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Biomedical subjects

I Morrison

Publications and source records attributed to I Morrison.

At least 19 recordsLinked to original sources

Must macrosomic fetuses be delivered by a caesarean section? A review of outcome for 786 babies greater than or equal to 4,500 g.

Because difficult vaginal delivery is more frequent with macrosomic fetuses, some writers recommend routine Caesarean section for the delivery of fetuses greater than or equal to 4,500 g. The purpose of this study was to evaluate the appropriateness of this recommendation. A retrospective review was undertaken to determine how many fetuses born in our hospital weighing greater than or equal to 4,500 g died or were permanently damaged as a consequence of mechanical difficulties at delivery. During a 10-year period, 590 (75%) of 786 cephalic babies weighing greater than or equal to 4,500 g and alive at the start of labour were born vaginally. No baby died or was permanently damaged as a consequence of mechanical difficulties at delivery. Routine Caesarean section for macrosomic fetuses to prevent death or damage from difficult delivery is not warranted by our results.

Birth Weight

Assessment of fetal well-being with ultrasound.

The practice of medicine is undergoing marked changes fueled by the infusion of vast amounts of new information concerning the etiology, the progressive pathophysiology, and the complexity of host response to disease states. It is only recently that we have begun to examine the present extent of fetal disease and to determine the characteristics of its advancements. This information now permits new and rational approaches to the management of fetal disease. Clinical significance, both real and potential, of this new wealth of information in reducing perinatal mortality and morbidity is difficult to overestimate. Cumulative experience with fetal biophysical scoring as a method for antepartum fetal risk assessment is now extensive. The cumulative data indicate that the method is sensitive for recognizing both the normal and the compromised fetus. Moreover, the method appears to offer the advantage of grading various degrees of fetal compromise. The additional information gained by real-time ultrasound scanning (gestational age determination, fetal morphometrics, and fetal anomaly screening), although not an integral part of the fetal biophysical profile score, nevertheless remains a critical aspect of antepartum fetal assessment. These data are collected simultaneously with fetal biophysical profile scoring. It is impossible to separate cleanly the advantage of fetal biophysical profile scoring in isolation of this additional information. It would, however, seem that such attempt at separation is artificial because the data in combination provide the key information that the physician needs to guide fetal management. It seems more reasonable to expect that continued modification and improvement of the existing fetal biophysical profile scoring method with inclusion of new testing techniques will be the steps that will occur to improve testing accuracy (Fig. 3). In medical schools in the 1960s, it was generally taught that the concept of "irreducible" perinatal mortality existed and that this figure was usually set at a perinatal mortality of around 8 per 1000. Now in the 1990s that perinatal mortality has already fallen below this irreducible level and continues to fall. We now observe perinatal mortality among tested fetuses of less than 7 per 1000 and corrected perinatal mortalities of less than 2 per 1000. These remarkable results strongly underscore the advantages obtained by ultrasound assessment of the fetus.

Amniotic Fluid

Fetal assessment based on fetal biophysical profile scoring. III. Positive predictive accuracy of the very abnormal test (biophysical profile score = 0).

The relationship between complete absence of all components of the fetal biophysical profile score (biophysical profile score = 0) and adverse perinatal outcome was examined. Twenty-nine of 28,655 fetuses studied (0.092%) had a last biophysical profile score of 0; 48.3% of these perinates died (14 of 29 fetuses), the majority of whom (11 of 14) were stillborn, with death occurring as early as 30 minutes to as long as 11 days after the last test. Three asphyxia-related neonatal deaths occurred despite aggressive and immediate intervention. All survivors exhibited at least one of the five discrete markers used to assess perinatal morbidity. The positive predictive accuracy of a biophysical profile score of 0, with mortality and morbidity used as end points, was 100%. These data indicate the very abnormal fetal biophysical profile score to be a perinatal emergency.

Acidosis

Fetal assessment based on fetal biophysical profile scoring. IV. An analysis of perinatal morbidity and mortality.

The relationship between the last biophysical profile score result and perinatal outcome was determined among a large referred population of high-risk pregnancies. A highly significant inverse linear correlation was observed for fetal distress, admission to neonatal intensive care unit, intrauterine growth retardation, 5-minute Apgar score less than 7, and umbilical cord pH less than 7.20 but not for the incidence of meconium or major anomaly. A highly significant inverse exponential (log 10) relationship was observed for perinatal mortality in total and by component parts and cause. These data strongly suggest the biophysical profile scoring method of fetal risk assessment is accurate and also provides insight into the extent of fetal compromise.

