James A. Penny

Automated, ambulatory, or conventional blood pressure measurement in pregnancy : Which is the better predictor of severe hypertension?

Abstract OBJECTIVES: Our purpose was to investigate the benefit, if any, of automated blood pressure monitoring over obstetric day unit conventional blood pressure measurement in the assessment of hypertensive pregnancies. STUDY DESIGN: A prospective, observational study was carried out in two large teaching hospitals. Three hundred and forty-eight women with a confirmed clinic blood pressure of at least 140/90 mm Hg were recruited. Conventional blood pressure measurements (≤5) were obtained on the day unit and simultaneously an ambulatory blood pressure monitor was applied for 24 hours. The predictive ability of day unit assessment (blood pressure >140/90 mm Hg) and automated blood pressure monitoring (blood pressure >130/85 mm Hg) was compared. Principal outcome measures included the occurrence of severe hypertension (>160/110 mm Hg) and proteinuria (>500 mg or 2+) within (a) 2 weeks and (b) the remainder of the pregnancy. Thompsons method was used to compare sensitivity and specificity of the day unit blood pressure and automated blood pressure monitoring. RESULTS: Three hundred and forty-eight women were recruited to the study. The comparison between automated blood pressure monitoring and conventional blood pressure measurement for both sensitivity and specificity for systolic and diastolic blood pressure revealed increased sensitivity and decreased specificity with automated blood pressure monitoring for all principal outcomes except development of proteinuria for systolic blood pressure. Sensitivity for the outcomes was increased with automated blood pressure monitoring by between 14% and 27% for systolic blood pressure and between 7% and 39% for diastolic blood pressure, with the greatest improvement seen for the development of severe hypertension within 2 weeks of assessment. CONCLUSIONS: In the assessment of hypertensive pregnancies, automated blood pressure measurement was a significantly better predictor (compared with conventional day unit assessment) for the development of severe hypertension within 2 weeks of assessment for both systolic and diastolic blood pressure. (Am J Obstet Gynecol 1998;178:521-6.)

Comparison of auscultatory and oscillometric automated blood pressure monitors in the setting of preeclampsia

OBJECTIVE The aim of this study was to compare the accuracy of 2 automated blood pressure monitors against mercury sphygmomanometry and intra-arterial blood pressure determination in women with preeclampsia. STUDY DESIGN The auscultatory and oscillometric monitors were compared with mercury sphygmomanometry according to the British Hypertension Society protocol and criteria of the Association for the Advancement of Medical Instrumentation in a group of 30 women with proteinuric preeclampsia. In addition both monitors were compared with intra-arterial blood pressure measurements in a group of 6 women with severe preeclampsia. The mean (+/- SD) of the differences was calculated and a paired t test was used to compare values obtained with each monitor with intra-arterial measurements. RESULTS Compared with mercury sphygmomanometry the auscultatory QuietTrak monitor markedly underestimated systolic and diastolic blood pressure by 13 +/- 15 mm Hg. The oscillometric SpaceLabs 90207 monitor also underestimated systolic pressure by 10 +/- 10 mm Hg and diastolic pressure by 8 +/- 7 mm Hg. According to the British Hypertension Society grading criteria both monitors achieved the lowest grade (D) for recording systolic and diastolic pressure. The 2 monitors also did not meet the accuracy criteria stipulated by the Association for the Advancement of Medical Instrumentation. Compared with intra-arterial readings the SpaceLabs monitor significantly underestimated systolic and mean arterial pressures (by 19 and 7 mm Hg, respectively, P <. 01). The QuietTrak monitor significantly underestimated systolic, diastolic, and mean arterial pressures (by 25 mm Hg, P <.05, 18 mm Hg, P <.01, and 20 mm Hg, P <.01, respectively). CONCLUSION Neither monitor can be recommended for clinical use in women with proteinuric preeclampsia.

