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Biomedical subjects

I Morrison

Publications and source records attributed to I Morrison.

At least 37 records · Page 2Linked to original sources
PubMed1997

A computer simulation of the transmission dynamics and the effects of duration of immunity and survival of persistently infected animals on the spread of bovine viral diarrhoea virus in dairy cattle.

This paper describes a computer model that mimics the spread of bovine viral diarrhoea virus (BVDV) infection through a closed herd. The model is able to simulate the spread of infection when a persistently infected (PI) animal is introduced into an infection-free herd, and it is used to investigate the role of persistently infected animals, seroconverting animals, loss of PI calves and duration of immunity on the level of infection within the herd. Under typical management conditions one persistently infected animal poses a real threat to a herd, and the prospect of the herd becoming infection free in a 10-year period without intervention is remote. Seroconverting animals are found to be an important source of infection in herds with few immune animals. The increased loss of PI calves is likely to restrict the numbers of PI animals in a herd, and loss of immunity is important since it increases the possibility of a PI calf being born.

Animals↗
PubMed1997

Fetal assessment based on the fetal biophysical profile score: relationship of last BPS result to subsequent cerebral palsy.

OBJECTIVE: The prime intent of this study was to determine the relationship if any between the last fetal biophysical profile score and the risk of cerebral palsy at age 3 years. The secondary objective was to examine the clinical characteristics of infants with cerebral palsy whose obstetric management included serial fetal biophysical profile scores. STUDY DESIGN: The incidence of a high risk pregnant population whose antenatal assessment was by serial fetal biophysical profile scoring was determined by cross-referencing two discrete data bases. The completeness and reliability of the data bases was confirmed by secondary audit. Obstetrical, neonatal and post-natal clinical records of index cases of cerebral palsy were subsequently reviewed, categorized and analyzed. RESULTS: Fetal biophysical profile scores (BPS) were recorded in 22,336 high risk pregnancies: 27 patients delivered an infant subsequently identified as having cerebral palsy (rate 1.21 per 1000). The relationship between last BPS result and cerebral palsy was inverse, exponential and highly significant (R2 = 0.987; p < 0.001). Affected infants with a last abnormal BPS result were significantly more likely to exhibit fetal distress (88.8%), acidosis (77.7%), and have neonatal seizures (88.8%). Antenatal asphyxia was the apparent cause of cerebral damage in 29.6% of cases. CONCLUSION: The last fetal biophysical profile score is a predictor of the risk of cerebral palsy.

Cerebral Palsy↗
PubMed1995

Perinatal outcome in relation to second-stage duration.

OBJECTIVE: The second stage of labor has been thought of as a time of particular asphyxial risk for the fetus. This perceived risk has been invoked to justify arbitrary time limits and high rates of operative vaginal delivery. The purpose of this study was to determine whether perinatal outcome worsened as the second stage lengthened. STUDY DESIGN: Over a 5-year period at one university teaching hospital, 6041 nulliparous women reached the second stage of labor with a live singleton cephalic fetus with birth weight > or = 2500 gm. A retrospective review of perinatal morbidity and mortality was performed and the results related to the duration of the second stage. RESULTS: The second stage lasted > 3 hours in 11% of nulliparous women and > 5 hours in 2.7%. There were no perinatals death unrelated to anomaly. There was no significant relationship between second-stage duration and low 5-minute Apgar score, neonatal seizures, or admission to the neonatal intensive care unit. CONCLUSION: Operative intervention in the second stage is not warranted merely because some set number of hours has elapsed.

Apgar Score↗
PubMed1993

Physicians' perspectives on caring for patients in the United States, Canada, and West Germany.

