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Biomedical subjects

J A Spencer

Publications and source records attributed to J A Spencer.

At least 19 recordsLinked to original sources
PubMed1995

Use facilitated case discussions for significant event auditing.

An important type of review undertaken routinely in health care teams is analysis of individual cases. This informal process can be turned into a structured and effective form of audit by using an adaptation of the "critical incident" technique in facilitated case discussions. Participants are asked to recall personal situations that they feel represent either effective or ineffective practice. From such review of individual cases arise general standards to improve the quality of care. On the basis of a study of audit of deaths in general practice, we describe how to implement such a system, including forming and maintaining the discussion group, methodology, and guidelines for facilitators. Problems that may arise during the case discussions are outlined and their management discussed, including problems within the team and with the process of the discussions.

Communication↗
PubMed1995

Alpha 1- and alpha 2-adrenoreceptor actions of phentolamine and prazosin on breathing movements in fetal sheep in utero.

1. We studied the effects of systemic administration of the alpha 1- and alpha 2-adrenoreceptor antagonist phentolamine and the selective alpha 1-adrenoreceptor antagonist prazosin on fetal breathing movements (FBM) and electrocortical activity (ECoG) in fetal sheep. In one group of fetuses (group I; n = 7) the effects of phentolamine were measured during normoxia and hypoxia. In the second group of fetuses (group II; n = 8) the effects of either phentolamine, or combined phentolamine and prazosin, or prazosin alone, were measured during normoxia. 2. In group I fetuses, the incidence of FBM increased after phentolamine treatment. An increase in the incidence and mean episode duration of low-voltage ECoG (LV-ECoG) was also measured after phentolamine treatment. These effects of phentolamine persisted during hypoxia. 3. In group II fetuses a pronounced decrease in the incidence of FBM occurred after administration of prazosin following either phentolamine or saline pretreatment. These effects of prazosin on FBM were independent of an effect on ECoG activity. 4. We conclude that catecholamines have a stimulatory role on FBM mediated via an alpha 1-adrenoreceptor mechanism. Phentolamine leads to an increase in FBM by preferentially antagonizing presynaptic alpha 2-adrenoreceptors over postsynaptic alpha 1-adrenoreceptors. This influence of phentolamine on FBM may be secondary to its effect on ECoG. Promotion of LV-ECoG by catecholamines is mediated via an alpha 1-independent mechanism.

Adrenergic alpha-1 Receptor Antagonists↗
PubMed1995

Effect of nuchal cord on fetal cerebral haemodynamics and oxygenation measured by near infrared spectroscopy during labour.

OBJECTIVE: To test the hypothesis that a nuchal cord has a significant effect upon fetal cerebral haemodynamics and oxygenation during labour. STUDY DESIGN: A specially designed optical probe was inserted through the dilated cervix and placed against the scalp of 37 fetuses during labour in a teaching hospital obstetric unit. Changes in total cerebral haemoglobin concentration were measured continuously together with fetal heart rate and uterine contraction frequency during the first and second stages. RESULTS: At birth 11 fetuses (30%) were noted to have a nuchal cord (cord around the neck). For these, significantly more contractions were associated with an increase in total cerebral haemoglobin concentration when compared with the control fetuses without a nuchal cord (40.2% (S.D.19.5) vs 5.9% (S.D.7.1), P < 0.001). A significantly greater number of variable decelerations was found in the nuchal cord group (4 per 30 min vs. 2 per 30 min in the controls) (P < 0.01). There was no significant difference between mean cerebral oxygen saturation determined at the end of the first stage of labour, which was 47.0% (S.D.13.3) and 50.1% (S.D.11.8) for the nuchal cord and control groups, respectively. CONCLUSION: A nuchal cord was associated with a significant increase in cerebral blood volume during uterine contractions, without any significant effect upon cerebral oxygenation.

Adult↗
PubMed1995

Fetal size and growth in Bangladeshi pregnancies.

