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Biomedical subjects

A Ohlsson

Publications and source records attributed to A Ohlsson.

At least 127 records · Page 7Linked to original sources
PubMed1994

Intrapartum chemoprophylaxis of perinatal group B streptococcal infections: a critical review of randomized controlled trials.

The purpose of this overview was to critically appraise all published randomized, controlled trials evaluating the efficacy of intrapartum chemoprophylaxis in reducing perinatal group B streptococcal infections. The Oxford Database of Perinatal Trials, Medline, Excerpta Medica, and personal files were used for the literature search. By means of present inclusion criteria to select relevant articles, two independent researchers identified nine randomized, controlled trials. Three trials were excluded because of duplicate publication, one because the randomization process was violated, and one because the outcome data were collected retrospectively. The quality of the methods of the four accepted trials was poor, and because of basic flaws meta-analyses of trial results were not performed. Results of three studies showed a statistically significant reduction in neonatal group B streptococcal colonization rates with intrapartum chemoprophylaxis. Although a trend toward a reduction in proved neonatal infection was reported in three studies, each lacked the power to reach statistical significance. Intrapartum chemoprophylaxis to reduce perinatal group B streptococcal infections is not supported by conclusive evidence from well designed and conducted randomized, controlled trials.

Bacteremia↗
PubMed1994

Systematic reviews--theory and practice.

The consumer of health care services experts that medical practice is based on scientific evidence with regard to efficacy and effectiveness. Randomized controlled trials provide the most valid basis for comparison of interventions in health care and offer the most reliable information to guide clinical practice. The need for well-designed and performed systematic reviews of the available information to address a specific clinical question should be obvious both to the practicing clinician and the consumer. A systematic review is defined as "the application of scientific strategies that limits bias to the systematic assembly, critical appraisal, and synthesis of all relevant studies on a specific topic". "Meta-analysis (quantitative overview) is a systematic review that employs statistical methods to combine and summarize the results of several trials". In a meta-analysis the individual studies are weighted according to the inverse of the variance; that is more weight is given to studies with more events. The pooling of data allows for an increase in power and thus a more precise estimate of the effect size. Systematic reviews that meet explicit criteria for validity offer the reader information that as a rule is less biased than the unstructured overview which has traditionally been performed by one or several experts in a specific content area. Recently statistical methods have been developed to summarize data from studies of diagnostic tests. Cumulative meta-analyses offer the caregiver and the health-care consumer with answers regarding the effectiveness of a certain intervention at the earliest possible date in time.

Humans↗
PubMed1993

A randomized, controlled trial of platelet transfusions in thrombocytopenic premature infants.

A multicenter prospective, randomized controlled trial was conducted to determine whether early use of platelet concentrates would reduce the incidence or extension of intracranial hemorrhage or both in sick preterm infants with thrombocytopenia. The effects on bleeding as reflected by the amount of blood product support administered and a shortened bleeding time were assessed as secondary outcomes. Premature infants with a platelet count < 150 x 10(9)/L within the first 72 hours of life were randomly assigned to receive either conventional therapy or conventional therapy plus platelet concentrates (10 ml/kg). The platelet count was maintained < 150 x 10(9)/L until day 7 of life by one to three platelet transfusions. In 22 (28%) of the 78 treated infants and 19 (26%) of the 74 control infants, either a new intracranial hemorrhage developed or an already-present one became more extensive (p = 0.73). Similar numbers of infants had each grade of intracranial hemorrhage on both initial and follow-up ultrasonography. Similar numbers of infants received fresh frozen plasma and packed red blood cells, but treated infants received less of both. The bleeding time was prolonged in the treated group before the infusion of platelet concentrates but subsequently shortened (mean difference, 79.0; 95% confidence interval, 73.1 to 84.9). Subanalysis of the control group showed that infants with platelet counts < 60 x 10(9)/L (n = 21) on at least one occasion received more fresh frozen plasma and packed red blood cells than did those with platelet counts > 60 x 10(9)/L.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Component Transfusion↗
PubMed1993

Leukocyte counts and colonization with Ureaplasma urealyticum in preterm neonates.

