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Biomedical subjects

Andrew H Shennan

Publications and source records attributed to Andrew H Shennan.

18 recordsLinked to original sources

Plasma lipid profiles of women with intrahepatic cholestasis of pregnancy.

OBJECTIVE: Intrahepatic cholestasis of pregnancy is associated with dyslipidemia, but the gestational lipid profile in relation to clinical diagnosis of the disease is unknown. The aim of this study was to undertake a detailed analysis of plasma lipids in women presenting with intrahepatic cholestasis of pregnancy and pruritus gravidarum. METHODS: Plasma lipid concentrations were assessed in nonfasting blood samples from 63 women with intrahepatic cholestasis of pregnancy (n = 54, recruited at the time of diagnosis, and n = 9, who later developed the disease), 43 women with pruritus gravidarum, and 26 healthy pregnant controls during pregnancy and at 4-6 weeks postpartum. RESULTS: Intrahepatic cholestasis of pregnancy was associated with an abnormal lipid profile. Low-density lipoprotein (LDL) cholesterol, apolipoprotein B-100, and total cholesterol concentrations were significantly raised during pregnancy in women with intrahepatic cholestasis of pregnancy compared with pruritus gravidarum and controls, and LDL-cholesterol was raised before clinical diagnosis. High-density lipoprotein cholesterol was lower in women with intrahepatic cholestasis of pregnancy compared with the pruritus gravidarum group. Ursodeoxycholic acid did not alter plasma lipid concentrations. CONCLUSION: Intrahepatic cholestasis is associated with dyslipidemia, which may contribute to the pathogenesis of the disease. The elevation of LDL cholesterol and reduction of high-density lipoprotein cholesterol before clinical diagnosis may prove to be a useful biomarker for the early identification of intrahepatic cholestasis of pregnancy and differentiation from pruritus gravidarum. LEVEL OF EVIDENCE: II-2.

Adult↗

Validation of a non-mercury digital auscultatory device with manual pressure registration (PMS Mandaus).

OBJECTIVE: To assess the clinical accuracy of a non-mercury digital auscultatory device (PMS Mandaus) with manual pressure registration in an adult population. METHODS: The accuracy of the device was assessed by predefined criteria (European Society of Hypertension protocol) in 33 study participants recruited from among patients and staff in a teaching hospital. A series of same-arm sequential blood pressure measurements were taken: first, two observers taking simultaneous mercury readings, followed by a reading with the device. A total of seven readings were taken from each participant in the sitting position. The data were then analysed according to the European Society of Hypertension protocol and the criteria of the Association for the Advancement of Medical Instrumentation. RESULTS: The device fulfilled the criteria of the European Society of Hypertension protocol, achieving a pass for both systolic and diastolic pressure. The device also passed the Association for the Advancement of Medical Instrumentation standard (the mean to be within 5+/-8 mmHg) with the mean differences being -3.2+/-3.8 mmHg for systolic blood pressure and -1.8+/-2.9 mmHg for diastolic blood pressure. CONCLUSION: The device performed in a satisfactory manner according to the European Society of Hypertension and the Association for the Advancement of Medical Instrumentation criteria. The systematic under-recording related to the delay of manual pressure registration is not sufficient to preclude clinical use.

Adult↗

Validation of the DINAMAP ProCare blood pressure device according to the international protocol in an adult population.