A longitudinal study of 20 uncomplicated pregnancies in Bangladeshi women was undertaken. Fetal growth was investigated by serial ultrasound scans performed between 26 and 38 weeks of pregnancy. Repeated measurements of abdominal circumference and estimates of fetal weight were best described by a log quadratic equation. The coefficients were not significantly different from those obtained from a previously reported study of fetal growth in 67 uncomplicated pregnancies with healthy outcomes in white Anglo-Saxon women. Further comparison between the two groups showed that the mean abdominal circumference and estimates of fetal weight of the Bangladeshi fetuses were smaller at 28, 32 and 36 weeks' gestation. These results suggest that, although Bangladeshi fetuses appear to be smaller than Anglo-Saxon fetuses, they grow at a similar rate during the third trimester.

Abdomen↗
PubMed1995

Late fetal heart decelerations and changes in cerebral oxygenation during the first stage of labour.

OBJECTIVE: To test the hypothesis that late fetal heart rate decelerations are associated with a decrease in cerebral oxygenation. DESIGN: Changes in fetal cerebral concentrations of oxyhaemoglobin and deoxyhaemoglobin were measured by near infrared spectroscopy, before, during and after contractions with late fetal heart rate decelerations and compared with changes during contractions with no alteration of heart rate. SETTING: Teaching hospital obstetric unit. SUBJECTS: Ten women in labour at term. RESULTS: The changes in fetal cerebral oxyhaemoglobin and deoxyhaemoglobin concentrations that occurred during contractions were quantitatively similar, irrespective of the fetal heart rate changes. However, late fetal heart rate decelerations were associated with a significantly greater fall, after the uterine contraction, in the mean concentration of fetal cerebral oxyhaemoglobin of 0.52 mumol/100 g (SD 0.25) (P < 0.001) and a significantly greater rise in the mean concentration of deoxyhaemoglobin of 0.36 mumol/100 g (SD 0.35) (P < 0.01). CONCLUSION: Late fetal heart rate decelerations are associated with a significant decrease in cerebral oxygenation.

Adult↗
PubMed1995

The effect of maternal posture on fetal cerebral oxygenation during labour.

OBJECTIVE: To measure the effect of changes in maternal posture on fetal cerebral oxygenation during normal labour. DESIGN: A prospective study comparing changes in the fetal cerebral concentrations of oxyhaemoglobin, deoxyhaemoglobin and cerebral blood volume, measured by near infrared spectroscopy, in women with effective epidural analgesia when moved from the left lateral to the supine position during labour. SETTING: A London teaching hospital obstetric unit. SUBJECTS: Fourteen women during uncomplicated labour at term. RESULTS: When compared with the left lateral position, the supine position was associated with a significant decrease in the mean concentration of fetal cerebral oxyhaemoglobin of 1.12 (SD 1.0, 95% CI 0.49 to 1.75) mumol. 100 g-1 (P < 0.01) without any significant change in the mean concentration of deoxyhaemoglobin and cerebral blood volume. These changes were associated with a significant decrease in the mean cerebral oxygen saturation of 8.3 (SD 8.8, 95% CI 1.5 to 15.1)% (P < 0.05, n = 9). CONCLUSION: Changes in maternal posture during labour, in women with effective epidural analgesia, are associated with a significant decrease in fetal cerebral oxygenation.

Adult↗
PubMed1995

The effect of maternal pushing on fetal cerebral oxygenation and blood volume during the second stage of labour.

OBJECTIVE: To measure the effect of maternal pushing during the second stage of labour on fetal cerebral oxygenation and blood volume. DESIGN: A prospective study comparing changes in the fetal cerebral concentrations of oxyhaemoglobin, deoxyhaemoglobin and cerebral blood volume, before and during maternal pushing in the second stage of labour. SETTING: Teaching hospital obstetric unit. SUBJECTS: Ten term fetuses during labour. RESULTS: Following the onset of maternal pushing, mean cerebral deoxyhaemoglobin concentration increased by a mean of 0.79 (SD 0.59) mumol.100 g-1, (P < 0.01) without any consistent change in the oxyhaemoglobin concentration. These changes were associated with a significant decrease in the calculated mean cerebral oxygen saturation from a mean of 46.8% (SD 8.6) to 38.1% (SD 5.2) (P < 0.01). Pushing was also associated with a significant increase in the mean cerebral blood volume, which rose by a mean of 0.33 ml.100 g-1 (SD 0.37) (P < 0.05). CONCLUSION: Maternal pushing during the second stage of labour leads to a significant decrease in fetal cerebral oxygenation, together with an increase in cerebral blood volume.

