critical care admission was required for 34 (1.3%) of 2,565 women admitted for deliveries; 38.5% of patients were delivered during their ICU admission. Preexisting medical conditions were present in 67.6% (76.5% were in the antenatal period vs. 23.5% in the postpartum period). Conditions leading to ICU admission included organ system failure, respiratory failure, central nervous system disease, cardiac failure, preeclampsia and postpartum hemorrhage. The median Acute Physiology and Chronic Health Evaluation II (APACHE II) score overall was 11.0 (antenatal 12.0, postpartum 10.5). Although the predicted maternal mortality rate was 12.9% (14.6% in the antenatal period and 12.1% in the postpartum period), the actual mortality rate was 0%. CONCLUSION: In this population, the antenatal period now accounts for the majority of ICU admissions. Respiratory failure (mainly from infectious etiologies) has surpassed obstetric hemorrhage as the primary reason for ICU admission. Finally, the APACHE II scoring system is inaccurate for use in an obstetric population.

Gravid hysterectomy: a decade of experience at an academic referral center.

OBJECTIVE: To evaluate the incidence of gravid hysterectomy (GH) and to examine the indications as well as risk factors and complications associated with the procedure at an academic perinatal referral center. STUDY DESIGN: Retrospective chart review of all patients who underwent GH from 1991 to 2001. Demographics, obstetric history, delivery information, complications and outcome were analyzed. RESULTS: There were 34 GHs out of 19,491 deliveries (1.74/1000). The preoperative indications were hemorrhage associated with atony (32.4%), placenta accreta (20.6%) and uncontrolled bleeding (17.6%). Of the patients, 87.5% were parous and 53.1% had previous cesarean section. GH was performed prior to viability in 3. GH followed cesarean delivery in 24 (68.6%). Uterine and/or hypogastric artery ligation were performed in 11 (32.4%). Postoperative complications included surgical re-exploration for recurrent hemorrhage in 5, transfusion of blood products in 30, disseminated intravascular coagulopathy in 15, prolonged (> 24 hours) ventilation in 10 and admission to the SICU for prolonged intensive care in 12. There were 2 maternal deaths (5.9%). A significant rise in GH rate from 1/800 to 1/299 occurred over the past 5 years despite constant cesarean rates (chi2, p < 0.05). CONCLUSION: Rates of GH increased over the period examined. Placenta accreta associated with previous cesarean section is the predominant risk factor for GH.

Shoulder dystocia: using simulation to train providers and teams.

Shoulder dystocia is an obstetric emergency that requires immediate recognition and a well-coordinated response. This response must include effective application of the maneuvers proven to relieve the impaction of the fetal shoulder and timely hand-off of the newborn to the neonatology team. The rare frequency of shoulder dystocia, coupled with patient safety concerns and the medico-legal environment, limits the opportunity of providers to learn and practice the management of shoulder dystocia. Training, especially simulation-based training, has been demonstrated to improve the management of shoulder dystocia. This article presents a review of the literature that supports simulation training for shoulder dystocia and provides guidance on creating and implementing shoulder dystocia training.

Obesity and pregnancy complications.

Maternal obesity increases the risk of numerous complications of pregnancy, labor, and birth for both mother and neonate, including diabetes and hypertensive disorders. As more women enter pregnancy with a body mass index (BMI) indicative of overweight or obesity, providers of obstetric care should be aware of the implications of this increased BMI on perinatal outcomes as well as become familiar with management options.

Kleihauer-betke testing is important in all cases of maternal trauma.

BACKGROUND: In maternal trauma, the Kleihauer-Betke (KB) test has traditionally been used to detect transplacental hemorrhage (TPH), so that Rh-negative women could receive appropriate Rh immune prophylaxis. Reasoning that the magnitude of TPH would reflect uterine injury, we evaluated Kleihauer-Betke testing as an independent predictor of preterm labor (PTL) after maternal trauma. METHODS: Admissions to the Shock Trauma Center, University of Maryland, from January 1996 to January 2002, were reviewed. Of 30,362 trauma patients admitted, 166 were pregnant, and 93 of these underwent electronic fetal monitoring. Their records were abstracted for demographics, injury type, three separate trauma scores, documented uterine contractions, PTL (contractions with progressive cervical change), and serious perinatal complications. In 71 cases, transplacental hemorrhage was assessed by maternal KB test. RESULTS: TPH, defined as KB-positive for greater than 0.01 mL of fetal blood in the maternal circulation, occurred in 46 women. Forty-four had documented contractions (25 had overt PTL) and 2 had no contractions. In 25 women with a negative KB test, none had uterine contractions. All patients with contractions or PTL had positive KB tests. By logistic regression, KB test result was the single risk factor associated with PTL (p < 0.001; likelihood ratio, 20.8 for positive KB test). Compared with other sites, abdominal trauma was associated more often with uterine contractions (p < 0.001), PTL (p = 0.001), and a positive KB test (p < 0.001, chi). None of the trauma scoring systems predicted PTL. CONCLUSION: Kleihauer-Betke testing accurately predicts the risk of preterm labor after maternal trauma. Clinical assessment does not. With a negative KB test, posttrauma electronic fetal monitoring duration may be limited safely. With a positive KB test, the significant risk of PTL mandates detailed monitoring. KB testing has important advantages to all maternal trauma victims, regardless of Rh status.