Female

The abnormal fetal biophysical profile score. V. Predictive accuracy according to score composition.

The relationship between last abnormal biophysical profile score, in total and by variable composition, and a spectra of abnormal perinatal outcome end points was examined in 525 fetuses. Highly significant inverse relationships between last test score and outcome were observed; relationships were linear for most end points and exponential for perinatal mortality end points. For biophysical profile scores less than or equal to 6, 25 of the 26 possible variable combinations were observed, at varying frequencies. For a biophysical profile score of 6, the positive predictive accuracy for some end points was significantly higher with either nonreactive nonstress test/fetal tone absent or nonreactive nonstress test/absent fetal breathing movement, and significantly lower with absent fetal breathing movement and decreased amniotic fluid volume. For a biophysical profile score of 4, the positive predictive accuracy for some end points was significantly higher with nonreactive nonstress test/absent fetal breathing movement/decreased amniotic fluid and was significantly lower with absent fetal movement/fetal breathing movement/fetal tone. No significant variation was observed for a biophysical profile score of 2. These data indicate that not all abnormal biophysical profile scores are equal.

Apgar Score

Severe fetal brain injury without evident intrapartum asphyxia or trauma.

Two appropriate-for-dates term infants were born after uncomplicated labors and atraumatic deliveries. They were depressed at birth, developed seizures on the first day of life, and followed clinical courses compatible with hypoxic-ischemic encephalopathy. However, the umbilical cord vessel pH and blood gases were normal. The children are now severely retarded and have cerebral palsy. These cases prove that the events of labor and delivery may not be responsible for all cases of brain damage in surviving children.

Adolescent

Fetal biophysical profile scoring: selective use of the nonstress test.

The fetal biophysical profile score was modified by selective use of the nonstress test. In 2712 study patients (7851 tests) the incidence of nonstress test was reduced to 2.7% with no measurable effect or test accuracy. The nonstress test was most useful in evaluation of abnormal ultrasound monitored variables.

Female

Fetal assessment based on fetal biophysical profile scoring: experience in 19,221 referred high-risk pregnancies. II. An analysis of false-negative fetal deaths.

The incidence of false-negative fetal death, which is defined as stillbirth unrelated to major anomaly or alloimmunization occurring after a last normal fetal biophysical score, was determined in 19,221 referred high-risk pregnancies. The calculated rate of fetal death after a last normal test was 0.726/1000 (14 deaths), which remained relatively constant despite a progressive increase in tests and patients studied. We conclude that a normal fetal biophysical profile score confers a high probability of perinatal survival.

Amniotic Fluid

Antepartum fetal risk assessment: the role of the fetal biophysical profile score.

In the art of medicine we have always known that establishing an accurate diagnosis of health or disease is essential. An active search for the physical signs, both the time honoured and newly discovered, are a crucial step in achieving diagnostic accuracy, in monitoring disease progression, and in assigning prognosis. In extrauterine medicine it is common practice to gather together sets of biophysical data in order to determine immediate health, to monitor condition, and to estimate prognosis: witness the use of vital signs, and, in the newborn, the Apgar score. The providers of perinatal care have known since biblical days that fetal biophysical activities were a reflection of fetal condition (Luke: Chapter 1, Verses 44-45), yet lacked the ability to categorize these activities in an objective and complete manner. The introduction of dynamic ultrasound imaging methods to perinatal medicine at last create the window through which the principles of extrauterine medicine may now be applied to the intrauterine patient--the fetus. Fetal biophysical profile scoring is a method that utilizes this new wealth of information to differentiate the normal fetus from the fetus at risk for death or damage in utero. The method is based on the concept that the discrimination of fetal health and disease improves as more variables are considered. The now extensive clinical experience with the method, in which both overall (gross) and selected (corrected) perinatal death are reduced, while maintaining a remarkably low false negative predictive error, indicate the validity of the concept. Comparative studies lead us to believe that reliance upon single biophysical variables, such as fetal movement counts, or antepartum fetal heart rate monitoring, is no longer of sufficient accuracy to support its use as a sole measure of fetal condition. Looking forward, we anticipate that while the concept on which fetal biophysical profile scoring is based will remain unchanged, inclusion of additional variables is likely to occur. It seems likely that addition of new variables, as may be now measured using high-resolution dynamic ultrasound methods, both B-mode and Doppler, will improve diagnostic accuracy even more. We believe that the application of the current and future modified methods of composite fetal risk assessment will render the occurrence of the tragedy of perinatal loss even more infrequent. While the goal of complete elimination of perinatal deaths remain elusive, this method may be one step towards this goal.