Oral and Vaginal misoprostol compared with dinoprostone for induction of labor: A randomized controlled trial

OBJECTIVE To evaluate the efficacy of oral and vaginal misoprostol compared with the standard regimen using dinoprostone for induction of labor. METHODS We conducted a multicenter, randomized controlled trial in Cape Town, South Africa. A total of 573 women admitted for induction of labor were randomized to receive oral misoprostol, vaginal misoprostol, or the control, dinoprostone. Misoprostol was given orally or vaginally as a 50‐μg dose at 6‐hour intervals to a maximum of four doses. The dinoprostone gel was given as a 1‐mg dose in the posterior fornix every 6 hours (maximum two doses). RESULTS There was no significant difference in vaginal delivery rate in 24 hours between the vaginal misoprostol and dinoprostone groups. However, significantly fewer women delivered vaginally in the oral misoprostol group compared with those in the dinoprostone group (relative risk 0.71, 99% confidence interval 0.51, 0.99). The median induction to vaginal delivery time in the vaginal misoprostol, oral misoprostol, and dinoprostone groups was 12 hours, 23 hours, and 14 hours, respectively. The cesarean rate was approximately 33% in all the groups. There were more cesareans performed for fetal distress in the vaginal misoprostol group compared with the dinoprostone group (relative risk 2.86, 99% confidence interval 1.49, 5.46). There was a higher incidence of tachysystole in the vaginal misoprostol group (5.8%) compared with the other two groups: oral misoprostol (0.8%) and dinoprostone (0.8%), but this difference was not statistically significant. There were no differences in maternal or fetal complications. CONCLUSION Vaginal misoprostol is as effective as dinoprostone in induction of labor, but it is associated with more tachysystole and cesarean sections for fetal distress compared with dinoprostone. Oral misoprostol results in fewer vaginal deliveries in 24 hours, but it is not associated with increased tachysystole or fetal distress.

Blood pressure measurement in severe pre-eclampsia

Hypertensive disease in pregnancy remains a leading cause of maternal mortality. Death is often associated with cerebral haemorrhage with severe hypertension being the most important aetiological factor. Accurate measurement of blood pressure (BP) is essential to prevent maternal morbidity and mortality, and most units rely on indirect BP measurements. Some automated BP monitors under-record in pregnancy and particularly in pre-eclampsia when compared with mercury sphygmomanometry. There are no published data comparing intra-arterial measurements in severe pre-eclampsia with mercury sphygmomanometry and automated devices. The objective of this study was to determine the best non-invasive method for measuring BP in women with severe hypertension. We recruited nine women who required invasive monitoring for complications of severe preeclampsia/eclampsia (eg, pulmonary oedema) and four controls with other medical conditions requiring invasive monitoring. All women were studied within 12 hours of delivery. Women gave verbal consent and the study was approved by the University of Cape Town research ethics committee. Comparison was made between intra-arterial BP and three methods of non-invasive BP measurement: conventional sphygmomanometry and two automated BP devices, the Dinamap XL 9301 (Johnson and Johnson Medical, Tampa, USA) and the SpaceLabs Scout (SpaceLabs, Redmond, USA). The signal from the radial arterial line was recorded digitally on to an IBM PC for subsequent analysis. A static calibration was performed at 0 and 100 mm Hg and optimum dynamic calibration verified with a fast-flush test. All patients were semi-recumbant and the radial catheter, transducer, BP cuff, and sphygmomanometer were at heart level. All sphygmomanometry readings were obtained by a single trained observer who was blinded to intra-arterial BP. Diastolic BP was recorded at the disappearance of sounds. Intra-arterial BP was recorded for 15 s followed by an indirect BP on the same arm. This cycle repeated ten times for each automated BP device and for mercury sphygmomanometry as recommended by the Association for the Advancement of Medical Instrumentation. The ten comparisons on each individual were reduced to a summary measure. For each indirect BP measuring device the mean and standard deviation of the differences from intra-arterial measurements were calculated. The 95% confidence intervals of the mean of the differences were calculated and if they were significantly different from zero the non-invasive measurements were considered significantly different from the intra-arterial measurements. In pre-eclamptic women both automated monitors significantly underestimated systolic and mean BP by 11–18 mm Hg (see table). Diastolic BP was also underestimated by the Dinamap (11 mm Hg). Individual measurements were underestimated by up to 40 mm Hg. Conventional sphygmomanometry underestimated systolic by 7 mm Hg, overestimated diastolic by 6 mm Hg, and therefore a calculated mean arterial pressure (MAP) was only 2 mm Hg less than intra-arterial pressure. At present the use of automated monitors for the management of women with pre-eclampsia must be regarded with caution. We do not know if the difficulty is specific to the two monitors that we have studied, or is more general since no other monitor has been evaluated in this way. Despite the disadvantages of mercury sphygmomanometry, it is the technique that should be used to confirm severe hypertension. If an automated BP monitor is to be used in a woman with pre-eclampsia, its accuracy must be verified by comparison with conventional sphygmomanometry in each individual.