BACKGROUND: The United States is considering enacting a national health plan and global health care budget similar to those in other countries. There are few data on the effects of such policies on physicians and patients. METHODS: We conducted a telephone survey of 602 physicians in the United States, 507 physicians in Canada, and 519 physicians in the former West Germany from February through May 1991; the response rates were 44 percent, 49 percent, and 41 percent, respectively. Among other topics, the questionnaire included measures of satisfaction with the health care system and with medical practice. RESULTS: In the United States, 23 percent of the physicians surveyed thought the health care system worked well, as compared with 33 percent in Canada and 48 percent in West Germany. Seventy-three percent of U.S. physicians reported that patients' inability to afford necessary treatment was a serious problem, as compared with 25 percent in Canada and 15 percent in West Germany. Seventy-seven percent of West Germany physicians, 56 percent of Canadian physicians, and 54 percent of U.S. physicians said the shortage of competent nurses was a serious problem. In Canada, 50 percent of the respondents cited the lack of well-equipped medical facilities as a problem, as compared with 14 percent in the United States and 20 percent in West Germany. CONCLUSIONS: Programs of universal coverage and cost containment necessitate important trade-offs. In Canada and West Germany, physicians do not report serious problems of access to care for the poor and uninsured. In the United States, doctors do not face the limited access to sophisticated forms of medical technology that was reported in Canada or the diminished quality of some services reported in West Germany.

Adult↗
PubMed1993

Fetal biophysical profile score. VI. Correlation with antepartum umbilical venous fetal pH.

OBJECTIVE: Our objective was to determine the relationship, if any, between the fetal biophysical profile score and antepartum umbilical venous pH. STUDY DESIGN: This was a prospective observational study conducted concurrently in two centers and involving two discrete high-risk groups of fetuses. Fetal biophysical profile scores were compared with umbilical venous pH values measured in blood obtained by immediate cordocentesis. A total of 493 paired observations of biophysical profile score and pH were made; 104 observations were of fetuses with intrauterine growth retardation and 389 observations were of fetuses with alloimmune anemia. RESULTS: In both data sets there was a highly significant linear correlation between biophysical profile score and umbilical venous pH. Poor biophysical profile score performance (a score of 0 of 10) was always associated with a pH < 7.20, whereas the pH was always > 7.20 when the biophysical profile score was 10 of 10. Sequenced sensitivity of short-term biophysical variables in the detection of acidemia was observed. CONCLUSION: The fetal biophysical profile score accurately predicts antepartum umbilical venous pH.

Analysis of Variance↗
PubMed1993

Observations of intrapartum fetal activities.

OBJECTIVE: The objective of this observational study was to document the frequency of biophysical activities such as breathing and body movements during spontaneous labor in the low-risk, term fetus. STUDY DESIGN: The fetuses of truly low-risk patients without medication during labor were observed serially with real-time ultrasonography for fetal breathing or body movements for a maximum scanning time of 1 hour. Fetal breathing movements, hiccups, and fetal body movements were recorded, as were cervical dilatation, status of the fetal membranes, and Apgar scores. RESULTS: Fetal breathing activity was recorded in 76% of fetuses in early labor and 90% in advanced labor. Fetal body movements were present during 85% of the observations. All babies had 5-minute Apgar scores > 7. CONCLUSION: Ultrasonographic evaluation of fetal breathing and body movements during spontaneous labor was associated with normal birth outcome in this low-risk population. The clinical utility of this noninvasive method in determining intrapartum fetal health remains to be tested in an unselected population.

Apgar Score↗
PubMed1993

Health reform lessons learned from physicians in three nations.

To explore the concerns of practicing physicians as a way to inform the health reform debate, the authors conducted a survey of physicians in the United States, Canada, and Germany. Survey results indicate that U.S. physicians are most likely to view affordability as the greatest barrier to access to care for their patients. However, unavailability of services and long waiting times were cited most often by Canadian physicians. German physicians did not cite access problems as frequently as Canadian physicians did; other measures of satisfaction were closer to U.S. levels, suggesting fewer trade-offs if the United States were to adopt aspects of the German health care system.

Attitude of Health Personnel↗
PubMed1992

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↗