Evaluation of a rapid optical immunoassay-based test for group B streptococcus colonization in intrapartum patients.

OBJECTIVE: To compare an optical immunoassay (OIA) rapid diagnostic kit to standard culture for the diagnosis of vaginal colonization with group B streptococcus (GBS) and to assess the accuracy and reproducibility of the OIA results. METHOD: A total of 301 patients in labor were prospectively evaluated for GBS colonization with a test approved by the Food and Drug Administration (STREP B OIA kit, Biostar, Boulder, CO, USA) and by culture. The vagina was simultaneously sampled with two swabs. Rectal culture was obtained separately. RESULTS: By the criterion of a positive culture, the vagina was colonized by GBS in 33 of 301 (11%) patients; and the rectum in 42 of 301 (13.9%). The vagina or rectum or both were colonized by CBS in 54 of 301 (17.9%) of patients. The OIA had sensitivity, specificity, positive predictive value and negative predictive value of 63.6%, 86.3%, 37.5% and 94.8%, respectively. The OIA had a kappa statistic score of 0.59. CONCLUSION: The OIA is not an adequately sensitive rapid kit for reliable detection of GBS colonization of the vagina. The results of the OIA were only moderately accurate and reproducible.

Management of burn injuries during pregnancy.

Burns suffered during pregnancy is rare and can be a devastating injury. The presence of a fetus creates many special maternal physiological changes, and the burn wound places additional great stress on systems that are already highly modified. Most of the literature has come from developing countries, and most reports from developed countries have come before 1980 and do not reflect the current standard of care. We have compiled a retrospective review of eight patients burned during pregnancy. The total body surface area (TBSA) burned ranged from 1 to 85% in these patients, and all survived the injury. All patients gave birth to healthy children except the most severely burned patient, whose child suffers from cerebral palsy. Based on our experience as well as a review of the literature, management recommendations are proposed. These include: (1) early pregnancy test for all female patients of childbearing age, (2) prompt and aggressive fluid resuscitation, (3) early supplemental oxygen and low threshold for mechanical ventilatory support, (4) early delivery of the fetus if the pregnancy is in the third trimester, and (5) high suspicion for venous thrombosis and sepsis, with early and aggressive treatment.

Massive fetomaternal hemorrhage and fetal death: are they predictable?

OBJECTIVE: To report the incidence of massive fetomaternal hemorrhage (FMH) associated with fetal death and to test the hypothesis that FMH is more likely to occur in those with risk factors for FMH. STUDY DESIGN: All cases of fetal death of infants weighing > 500 gm between January 1, 1990 and December 31, 1994 were reviewed for evidence of massive FMH (> or = 2% fetal cells in the maternal circulation as measured by the Betke-Kleihauer test). Women with risk factors were compared with those without risk factors with respect to the occurrence of massive FMH. RESULTS: The prevalence of massive FMH was 14 of 319 (4.4%) cases, occurring in 4 of 102 (3.9%) of those with risk factors and 10 of 217 (4.6%) of patients without risk factors (p = 0.78). Otherwise unexplained fetal death was associated with massive FMH in 5 of 141 (3.5%). Major fetal anomalies were present in 5 of 14 (35.7%) cases of massive FMH. CONCLUSION: Clinical risk factors do not predict an increased likelihood of massive FMH. Massive FMH is associated with fetal anomalies. Betke-Kleihauer testing should be performed in all cases of fetal death, including those with anomalies regardless of the presence or absence of risk factors for FMH.

Umbilical arteriovenous PO2 and PCO2 differences and neonatal morbidity in term infants with severe acidosis.

OBJECTIVE: In term infants umbilical cord gas analysis is a poor predictor of immediate newborn complications associated with intrapartum asphyxia, unless the umbilical arterial pH is less than 7.00. We investigated whether umbilical arteriovenous blood gas differences may better predict asphyxia-related complications. STUDY DESIGN: The study population consisted of 82 term, nonanomalous, singleton, live-born infants with severe umbilical acidosis (pH < 7.00). Umbilical arteriovenous pH, PCO2, and PO2 differences were correlated with Apgar scores and the presence of seizures, hypoxic-ischemic encephalopathy, cardiopulmonary and renal dysfunction, and abnormal development in the neonatal period. RESULTS: Umbilical arteriovenous pH, PCO2, and PO2 differences were interrelated (p < 0.0001), but these parameters correlated only weakly with 1-minute and 5-minute Apgar scores. An arteriovenous PCO2 difference > 25 torr was a highly sensitive and specific parameter in identifying asphyxiated infants with seizures, hypoxic-ischemic encephalopathy, cardiopulmonary and renal dysfunction, and abnormal development in the neonatal period. Arteriovenous PO2 differences were less sensitive in the detection of neonatal morbidity than arteriovenous PCO2 differences. CONCLUSION: Umbilical cord blood arteriovenous PCO2 differences provide a new tool to predict neonatal morbidity and permanent neurologic injury in term infants with perinatal asphyxia.

