Rapid oscillometric blood pressure measurement compared to
conventional oscillometric measurement
Steven A. Yarowsa, Ketul Patelb and Robert Brooka
There have been few reports studying the
necessary interval between blood pressure
Oscillometric blood pressure measurement has largely
measurements, after the initial rest period.
replaced the auscultatory method in electronic bloodpressure monitors today. Although the measurementmethods are different, the results are clinically equiva-
Blood pressure was measured in 50 patients
lent and the devices are easier to manufacturer w1,2x.
using the conventional oscillometric technique (
and the rapid oscillometric technique (
Measurement of blood pressure Ž
BP in research studies
has used the average of three measurements w3,4x. The
The difference between COT and ROT was
recommended technique is to have the patient sit for 5
y1.1/y0.1 mmHg, which was not significantly different
min and take measurements with 1᎐2 min between the
1.0 and the pulse difference was y0.8 beats
measurements. The recommendation from the Ameri-
per minute ( p
can Heart Association to wait 1᎐2 min is based on theauscultatory method of measurement, however this re-
It is concluded that a 15-second interval
commendation has not been scientiﬁcally validated. It is
between blood pressure readings is as accurate as a
theorized that venous engorgement that occurs with toorapid cuff re-inﬂation induces measurement errors w x
one-minute interval providing that these measurements
are started after a 5-minute rest period. Blood Press
Unfortunately, these errors are not considered in clinical
6:145– 147 䊚 2001 Lippincott Williams &
practice and most clinicians do not use average BP but
rather use single blood pressures to make clinical deci-sions and save time w x
Blood Pressure Monitoring
:145 – 147
Keywords: blood pressure determination, hypertension, oscillometry
The purpose of this study was to determine if, after
being seated for 5 min, waiting 15 sec between oscillo-
Division of Hypertension, University of Michigan Health System, bCollege
of Literature, Science and the Arts, University of Michigan, Ann Arbor,
metric blood pressure readings was equivalent to wait-
ing 1 min between readings. If the rapid method is as
Correspondence and requests for reprints to Steven A. Yarows, MD,
effective, this will save time for the busy health care
Chelsea Internal Medicine, 128 Van Buren, Chelsea, Michigan 48118,USA.
providers, which may increase the likelihood of repeti-
Tel: +1 734 475 8677; fax: +1 734 615 1176; e-mail: syarows@ umich.edu
tive blood pressures, which could improve the accuracy
05 January 2001 Revised
04 April 2001
of measurement of hypertension.
24 April 2001
Blood pressure was measured in 50 patients of at least
18 years of age using an Omron HEM-705CP automatic
oscillometric device. The experimental protocol and the
process for obtaining consent from the subjects was
approved by the University of Michigan Medical School
Institutional Review Board. The patients were nor-
motensive and hypertensive volunteers from a general
internal medicine practice. Each patient was seated
upright for 5 min before measurement began and was
instructed not to speak during measurement. During
measurement, the patient was seated upright in a chair
with back support. Each subject had three measure-
ments with each technique Žsix measurements total per
subject using the same arm for both the conventionaloscillometric technique Ž
COT and the rapid oscillo-
metric technique Ž
ROT , Figure 1. The COT measured
three readings with 1 min between measurements, andthe ROT measured three readings with 15 sec betweenmeasurements. Patients with odd patient numbers had
1359-5237 䊚 2001 Lippincott Williams & Wilkins
146 Blood Pressure Monitoring
2001, Vol 6 No 3
the COT ﬁrst, while patients with even patient num-
% CI 120.7᎐130.5 r77.0 95% CI 73.8᎐80.1 mmHg
bers had the ROT ﬁrst.
with a pulse of 75.9 Ž95
% CI 72.5᎐79.3bpm. The BP
difference was ᎐1.3ry 0.1 mmHg with a pulse differ-ence of
᎐0.5 bpm p
s0.72r0.98 and pulse p of 0.83.
The ﬁrst readings for each subject were always after 5
min of rest. The ﬁrst reading was alternated with con-
161r104 mmHg and in the ROT group 170r101 mmHg.
secutive subjects between the COT and the ROT to
The minimum BP in the COT group was 90r55 mmHg
avoid bias from the initial 5 min of relaxation. The ﬁrst
and in the ROT group 87r54 mmHg.
readings from each of the methods were not included inthe analysis to avoid skewing the results due to the5-min initial baseline rest before the ﬁrst of the six
The measurements were analysed according to con-
readings per subject. Thus, the analysis only included
ventional systolic BP ranges - 110, 110᎐139, and
measurements that allowed 15 sec Ž
)139 mmHg. The greatest difference was seen in the
COT between readings.
conventional systolic BP Ž
SBP - 100 mmHg in which
the ROT under-measured the systolic by 2.3mmHg.
The diastolic and pulse in this range and all the mea-
Microsoft Excel 97 was used for analysis of the data.
surements for the other blood pressure ranges all de-
The student's t
-test with two-tail distribution and two-
monstrated differences of less than 1.6 mmHg between
sample equal variance was used to determine any sig-
the techniques and these differences for systolic, dias-
niﬁcance in the relationship between blood pressure
tolic, and pulse differences were not signiﬁcant Ž p
and pulse. 50 subjects were calculated to have the 80%
0.05. 8 percent of the ROT group was misclassiﬁed
power to detect a 3mmHg difference Ž p
ﬁdence intervals were calculated with an alpha of 0.05.
-110 mmHg. 12 percent was misclassiﬁed within theconventional SBP range of 110᎐139 mmHg, whereas 5%misclassiﬁed within the )139 mmHg range.