OBJECTIVE: Inaccurate blood pressure measurement has serious implications for both the patient and the health service. It results in inappropriate treatment and underestimation of clinical risk. Few automated devices have been shown to be accurate when compared with mercury sphygmomanometery. The DINAMAP ProCare has been developed to be accurate compared with an auscultatory standard. We used the International Protocol of the European Society of Hypertension to assess the accuracy of this device in an adult population. METHODS: Thirty-eight participants were recruited from outpatient clinics and staff at Groote Schuur Hospital, Cape Town, RSA. Of these, 33 participants who fulfilled the requirements of the International Protocol were selected for final analysis. Demographic data were obtained from each participant, followed by nine sequential same-arm measurements, alternating between two trained observers and the device. The last seven readings were analysed according to the guidelines of the International Protocol. RESULTS: The ProCare Monitor achieved all the required criteria of the International Protocol by successfully passing phase 1, phase 2.1 and phase 2.2 of the study protocol. The mean difference (standard deviation) for systolic and diastolic pressures, respectively, were -2.5 (5.4) and 0.5 (4.5) mmHg, which also falls within the passing criteria for the Association for the Advancement of Medical Instrumentation Standard (ANSI/AAMI SP-10). CONCLUSION: The DINAMAP ProCare Monitor can be recommended for clinical use in an adult population.

Adult↗

Optimal bedside urinalysis for the detection of proteinuria in hypertensive pregnancy: a study of diagnostic accuracy.

OBJECTIVE: To compare semi-quantitative visual and automated methods of urine testing with fully quantitative point of care urinalysis for the detection of significant proteinuria (0.3 g/24 hours) in pregnancy complicated by hypertension. DESIGN: A prospective comparative study. SETTING: A large teaching maternity hospital. SAMPLE: One hundred and seventy-one pregnant women referred to the obstetric day-care unit for assessment of newly arisen hypertension. METHODS: Early morning urine specimens were tested with four dipstick techniques (Multistix 8SG visual and automated and microalbumin/creatinine ratio visual and automated; Bayer, Elkhart, USA) as well as a fully quantitative measure of the microalbumin creatinine ratio with the DCA 2000 (a point of care assay for albumin; Bayer). These results were compared to a 24-hour urine protein measurement and measures of diagnostic accuracy/prediction are reported. MAIN OUTCOME MEASURES: Significant proteinuria (> or =0.3 g/24 hours) measured by laboratory assay. RESULTS: Automated dipstick urinalysis using the Clinitek 50 has significantly better predictive values for significant proteinuria (LR(+) 4.27, 95% CI 2.78 to 6.56; LR(-) 0.225, 95% CI 0.14 to 0.37) than conventional visual dipstick urinalysis (LR(+) 2.27, 95% CI 1.47 to 3.51; LR(-) 0.635, 95% CI 0.49 to 0.82). Dipstick microalbumin/creatinine ratio testing did not improve overall detection rates with automated or visual testing. Fully quantitative point of care measurement of albumin/creatinine ratio (ACR) was significantly better than any dipstick technique (LR(+) 14.6, 95% CI 6.74 to 31.8; LR(-) 0.069, 95% CI 0.030 to 0.16). CONCLUSIONS: This study confirms that in pregnancy automated dipstick urinalysis is a more accurate screening test for the detection of proteinuria than visual testing. ACR testing can offer a significant improvement over conventional urinalysis if a fully quantitative method of detection is employed that uses pregnancy-specific thresholds. Dipstick assessment of ACR does not improve the detection rate of significant proteinuria.

Adult↗

TOCOX--a randomised, double-blind, placebo-controlled trial of rofecoxib (a COX-2-specific prostaglandin inhibitor) for the prevention of preterm delivery in women at high risk.