Should the same glucose values be targeted for type 1 as for type 2 diabetics in pregnancy?

OBJECTIVE: Our purpose was to determine whether the same maternal glycemic control is necessary to achieve similar perinatal outcomes for type 1 as for type 2 diabetics. STUDY DESIGN: The subjects were all women with pregestational diabetes mellitus delivered of live-born singletons. Glycemic control was achieved with diet and insulin. Self-monitoring of blood glucose was performed before meals and at bedtime. Target glucose values were 60 to 90 mg/dl fasting and 60 to 105 mg/dl at other times. RESULTS: Of 60,628 deliveries, 46 type 1 and 113 type 2 diabetic women met inclusion criteria. Respective differences were found between type 1 and type 2 diabetics in average daily glucose levels (112 mg/dl vs 97 mg/dl, p < 0.001), percent of values within target ranges (35% vs 57%, p < 0.001), and mean amplitude of glycemic excursion (48.1 mg/dl vs 24.9 mg/dl, p < 0.001). At least one daily glucose value was < 50 mg/dl during 19% of observation days for type 1 vs 2% of observation days for type 2 pregnancies (p < 0.001). There were no statistically significant differences between type 1 and type 2 diabetic pregnancies in neonatal macrosomia (30% vs 34%), proportion of cesarean deliveries during labor for arrest disorders (67% vs 69%), shoulder dystocia (2% vs 6%), and neonatal hypoglycemia (18% vs 26%). CONCLUSIONS: Less stringent maternal glycemic control may permit comparable maternal and neonatal outcomes for type 1 compared with type 2 diabetics. Higher target values for type 1 diabetics may decrease the frequency of maternal hypoglycemic episodes.

The effect of thigh-length support stockings on the hemodynamic response to ambulation in pregnancy.

OBJECTIVE: Our purpose was to determine the effect of thigh-length support stockings on hemodynamic response when pregnant subjects change from the sitting to the lateral recumbent position and then after standing with ambulation. STUDY DESIGN: Eighteen subjects in the late second and early third trimester of pregnancy acted as their own controls. The cardiovascular status of the subjects was assessed by a noninvasive technique--thoracic electrical bioimpedance before and after wearing support stockings for 1 week. Urine catecholamines were measured in 13 patients before and after wearing support stocking to assess the release of catecholamines. Samples were collected after the subjects had been in the lateral recumbent position 40 minutes and again 40 minutes later after standing with ambulation. RESULTS: Heart rate and mean arterial blood pressure decreased significantly when subjects changed from the sitting to the lateral recumbent position and then increased with ambulation. Wearing compression stockings significantly increased mean arterial pressure and afterload in all three positions. Position change from lateral recumbent to standing and ambulation marginally increased urinary dopamine levels (p = 0.097) and significantly increased norepinephrine levels (p = 0.006). CONCLUSIONS: There are significant hemodynamic changes in pregnant subjects when they change from the sitting position to the lateral recumbent position and then change to standing with ambulation. Support stocking have a significant mechanical effect: they significantly increase afterload and systemic vascular resistance by preventing pooling of blood in the lower extremities. There may also be a biochemical effect that results in less catecholamine release. These results suggest that compression stockings could play an important role in supporting the circulation during ambulation.

Amniotic fluid alpha fetoprotein (AFAFP) and maternal serum alpha fetoprotein (MSAFP) in abdominal pregnancies: correlation with extent and site of placental implantation and clinical implications.

The hypotheses are evaluated that in abdominal pregnancies 1) elevated MSAFP is due to an altered maternal-placental interface, and 2) differences in MSAFP levels may reflect placental location within the peritoneal cavity. A review of 1,193 ectopic pregnancies from 1983-1993 identified three cases of advanced abdominal pregnancy. All three had undergone second trimester genetic amniocentesis for amniotic fluid alpha fetoprotein (AFAFP) and karyotype. The clinical course was reviewed (including presentation and surgical findings). MSAFP was elevated in two of the three cases (3.63 and 4.88 MoM). AFAFP and fetal karyotype were normal in all three cases. Elevated MSAFP values were associated with more extensive visceral implantation, longer surgical operative time, greater blood loss and transfusion requirements. Abdominal pregnancies with elevated MSAFP appear to have more extensive placental involvement of the abdominal viscera; this would, in fact, account for the elevated MSAFP values given the normal AFAFP.

Apparent heparin resistance form elevated factor VIII in a patient with postoperative deep venous thrombosis. A case report.