Adult↗
PubMed1995

Third trimester fetal growth and umbilical venous blood concentrations of IGF-1, IGFBP-1, and growth hormone at term.

Insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein-1 (IGFBP-1) and growth hormone (GH) concentrations were measured in umbilical venous blood after delivery of 78 term newborn infants. Three groups of pregnancies were prospectively identified during the third trimester, according to fetal size and subsequent fetal growth, assessed by repeated ultrasound scans. Fetal size was considered either appropriate for gestational age (AGA) or small for gestational age (SGA), according to whether the first ultrasound measurement of abdominal circumference was equal to or above, or below the tenth centile for gestational age, respectively. Subsequent fetal growth was quantified by the change in the standard deviation score of abdominal circumference measurements between the first and last scans before delivery. Fetal growth retardation (FGR) was defined as a (negative) change in SD score of greater than -1.5. Eighteen SGA fetuses with evidence of FGR had significantly lower IGF-1 (median 0.05 (range 0.0-0.24) U/ml) at delivery than 35 SGA fetuses with normal growth (median 0.13 (range 0.0-0.94) U/ml; P < 0.05) and 25 AGA fetuses with normal growth (median 0.31 (range 0.0-0.84) U/ml; P < 0.05). The median concentration in the SGA group with normal growth was also significantly lower than that of the AGA group with normal growth. There were no significant differences in IGFBP-1 or GH concentrations between the three groups. These observations indicate that umbilical blood concentrations at birth of IGF-1, but not IGFBP-1 or GH, relate to both fetal size and fetal growth during the third trimester of pregnancies reaching term.

Embryonic and Fetal Development↗
PubMed1995

Multispiral three-dimensional computed tomography in the investigation of craniosynostosis: technique optimization.

21 infants with craniosynostosis were studied with a new three-dimensional (3D) computed tomography (CT) methodology. We describe technique optimization using multiple spiral data acquisitions with low dose (85 mAs) technique. One caudal volume of 3 mm slice thickness was obtained with a further two volumes of 1 mm slice thickness at the vertex. Image reconstruction of spiral raw data allowed overlapping 3 mm sections to be generated without the dose increase that would result from conventional axial CT scanning. We illustrate common technical artefacts of 3D CT and explain their cause and solution. A dramatic dose reduction to the lens was achieved with no loss in 3D image quality. Lens dose was 8.91 mSv compared with 24.6 mSv using the standard paediatric head technique.

Craniosynostoses↗
PubMed1994

General practitioners' views about the statutory annual practice report.

OBJECTIVE: To ascertain the views of primary care professionals about the current purpose, uses, potential, and workload implications of the statutory general practice annual report. DESIGN: Postal questionnaire survey. SETTING: General practices in the Northern region. SUBJECTS: All practices in the region that were singlehanded, fundholding, non-fundholding and with more than five partners, and a one in three random sample of all non-fundholding practices (n = 318). RESULTS: 263 practices responded (83%). The report took a median of 12 hours to produce (95% confidence interval 11 to 15 hours; interquartile range 7-35). The main perceived purpose of the report was to monitor practice activity (165 respondents; 63% (95% confidence interval 57% to 69%)), but 44 respondents (17%; 13% to 22%) produced it only because it was contractually required. Practices included statutory and non-statutory data in these reports and would have liked comparative practice activity information (155 respondents; 59%) and "good ideas" (165 respondents; 63%) fed back to them. Respondents would have liked the annual report used to improve practice development planning (122 respondents; 46% (40% to 52%)), to facilitate audit (115 respondents; 44% (38% to 50%)), and to influence resource allocation (104 respondents; 40% (34% to 46%)). One hundred and eighteen practices (45%; 39% to 51%) would produce an annual report even if not contractually required. Data collected were perceived to be already available elsewhere. CONCLUSIONS: Primary care professionals have concerns about the current annual report. They would prefer to collect relevant, standardised data which could lead to better audit, planning, and resource allocation.

