The fourth sound of Korotkoff in pregnancy: a myth

Measuring arterial blood pressure in humans: Auscultatory and automatic measurement techniques for human biological field studies

Human biologists have been examining arterial blood pressure since they began studying the effects of the environment and culture on the health of diverse populations. The Korotkoff auscultatory technique with a trained observer and aneroid sphygmomanometer is the method of choice for blood pressure measurement in many bioanthropological field contexts. Korotkoff sounds (the first and fifth phases) are the preferred determinants of systolic and diastolic pressure, even in infants, children, pregnant women, and the elderly. Training of observers, positioning of individuals, and selection of cuff size are all essential for obtaining standardized measurements. Automatic electronic devices are increasingly being used for blood pressure measurement in human biological studies. The automatic monitors often use the oscillometric method for measuring pressure, but must be validated before use. The emergence of automatic ambulatory blood pressure monitors has opened another avenue of research on blood pressure in human biology, where allostasis and circadian responses to environmental change and real life behavioral challenges can be defined and evaluated, largely because there is now the ability to make multiple measurements over time and in varying contexts. Stand-alone automatic monitors can also be substituted for manual auscultated readings in field contexts, although in studies where participants measure their own pressure, education about how the devices work and protocol specifics are necessary. Finally, computer-driven plethysmographic devices that measure pressure in the finger are available to evaluate short-term reactivity to specific challenges.

Time Poor: Rushing Decreases the Accuracy and Reliability of Blood Pressure Measurement Technique in Pregnancy

BACKGROUND

In pregnancy, absolute blood pressure (BP) limits define preeclampsia. Therefore, BP in pregnancy should be measured accurately and in accordance with accepted guidelines. Accuracy of BP readings determined by rate of cuff deflation was analyzed. This study also investigated the compliance of clinical staff at Royal Prince Alfred Hospital, Australia, to guidelines for BP measurement.

METHODS

The study was an observational trial of 98 normotensive antenatal or recently postnatal patients. Two BP readings were taken, each with fast (>5 mm Hg/sec) and slow (<or=2 mm Hg/sec) descent of mercury and compared by Bland-Altman analysis. Also, BP techniques used by junior doctors, specialist obstetricians, and midwives were compared using a 9-point scale.

FINDINGS

Australian national guidelines recommend slow descent of mercury. Fast descent underestimated the systolic BP by 9 mm Hg (95% confidence interval [CI], -23 to +5 mm Hg) (p < 0.001). Fast descent measured the diastolic BP within 2 mm Hg (95% CI, -10 to +14 mm Hg) (not different, p = 0.151). Accuracy of fast cuff deflation was 28% for systolic BP and 50% for diastolic BP for <5 mm Hg, and respectively, 64% and 68% for <10 mm Hg, 84% and 80% for <15 mm Hg and 91% and 87% for <20 mm Hg. Compliance with guidelines was greatest for specialists and midwives (p = 0.001) and their most commonly missed feature (76% to 100%) was slow cuff deflation.

INTERPRETATION

Rapid cuff deflation underestimates the systolic BP compared to accepted guidelines (<or=2 mm Hg/sec). Medical and midwifery staff may not follow accepted guidelines for BP measurement, particularly with regard to rate of cuff deflation. Potential misdiagnosis and under-treatment of patients with hypertension may compromise pregnancy outcomes.

The effect of small peer group continuous quality improvement on the clinical practice of midwives in The Netherlands

OBJECTIVE

To study the effects of small group continuous quality improvement (CQI) on the clinical practice of midwives in the Netherlands.

DESIGN

Randomised pre-/post-test (balanced block).

INTERVENTION

The CQI groups were assigned to either the set of peer review topics including 'perineal repair' and 'artificial rupture of the membranes (ARM)', or to the set of topics including 'airway aspiration' and 'measuring blood pressure'. The two research groups acted as each other's control group.

SETTING

The Netherlands.

PARTICIPANTS

Two hundred and fifty-five individual midwives practising in primary and secondary care who made up 28 peer groups. MEASUREMENT AND KEY FINDINGS: Questionnaires were used to collect data on clinical practice prior to the start of the intervention and one year later. Pre- and post-test data were received from 156 respondents. The intervention had a positive effect on adherence to the recommendations with respect to airway aspiration of the baby and measuring blood pressure. For ARM, no difference was found between pre- and post-test adherence to recommendations in the intervention group, while in the control group, the percentage of midwives that adhered to the recommendations decreased in the period between pre- and post-test. No significant effect was found for perineal repair.

IMPLICATIONS FOR PRACTICE

Small group CQI had a positive effect on changing clinical practice when the learning of new skills (e.g. learning a new suturing technique) was not necessary. Additional interventions are needed when implementing guidelines that recommend the learning of new skills.