OBJECTIVE: To assess the safety and efficacy of the long term prophylactic use of rofecoxib (a COX-2-specific inhibitor) in women at high risk of preterm delivery. DESIGN: A randomised, double-blind, placebo-controlled trial. SETTING: Queen Charlotte's and Chelsea Hospital, London and Guys and St Thomas' Hospitals, London. POPULATION: Ninety-eight singleton pregnancies at high risk of preterm labour. METHODS: Treatment from 16 to 32 weeks. Weekly ultrasound surveillance. MAIN OUTCOME MEASURES: Fetal renal function and ductus arteriosus blood flow changes. Preterm delivery rates and neonatal outcome. RESULTS: Rofecoxib caused a reduction in hourly fetal urine production rates (-34%, 95% CI -13 to -50%, P = 0.004) and amniotic fluid index (-2.2, 95% CI -3.2 to -1.2, P < 0.001). This effect did not increase with time on treatment and reversed in all cases on discontinuation of treatment. Rofecoxib had an effect on the ductus arteriosus, increasing maximum systolic velocity (0.1 m/s, 95% CI 0.03-0.16, P = 0.02) and minimum diastolic velocity (0.007 m/s, 95% CI 0.0007-0.013, P= 0.03). This effect increased with time on treatment but was reversed with discontinuation of treatment and had no long term clinical sequelae. There was no difference in preterm delivery rates <30 weeks (28% on placebo vs 33% on rofecoxib, Mantel-Haensel [M-H]-adjusted risk 1.11, 95% CI 0.67-1.87). There were more deliveries <37 weeks in those on rofecoxib (40%vs 67%, M-H-adjusted risk 1.59, 95% CI 1.09-2.32). Rates of preterm prelabour rupture of membranes (PPROM) were higher in those on rofecoxib (RR 2.5, 95% CI 1.3-4.7). CONCLUSION: Rofecoxib has a significant but reversible effect on fetal renal function and the ductus arteriosus. It does not reduce the incidence of early preterm delivery <30 weeks and is associated with an increased risk of delivery before 37 weeks in women at high risk.

Adult↗

Elective cervical cerclage versus serial ultrasound surveillance of cervical length in a population at high risk for preterm delivery.

OBJECTIVE: To compare pregnancy outcome for women at risk of preterm delivery undergoing elective cervical cerclage in the first trimester or serial transvaginal assessment of cervical length with cerclage only if indicated (control cases). DESIGN: A matched case control study. SETTING: Prematurity clinic at two London teaching hospitals. POPULATION: Women at high risk for preterm delivery. METHODS: Cases of elective cervical cerclage were matched for maternal age, ethnic group, previous cervical surgery, previous second trimester loss and early preterm delivery to women undergoing serial ultrasound surveillance of cervical length. Pregnancy outcome data was collected. Data was analysed using Fisher's exact, Mann-Whitney and Student's t-tests. MAIN OUTCOME MEASURES: Gestation at delivery, rate of delivery <24, 24-32 and 32-37 weeks gestation. RESULTS: Thirty-nine cases of elective cervical cerclage were matched to control cases. Both groups were similar for maternal age, ethnic group, previous cervical surgery, previous second trimester loss and early preterm delivery. Cervical cerclage was performed in 14 (36%) of the control cases due to cervical changes. There was no significant difference in median gestation at delivery (266 days versus 260 days P=0.9), number delivering <24 weeks (15% versus 13% P=0.9), at 24-32 weeks (7.5% versus 15% P=0.6) and at 32-37 weeks (15% versus 13% P=0.9). CONCLUSION: Serial transvaginal ultrasound surveillance of cervical length in women at high risk of preterm delivery appears to reduce cerclage rates without compromising pregnancy outcome. A large multicentered randomised trial is required to confirm these findings.

Adult↗

Glutathione S-transferase and liver function in intrahepatic cholestasis of pregnancy and pruritus gravidarum.

Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-specific liver disease associated with poor maternal and fetal outcome. The diagnosis is based on pruritus with abnormal liver function in the absence of other pathological conditions. However, pruritus in pregnancy is common, and it may be the only presenting feature in ICP. No reliable test currently exists that can discriminate between those women destined to develop ICP and those with the benign condition of pruritus gravidarum (PG). The purpose of this prospective study was to investigate longitudinally the serum concentration of glutathione S-transferase alpha (GSTA, a specific marker of hepatocellular integrity) and to compare this with the temporal profile of conventional liver function markers in women with ICP (n = 63), PG (n = 43), and normal pregnant controls (n = 26). Blood was sampled on at least 3 separate occasions between 16 weeks of gestation and 4 weeks postpartum. Serum concentrations of GSTA increased with gestation in ICP, being significantly higher from 24 (+/-2) weeks compared with controls (400% difference; 95% CI, 240%-734%; P < .001). GSTA was also higher in ICP versus PG (433% difference; 95% CI, 228%-790%; P < .001) throughout the gestational period studied. Significant differences in the ICP compared with control and PG groups were also found for total bile acids, alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transpeptidase and alkaline phosphatase. In conclusion, the measurement of GSTA provides a test of liver dysfunction that distinguishes women with ICP from those with PG. Additionally, on the basis of this study, reference ranges for biochemical markers of liver function require reevaluation in pregnancy.

