       
|
 |
 |
 |
 |
|
Summary
Sphygmomanometric blood pressure measurements induce an alerting reaction and
thus an increase in the patient’s blood pressure and heart rate.Whether and
to extent this “white-coat” effect is accompanied by detectable changes
in sympathetic nerve traffic has never been investigated.
In 10 mild untreated essential hypertensives (age 37.9 ± 3.8 years, mean
± SEM), we measured arterial blood pressure (by Finapres), heart rate (by
ECG), and postganglionic muscle and skin sympathetic nerve activity via microneurography.
Measurements were performed with the subject supine during (1) a 15-minute control
period, (2) a 10-minute visit by doctor unfamiliar to the patient who was in charge
of measuring his or her blood pressure by sphygmomanometry, and (3) a 15-minute
recovery period after the doctor’s departure. The entire procedure was performed
twice at a 45-minute interval to obtain, in separate periods, muscle or skin sympathetic
nerve traffic recordings, whose sequence was randomized. The doctor’s visit
induced a sudden, marked, and prolonged pressor and tachycardic response, accompanied
by a significant increase in skin sympathetic nerve traffic (+ 38.6 ± 6.7%,
P < 0.01). In contrast, muscle sympathetic nerve traffic was significantly
inhibited (-25.5 ± 4.1%, P < 0.01).All changes persisted throughout
the doctor’s visit and, with the exception of skin sympathetic nerve traffic,
showed a slow rate of disappearance after the doctor’s departure.
Thus, the pressure and tachycardic responses to the alerting reaction that accompanies
sphygmomanometric sympathoinhibition and skin sympathoexcitation.
Circulation. 1999;100: 222-225.
|
|
|
 |
 |
 |
|
|
|
|
|
|
Commentary
The measurement of blood pressure (BP) by means of a sphygmomanometric method
is known to induce an alerting reaction associated with a rise in blood pressure
(BP) and heart rate (HR).
In the present investigation the authors established hae-modynamic effects and
changes in sympathetic nervous system (SNS) activity in 10 mild, untreated essential
hypertensives (37.9 ± 3.8 years of age). The doctor’s visit was
associated with a sudden, marked, and prolonged pressor and tachycardic response.
Skin sympathetic traffic, established via microneurography, was significantly
elevated by almost 39%. However, muscle sympathetic activity was significantly
reduced by approximately 25%.
Most changes persisted throughout a few hours, with the exception of the skin
sympathetic nerve traffic which disappeared more rapidly.
In conclusion, the "white coat" effect provoked by sphyg-momanometric
measurements caused an alerting reacting as to be expected.Accordingly, BP,
HR, and skin sympathetic activity were increased, whereas muscle sympathetic
activity was depressed.
The muscle sympathetic inhibition was probably a reflex phenomenon, induced
by the various hemodynamic activation phenomena.
|
|
|
|
|
|
|
with an educational grant
from Servier
©2004 Les Laboratoires Servier. All rights reserved
|
|
