The effect of different body positions on blood pressure

Noninvasive effects measurements for air pollution human studies: methods, analysis, and implications

Human exposure studies, compared with cell and animal models, are heavily relied upon to study the associations between health effects in humans and air pollutant inhalation. Human studies vary in exposure methodology, with some work conducted in controlled settings, whereas other studies are conducted in ambient environments. Human studies can also vary in the health metrics explored, as there exists a myriad of health effect end points commonly measured. In this review, we compiled mini reviews of the most commonly used noninvasive health effect end points that are suitable for panel studies of air pollution, broken into cardiovascular end points, respiratory end points, and biomarkers of effect from biological specimens. Pertinent information regarding each health end point and the suggested methods for mobile collection in the field are assessed. In addition, the clinical implications for each health end point are summarized, along with the factors identified that can modify each measurement. Finally, the important research findings regarding each health end point and air pollutant exposures were reviewed. It appeared that most of the adverse health effects end points explored were found to positively correlate with pollutant levels, although differences in study design, pollutants measured, and study population were found to influence the magnitude of these effects. Thus, this review is intended to act as a guide for researchers interested in conducting human exposure studies of air pollutants while in the field, although there can be a wider application for using these end points in many epidemiological study designs.

Differences in blood pressure by body position (supine, Fowler's, and sitting) in hypertensive subjects

BACKGROUND

Although blood pressure (BP) differences from supine to sitting position have long been recognized, limited data are available on other commonly used body positions. We performed a cross-sectional study to compare BP values obtained in supine, sitting, and Fowler's positions in essential hypertensive subjects.

METHODS

Systolic BP (SBP) and diastolic BP (DBP) were recorded using an automatic oscillometric device. Nine measurements were taken: three measurements, in random order, in supine, Fowler's, and sitting position. Two generalized estimating equations models were used to evaluate potential predictors of SBP and DBP adjusting for heart rate and measurement order.

RESULTS

The sample consisted of 250 subjects (mean age 66.3 ± 13.4 years; 44.4% males). Measured in supine, Fowler's, and sitting position, mean SBPs were 139.3 ± 14.0; 138.1 ± 13.8; 137.2 ± 13.7 mm Hg, respectively, and mean DBPs 80.1 ± 9.1; 81.9 ± 9.4; 83.0 ± 9.6 mm Hg, respectively. At multivariate analysis, mean SBP significantly decreased if measured in Fowler's and sitting positions, as compared to supine. In contrast, DBP significantly increased. A relevant proportion of subjects showed large differences (≤ or ≥10 mm Hg) in mean SBP across positions: i.e., 30.0% comparing supine vs. sitting SBP. An even higher prevalence of large differences was observed according to the measurement order within the same positions, with no univocal direction (random variation).

CONCLUSIONS

Fowler's position may represent a valid alternative to sitting and supine positions for BP measurement in clinical practice. BP random variability was found to be large regardless of body position, reinforcing the need for operators to closely follow current guidelines that recommend ≥2 recordings at each measurement.

The effect of clothes on sphygmomanometric blood pressure measurement in hypertensive patients

AIMS

To test whether there is any difference between blood pressure readings with patients wearing clothes under the manometer's cuff and not wearing clothes.

BACKGROUND

The few studies published on this subject have shown that blood pressure measurements give similar results whether the patients' arm is covered by clothing or not. However, it has not been clarified whether this is also true in hypertensive patients.

METHOD

Blood pressure was measured on non-sleeved arm, sleeved arm and again on non-sleeved arm in 258 hypertensive patients using a mercury-filled column sphygmomanometer. Three nurses who were experienced and specially trained for the study performed blood pressure measurements. They were unaware of the purpose of the research.

RESULTS

Measuring blood pressure with the manometer's cuff over participant's sleeved arm did not differ significantly from non-sleeved arm measurements.

RELEVANCE TO CLINICAL PRACTICE

Sleeves have no effect on blood pressure results. Blood pressure readings taken over the sleeves will be much more practical and time saving in busy departments like emergency rooms, during disasters like earthquake where decisions have to make in minutes. Additionally, it will be time saving for general health screening surveys. Finally, it may have preferable because of hygiene concerns, patient privacy and religious beliefs.

The effect of crossing legs on blood pressure in hypertensive patients

AIMS

The aim of this study was to examine whether there is any difference between BP readings with patients crossing a leg at the knee level and uncrossing during BP measurement.

BACKGROUND

It is clear that numerous factors influence an individual's blood pressure (BP) measurement. However, guidelines for accurately measuring BP inconsistently specify that the patient should keep feet flat on the floor.

DESIGN

Repeated measures.

METHOD

Using a mercury-filled column sphygmomanometer, BP was measured at uncrossed leg position, crossed leg position and again at uncrossed leg position in 283 unmedicated or medicated patients. Three experienced nurses specially trained for the study performed BP measurements.

RESULTS

The results indicated that BP increased significantly with the crossed leg position. Systolic and diastolic BP significantly increased approximately 10 and 8 mmHg, respectively.

CONCLUSION

Crossing the leg at knee results in a significant increase in BP.

RELEVANCE TO CLINICAL PRACTICE

Leg position during measurement of BP should be standardised and mentioned in publications.

Forearm and Upper-Arm Oscillometric Blood Pressure Comparison in Acutely III Adults

When patients’ upper arms are not accessible and/or when cuffs do not fit large upper arms, the forearm site is often used for blood pressure (BP) measurement. The purpose of this study is to compare forearm and upper-arm BPs in 70 acutely ill adults, admitted to a community hospital’s 14-bed ICU. Using Philips© oscillometric monitors, three repeated measures of forearm and upper-arm BPs are obtained with head of bed flat and with head of bed elevated at 30°. Arms are resting on the bed. Paired t tests show statistically significant differences in systolic BPs, diastolic BPs, and mean arterial pressures in the supine and head-elevated positions. Bland—Altman analyses indicate that forearm and upper-arm oscillometric BPs are not interchangeable in acutely ill adults.

Providing best practice in manual blood pressure measurement

This article discusses the practical skills and underpinning knowledge needed when manually taking a patients blood pressure. The author defines blood pressure and the terms systolic and diastolic and explores the purpose of manual measurement. The article also goes on to examine what is meant by normal blood pressure, hypertension and hypotension, as well as factors that may influence blood pressure measurement. There is a brief outline of the equipment used for manually measuring blood pressure, followed by some factors that may affect the accuracy of the final reading. The author also highlights the different positions used for taking blood pressure and the arguments surrounding their respective merits. Finally, the article includes a practical step-by-step guide to manual blood pressure measurement.