AACN Clinical Issues
Volume 13, Number 2, pp. 263-276
© 2002, AACN
The Effect of Bed Rest and
Potential of Prehabilitation on
Patients in the Intensive Care Unit
Robert Topp, PhD, RN; Marcia Ditmyer, MA, MS; Karen King, BS;
Kristen Doherty, BS, RKT; Joseph Hornyak, III, MD
■ Declines in physical activity that
functional capacity through increased
physical activity prior to an ICU
admission, it seems reasonable that the
patient would retain a higher level of
functional capacity over their entire ICU
admission. The process of enhancing
functional capacity of the individual to
enable them to withstand the stressor of
inactivity associated with an admission to
ICU is termed prehabilitation. A generic
program of prehabilitation includes warmup, aerobic, strength, flexibility, and
functional task components. The initial
level of prehabilitation training and the
progression of the training will be
different for each individual based upon
their initial functional capacity and the
degree to which they individually respond
to increases in physical activity. Declines
in physical activity among ICU patients
represents a significant health risk that
may be reduced through introducing
prehabilitation interventions.
(KEYWORDS: bed rest, exercise,
prehabilitation)
accompany an admission to an intensive
care unit (ICU) represent a significant
stress to the body. Decreases in physical
activity have been demonstrated to result
in losses in functional capacity of the
musculoskeletal and cardiovascular
systems. These two systems are central
to achieving and maintaining functional
independence, which is a prerequisite for
discharge from a healthcare facility, as is
independent functioning of the individual
in the community setting. Whereas a
decrease in physical activity will result in
an attenuation in the functioning of the
cardiovascular and musculoskeletal
systems, increases in physical activity
can stimulate gains in their functional
capacity.
The concept of improving the functional
capacity of the body to withstand
anticipated musculoskeletal stressors
has had limited application to the effects
of inactivity associated with an ICU
admission. By increasing an individual’s
▪▪▪▪▪▪▪▪▪▪
School of Medicine, University of Michigan, Ann Arbor, Michigan (Dr Hornyak).
Reprint requests to Robert Topp, PhD, RN, School
of Nursing, Medical College of Georgia, 997 St. Sebastian Way, Augusta, GA 30912 (e-mail:RTOPP@mail.
mcg.edu).
From the Medical College of Georgia, School of
Nursing, Augusta, Ga (Dr Topp); The University of
Toledo (Ms Ditmyer, doctoral candidate); the department of Exercise and Excellence, The University of
Toledo, Toledo, Ohio (Ms King, Ms Doherty); and the
263
264
TOPP ET AL
Physical activity is essential for healthy
functioning of the human body. All organ
systems of the body respond favorably to
regular moderate intensity physical activity and conversely deteriorate or dysfunction in response to a lack of regular physical activity. The earliest healthcare
professionals recognized the benefits of
regular physical activity for health promotion and disease prevention.1-3 As medical
science emerged as the dominant director
of healthcare in the early 1900s, rest became a panacea treatment for a wide variety of maladies.4 Prolonged bed rest became the mainstay treatment for many
medical conditions including arthritis,
congestive heart disease, peripheral vascular disease, cancers, and even childbirth. More recently, bed rest and low levels of physical activity have been
empirically identified as risk factors for a
variety of acute and chronic conditions.5
In addition, over the past quarter century,
a number of investigators have determined physical activity is essential to
maintaining optimal functioning of most
organ systems of the body.5-8 Thus, a substantial risk to healthy functioning of the
body is a stay in an intensive care unit
(ICU), which includes a decrease in physical activity in the form of total bed rest.
The stress that reduced physical activity
or inactivity presents in an ICU is explored
in three sections in this article. The first
section reviews the impact of inactivity on
the functioning of a number of major organ systems. The second section introduces the concept of prehabilitation. Prehabilitation is defined as the process of
enhancing functional capacity of the individual to better withstand the stressor of
inactivity. The stressor of inactivity is commonly associated with an admission to an
ICU. This section also explores the theoretical and empirical support for introducing prehabilitation as an intervention for
potential ICU patients. The final section
describes a prehabilitation program for
ICU patients. The program description includes exclusion criteria and developing
program goals, as well as general and specific components of the prehabilitation intervention.