Annual Reports as Topic↗
PubMed1994

The placental transfer of cefuroxime at parturition.

Maternal and fetal serum concentrations of cefuroxime were determined at birth in 39 women who were given a single intravenous dose of either 750 mg or 1500 mg of cefuroxime before delivery. Mean serum cefuroxime concentrations in maternal venous and umbilical venous blood were dose dependent, being significantly higher after 1500 mg of cefuroxime (55.0 mg/l, 95% CI 33.4-80.9 and 19.5 mg/l, 95% CI 9.5-26.3, respectively) than after 750 mg (14.7 mg/l, 95% CI 10.5-21.1 and 8.8 mg/l 95% CI 5.8-9.4, respectively). Antibiotic concentration in maternal blood correlated with sampling time but a similar relationship was not found in cord blood. Fetal concentrations did not correlate with mode of delivery or initial maternal blood pressure. No relationship could be demonstrated between cefuroxime concentration in maternal or cord blood and maternal weight, maternal weight gain, birthweight of baby or volume of fluid infused prior to epidural anaesthesia. It is concluded that maternal and fetal concentrations likely to be effective for prophylaxis before delivery require a maternal dose of 1500 mg of cefuroxime and are independent of these physiological variables.

Analysis of Variance↗
PubMed1994

Phosphoglycerate kinase pseudogenes in the tammar wallaby and other macropodid marsupials.

Phosphoglycerate kinase (EC 2.7.2.3; PGK) exists in two forms in marsupials. PGK1 is an X-linked house-keeping enzyme, and PGK2 is a mainly testis-specific enzyme under autosomal control. We have used PGK1 probes derived from two closely related species of macropodid marsupials (kangaroos and wallabies) to demonstrate the existence of a large family of pseudogenes in the tammar wallaby (Macropus eugenii). Over 30 fragments are detectable after Taq digestion. We estimate that there are 25-30 copies per genome. Most are autosomally inherited and are apparently not closely linked. Only two restriction fragments that appeared to be sex linked could be detected. Varying degrees of hybridization of fragments to the probes suggest different levels of homology, and hence different ages of origin. The existence of two PGK1 homologous restriction fragments from the X and a large number from the autosomes was also demonstrated by somatic cell hybridization for two other macropodid species, the wallaroo (M. robustus) and the red kangaroo (M. rufus). These results are compared with those from human and mouse, and it is suggested that the propensity of PGK1 to form pseudogenes is an ancient (approximately 130 MYR BP) characteristic of mammals. The high level of polymorphism detected in the tammar makes these PGK1 probes potentially useful for measuring genetic variability in this species and other macropodids.

Animals↗
PubMed1994

Ultrasound-guided four quadrant biopsy of the prostate: efficacy in the diagnosis of isoechoic cancer.

Five hundred and eighty men underwent transrectal ultrasound-guided biopsy of the prostate using the four quadrant biopsy (4QB) technique. Four hundred and three men had focal hypoechoic lesions of the peripheral gland but the other 177 men referred because of concern for the presence of cancer had no discrete sonographic lesion. Cancer was found from 4QB in only 32 of these 177 men (18.1%) compared to 158 of the 403 men (39.2%) with focal hypoechoic lesions (P < 0.001). Additional biopsy evidence of cancer was found in contralateral isoechoic (sonographically normal) quadrants in 41 men with focal hypoechoic cancerous lesions. In 17 men with hypoechoic lesions that were biopsy-benign, cancer was found in other isoechoic quadrants. There was no difference between the average Gleason scores of hypoechoic cancers and isoechoic cancers, other than when cancers were incidentally found in men with benign focal hypoechoic lesions. These had significantly lower scores (P = 0.02). Cancer yield in the 177 men without hypoechoic lesions increased as a function of prostate-specific antigen (PSA) level; 11% if PSA < 10ng/ml, 32% if > 20ng/ml. Prostatitis was the most common abnormal biopsy finding in these men. 4QB increases the yield of prostate cancer compared to simple biopsy of hypoechoic lesions and improves knowledge of local disease extent. 4QB is recommended for men with elevated PSA levels but no peripheral gland sonographic abnormality.