50 subjects volunteered for the study. The average age
Figure 2 shows the Bland᎐Altman plot indicating a lack
" 17 years old range 18᎐97 with 55% of the
subjects being male. The average blood pressure in the
of difference in the measurement techniques based on
COT group was 123.4
conventional systolic and diastolic pressures. Most of
% CI 120.0᎐126.9 r76.4 95%
the readings were within two standard deviations. The
᎐78.6 mmHg and in the ROT group was 124.5
COT pulse was slightly greater than the ROT pulse at
% CI 121.0᎐128.1 r76.5 95% CI 74.3᎐78.6 mmHg
higher pulses and less than ROT at lower pulses, how-
% CI 72.7᎐77.8 and 76.1 95% CI
ever this difference was slight and most of the readings
᎐78.6 beats per min bpm , respectively. The dif-
ference between COT and ROT was y1.1ry
were within two standard deviations.
0.0 mmHg, which was not signiﬁcantly different Ž p
r1.0 and the pulse difference was y0.8 bpm p
One patient had a 21 mmHg systolic difference between
0.8. Including the ﬁrst measurements with the second
the techniques and this patient had a rapid 24 mmHg
and third measurements produced similar results. The
decrease in systolic BP over the ﬁrst 8 min including
COT average was 124.0 Ž95
% CI 119.5᎐129.1 r76.9
the 5-min waiting period. This suggests that the usual
% CI 73.9᎐79.9 mmHg with a pulse of 75.4 95% CI
5-min waiting period was not adequate for this patient.
᎐78.9 bpm. The ROT group average was 125.6
Another patient had a 33 bpm change in heart rate
ROT measurement compared to COT measurement
Yarows et al.
mended that 1᎐2 min should elapse between measure-ments to allow the release of blood trapped in the veinsbefore further determinations are made, although evi-dence supporting this was not cited w x
5 . Ischemia in an
arm distal to the measurement will lower BP by5r15 mmHg if the ischaemia is 20 mmHg above thesystolic BP Ž
SBP for 90 sec, however it raises the BP
slightly if the ischaemia is sustained for only 30 sec w x
Since proper technique is to inﬂate the 20 mmHg abovethe SBP and use a deﬂation rate of 2 mmHgrsecond,ischaemia above the SBP would only last 10 sec and itis unlikely to change the measurement of the BP.
There was a non-signiﬁcant Ž
-1.1 mmHg difference
between the rapid and conventional BP measurementtechniques for systolic, diastolic and pulse readings.
The rapid technique had the greatest difference com-pared to the conventional technique between systolicBP 90᎐109 mmHg based on the conventional tech-nique, however this difference was also not signiﬁcantŽ p
Blood pressure readings may be repeated after 15 sec
without affecting the accuracy of the measurements.
The proper technique is to have the patient seated for
ﬁve minutes and perform 2᎐3measurements with 15
sec between readings.
We are grateful to Andrew Zweiﬂer, MD, John Amer-
ena, MD, and Osamu Shirasaki for their assistance in
Zachariah PK, Sheps SG, Smith RL. Role of self-monitoring and ambu-
latory monitoring in diagnosis and evaluation of hypertension. Pract
:1 – 7.
Mieke S. Substitution of simulators for human subjects. Blood Press
:251 – 256.
Dahlof B, Devereux RB, Julius S, Kjeldsen SE, Beevers G, de Faire U et
. Characteristics of 9194 patients with left ventricular hypertrophy: the
LIFE study. Losartan intervention for endpoint reduction in hypertension.Hypertension
:989 – 997.
Hansson L, Zanchetti A, Carruthers SG, Dahlof B, Elmfeldt D, Julius S
Conventional minus rapid oscillometric technique differences (y-axis)
. Effects of intensive blood-pressure lowering and low-dose aspirin
compared to conventional systolic BP, diastolic, and pulse (
in patients with hypertension: principal results of the Hypertension
Two-standard deviations indicated as dark horizontal line.
Optimal Treatment (HOT) randomized trial. HOT Study Group. Lancet
:1755 – 1762.
Kirkendall WM, Feinleib M, Freis ED, Mark AL. Circulation
1146A – 1155A.
between the two techniquesᎏa total variation of 50 bpm
Yarows SA. Home blood pressure monitoring in primary care. Blood
suggests an arrhythmia as the etiology.
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S11 – S17.
Rabbany SY, Drzewiecki G, Melbin J, Noordergraaf A. The effect ofperipheral resistance on the Korotkoff sound: experiments
. AAMI 19 thAnnual Meeting 1984.
There is little experimental evidence to indicate the
proper interval between BP measurements. The Ameri-
can Heart Association Committee in 1980 recom-
EL COMERCIO PARALELO DE MEDICAMENTOS* Ángel garcía Vidal Profesor Titular de Derecho Mercantil Universidad de Santiago de Compostela Recibido: 11.07.2013 / Aceptado: 15.07.2013 Resumen: El presente trabajo analiza la problemática generada por el comercio paralelo de medi- camentos. Tras exponer el concepto y los intereses encontrados en torno a esta práctica comercial, se exa-minan las implicaciones jurídicas de algunas de las actuaciones tendentes a minimizar el comercio paralelo de fármacos: en especial, las restricciones de suministro, los supply quota systems, los sistemas de doble precio y la invocación de excepciones al agotamiento de los derechos de exclusiva sobre los medicamentos.
OF CONTENTS These patient care protocols will go into effect in January 2016 for EMS Responders of the Aumsville Fire District, Gates Fire District, Falck Ambulance, Idanha Detroit Rural Fire Protection District, Keizer Fire District, Lyons Fire District, Marion County Fire District #1, Mill City Fire District, Salem Fire Department, Santiam Ambulance, Stayton Fire District, Sublimity Fire District and Turner Fire District.