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Biomedical subjects

C W Redman

Publications and source records attributed to C W Redman.

At least 145 records · Page 8Linked to original sources
PubMed1991

The advantages of computerized fetal heart rate analysis.

A brief account is given of the advantages of computerized analysis of human fetal heart rate (FHR) traces antenatally, based on clinical use over 8 years. Accuracy is greater. Results are presented quantitatively and consistently. The numerical measures of the FHR pattern are related to other objective measures of fetal health, e.g. initial compensated hypoxaemia or terminal acidaemia. Computerized analysis has shown that changes in FHR variation are a better guide than the presence or absence of large decelerations. Recording time is used better. Synoptic displays of data over 4 weeks show significant trends in fetal heart rate variation and movements with time. And the problems generated by the limitations of fetal heart rate monitors are identified to exclude spurious information.

Cardiotocography↗
PubMed1991

System 8000: computerized antenatal FHR analysis.

SYSTEM 8000 is a computerized system for antenatal fetal heart rate (FHR) analysis, with interaction online to ensure good quality recording and to minimize the time required to obtain the necessary information (based on fetal movements and tocodynamometer readings as well as FHR). The equipment consists of a Personal Computer with hard disk, interfaced to a fetal monitor. Software is written in C. An extensive definition is given on most of the functions and parameters as calculated by the system, e.g. record quality, uterine contraction peaks, basal heart rate, variation, decelerations and accelerations. System 8000 is designed to take account of the episodic changes in FHR and fetal movements characteristic of sleep states. Their presence naturally affects the mean FHR variation calculated over, say 20-30 mins. But, as the amplitude of these episodes is attenuated in association with growth retardation and hypoxaemia, the measurements of variation decline. In practice inter- and intra-observer variation is greatest in assessing FHR variation. Yet a decrease in variation is the most reliable index of fetal deterioration. The system measures FHR variation accurately and reproducibly, as well as fetal movements. In the synoptic display these two equally important fetal variables are given their rightful prominence. It has been interesting to observe how rarely the basal FHR changes in fetuses suffering progressive respiratory insufficiency, and how extreme tachycardia (a basal rate greater than 170/min) tends to reflect other fetal problems such as infection or maternal pyrexia.

Cardiotocography↗
PubMed1991

Umbilical artery resistance index as a screening test for fetal well-being. II: Randomized feasibility study.

To determine whether the time taken for fetal assessment could safely be reduced by preliminary screening with Doppler ultrasound, 897 women having fetal assessment in the high-risk unit of the John Radcliffe Hospital, Oxford, were randomly allocated to two groups. In the Doppler group, preliminary assessment was by umbilical artery resistance estimation, and in the fetal heart rate (FHR) group by computerized FHR analysis. To minimize the risk of failing to recognize fetal distress, the criteria for using the nonallocated method as well were deliberately conservative. Thus, 66% of the 1869 Doppler studies done in the Doppler group and 39% of the 2069 FHR tests done in the FHR group needed to be followed by the nonallocated tests. Trained nursing staff performed the Doppler studies as part of their routine duties. Doppler studies were unsuccessful in obtaining a result on 26% of the occasions. Under the above clinical circumstances, preliminary Doppler screening did not reduce the time taken for fetal assessment. There were no significant differences in perinatal outcome between the groups, except that emergency as opposed to elective cesareans were less frequent in the Doppler group. As this finding was not predicted by previous hypothesis, it needs to be confirmed.

Adult↗
PubMed1991

Qualitative and quantitative analysis of peritoneal fluids from women with gynecologic diseases. Comparison of cytology and flow cytometry for the detection of malignancy in lavage and ascitic fluids.

A prospective study was undertaken to compare flow cytometric (FCM) analysis to conventional cytologic evaluation for the detection of malignant cells in peritoneal fluids (peritoneal lavages and ascitic fluids) from women with gynecologic diseases. The 94 peritoneal fluids analyzed came from 63 cancer patients (with epithelial ovarian carcinomas) and 31 control patients (with benign gynecologic diseases). The FCM DNA histograms were generated using propidium iodide as a DNA fluorochrome. Samples for cytologic analysis were stained with the standard May-Grünwald-Giemsa or Papanicolaou stains. Of the 94 samples, 90 were evaluable cytologically while 70 were suitable for FCM analysis. The sensitivities were 55% for FCM DNA analysis and 80% for cytologic analysis. FCM DNA analysis had a 30% false-positive rate; cytologic analysis produced no false-positive results. These results indicate that there is no advantage in employing FCM analysis instead of conventional cytologic evaluation for the detection of malignant cells in peritoneal fluids from gynecologic cases.