BACKGROUND: During the puerperium, heparin levels, rather than the adjusted partial thromboplastin time test, can be used to identify heparin resistance and guide heparin therapy. CASE: A patient receiving heparin for deep venous thrombosis had artifactual resistance to heparin, with a short adjusted partial thromboplastin time due to elevation of factor VIII. Heparin assay revealed a heparin level above the therapeutic range. CONCLUSION: Direct measurement of heparin concentration and factor VIII activity should be performed when heparin resistance is suspected.

Systemic vascular resistance index determined by thoracic electrical bioimpedance predicts the risk for maternal hypotension during regional anesthesia for cesarean delivery.

OBJECTIVE: Our purpose was to evaluate the predictive value of the baseline systemic vascular resistance index for the development of maternal hypotension during regional anesthesia for cesarean delivery. STUDY DESIGN: Patients receiving a standardized spinal or epidural anesthetic for nonemergency cesarean delivery were studied prospectively. Hemodynamic data were obtained noninvasively with an NCCOM-3 cardiac output monitor (Bomed Medical Manufacturing, Irvine, Calif.), which uses thoracic electrical bioimpedance to estimate stroke volume and cardiac output. Measurements obtained were indexed to body surface area. The systemic vascular resistance index was calculated from mean arterial pressure and thoracic electrical bioimpedance-derived cardiac index. Hemodynamic data obtained were analyzed to identify statistically significant predictors of maternal hypotension. RESULTS: Maternal hypotension occurred in 24 of 42 (57%) patients studied. The incidence of hypotension did not differ between the types of anesthesia: spinal 17 of 274 (62%) versus epidural 7 of 15 (47%, p=0.48). The mean interval to the onset of hypotension was 12.2 minutes (SD 2.2 minutes, range 2 to 24 minutes). Mean (SD) baseline maternal systolic blood pressure was higher in patients who had hypotension (145 torr [4]) than those who did not (129 torr [4], p=0.01). The mean (SD) baseline systemic vascular resistance index was higher in patients who had hypotension (633 [SD 36] dyne . cm . sec-5/m2) than those who did not (454 [SD 29] dyne . cm . sec-5/m2; p =0.001). With receiver-operator characteristic curves, a baseline systemic vascular resistance index of 500 had a sensitivity of 83%, a specificity of 78%, a positive predictive value of 83%, and a negative predictive value of 78% for maternal hypotension (odds ratio 17.5, 95% confidence interval 3.1 to 109.4). A baseline systolic blood pressure of 140 torr had a sensitivity and specificity of 42% and 72%, respectively (odds ratio 1.9, 95% confidence interval 0.4 to 8.8). CONCLUSIONS: Baseline systemic vascular resistance index obtained by noninvasive cardiac output monitoring with thoracic electrical bioimpedance and systolic blood pressure are useful to predict the risk for maternal hypotension with regional anesthesia. Patients with increased baseline systemic vascular resistance index or systolic blood pressure are at increased risk for hypotension.

Hepatitis B virus serology in pregnant women: transmittal of results from obstetricians to pediatricians in California.

From late 1992 to early 1993, in order to assess the knowledge, attitudes and practice patterns of California obstetricians regarding hepatitis B virus screening of pregnant women and how maternal hepatitis B virus serologies are communicated by obstetricians to pediatricians, we mailed questionnaires to a random sample of 801 California obstetricians and 1030 California pediatricians. Response rates were 65.7% (526) for obstetricians and 71% (732) for pediatricians. Although 99.8% of the surveyed obstetricians indicated that they routinely screened all pregnant women for hepatitis B virus, their knowledge of the correct screening tests to order and their interpretation was mixed. Only 56.3% (95% confidence interval, 51.2 to 61.2) were aware of the California law and approximately 12% did not understand that it mandated universal screening of pregnant women. There was a great difference of opinion between obstetricians and pediatricians regarding how to communicate hepatitis B virus serology results on the mother. Forty-nine percent of obstetricians report that they always request the nurse to inform the pediatrician (48.6%), 51.2% always verbally inform the pediatrician, 39.1% always place an order in the mother's chart and 5.7% always send a letter to the pediatrician. In contrast only 12.9% of pediatricians responded that they always received maternal hepatitis B virus serology results from the obstetrical or nursery nurse, only 2.6% always received a verbal communication from the obstetrician, 14.1% always retrieved it from a written report in the mother's chart and 4.2% reported that they always received a letter from the obstetrician. A uniform system should be adopted to ensure efficient transmission of maternal hepatitis B serology results from obstetricians to pediatricians to ensure prompt treatment to prevent vertical transmission of hepatitis B.

Evaluation of lamellar body number density as the initial assessment in a fetal lung maturity test cascade.