AACN Clinical Issues
The
Impact of Inactivity
Regular physical activity influences most of
the major organ systems of the body. Increased regular physical activity improves
the functional capacity of these organ systems, while decreases in or a lack of regular
physical activity results in declines or dysfunction of these organ systems. This phenomenon has been documented under a
number of conditions that restrict activity,
and within a number of organ systems. The
impact of inactivity in the form of bed rest
on the musculoskeletal and cardiovascular
systems are reviewed because these systems
are the focus of rehabilitation. In addition,
these two systems are central to facilitating
increases in the individual’s functional independence, which is a goal after an ICU stay
and hospital discharge.
Musculoskeletal System
Muscles are the most prevalent type of tissue
in the body. Approximately 45% of the human body weight is muscle and if the 450
skeletal muscles of the body contracted simultaneously 25 tons of force could be generated.9 The principle function of the musculoskeletal system is support and movement
of the body and support of systems within
the body. All skeletal muscles respond to declines in regular physical activity by atrophying, with an accompanying loss in contractility and strength.10 In other studies, skeletal
muscle strength declined by 1% to 1.5% per
day after strict bed rest.11,12 Decline in
strength is even more profound (1.3%-5.5%
per day) with cast immobilization.13-15 Loss
of strength was found to be greatest during
the first week of immobilization, declining
by as much as 40% in muscle strength after
that first week.16,17 Declines in skeletal muscle strength as a result of immobility vary
among muscle groups and muscle types.
The strength of fast-twitch (type II) fibers
appears to decline at an accelerated rate
compared to declines in strength measured
within slow-twitch (type I) fibers.18 Fasttwitch fibers are involved with rapid high intensity bursts of muscle contraction for
strength and fatigue quickly because they
use primarily glycocytic processes. Slow-
Vol. 13, No. 2 May 2002
twitch fibers use oxidative processes and involve less intense endurance contractions
that can be maintained over a prolonged period of time. Declines in slow-twitch fibers
that accompany reduced physical activity
may account for the finding that antigravity
muscles, which have a high cross-sectional
area of type I fibers, appear to selectively atrophy as a result of immobilization when
compared to non-antigravity muscles.19-24
Therefore, selective atrophy is dependent
upon the location and the function of the
specific muscle. For example, the antigravity
muscles of the calf and back appear to lose
strength with bed rest at an accelerated rate
compared to muscles involved with grip
strength.16,25,26 Further, antigravity muscles
have been observed to lose contractile proteins with an increase in noncontractile tissue
content, including collagen, while the total
number of muscle fibers remain unchanged
as a result of immobilization.10,19,23,27,28
Findings clearly indicate that skeletal muscle, particularly the type I fibers of the antigravity muscles lose myofilaments (cross-sectional area) in response to reduced physical
activity. This finding is important to ICU
healthcare providers because the muscle
groups that lose strength most quickly as a
result of immobilization or bed rest are the
groups involved with transferring position
and ambulation. Muscle atrophy in response
to inactivity is not an unexpected event. The
pattern of most body tissues is to respond
proportionally to encountered stress. Thus,
skeletal muscles, particularly type I fibers involved in ambulation, lose strength and contractile proteins with bed rest.
The loss of contractile proteins with
preservation of fiber count during bed rest is
also of interest to ICU healthcare providers.
This finding suggests that skeletal muscle
has the potential to regain contractile protein
content and strength because the number of
muscle fibers is not initially affected by immobilization. A number of authors have
demonstrated that various programs of increased physical activity can reverse or preserve strength during and after prolonged
immobilization.20-33 Additionally, stretching
the muscle during immobilization appears to
retard atrophy and may even stimulate
growth as a result of stabilizing the muscle in
a lengthened position, delaying invasion of
EFFECTS OF BED REST
265
noncontractile proteins into the muscle and
tendons.30 This delay may limit contractures
including foot drop, which is common with
prolonged bed rest.