Biophysical Phenomena

Unusual paraspinal muscle lesions in ankylosing spondylitis.

Minicore, multicore, core-targetoid and other ultrastructural lesions were found in the paraspinal muscles of patients with AS. The 10 patients studied, all men with AS, showed varying degrees of muscle fibre atrophy, Z band streaming, rod body formation, minicores, multicores and core-targetoid fibres. Central core disease, rod body myopathy, minicore and multicore diseases are recognized clinical entities within the congenital group of structural myopathies. Target fibres are believed to be a feature of reinnervation. It is also known that experimental tenotomy causes core-targetoid changes, rod bodies, minicores and multicores. Therefore, it seems possible that tension is a necessary stimulus for the correct programming of synthetic muscle enzymes, and without this disorganization occurs. It may also be assumed, but in this case for genetic reasons, that similar biochemical systems are disturbed in the group of congenital myopathies.

Adult

Ultrasound evaluation of amniotic fluid: outcome of pregnancies with severe oligohydramnios.

Severe oligohydramnios, defined as a condition in which the largest pocket of amniotic fluid measures less than 1 cm in its vertical axis as determined by an ultrasound method, was observed in 113 patients in a population of 15,431 referred high-risk patients (0.7%). In all cases, intervention took place unless there was a recognized structural anomaly or extreme prematurity. Overall gross perinatal mortality was 132.7/1000, and the incidence of major anomaly was 13.3%. With intervention the corrected perinatal mortality rate was 17.7/1000, a rate not significantly different from that observed in the entire population. All end points of perinatal mortality were significantly increased in patients with severe oligohydramnios, in comparison with randomly selected control subjects with normal amniotic fluid. These findings are interpreted to indicate that severe oligohydramnios in a structurally normal fetus is an indication for delivery.

Adolescent

Fetal assessment by biophysical profile scoring: 1985 update.

In extrauterine medicine, physicians have come to rely upon sampling of multiple biophysical variables as a means of differentiating states of well-being and compromise. This basic tenet of medicine is expressed by obtaining an Apgar score or some variant in the newborn and as a measure of vital signs in later life. Few, if any, decisions regarding well-being are ever based on a single-variable assessment and, conversely, definition of compromise is rarely based upon a single variable. Through the use of dynamic ultrasound imaging it now becomes possible to visualize the fetus and its biophysical responses in health and disease. Through such visualization it becomes possible to bring to bear some of the basic principles that sustain extrauterine medicine on the intrauterine patient, the fetus. Fetal biophysical profile scoring describes a method that encompasses this concept. The results obtained by application of this method are promising. We would argue that consideration of multiple fetal biophysical variables will, in most instances, yield superior results to single-variable monitoring alone. Hence we have abandoned antepartum fetal heart rate testing as the sole method of fetal risk assessment and used the tool only in conjunction with others of the many variables that may be monitored by dynamic ultrasound methods. This concept of multiple-variable analysis as the superior method for fetal assessment seems clear and well-justified. It is our opinion, however, that the concept of fetal bioprofile scoring may be more important than the method itself in its original description.(ABSTRACT TRUNCATED AT 250 WORDS)

Amniotic Fluid

Weight-specific stillbirths and associated causes of death: an analysis of 765 stillbirths.

An analysis of 765 consecutive stillbirths associated with 98,927 pregnancies during a 6-year interval showed significant differences for cause of death at specific weight categories. In addition, 57% of stillbirths occurred at infant weights of greater than or equal to 1500 gm. Hypoxia accounted for 43% of all stillbirths. The implications with respect to preventability and for changes in routine prenatal care through the incorporation of the several methods of fetal assessment currently available are discussed.

Birth Weight

Cord prolapse: is antenatal diagnosis possible?

Cord presentation was diagnosed antenatally in nine patients at term referred for fetal ultrasound assessment (incidence of 0.61%). Seven patients were delivered by cesarean section; cord position was confirmed in four and suspected in three patients. There were two vaginal deliveries, one following spontaneous version and the other a stillbirth associated with cord prolapse.

Breech Presentation