Adult↗

Clinical evaluation of an automated oscillometric blood pressure wrist device.

OBJECTIVES: Up to one-third of all blood pressure devices sold are for measurement at the wrist. Wrist monitors are thought to be subject to errors associated with movement and incorrect posture. We used the British Hypertension Society protocol to determine the accuracy of the Omron Rx automated wrist blood pressure monitor in adults. We also investigated the errors associated with miscuffing and posture with measurements at the wrist compared to the upper arm. METHODS: The study was conducted at a large teaching hospital in the UK. Participants 18 years and over were eligible for inclusion. Exclusion criteria were cardiac arrhythmias and inaudible Korotkoff sounds. Eighty-five participants were selected for the main validation study. Thirty-four subjects took part in the study investigating miscuffing issues and 15 subjects were included in the study investigating postural errors. RESULTS: The Omron Rx achieved an overall grade B according to the British Hypertension Society Protocol. The mean differences (standard deviation) between the observers and the device were 0.3 (9.0) and 2.5 (8.8) mmHg for systolic and diastolic blood pressure respectively. In the medium and high-pressure ranges (> or =130/80 mmHg) the device achieved a grade C. When used at home the mean blood pressure reading over 60 measurements in 15 subjects was 123/75 mmHg when taken with the Omron Rx and 124/77 mmHg when taken with the automated upper arm device with no significant difference in the standard deviation of the readings. When compared with mercury sphygmomanometry using both a medium and large cuff, the wrist device readings were closest to the mercury measurements when the most appropriately sized cuff was used. CONCLUSIONS: The Omron Rx wrist monitor is accurate according to the British Hypertension Society protocol, but narrowly fails the Association of the Advancement of Medical Instrumentation criteria. Measurements at the wrist are not associated with miscuffing errors. Use of the wrist device by patients in the home setting gives comparable readings to a standard upper arm device.

Adolescent↗

The Maxi Stabil 3: validation of an aneroid device according to a modified British Hypertension Society protocol.

BACKGROUND: Measuring blood pressure with mercury-independent alternatives is rapidly gaining attention. Mercury will be phased out of clinical use as a result of environmental, health and safety concerns and it is of vital importance that any alternative to mercury has to be of a recognized standard. We assessed the accuracy of the Maxi Stabil 3 aneroid device in an adult population according to a modified British Hypertension Society protocol (with the low systolic category changed from less than 90 mmHg to less than 100 mmHg). POPULATION: Eighty-five subjects were recruited from among staff and patients at Guy's and St Thomas' Hospitals, London, UK. METHODS: The aneroid device was connected in parallel to two mercury sphygmomanometers. Nine sequential same-arm measurements were taken from each subject by two trained observers, alternating between mercury sphygmomanometry and the aneroid device. Simultaneous mercury readings were also recorded for additional analysis. RESULTS: The device achieved an A grade for both systolic and diastolic pressures and fulfilled the requirements of the Association for the Advancement of Medical Instrumentation. The mean and standard deviation for systolic and diastolic pressures respectively were -0.6 (4.6) mmHg and -1.3 (3.5) mmHg in sequential analysis, and -1.3 (2.2) mmHg and -1.9 (2.7) mmHg in simultaneous analysis. CONCLUSION: The Maxi Stabil aneroid device can be recommended for use in an adult population.