A number of authors have indicated that
strength training during bed rest can prevent
muscle atrophy and loss of strength and contractile proteins.34-40 Thus, the deleterious effects of bed rest can be reduced or prevented through various types of physical
activity programs implemented during the
period of immobilization.7,41-43 Therefore, a
possible advantage of increased physical activity prior to immobilization may be that the
trained individual would begin muscle atrophy from a higher level of absolute strength
than the untrained individual, thus preserving a higher level of strength over the period
of immobilization.
Similar to muscle, bone tissue is in a dynamic state and responds to changes in physical activity. The ratio of bone formation to
bone resorption is influenced by stress
placed upon the bone, a phenomenon referred to as Wolff’s law. Wolff’s law states that
the density of a bone is directly proportional
to the stress placed upon the bone.44 Weightbearing exercise as well as strength training
have been shown to sufficiently stress bones
or stress the muscles attached to the bones
and result in increases in bone density.45,46
These authors also found that lack of stress
on the bones, as with declines in physical activity and immobility, results in a greater percentage of bone resorption than bone formation, resulting in a net decrease in bone
mass. The degree of loss of bone mass varies
with the degree of decrease in physical activity and the functional integrity of the bone.
During periods of immobilization, bones of
persons involved in antigravity activities do
not appear to reabsorb at the accelerated rate
of bones of persons involved in weight-bearing activities.16,45-49 For example, during bed
rest (or the weightlessness of space flight) up
to 1% of the bone density of the vertebral
column is lost per week.50 Bone loss of the
calcaneus has been observed to be 25% to
45% after 30 to 36 months of bed rest, with
an accompanying 4.2% loss in total body calcium.51 Bloomfield16 found from 6% to 40%
decreases in bone density as a result of bed
rest in just 4 to 6 weeks. In addition to selectively affecting weight-bearing bones,
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TOPP ET AL
Bloomfield observed demineralization during
reduced physical activity to a greater extent
in trabecular rather than cortical bone. Trabecular bone forms a matrix at the articulations within the bones, such as the neck of
the femur. These matrices provide tensile
strength to the bone and allow it to absorb
gravitational forces without fracturing. A loss
of this trabecular bone predisposes the individual to fractures resulting from even minor
impact to the bone.
Osteoporosis, a disease characterized by
low bone mass, is best treated by preventative measures, such as participation in physical activity that stresses the bone. Theoretically, building the bone density prior to an
anticipated period of reduced physical activity or immobility will allow the bone to begin demineralization from a higher threshold
than if bone density were not increased with
increased physical activity.52,53 Stressing the
bone during bed rest has not been demonstrated to be effective in preventing the demineralization that accompanies bed rest.
However, training after a period of reduced
activity has been shown to arrest and reverse
the demineralization,45,54,55 although it has
been postulated that after long-term immobilization trabecular bone never completely recovers normal architecture.56 Another condition is an increase in serum calcium level
that accompanies bone demineralization
during immobilization.57,58 Symptoms of hypercalcemia include muscle weakness, cardiac arrhythmias, abdominal pain, kidney
stones, nausea/vomiting, and anorexia. Under some circumstances individuals experiencing hypercalcemia have developed calcium deposits or bone spurs within synovial
joints, which further contribute to joint pain
and immobility.