The objective of this study was to assess the sensitivity and specificity of lamellar body number density in the prenatal prediction of the respiratory distress syndrome. Seventy consecutive amniotic fluid specimens obtained by amniocentesis within 72 hours of delivery were assessed for lamellar body number density, optical absorbance at 650 nm, lecithin/sphingomyelin ratio and phosphatidylglycerol. A maturity criterion of > or = 46,000/microL for lamellar body number density yielded values for diagnostic sensitivity of 100% (7/7), specificity of 89% (49/55), positive predictive value of 54% (7/13) and negative predictive value of 100% (49/49). These values were also determined for the other analytes, with results similar to those reported elsewhere. Lamellar body number density is an effective and inexpensive first test for the rapid identification of the fetus at high risk for the respiratory distress syndrome. A cascade approach, using lamellar body number density as the first test and optical absorbance at 650 nm as the second test, improves the predictive value as compared to any single test of fetal lung maturity.

Toward universal criteria for gestational diabetes: the 75-gram glucose tolerance test in pregnancy.

OBJECTIVES: The purpose of this study was to determine the distribution of values for the 75 gm glucose tolerance test in pregnancy and to define glucose intolerance by the relationship between maternal glucose values and neonatal macrosomia. STUDY DESIGN: A total 3505 unselected pregnant women were given a 75 gm, 2-hour glucose tolerance test. Diet or insulin therapy was offered only to patients with a fasting plasma glucose level > or = 105 mg/dl or a 2-hour post-glucose-load value > or = 200 mg/dl. Birth weights of live-born singletons delivered from 36 to 42 weeks whose mothers had a fasting plasma glucose level < 105 mg/dl and 2-hour post-glucose-load value < 200 mg/dl were used to calculate relationships between glucose levels and birth weights. RESULTS: At 24 to 28 weeks' gestation the mean and SD plasma glucose values were fasting 83.6 (8.9) mg/dl, 1 hour 128.4 (32.9) mg/dl, and 2 hour 108.4 (24.8) mg/dl. In a multiple logistic regression model the factors found to be statistically significantly associated with macrosomia were maternal race, parity, prepregnancy body mass index, weight gain, gestational age at testing, fasting plasma glucose level, and 2-hour post-glucose-load value. A positive association was found between maternal glucose values and birth weight percentiles. No clinically meaningful glucose threshold values relative to birth weight or macrosomia were found. CONCLUSION: In the absence of a meaningful threshold relationship between glucose tolerance test values and clinical outcome, criteria defining gestational diabetes will probably be established by consensus.

Fetal surveillance. Should it begin at 40 weeks' gestation in a low-risk population?

We evaluated the possible benefits of antepartum surveillance during the 41st week of pregnancy in a low-risk population. Three hundred low-risk patients (study group) underwent a nonstress test (NST) at the beginning of the 41st week of pregnancy. Outcomes in study group patients who delivered during the 41st week were compared to those in 100 similar control patients who were not tested. One antepartum fetal demise occurred in each group: study group rate, 1/300 (0.3%); control group rate, 1/100 (1%), P > .05. During the 41st week, 158 of 300 (53%) study patients and 59 (59%) control patients delivered. Four of 158 (2.5%) study patients had labor induced for the indication of an abnormal antepartum test during the 41st week. Cesarean delivery for distress during the 41st week was performed on 1/157 (0.6%) study and 1/58 (1.7%) control patients (P > .05). No statistically significant improvement in outcome occurred in the study group even though 4 of 300 study group patients required induction of labor for abnormal antepartum testing during the 41st week of gestation. The current practice of not evaluating low-risk pregnancy with an NST until after the completion of 41 weeks is supported by the results of this study.

Pasteurella multocida Bacteremia in a Patient With Ovarian Cancer and Chemotherapy-induced Neutropenia.

BACKGROUND: Pasteurella multocida is a commensal organism found in the saliva and oropharynx of domestic animals. It causes a variety of human infections ranging from cellulitis to bacteremia and sepsis. The severity of infection is somewhat related to the immunocompetency of the infected host. An immunocompromised host is more likely to suffer a disseminated infection as a result of contact with this organism than an immunocompetent host. This case report and review of the literature are presented to further evaluate the types of infections caused by this organism in oncology patients. CASE: A 54-year-old woman with epithelial ovarian cancer and a chemotherapy-induced nadir of her WBC count developed P. multocida bacteremia after she incurred a scratch from her pet cat. She was treated with ceftazidime and then penicillin G with prompt resolution of the bacteremia. CONCLUSION: This paper summarizes an infectious complication that is likely to become more common as chemotherapy-induced neutropenia and pet ownership in the elderly become common coincidences. As such, oncologists and infectious disease physicians should keep this organism in mind when selecting antibiotics to treat the febrile, nadiring cancer patient who has known pet contact.