Page 823 - Cardiac Nursing

9
9
2
/
2
6
0
d
9-8
9-8
p79
22.
qx
qx
22.
009
e 7
g
Pa
99
a
ar
Apt
Pa
8:
0
009
8:
M
9 P
5
3
0-c
5
3
K34
LWB
LWB K34 0-c 3 5 _ _ p79 9-8 22. qx d 2 9 / 0 6 / / 2 009 0 8: 5 9 P M Pa g e 7 99 Apt ar a
K34
LWBK340-c35_p799-822.qxd 29/06/2009 08:59 PM Page 799 Aptara
CHAPTER
n
s
y
p
p
y
i
H H H H Hypertension
y
Cheryl R. Dennison / Nancy Houston Miller /
/
/
Susanna G. Cunningham
7 7
Hyperten ision (HTN), also known ass high blood pressuree (BP), is
Hy pe rt ( HT N) al so k no wn a hi gh b lo od p re ss ur (B P) is stages off HTNN have been dellineated ass shown in Table 35-1. Op- -
HT
o
de
ha
s
n
ed
a
Op
3
1
5-

p
re
the most common risk factor for cardiovascular disease (CVD) in timall or normal BP is 120/80 mm Hg. The term prehypertension
hy
s
ma
g
ed
t
o
fy
13
8
0
ti
id
d
9
en
developed and developing countries. The prevalence of HTN in (d fiefined as BP 120–1399/80–89 mm Hg) is intendded to identify
e
os
Am er ic is 7 3 mi ll io an ma ny m or in di vi du al ha ve p re hy pe r- th those individuals iin whom early intervention by adoption of
Americaa is 73 millionn andd many moree individualss have prehyper-
du
al
vi
in
di
tension, which indicates they are at high risk for developing healthy lifestyles could reduce BP, decrease the rate of progression
1
HTN. Since the 1970s there has been a dramatic decrease in the of BP to hypertensive levels with age, or prevent HTN entirely. 7
mortality rate from hypertensive heart disease in Europe and the HTN (defined as BP 140/90 mm Hg) is classified as either
United States, primarily because of the development of effective Stage 1 (SBP 140 to 159 mm Hg and/or DBP 90 to 99 mm Hg)
antihypertensive drugs in conjunction with increased awareness, or Stage 2 (SBP 160 mm Hg and/or DBP 100 mm Hg). Iso-
treatment, and control of HTN. 2,3 Despite this progress, world- lated systolic HTN is defined as the occurrence of SBP at or
wide, an estimated 7.1 million premature deaths are caused each greater than 140 mm Hg with DBP less than 90 mm Hg. The in-
year by HTN. 4 cidence of isolated systolic HTN increases dramatically with age
8
and thus is of particular concern among older adults. Types of
HTN are classified as (1) systolic and diastolic HTN (either pri-
EVIDENCE FOR MANAGEMENT mary or secondary) and (2) isolated systolic HTN caused by in-
creased cardiac output or increasing rigidity of the aorta.
Definitions
Children
BP has two components, which are continuous variables: systolic Criteria used for categorizing BP in adults are not applicable to
BP (SBP) and diastolic BP (DBP). Elevations in either SBP or children. The level of BP, which is considered normal, increases
9
DBP increase a person’s risk for a clinical event. Death from both gradually from infancy to adulthood. The definition of HTN in
ischemic heart disease and stroke increases progressively and lin- children and adolescents is based on the normative distribution of
early from levels as low as 115 mm Hg SBP and 75 mm Hg DBP BP in healthy children. 10 Normal BP is defined as SBP and DBP
upward among individuals whose ages range from 40 to 89 years. 5 less than 90th percentile for gender, age, and height. HTN is de-
For every 20 mm Hg systolic and 10 mm Hg diastolic increase in fined as average SBP or DBP at or greater than 95th percentile for
BP, there is a doubling of mortality from ischemic heart disease gender, age, and height on at least three separate occasions. Chil-
5
and stroke. Conversely, it is generally true that the lower the pres- dren and adolescents with BP 120/80 mm Hg but less than
sures, the lower the risk of morbidity and mortality, except in the 95th percentile should be considered prehypertensive. Tables list-
relatively uncommon situations of sympathetic nervous system ing BP levels by age and height percentile for boys and girls can
dysfunction or hypovolemia. be found in the Fourth Report on the Diagnosis, Evaluation, and
The word “hypertension” can be confusing to patients, who Treatment of High Blood Pressure in Children and Adolescents. 10
might believe that they are neither “tense” nor “hyper” and there-
fore unlikely to have HTN. For this reason, “high blood pressure” Epidemiology
may be a better term to use when communicating with the pub-
lic. HTN can be considered as a sign, a risk factor, and a disease. Prevalence of HTN
Approximately 33.6%, or just over 73 million Americans have
1
Adults HTN. Based on data from the National Health and Nutrition
As new research has become available, many countries have estab- Examination Survey (NHANES), conducted between 2003 and
lished guidelines on the detection, evaluation, and treatment of 2004, 75% of hypertensive individuals were aware of their con-
6
HTN. Two widely promulgated guidelines defining normal and dition, and 65% were being treated for HBP. Of those treated,
elevated BP levels were developed by The Joint National Com- only 56.6% had achieved BP control (BP 140/90 mm Hg).
mittee of the National High Blood Pressure Education Program Only 37.5% of individuals being treated for both HTN and di-
and the Guidelines subcommittee of the World Health Organiza- abetes mellitus had achieved the lower goal BP of 130/80. 3
tion and the International Society of Hypertension. 4,7 These While the prevalence of HTN has increased, rates of HTN
guidelines define HTN as SBP of 140 mm Hg and/or DBP of awareness, treatment, and control have also increased over the
90 mm Hg. Both reports recommend considering BP together last decade. 2,3
with other risk factors for atherosclerotic CVD when making de-
cisions about when to initiate treatment. Age, Gender, and Weight
9
To reflect the curvilinear nature of the relationship between SBP and DBP levels correlate with age, height, and weight. Evi-
SBP and DBP and risk, “normal” BP, prehypertension, and two dence suggests that HTN begins in childhood, perhaps even in
799