Adolescent↗
PubMed1991

Computerized fetal heart rate analysis in labor.

Observer variation in visual analysis of fetal heart rate (FHR) records is reportedly high, but can be avoided by computerized numerical analysis. The FHRs of 394 women in labor at 37 or more weeks' gestation were recorded on-line and analyzed to examine how different patterns related to outcome, as judged by umbilical arterial base deficit or Apgar score on delivery. The range of normality and the diversity of patterns of those delivered without acidemia were great. Late decelerations were of poor prognostic value. There was an increase in FHR variation during labor averaging 40%. In this preliminary study, conventional attributes of the FHR, alone or in combination, did not predict metabolic acidemia. Epidural analgesia in 240 women was identified as a confounding variable that significantly affected FHR patterns without influencing the condition of the infant at birth. It was associated with a higher FHR, less FHR variation and fewer decelerations, primiparity, longer labors, more operative deliveries, and a threefold greater cesarean rate. The rise in basal FHR, perhaps due to a rise in maternal temperature, may partly explain the high intervention rate in those without fetal acidemia.

Acid-Base Imbalance↗
PubMed1991

Ambulatory blood pressure monitoring during pregnancy: validation of the TM-2420 monitor.

To validate the accuracy of the TM-2420 ambulatory blood pressure monitor in pregnant women, its measurements were compared with those taken simultaneously by two trained observers using a random zero sphygmomanometer. Each of 30 pregnant women had her blood pressure measured three times. The mean differences between the monitor and the averaged observer measurements were -0.53 +/- 2.7 mmHg for systolic blood pressure, -5.4 +/- 5.3 mmHg for Korotkoff phase 4 (P less than .001), and 0.87 +/- 3.7 mmHg for phase 5 diastolic blood pressure. The TM-2420 ambulatory monitor provides reliable estimates of systolic and Korotkoff phase 5 diastolic blood pressures during pregnancy.

Blood Pressure Monitors↗
PubMed1990

Obstetric audit using routinely collected computerised data.

OBJECTIVE: To examine the use of routinely collected computerised data in clinical audit. DESIGN: Retrospective review of all analyses of obstetric practice based on a computerised data system from January 1983 to June 1988. SETTING: Maternity department of the regional referral hospital in Oxford. MAIN OUTCOME MEASURES: Congruence with the principles of clinical audit; that is, comparing clinical practice with previously agreed standards and changing practice to meet these standards if necessary. RESULTS: Over the five and a half years of the study the data formed the basis of 130 special inquiries into different aspects of obstetric practice. Most inquiries seemed to be aimed only at describing current activities and identifying trends. Genuine clinical audit was rare. Simple audits--for example, concerning induction for pregnancy after term--could be supported by the computerised data, but for detailed and wide ranging audits--for example, reducing antenatal clinic visits for low risk multiparas--the data had to be supplemented from other sources. CONCLUSIONS: Routinely collected computerised data enable ongoing clinical audit, but it becomes a reality only when clinicians agree on standards of practice and have a flexible attitude towards change. Even then, genuine clinical audits of obstetric practice demand more detailed and comprehensive data than are generally available on such systems.

Data Interpretation, Statistical↗
PubMed1990

Flow cytometric characterisation of cell populations in human pregnancy decidua and isolation of decidual macrophages.

Methods have been developed for isolating human tissue macrophages from first trimester or term pregnancy decidua. After a two stage enzymic digestion, viable cells were separated from cellular debris by velocity sedimentation at unit gravity or by Percoll centrifugation. Cell populations were analysed by flow cytometry after labelling with monoclonal antibodies. In term decidua, 47% of the cells were of bone marrow origin, comprising 18% macrophages, 3% large granular lymphocytes and 8% T cells. The remaining cells, the proportion of which varied between individuals, were CD16-positive granulocytes. Macrophages were isolated flow cytometrically from both first trimester and term decidual cell dispersions after labelling with an antibody to MHC class II. Yields of up to 4 X 10(6) macrophages, greater than 95% pure, were routinely obtained.

Antibodies, Monoclonal↗
PubMed1990

Loop diathermy excision of the cervical transformation zone in patients with abnormal cervical smears.