Cardiovascular System
Functioning of the cardiovascular system is
particularly sensitive to changing levels of
physical activity. Attenuation in cardiovascular function is a response to a reduction in
physical activity. Cardiovascular adaptations
to reduced activity, in particular bed rest, are
considered detrimental to the individual’s
health and functioning. Chronic inactivity
has been identified as a positive cardiovascular disease risk factor for cardiovascular
AACN Clinical Issues
disease, along with hypertension, smoking,
and elevated cholesterol.59 Bed rest affects
both the central and peripheral components
of the cardiovascular system. With bed rest,
resting heart rate and heart rate in response
to activity increase and is termed cardiac deconditioning.60 After 3 to 4 weeks of bed
rest, resting heart rate was reported to increase by one half beat per minute (11 - 14
beats).60 Although heart rate response to
submaximal exercise was reported to be 30
to 40 beats/minutes higher in response to
the same level of submaximal exercise.41
Similarly to rest, stroke volume at submaximal exercise after 3 to 4 weeks of bed rest
was observed to decrease up to 30%.61 Additionally, Saltin60 found overall cardiac output
unchanged after bed rest but the decreased
stroke volume and increase in heart rate appear to be accompanied by a loss in cardiac
size, or atrophy of the cardiac muscle. Bed
rest does not appear to affect resting blood
pressure.60,61 It appears that the heart muscle
responds to inactivity in a similar fashion as
skeletal muscle. Thus, after bed rest the
heart muscle atrophies, stroke volume declines, heart rate increases, and the individual’s cardiac capacity to respond to any level
of physical activity declines.62
Declines in physical activity have a similar
detrimental effect on the functioning of the
peripheral cardiovascular system. Prolonged
bed rest results in a shift in blood volume to
the thorax. When a body rises from a supine
position, the blood volume in the thorax
drops causing venous return to the heart to
decrease thus reducing cardiac output.61,63
After prolonged bed rest, this reduction in
cardiac output is countered by an immediate
increase in peripheral vascular vasoconstriction or an increase in heart rate as in a
healthy individual. Therefore, the physically
inactive individual may experience an unusually large surge in heart rate when transferring quickly from a supine to standing position (⬎35 beats/min), which is often
accompanied by other symptoms of orthostatic intolerance.63-66 The individual who has
experienced prolonged bed rest can develop
orthostatic intolerance as a result of a baroreceptor dysfunction.8,61,67 Signs of orthostatic
intolerance begin to appear within 3 to 4
days of the beginning of bed rest.43,61 Symptoms of orthostatic intolerance develop dur-
EFFECTS OF BED REST
Vol. 13, No. 2 May 2002
ing the period of bed rest and appear more
rapidly in the elderly or among individuals
with underlying cardiovascular conditions in
addition to healthy adults. Increases in orthostatic intolerance and decreases in muscle
strength increase the risk for falls. This ultimately can lead to an increased risk of injury
in the elderly. Orthostatic intolerance can be
reversed through regular physical activity but
may take twice the duration to ameliorate as
it took to develop.65 Other investigators have
indicated that the symptoms can be delayed
or prevented through regular exercise even
during bed rest.8,62,65
Declines in physical activity among ICU
patients due to bed rest can result in profound declines in the functional reserve of
the musculoskeletal and cardiovascular system (Table 1) These two systems are central
to achieving and maintaining functional independence, which is a common prerequisite for discharge from a healthcare facility
TABLE 1 Effects of Inactivity on Musculoskeletal and Cardiovascular Systems
Musculoskeletal
Muscles
Bone
Joints
Cardiovascular
Cardiac (at rest)
Cardiac (with exercise)
Neurovascular
Fluid balance
Cardiovascular
Blood coagulation
Adapted from Buschbacher.85
267
Atrophy; decreased strength and endurance
Contractures
Altered electrical activity; excitation
Weakened myotendinous junction
Decreased strength of tendons and ligaments and their
insertions on bone
Osteoporosis
Cartilage degeneration
Fibrofatty tissue infiltration
Synovial atrophy
Ankylosis
Increased heart rate
Decreased stroke volume
Cardiac output unchanged or slightly decreased, VO2
unchanged
Decreased cardiac size/volume
Decreased left ventricular end-diastolic volume
Systolic-diastolic blood pressure unchanged
Arteriovenous oxygen difference unchanged or slightly
increased
Increased heart rate response to submaximal exercise
Maximum heart rate unchanged
Decreased VO2 maximum
Decreased stroke volume (submaximal/maximal)
Decrease cardiac output (submaximal/maximal)
Increased arteriovenous oxygen difference (submaximal)
(maximal is unchanged)
Orthostatic intolerance
Decreased volume
Decreased total blood volume
Decreased red blood cell mass
Mineral and plasma protein loss
Increased venous thrombosis
Decreased calf blood flow (possible)
Increased blood fibrinogen
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TOPP ET AL
and independent functioning of the individual in the community setting. A number of
authors have demonstrated the responsiveness of the musculoskeletal and cardiovascular systems to changes in physical activity
before and after periods of decreased physical activity and bed rest. Persons of all ages,
degrees of chronicity, and various stages of
detraining respond favorably to increases in
physical activity. Many investigators have focused their research on developing physical
activity protocols to be introduced after periods of inactivity and bed rest. There has
been little emphasis on examining the potential of enhancing the functional reserve of
an individual through exercise prior to a detraining experience, such as a stay in an ICU.