Adult↗

Ultrasound-indicated cervical cerclage: outcome depends on preoperative cervical length and presence of visible membranes at time of cerclage.

OBJECTIVE: The purpose of this study was to assess cases of ultrasound-indicated cervical cerclage and to relate preoperative cervical length, operative findings, postoperative cervical length, and pregnancy outcome to establish the appropriate criteria to offer cervical cerclage. STUDY DESIGN: A prospective observational study comprised 380 women at high risk of preterm labor who underwent serial transvaginal ultrasonographic assessment of cervical length. Seventy-three women had criteria for and underwent cervical cerclage. Data concerning preoperative cervical length, operative findings, postoperative cervical length, and pregnancy outcome were collected. Statistical analysis was performed with Mann-Whitney and Fisher exact tests. RESULTS: There was a significant increase in median cervical length after cerclage, 15.0 versus 25.0 mm (P <.0001). Preoperative cervical length and postoperative upper cervical length were independently better predictors of outcome than postoperative entire cervical length. Fetal membranes were visible in 18% of cases at the time of suture insertion, which was associated with a significantly worse outcome, regardless of preoperative cervical length. Of those 41 women with a very short preoperative cervical length (< or = 15 mm), outcome was significantly worse in those women with visible fetal membranes at the time of cerclage compared with those women with no visible fetal membranes at the time of cerclage: median gestational age at delivery, 23 weeks versus 37 weeks 4 days (P =.002); suture insertion to delivery interval, 19 days versus 108 days (P =.0004); and fetal survival rates, 50% versus 86% (P =.03). CONCLUSION: In a high-risk population that undergoes serial transvaginal ultrasound surveillance of cervical length, the presence of visible fetal membranes at the time of suture insertion, regardless of preoperative cervical length, is associated with a poor outcome. Fetal membranes were not visible in any cases with a preoperative cervical length of >15 mm. These findings lend support to a practice of offering cerclage at or above a cervical length of 15 mm.

Adult↗

Hidden errors of aneroid sphygmomanometers.

BACKGROUND: Measurement of blood pressure remains the most commonly performed screening test in medical practice. With the likely removal of mercury sphygmomanometers from the workplace alternative devices are required. Of these the aneroid sphygmomanometer is popular both in the community and hospital setting. We investigated the accuracy of all the aneroid and mercury sphygmomanometers during dynamic calibration within a tertiary referral maternity hospital. METHODS: We compared the accuracy of 39 aneroid and 36 mercury sphygmomanometers to a recently calibrated and serviced mercury sphygmomanometer (the accepted gold standard). All devices were in current clinical use. Using three blinded, trained observers, 30 different pressures were checked throughout the pressure range following British Hypertension Society protocol guidelines. RESULTS: Only 31 (86%) of the mercury devices and 36 (92%) of the aneroid devices were in adequate working condition and suitable for analysis. Significantly more aneroid devices had systematic errors of > 5 mmHg (19 versus 3%, < 0.05). Fifty percent of aneroid devices had at least one reading > 10 mmHg out compared to only 10% of mercury devices (chi square programme). CONCLUSIONS: Aneroid sphygmomanometers in apparent good working order are inaccurate compared to mercury devices. Some of these faults can only be detected during dynamic testing. To minimize the risk of erroneous blood pressure recording, aneroid devices should be regularly checked for accuracy using dynamic calibration methods as recommended in validation protocols.

Adult↗

Validation of the Microlife BP 3BTO-A oscillometric blood pressure monitoring device according to a modified British Hypertension Society protocol.