In this paper we review the literature, present previously unpublished case reports for a pair of twins, and provide data from two prospective cohort studies to determine whether nasopharyngeal and/or endotracheal colonization with Ureaplasma urealyticum in preterm neonates is associated with an elevated white blood cell (WBC) count. We observed an association between colonization of the respiratory tract and elevation in the WBC count caused by an increase in the number of mature and immature neutrophils. Such a response indicates that U. urealyticum is capable of eliciting an inflammatory reaction and may be a true pathogen in the neonate. If these increases in the WBC count are confirmed, the WBC count may be a useful marker in future trials of interventions directed at U. urealyticum.

Cohort Studies↗
PubMed1993

Perinatal clinical epidemiology.

A literature search of personal files, the Oxford Database of Perinatal Trials, Medline, and the Research Update databases, identified 19 perinatal trials published between October 1991 and September 1992. Included were only those trials in which the efficacy or effectiveness of an antenatal intervention was assessed by a neonatal outcome. A quality assessment of each study was performed. Quality scores ranged from 0.25 to 0.80 (maximum possible score, 1.00). Most trials did not show a statistically significant change in the primary outcome measure, because of an overestimate of the treatment effect on which the sample size had been based. Thus, clinically important treatment effects often may be overlooked. None of these trials on their own showed beyond doubt whether the intervention under study did more good than harm. There is a need to base sample size calculations on more realistic, but still clinically important, event rate differences to show the effectiveness of perinatal interventions aimed at improving neonatal outcomes. To do so usually requires a large sample size, necessitating multicenter trials with national and international cooperation.

Female↗
PubMed1993

Effect of indomethacin on cerebral blood flow velocities in very low birth weight neonates with a patent ductus arteriosus.

The effect of repeated doses of indomethacin on mean peak velocity (MPV) and time-averaged mean velocity in the middle cerebral artery was assessed in 10 ventilated neonates with a patent ductus arteriosus using colour/duplex Doppler technique prior to, and 10, 30, and 120 min after the first and the third dose. Velocities were significantly reduced up to 120 min after the first dose. The third dose resulted in a significant reduction in MPV at 10 and 30 min following treatment. This reduction was half of that observed after the first dose. Systemic blood pressure (BP) and heart rate did not change significantly after each separate dose. However, by the third dose, mean and diastolic BP were significantly increased from pretreatment levels. The attenuated response of cerebral blood flow (CBF) velocities to the third dose of indomethacin compared with the first dose is probably related to altered haemodynamics. Indomethacin should be used cautiously in infants with other conditions which are known to decrease CBF such as hypotension, hypocarbia and polycythaemia.

Blood Flow Velocity↗
PubMed1992

Randomized controlled trial of dexamethasone treatment in very-low-birth-weight infants with ventilator-dependent chronic lung disease.

This randomized controlled trial was designed to answer the question: does administration of dexamethasone to neonates with bronchopulmonary dysplasia decrease the need for assisted ventilation? Twenty-five infants with a birth weight < 1501 g, requiring mechanical ventilation and FiO2 of > or = 0.30 at 21-35 days of age, were randomized to treatment with iv dexamethasone or to sham injections for 12 days. The primary outcome criterion was extubation within seven days after study entry. Treatment (n = 12) and control (n = 13) groups were well matched at entry. Dexamethasone facilitated weaning from assisted ventilation (p = 0.0154). There was no increased incidence of infection. Dexamethasone treatment resulted in a significant increase in glucosuria (p = 0.0002) and in systolic blood pressure (p = 0.0034). There was a significant decrease in heart rate (p = 0.0001) and a significant weight loss (p = 0.0002) following dexamethasone treatment. Dexamethasone treatment facilitated weaning from assisted ventilation but several systemic effects were noted that deserve further evaluation before dexamethasone becomes routine treatment.