Previous work indicates that individuals can
enhance their functional reserve through exercise prior to an admission to an ICU. A resultant higher level of functional reserve may
attenuate declines in their functional status,
allowing them to maintain or return more
quickly to functional independence and decrease the duration of rehabilitation after
their ICU stay.
Prehabilitation
Within genetic limits, the body can be
trained to be stronger, faster, and, in general,
more physically fit. Increased physical activity can improve the functional capacity of a
number of organ systems, thus resulting in a
body that is better prepared to withstand external stressors. The improvement in functional capacity as a result of increased physical activity has been observed in individuals
of all ages over the entire life span.68-71 Positive adaptations to regular physical activity
have been observed across the life span of
individuals being treated for a variety of
chronic health conditions.72-75
Prehabilitation is process of enhancing
functional capacity of the individual to enable him or her to withstand the stressor of
inactivity. The concept of prehabilitation has
been used in a number of fields under the
terminology of “conditioning,” “physical
preparation,” or “training.” Prehabilitation
has had limited application to the stressor of
inactivity while staying in an ICU. Several
programs have attempted to prepare individ-
AACN Clinical Issues
uals for the stressors of postsurgical recovery
through educational programs, while a limited number of programs have been developed to prepare individuals for the physical
stressors after a surgical procedure. Thus it
seems appropriate to attempt to enhance the
individual’s functional capacity before encountering the stressor of inactivity accompanying an ICU admission, such as a planned
surgery or admission into the hospital.
Prehabilitation has been used by athletes
to reduce injuries during the stress of athletic
competition. Prehabilitation in this context is
commonly referred to as conditioning or
training to prevent injury. Training for an
athletic event not only improves the skills required during the event but also decreases
the risk of injury because the body is better
prepared to withstand the stress of competition. For example, numerous clinical trials
have supported the efficacy of increased
physical activity to decrease injuries during
athletic competition. Caraffe et al76 have
shown that training prior to an athletic season will increase muscle proprioception,
which inversely decreases the number of anterior cruciate ligament injuries encountered
by an athlete.77 Further, Heidt et al78 demonstrated that a 7-week preseason training program significantly decreased the risk of leg
injuries among adolescent female soccer
players. Two reviews of the literature confirm the efficacy of training in preventing injuries during physically demanding events.
Jones et al79 concluded that army recruits
who initially were in better physical condition experienced a lower percentage of injuries during basic training. Similarly, Smith80
recommended stretching before athletic
competition as a method of preventing injuries caused by over-exertion.