OBJECTIVE: To determine the efficacy and morbidity of fine loop diathermy excision of the cervical transformation zone as applied to the management of outpatients with abnormal cervical smears. DESIGN: Prospective programme trial with six month follow up. SETTING: Two hospital based colposcopy clinics. PATIENTS: 616 Patients aged 16-60 with abnormal cervical smears. INTERVENTIONS: After colposcopic and cytological assessment excision of the cervical transformation zone by fine loop diathermy under local anaesthesia in the outpatient department. MAIN OUTCOME MEASURES: Time to complete the treatment, immediate morbidity in terms of discomfort and bleeding, and cytological and colposcopic findings at six months. RESULTS: Treatment was completed in a mean of 3.47 minutes (SD 1.99). Immediate morbidity was minimal, and histological specimens were adequate in over 90% of cases. Almost two thirds of patients were treated at their first visit to the clinic. 58 Patients (9.4%) failed to attend for follow up at six months and one had had a hysterectomy. Of the 557 patients who attended for colposcopic and cytological follow up at six months, 506 (91%) were normal cytologically and 19 (3.4%) had histologically confirmed persistence of cervical intraepithelial neoplasia. The overall confirmed failure rate of the technique was 4.4%. CONCLUSION: Loop diathermy excision is an effective treatment with low morbidity and is an appropriate modality for patients with abnormal cervical smears.

Adolescent↗
PubMed1990

The potential for adjuvant therapy in early-stage cervical cancer.

Adjuvant therapy may potentially improve prognosis in women with early-stage cervical cancer who are at high risk of relapse after primary therapy. Patients with lymph node involvement at surgery are at high risk of recurrence and may benefit from adjuvant therapy, but many patients are treated with radical radiotherapy. At present there is no method of accurately identifying patients at high risk of recurrence in the latter group. A retrospective analysis of 141 surgically managed cases with stage I/II a cervical cancer is presented. The study aims were to characterize patients at high risk of relapse, identify independent prognostic variables predicting for relapse and, using these variables, develop a model, that would accurately predict high-risk patients. Univariate analysis identified depth of invasion, substage, lymph node involvement, lymphatic and blood vessel invasion and tumour differentiation as significant prognostic variables. After stratification for depth of invasion, which did not conform to the proportional hazards assumption implicit in the Cox model, Cox regression analysis showed substage, lymphatic and vascular invasion and histological tumour type to be independent prognostic variables. Using these variables, classification models were constructed that would be applicable to patients treated with either surgery or radiotherapy. Applying the models to 110 cases with greater than 18 months follow-up, 11/18 (61%) and 11/19 cases (58%) predicted as being at high risk of relapse have developed recurrence. Highly active chemotherapy is now available for this disease. We have demonstrated that combined bleomycin, ifosfamide and cisplatin (BIP) is one of the most active regimens in this disease. BIP produces cytoreduction in around 70% of patients with recurrent and primary advanced disease. Responses are achieved rapidly and acute radiotherapy toxicity is not enhanced by giving chemotherapy prior to radical local radiotherapy. A multicentre, prospective randomized trial testing the role of BIP as adjuvant therapy in patients with positive nodes at radical hysterectomy is now in progress. A complementary study testing the role of adjuvant chemotherapy in high-risk patients treated with radical radiotherapy is in preparation.

Adenocarcinoma↗
PubMed1990

Limitations of antenatal fetal heart rate monitors.

Erroneous or doubtful decelerations in fetal heart traces were present in 111 of 1000 consecutive antenatal clinical records obtained by monitors with autocorrelation. The incidence was 20% in fetuses less than 30 weeks of gestational age. Their elimination reduced the number of "decelerative" records by 42%. Erroneous or doubtful accelerations were also present in 11% of records. These errors are caused by the fetal heart rate monitor and may contribute to the high intraobserver and interobserver variation on visual analysis. They can be detected by computer analysis.

Equipment Failure↗
PubMed1990

Criteria for the design of fetal heart rate analysis systems.

Criteria are described for the automated analysis of fetal pulse intervals, fetal movements and of uterine contractions measured externally, antenatally and interactively on-line, for implementation on a personal computer interfaced to an appropriate fetal monitor, and tested on 10,000 records. Measurements of short and longer term fetal heart rate variation are compared; both are required to identify sinister records. Recall and display of records acquired on the same patient over several weeks has proved a useful diagnostic aid.

Computer Graphics↗
PubMed1990

Early serum CA125 response and outcome in epithelial ovarian cancer.

The prognostic value of serum CA125 levels before and after two courses of chemotherapy was assessed in 50 patients with advanced epithelial ovarian cancer. Patients with serum CA125 values below 35 U/ml after two courses were significantly more likely to achieve complete remission and had a significantly longer median survival. In multivariate analysis, serum CA125 levels after two courses were the most important independent prognostic factor: it was possible to predict survival status at 12 months with an overall accuracy of 93%. Serum CA125 can be used to evaluate quantitatively chemotherapeutic response and at an early stage classify patients into good and poor risk groups. Such an approach would facilitate the selection of appropriate therapy and could reduce toxicity.

Antigens, Tumor-Associated, Carbohydrate↗