Blood Pressure↗
PubMed1991

Cerebral-blood-flow-velocity measurements in neonates: technique and interobserver reliability.

The interobserver reliability for absolute cerebral-blood-flow-velocity measurements by colour and duplex Doppler sonography was tested in 32 neonates with a mean birth weight of 1489 (SD 644) g, and a gestational age of 29.9 (SD 3.5) weeks. Using standardized technique, two observers recorded on videotape, the Doppler spectrum of the anterior cerebral artery, the intracranial internal carotid artery and the middle cerebral artery. Peak systolic flow, end diastolic flow, mean flow velocity, resistive index and pulsatility index were computed from 3 consecutive waveforms by each observer. The estimates of interobserver reliability using the intraclass correlation coefficient of the examiners varied from 0.95 to 1.00. Therefore, cerebral blood flow velocity can be reliably measured in premature infants.

Blood Flow Velocity↗
PubMed1991

Can the nonstress test predict congenital sepsis?

The possible role of the nonstress test (NST) in the prediction of congenital sepsis in pregnancies complicated by prolonged premature rupture of the membranes (PROM) was investigated in a retrospective controlled study. Thirteen NSTs performed within 24 hours of the delivery of infants with congenital sepsis were coded, blinded, and mixed with an equal number of blinded NSTs derived from randomly selected patients matched for gestational age with PROM but without neonatal or maternal infection. Eleven of 13 infants with congenital sepsis had a reactive NST, and two had a nonreactive test. Among the controls, there were also 11 reactive and two nonreactive NSTs. The sensitivity and specificity of the NST in predicting congenital sepsis in patients with PROM were 15.4% and 84.6%, respectively. The positive predictive value and the negative predictive value were 50%. Our results suggest that the NST is not a useful tool for prediction of congenital sepsis.

Case-Control Studies↗
PubMed1991

Prediction of lethal pulmonary hypoplasia and chorioamnionitis by assessment of fetal breathing.

Twenty-three pregnancies with fetuses at risk for pulmonary hypoplasia were studied weekly until delivery. The amount of time spent in fetal breathing activity was recorded under controlled conditions during 1 h using real-time ultrasound. An amniotic fluid index was determined. The clinicians and the pathologist were unaware of the ultrasound findings. Eight of 23 fetuses did not breathe at the last ultrasound examination. Three babies died of pulmonary hypoplasia and two of these showed fetal breathing before birth. The three deaths were associated with rupture of the membranes at less than or equal to 20 weeks gestation and of greater than or equal to 44 days duration. One infant developed bronchopulmonary dysplasia. The amniotic fluid index in these four pregnancies was low and the newborn infants had limb contractures. Chorioamnionitis/funisitis was noted in 13 placentas. Eight fetuses were assessed for fetal breathing within 2 days of birth. The lack of fetal breathing had sensitivity, specificity, positive and negative predictive values of 0.75 for chorioamnionitis/funisitis. In this pilot study the absence of fetal breathing was of no value in predicting lethal pulmonary hypoplasia, but was related to chorioamnionitis/funisitis. We recommend further studies of fetal breathing in relation to fetal/neonatal infections.

Chorioamnionitis↗
PubMed1991

The effect of aminophylline on the excursions of the diaphragm in preterm neonates. A randomized double-blind controlled study.