Prehabilitation concepts have been applied as method of preventing a specific injury or progress of a specific medical condition. In the article by Teiz and Cook,81 the
authors recommend flexibility and strength
training exercises as interventions to prevent
neck and low back injuries. These authors
describe specific strengthening and flexibility exercises not only as methodologies of
prevention but also to enhance rehabilitation
after a neck or back injury. In a descriptive
study, Katz et al82 noted a significant positive
relationship between preoperative physical
EFFECTS OF BED REST
Vol. 13, No. 2 May 2002
capacity and postoperative progress among
patients undergoing surgery for lumbar
spinal stenosis. Prehabilitation has the potential to attenuate the physiological decrements associated with bed rest during hospitalization.
Prehabilitation prepares the body to withstand a stressful event through increasing
regular physical activity. This intervention
appears to be effective in preventing athletic-related injuries due to the stress of competition. Prehabilitation also seems effective
in facilitating recovery from various types of
stress induced by surgery. This concept, although supported theoretically, has had limited application as an intervention. Prehabilitation has the potential to decrease the
duration of dependent functioning and return the individual to his or her initial level
of functioning after an anticipated admission
to an ICU.
Broadly defined, prehabilitation is preparing an individual in advance to withstand a
stressful event through enhancement of
functional capacity. Functional capacity is
most commonly enhanced through increases
in regular physical activity. Figure 1 presents
a conceptual model of the potential effect of
prehabilitation on the patient who antici-
269
pates an ICU admission. The dotted horizontal line indicates the minimal amount of
functional capacity required for independent
functioning. The functional capacity of two
individuals is shown in Figure 1. One individual participates in prehabilitation before
their anticipated ICU admission, and the
other individual does not participate in prehabilitation. Before an ICU admission, the
level of functional capacity is hypothesized
as an increase due to a result of prehabilitation. The magnitude of this increase in functional capacity is directly related to the duration, intensity, frequency, and mode of the
prehabilitation physical activities. Once
these individuals are admitted to the ICU
and the stress of decreased physical activity,
their functional capacity begins to decline.
Based on previous detraining studies, both
the prehabilitated and the non-prehabilitated
individual are believed to exhibit similar percentage declines in their functional capacity.
Because the prehabilitated individual was
admitted to the ICU with an initially higher
functional capacity he or she should retain a
higher functional capacity compared to the
non-prehabilitated individual throughout
ICU admission. During the ICU stay it is possible that declines in functional capacity may
Figure 1. Proposed effect of prehabilitation on an ICU patient.
270
TOPP ET AL
progress to the point where the individual is
unable to maintain independent functioning.
Theoretically, this point should occur later in
the prehabilitated individual’s ICU stay compared with the individual who did not participate in prehabilitation. The model also indicates that the enhanced level of functional
capacity exhibited by the prehabilitated individual may decrease the duration of time this
individual requires to return to initial level of
functional capacity. Thus, this model hypothesizes that prehabilitation before an ICU
admission decreases the duration of dependent functioning and returns the individual
to his or her initial level of functioning
sooner after discharge from the ICU.
Prehabilitation
of the ICU Patient
As stated previously, the goal of prehabilitating an individual who anticipates an ICU admission is to prepare the patient to withstand the stressful event of decreased
physical activity during the ICU visit. A secondary goal of prehabilitation is to decrease
the duration of dependent functioning by returning the individual to the initial level of
functioning sooner after discharge from the
ICU. The design of a prehabilitation program
should consider inclusion criteria, individual
goal development, and a specific physical
activity prescription designed to enhance the
physical capacity of the individual.
Prehabilitation before an ICU admission is
not realistic for every ICU patient. A substantial proportion of ICU patients are unable to
anticipate their ICU admission. These patients include those with trauma or patients
who develop an acute medical condition.
Conversely, some ICU patients can anticipate their admissions by as many as 6
months. Common examples of those who
can anticipate an ICU admission include organ transplant, major orthopedic surgery, or
other major elective surgery patients. These
individuals may be excellent candidates for a
prehabilitation intervention.
Other factors must be considered when
judging an individual to be a candidate for
prehabilitation. These factors include any
limitations the individual may have regarding regular physical activity, the individual’s
AACN Clinical Issues
initial level of functional capacity, and the
objectives of participating in prehabilitation.