Adult↗
PubMed1994

The need for teaching in medical audit: a survey in one medical school.

A questionnaire survey was carried out among senior clinical teachers at Newcastle upon Tyne Medical School, UK about their current practice and attitudes toward the teaching of medical audit in the undergraduate curriculum. A response rate of 88% was achieved. Less than a fifth of respondents provided such teaching, but the majority were in favour of seeing the topic introduced. A variety of teaching methods were used, and feedback from students was generally favourable. A number of concerns were expressed, including the problem of curriculum overload, the timing of the teaching, and the need to ensure that the learning was experiential with a minimum of theoretical teaching. Those who were in favour of introducing such teaching, or who were unsure, were also concerned about pressures on curricular time, but some felt in addition that the topic was more appropriately a postgraduate one. A short attitude scale demonstrated a skew towards favourable attitudes among the whole group. The implications of the survey for teaching about audit and quality are discussed.

Attitude↗
PubMed1994

Prediction of perinatal morbidity at term in small fetuses: comparison of fetal growth and Doppler ultrasound.

OBJECTIVE: To compare fetal growth assessed by ultrasound (change in standard deviation score of abdominal circumference and estimated fetal weight) during the third trimester with predelivery ultrasound measurements of fetal size and Doppler measurements from the umbilical and fetal arteries in order to predict suboptimal perinatal outcome in small babies at term. DESIGN: Prospective observational study. SETTING: Day assessment unit in a university hospital. SUBJECTS: One hundred and four consecutive women with a clinical suspicion of a small fetus during the third trimester confirmed by ultrasound (abdominal circumference below the 10th centile) and ultimately delivered at term. MAIN OUTCOME MEASURES: Acidaemia at birth, fetal distress requiring emergency caesarean section in labour, admission to the neonatal intensive care unit. RESULTS: Ninety-four babies (90%) weighed less than the 10th centile and the incidence of suboptimal perinatal outcome was 27%. The largest areas under the receiver operating characteristic curves for suboptimal perinatal outcome were obtained with the change in standard deviation score of abdominal circumference and estimated fetal weight, and the ratios of aortic/middle cerebral and renal/middle cerebral pulsatility index. Although low, the odds ratios of the change in estimated fetal weight standard deviation score and the Doppler ratios were significantly different from zero. CONCLUSION: Ultrasound assessment of fetal growth and predelivery fetal Doppler pulsatility index ratios were superior to predelivery estimates of fetal size and umbilical artery pulsatility index in predicting suboptimal perinatal outcome in small fetuses delivering at term, although the clinical value of such a prediction may be limited.

Acidosis↗
PubMed1994

The effect of maternal oxygen administration on human fetal cerebral oxygenation measured during labour by near infrared spectroscopy.

OBJECTIVE: To test the hypothesis that intrapartum maternal oxygen administration increases fetal cerebral oxygenation during normal labour. DESIGN: A prospective study comparing changes in fetal cerebral concentrations of oxyhaemoglobin, deoxyhaemoglobin and cerebral blood volume measured by near infrared spectroscopy, before, during and after maternal oxygen administration using a 60% Ventimask. SETTING: Teaching hospital obstetric unit. SUBJECTS: Ten term fetuses during uncomplicated labour. RESULTS: Maternal oxygen administration for 15 min resulted in a significant increase in the mean concentration of fetal cerebral oxyhaemoglobin (0.78 mumol (SD 0.42) 100 g-1 brain tissue, P < 0.001) and a significant decrease in the mean concentration of deoxyhaemoglobin (0.80 mumol (SD 0.51) 100 g-1, P < 0.001). These changes were associated with a significant increase in the calculated mean cerebral oxygen saturation from 43.9% (SD 6.3) to 57.3% (SD 5.6) (P < 0.001). The maximum rise in cerebral oxyhaemoglobin concentration occurred at a mean of 10.7 min (SD 3.9) following commencement of oxygen administration. On returning to air breathing these changes reversed. There were no changes in cerebral blood volume. CONCLUSION: Maternal oxygen administration during normal labour leads to a significant rise in fetal cerebral oxygenation.

Adult↗