Aminophylline is used to treat apnoea and to facilitate weaning from assisted ventilation in preterm infants. Aminophylline is thought to increase respiratory drive centrally. We performed a randomized controlled double-blind study to determine if aminophylline increases the excursions of the diaphragm indicating a possible direct peripheral effect. Twenty-two neonates were randomized to treatment with intravenous aminophylline (n = 11) or to no treatment (n = 11). An ultrasonographer, who was blinded to the group assignment, studied the diaphragmatic excursions using a real time sector scanner. The posterior one-third of the right hemidiaphragm was localized and M-mode was used to record the diaphragmatic excursions on paper. The neonates were studied in an awake but quiet state. Aminophylline resulted in an increase (43%) in the excursions of the diaphragm (p = 0.012) with no change in respiratory rate or pCO2. These findings indicate that aminophylline had a measurable effect on the diaphragmatic motion. Further studies combining this technique with other techniques are needed to determine if the main effect of aminophylline in the prevention of apnoea is mainly central or peripheral.

Aminophylline↗
PubMed1991

Factor XII deficiency and pregnancy.

A 19-year-old primigravida with known factor XII deficiency (prepregnant factor XII level of 21%) presented with placental abruption and preterm labor at 26 weeks' gestation. A healthy 925-g female infant was born by spontaneous vaginal delivery. The mother had no postpartum hemorrhage or further complications, and the infant demonstrated no intracranial or other forms of hemorrhage up to 70 days of age. The infant's factor XII level was 34% (normal for her age). There are only two previous reports of factor XII deficiency in pregnancy cited in the English literature, and both were uncomplicated. In view of the risk of thromboembolic complications in nonpregnant individuals with factor XII deficiency, pregnant women with a prolonged activated partial thromboplastin time and no lupus anticoagulant or anticardiolipin antibody syndrome should also be investigated for deficiencies of factors VIII, IX, and XII. These patients should be given the appropriate counseling and should be monitored for features of thromboembolism if factor XII deficiency is confirmed.

Abruptio Placentae↗
PubMed1990

The outcome of triplet, quadruplet, and quintuplet pregnancies managed in a perinatal unit: obstetric, neonatal, and follow-up data.

Multifetal gestation is associated with increased frequency of maternal complications and higher perinatal morbidity and mortality. The need for contemporary data on the outcome of multifetal gestations is further underscored when selective reduction is considered. The present study details the obstetric management, neonatal outcome, and follow-up data of 24 triplet, five quadruplet, and one quintuplet pregnancies delivered in a perinatal center. The early neonatal mortality rate was 31.6, the late neonatal mortality rate was 21, and the perinatal mortality rate was 51.5. Survival to discharge was 93%. The incidence of respiratory distress syndrome was 43%, bronchopulmonary dysplasia 6%, retinopathy of prematurity 3%, intraventricular hemorrhage 4%, and cerebral palsy 2%. Follow-up from 1 to 10 years shows that only one child is moderately handicapped, whereas 99% have no significant medical problem. Early diagnosis by ultrasonography, meticulous antenatal care, early hospitalization, delivery by cesarean section, and on-site availability of a neonatologist for each baby at the time of delivery are the probable major determinants of improved outcome.

Child Development↗
PubMed1990

An analysis of antenatal tests to detect infection in preterm premature rupture of the membranes.

The purpose of this study was to critically review published studies regarding sensitivity, specificity, and positive and negative predictive values of antenatal tests to diagnose chorioamnionitis or fetal-neonatal sepsis in preterm premature rupture of the membranes. A Medline Data-Base computer program search from 1980 to 1988 identified 39 studies, 23 of which were accepted after independent review with preset criteria. An ideal test to predict chorioamnionitis or neonatal sepsis was not found. The low success rate for amniocentesis and the need for repeat taps preclude the acceptance of tests on the basis of amniotic fluid. Single, small studies, the precision of which has never been tested, show good indices for repeatedly increased serum levels of C-reactive protein (greater than 20 mg/L), a high level of C-reactive protein greater than 40 mg/L, or a day-to-day coefficient of variation for C-reactive protein of greater than 30% in the prediction of histologic or clinical chorioamnionitis. Ultrasonographic observation of fetal activity, if published study results are confirmed, may be of value to predict amniotic fluid bacterial colonization.

Amniotic Fluid↗