Most individuals can participate in some
form of prehabilitation program involving increases in regular physical activity. However,
for a limited number of individuals with specific health conditions even minor increases
in physical activity may pose a health risk
(Table 2).83 Thus, it is recommended that
physician consent be obtained before recommending prehabilitation to anyone who
is anticipating an ICU admission.
Once an individual is deemed eligible for
a prehabilitation program, individual objectives must be developed so that the patient
and the practitioner understand the purpose
of the program. Once objectives are established, the practitioner can design a program
specific to the needs and capabilities of the
individual. Objectives of all physical activity
programs must be significant, measurable,
attainable or realistic, related to the individual patient, and time-limited (SMART).84 The
significant component of the objective is a
meaningful change in some functional task.
The measurable implies that the functional
task can be objectively assessed and described in terms of numbers. Attainable distinguishes the objective as realistic or possible to achieve. The components of the
objective must be related to or under the
control of the individual who is setting the
objective. This means that ultimately the individual patient must determine if the objective is being addressed through the prehabilitation intervention. Finally, an objective
includes a time frame after which achievement of the objective can be evaluated. To
individualize these objectives, the practitioner should evaluate the individual’s initial
ability to perform specific tasks necessary to
maintain functional independence and engage in a variety of physical activities. This
initial assessment provides the practitioner
with the basis for designing the prehabilitation program. For example, if the individual
has difficulty or is unable to arise from a
chair the prehabilitation program should focus on improving leg and arm strength and
practicing getting in and out of a chair.
A generic prehabilitation program is presented in Table 3 This program includes
warm-up, aerobic, strength, flexibility, and
functional task components. Corresponding
Vol. 13, No. 2 May 2002
EFFECTS OF BED REST
271
TABLE 2 Health Conditions That Absolutely
Contraindicate Prehabilitation
• Unstable angina
• Resting systolic blood pressure of ⬎ 200 mm Hg or resting diastolic blood
pressure of ⬎ 110 mm Hg should be evaluated on a case-by-case basis
• Orthostatic blood pressure drop of ⬎ 20 mm Hg with symptoms
• Critical aortic stenosis (peak systolic pressure gradient of ⬎ 50 mm Hg with an
aortic value orifice area of ⬍ 0.75 cm2 in an average size adult)
• Acute systemic illness or fever
• Uncontrolled atrial or ventricular dysrhythmias
• Uncontrolled sinus tachycardia (heart rate ⬎ 120 beats/min)
• Uncompensated congestive heart failure
• 3⬚ atrioventricular block (without pacemaker)
• Active pericarditis or myocarditis
• Recent embolism
• Thrombophlebitis
• Resting ST segment displacement (⬎ 2 mm)
• Uncontrolled diabetes (fasting blood glucose of ⬎ 400 mg/dL)
• Severe orthopedic conditions that would prohibit exercise
• Other metabolic conditions, such as acute thyroiditis, hypokalemia or hyperkalemia, hypovolemia, etc.
Data from American College of Sports Medicine.83
with each of these components is a brief description of the technique and a recommended initial level of training. This generic
program will need to be modified to each individual’s initial level of functional capacity
and possible limitations imposed by any
medical conditions. Patients may exhibit initial functional capacities that are above or
below the initial level of training stated in
this generic program. The practitioner must
assess the individual patient’s capacity to
perform the initially recommended level of
training and adjust the intensity, duration,
frequency, or mode of the training to this initial functional capacity. Optimally, the initial
level of training should require the individual to engage in physical activity, which is
beyond their normal daily levels without
risking injury resulting in undue stress. Similarly, progression in a prehabilitation program should constantly increase the intensity, duration, and frequency of the training
until achieving a predetermined objective.
Again, increases should be individualized to
the individual’s capacities and responses to
the training and should minimize risk and
undue stress. Thus, the initial level of train-
ing and the progression of the intensity, duration, frequency, and mode of training will
be different for each individual based on
their initial physical capacity and the degree
to which they individually respond to the increases in physical activity.