BACKGROUND: The market for devices for the self-measurement of blood pressure is growing, and as accuracy is of prime importance, there is increasing pressure for manufacturers to provide evidence of independent testing. Recent reviews have shown that only five automated upper arm devices for self-measurement of blood pressure have been recommended for use. We tested the Microlife BP 3BTO-A, a lightweight, upper arm, automated oscillometric device, according to a modified version of the British Hypertension Society protocol and also analysed the computer-generated oscillograms for possible causes of inaccuracy. METHODS: One hundred and twenty-six subjects were recruited from general medical and specialist clinics and from amongst the staff at Guy's and St Thomas' Hospital, London, UK. Only 85 of these were included in the final analysis. Nine sequential readings were taken by two trained observers alternating between the mercury sphygmomanometer and the device. The last seven readings were analysed according to the British Hypertension Society protocol. Modifications to the protocol were: (1) the exclusion of patients whose blood pressure varied by more than 15 mmHg between sequential observer readings and (2) limited testing in the low systolic pressure range. RESULTS: The Microlife achieved a grade A for both systolic and diastolic pressure according to the British Hypertension Society protocol. The mean differences (standard deviation) between the observers and the device were -1.6 (7.7) mmHg and -2.1 (6.3) mmHg for systolic and diastolic blood pressure, respectively, therefore also fulfilling the criteria set by the Association for the Advancement of Medical Instrumentation. Sub-analysis for different pressure ranges showed that the device was less accurate in the high-pressure range (>160/100 mmHg). CONCLUSION: The Microlife can be recommended for clinical use in an adult population.

Adult↗

Inflationary oscillometric blood pressure monitoring: validation of the OMRON-MIT.

BACKGROUND: To evaluate the accuracy of the OMRON-MIT, (an automated inflationary oscillometric blood pressure monitoring device) for use in the general population by direct comparison to standard auscultatory mercury sphygmomanometry. DESIGN: Two trained, blinded observers taking simultaneous blood pressure measurements alternating between a mercury sphygmomanometer and the OMRON-MIT. METHODS: The evaluation was carried out according to the revised British Hypertension Society protocol. The validation data was also classified by the American Association for the Advancement of Medical Instrumentation (AAMI). RESULTS: The OMRON-MIT device achieved a BHS grade A for both systolic blood pressure (SBP) and diastolic blood pressure (DBP). It also met the criteria for the AAMI protocol, the mean difference between the MIT and standard was -2.0 +/- 7 mmHg for SBP and -2.0 +/- 6 mmHg for DBP. CONCLUSIONS: Inflationary oscillometry is a valid technique for the measurement of blood pressure. The OMRON-MIT, which uses this technique, is accurate and can be recommended for clinical use in the adult population.

Adult↗

Inflationary oscillometry provides accurate measurement of blood pressure in pre-eclampsia.

OBJECTIVE: To evaluate the accuracy of the OMRON-MIT inflationary oscillometric device for blood pressure measurement in pregnancy and pre-eclampsia. DESIGN: Prospective observational study, using validation methods recommended by the British Hypertension Society (BHS) and the Association for the Advancement of Medical Instrumentation (AAMI). SETTINGS: Antenatal clinics and ward, Guy's Hospital, London. POPULATION: Normotensive pregnant women and those diagnosed with pre-eclampsia according to the definition of the International Society for the Study of Hypertension in Pregnancy. METHODS: Validation according to BHS protocol. MAIN OUTCOME MEASURES: Proportion of readings within 5, 10 and 15 mmHg (absolute differences) between the automated device and two trained, blinded observers, according to the BHS and AAMI criteria. RESULTS: The OMRON-MIT achieved an overall BHS grade B for systolic and grade A for diastolic blood pressure measurement in both pregnancy and pre-eclampsia. The mean (SD) differences between the standard and the test device were -5 (7) mmHg for systolic and 2 (6) mmHg for diastolic blood pressure in pregnancy and -4 (6) mmHg for systolic and 2 (7) mmHg for diastolic blood pressure in pre-eclampsia. This device therefore fulfils the AAMI criteria. CONCLUSION: The OMRON-MIT is the only automated oscillometric device that has proven to be accurate for blood pressure measurement in pre-eclampsia according to the BHS protocol in pregnancy. Inflationary oscillometry may correct the error associated with oscillometric devices in pre-eclampsia.

Adolescent↗