Validation of the Welch Allyn Quiettrak Ambulatory Blood Pressure Monitor in Pregnancy

Objective: To assess the accuracy of the Welch Allyn QuietTrak ambulatory blood pressure monitor in pregnancy.Method: The QuietTrak ambulatory blood pressure monitor was validated for accuracy using the protocol of the British Hypertension Society (BHS).Results: The machine achieved a grade B for systolic and diastolic blood pressure according to the BHS grading criteria. The mean difference (standard deviation) between observer and machine for systolic was 0.34 mm Hg (9 mm Hg) and for diastolic was -1.6 mm Hg (8 mm Hg).Conclusions: The Welch Allyn QuietTrak ambulatory blood pressure monitor is accurate for use in pregnancy according to BHS and narrowly failed the criteria of the Association for the Advancement of Medical Instrumentation (AAMI) criteria.

Ambulatory or conventional blood pressure measurement in pregnancy — Which is the better predictor of severe hypertension?

OBJECTIVES Our purpose was to investigate the benefit, if any, of automated blood pressure monitoring over obstetric day unit conventional blood pressure measurement in the assessment of hypertensive pregnancies. STUDY DESIGN A prospective, observational study was carried out in two large teaching hospitals. Three hundred and forty-eight women with a confirmed clinic blood pressure of at least 140/90 mm Hg were recruited. Conventional blood pressure measurements (< or =5) were obtained on the day unit and simultaneously an ambulatory blood pressure monitor was applied for 24 hours. The predictive ability of day unit assessment (blood pressure > 140/90 mm Hg) and automated blood pressure monitoring (blood pressure > 130/85 mm Hg) was compared. Principal outcome measures included the occurrence of severe hypertension (> 160/110 mm Hg) and proteinuria (> 500 mg or 2+) within (a) 2 weeks and (b) the remainder of the pregnancy. Thompsons method was used to compare sensitivity and specificity of the day unit blood pressure and automated blood pressure monitoring. RESULTS Three hundred and forty-eight women were recruited to the study. The comparison between automated blood pressure monitoring and conventional blood pressure measurement for both sensitivity and specificity for systolic and diastolic blood pressure revealed increased sensitivity and decreased specificity with automated blood pressure monitoring for all principal outcomes except development of proteinuria for systolic blood pressure. Sensitivity for the outcomes was increased with automated blood pressure monitoring by between 14% and 27% for systolic blood pressure and between 7% and 39% for diastolic blood pressure, with the greatest improvement seen for the development of severe hypertension within 2 weeks of assessment. CONCLUSIONS In the assessment of hypertensive pregnancies, automated blood pressure measurement was a significantly better predictor (compared with conventional day unit assessment) for the development of severe hypertension within 2 weeks of assessment for both systolic and diastolic blood pressure.

The definition of pre‐eclampsia

antibodies play an important role in the pathogenesis of infertility and of pregnancy loss after assisted conception. APA have been reported to be present significantly more often in women with unexplained infertility than normal controls3. Birkeneld et al.‘ have reported that women who fail to conceive after IVF-ET (which represents a failure of implantation) are significantly more likely to have AF’A than those who conceived and had either delivered or had ongoing pregnancies (32 % versu.7 O%O). The pathogenesis of fetal loss in women with APA has traditionally been ascribed to thrombosis of the uterwplacental vasculature. This is not the full story. Evidence suggests that APA also impair trophoblast function via mechanisms unrelated to thrombosis and have a direct effect on the placenta. The binding of APA to surface phospholipids on the trophoblast, resulting in direct cellular injury and inhibition of syncytial formation has been demonstrated5* 6. Another point of interest is that serum levels of APA are increased after IVF49’. This may be due to the massively increased levels of oestradiol that are seen in women undergoing ovulation induction. Oestrogens are known to influence the development and course of autoimmune disease, perhaps by augmenting CD5’ B cell function8. Indeed, Ben-Chetrit and BenChetrit’ have recently reported a series of three women who developed systemic lupus erythematosus following ovulation induction. Recognition of the association between infertility, defective implantation and APA opens the way to therapeutic interventions to improve the poor live birth rate following IVF-ET. Sher et ~ 1 . ’ ~ reported that the pregnancy rate following IVF-ET was significantly higher amongst APA-positive women if they were treated with a combination of low dose aspirin and heparin (49 %) than if they were untreated (16%). Further study of APA and the elucidation of their mechanism of action in causing pregnancy failure is needed to improve the successful pregnancy rates following both IVF-ET and natural conception.