Implementing a prehabilitation program
for a patient should begin as soon as they
are able to anticipate an ICU admission. The
longer the duration of the prehabilitation
program the greater the gains in functional
capacity, which can be realized as a result of
participating in the program. The greater the
gains in functional capacity realized by this
participation, the greater the functional reserve that can be called upon when encountering the stress of immobility encountered
during the ICU admission. Once the practitioner identifies a patient as a candidate for
prehabilitation, the concept should be introduced as a method that the patient can implement to improve their outcomes during
and after their ICU admission. Objectives
and prehabilitation program components
can then be developed specific to the patient’s initial functional ability. The practitioner should periodically monitor, by phone
272
TOPP ET AL
AACN Clinical Issues
TABLE 3 Generic Prehabilitation Program
Component
Technique and Initial Level
Progression and Goal
Warm up
Slow walking for 3–5 minutes
Increase by 1 minute per week to 5 minutes
Aerobic
Intensity: heart rate increases by
10–15 beats over resting
Duration: 5 minutes
Intensity: As tolerated to 20–25 beats above
resting heart rate
Duration: Increase by 5 minutes each week up to
20–30 minutes
Frequency: Increase as tolerated to 5 days per week
Frequency: 2–3 times per week
Mode: walking, stationary cycling,
swimming, stair climbing
Strength
Intensity: fatigue after 6 repetitions
Repetitions: 6–8 repetitions
Frequency: 2 days per week
Mode: use gravity for resistance,
light hand/ankle weights,
elastic bands
Upper body
Biceps curls
Overhead press
Triceps extensions
Lateral raises
Rows
Lower body
Knee extension/flexion
Plantar/dorsi flexion
Hip abduction/adduction
Hip extension/flexion
Trunk
Chair sit ups
Intensity: fatigue after 10–12 repetitions
Repetitions: single set of 12 repetitions
Frequency: Increase as tolerated to 5 days per week
Flexibility
Intensity: moderate feeling of tension
Repetitions: 2 per exercise
Duration: 30 seconds
Frequency: 2–3 times per week
Mode:
Touch toes
Over head stretch
Intensity: moderate feeling of tension
Repetitions: 5 per exercise
Duration: 30 seconds
Frequency: Increase as tolerated to 5 days per week
Functional tasks
Repetitions: 2–5
Repetitions: 5–10
Frequency: 2–3 times per week
Frequency: Increase as tolerated to 5 days per week
Mode:
Into and out of a chair
Up and down off of the floor
In and out of bed
In and out of the car
Up and down the stairs
Carrying a laundry basket
Carrying a bag of groceries
Up and down off the commode
Retrieving object from lower/upper cabinet
Data from Topp.84
Vol. 13, No. 2 May 2002
or in person, the patient’s understanding and
compliance with the program to ensure
maximal gains in functional capacity as a result of the program.
Summary
Declines in physical activity, which accompany an admission to an ICU, represent a
significant stress to the body. Decreases in
the functional capacity of the musculoskeletal and cardiovascular systems are in response to declines in physical activity common during an ICU admission. These two
systems are central to achieving and maintaining functional independence, and independent functioning. These two systems respond to increases as well as decreases in
physical activity. Decreases in physical activity will result in declines in the functional capacity of the cardiovascular and musculoskeletal systems, whereas increases in
physical activity can stimulate gains in the
functional capacity of these two systems. Increasing an individual’s functional capacity
through increased physical activity prior to
an ICU admission seems to be a reasonable
intervention to minimize the impact of the
stressor of inactivity on the individual, which
is common during an ICU admission. The
process of enhancing functional capacity of
the individual to enable him or her to withstand the stressor of inactivity is termed prehabilitation. Decline in physical activity
among ICU patients represents a significant
health risk that may be reduced through introducing prehabilitation interventions.
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