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Biomedical subjects

P Trevillian

Publications and source records attributed to P Trevillian.

5 recordsLinked to original sources
PubMed2003

Arm position and blood pressure: a risk factor for hypertension?

The objective of this study was to re-evaluate the effect of arm position on blood pressure (BP) measurement with auscultatory and oscillometric methods including ambulatory blood pressure monitoring (ABPM). The setting was the hospital outpatient department and the subjects chosen were normotensive and hypertensive. The effect of lowering the arm from heart level on indirect systolic BP (SBP) and diastolic BP (DBP) measurement as well as the importance of supporting the horizontal arm were measured. In the sitting position, lowering the supported horizontal arm to the dependent position increased BP measured by a mercury device from 103+/-10/60+/-7 to 111+/-14/67+/-10 mmHg in normotensive subjects, a mean increase of 8/7 mmHg (P<0.01). In hypertensive subjects, a similar manoeuvre increased BP from 143+/-21/78+/-17 to 166+/-29/88+/-20 mmHg, an increase of 23/10 mmHg (P<0.01). Combined results from normotensive and hypertensive subjects demonstrate a direct and proportional association between BP (SBP and DBP) and the increase produced by arm dependency. Similar changes and associations were noted with oscillometric devices in the clinic situation. However, supporting the horizontal arm did not alter BP. Of particular interest, analysis of 13 hypertensive subjects who underwent ABPM on two occasions, once with the arm in the 'usual' position and once with the arm held horizontally for BP measurement during waking hours, demonstrated changes comparable to the other devices. The mean 12-hour BP was 154+/-19/82+/-10 mmHg during the former period and significantly decreased to 141+/-18/74+/-9 mmHg during the latter period (P<0.01). Regression analysis of the change in SBP and DBP with arm position change again demonstrated a close correlation (r(2)=0.8113 and 0.7273; P<0.001) with the artefact being larger with higher systolic and diastolic pressures. In conclusion, arm movements lead to significant artefacts in BP measurement, which are greater, the higher the systolic or diastolic pressure. These systematic errors occur when using both auscultatory and oscillometric (clinic and ABPM) devices and might lead to an erroneous diagnosis of hypertension and unnecessary medication, particularly in individuals with high normal BP levels. Since clinical interpretations of heart level vary, the horizontal arm position should be the unambiguous standard for all sitting and standing BP auscultatory and oscillometric measurements.

Adolescent↗
PubMed1979

The interaction of anti-glomerular basement membrane antibody deposition with immune elimination of bovine serum albumin in the rabbit.

We studied the interaction of two different forms of immune glomerular damage occurring simultaneously: anti-glomerular basement membrane (GBM) antibody fixation and immune elimination of bovine serum albumin (BSA). 125I-radiolabelled BSA anti-BSA immune complexes, formed in response to a single small intravenous dose (150 mg/kg) of 125I BSA, did not cause proteinuria in control animals within 15 days, despite evidence of immune elimination of the antigen. Similarly, a small dose of nephrotoxic globulin (NTG)(3.0 mg/kg) did not cause immediate proteinuria in controls. Test animals received the BSA injection followed by the NTG injection 5, 7 or 9 days later. In this way, antibody fixed to glomerular basement membrane antigens at various times after BSA anti-BSA complexes first appeared in the circulation. Animals were killed on day 15. Fifteen of the eighteen test animals developed moderate to severe clinical nephritis. The onset of the nephritis coincided with BSA elimination irrespective of when the NTG was given. Greatly increased amounts of nonlinear immunofluorescent deposits were demonstrated in the glomeruli of test animals. We concluded that there was a marked synergistic effect between two forms of immune glomerular damage (i.e. that mediated by anti-GBM antibody and immune complexes), which appeared to be due to the increased deposition of complex material in the presence of active fixation of anti-GBM antibody. The relevance of this finding to human glomerulonephritis is discussed.

Animals↗