Effects of Mobility Devices on Nursing Compliance With Mobility Protocols

Background Critical care costs an estimated 90 billion dollars per year in the United States,
comprising approximately 1% of the gross national product.1 Though this expenditure is
enormous, together with advances in critical care medicine and mechanical ventilation
technology, it has produced a priceless trend in decreasing intensive care unit (ICU)
mortality.1 Of all ICU admissions, about 40% require mechanical ventilation, often with
accompanying necessary periods of sedation and inactivity.1 Although more patients are
surviving their ICU stay, it is becoming apparent that our current ICU culture of heavy
sedation and inactivity is taking its toll on the complete recovery of the critically ill
patient. 1,2 Several studies have shown significant disability one year after discharge, as
well as major declines in functional status and health-related quality of life; half of ICU
patients were unable to return to work due to persistent fatigue, weakness, and poor
functional status. 4 The primary contributor was muscle wasting and weakness,5 due to the
prolonged immobilization brought about by illness, lengthy bed rest, deep sedation, and the
use of paralytic agents.6 It is estimated that just a single day of inactivity causes muscle
strength to decrease by 1-1.5%.7 Although 94% of survivors with critical illness
myoneuropathy can demonstrate meaningful clinical recovery of muscle strength 9 months out
from their hospital stay, there are still some patients whose weakness may persist, resulting
in severe and prolonged functional deficits.14,18 To combat the deleterious effects of
inactivity and improve complete recovery, some hospitals have instituted programs under the
rubric early mobility, wherein sedation is reduced and patients are engaged in progressive
levels of activity as soon as physically possible. Early mobilization starts with passive
range of motion exercises, then progresses to active range of motion, sitting, standing, and,
finally, walking. Early mobility in the ICU has been proposed as a crucial instrument in
muscle preservation and protection from neuropathy of critical illness, thereby decreasing
long-term morbidity and physical debilitation.18

There is a growing body of evidence indicating that early mobilization of ventilated patients
can have a significant positive impact on length of stay, muscle condition, and the patient's
overall sense of well-being. The use of early mobility in patients with respiratory failure
has been proven safe with the implementation of proper monitoring in a physiologically stable
and awake patient.2 Hopkins et al. implemented an early activity program and demonstrated a
decline in length of ICU stay of 3 days.1 Morris et al. implemented a similar early
mobilization program that showed a statistically significant decrease in the length of stay
in the ICU (6.9 vs. 5.5 days, P=0.025) as well as in the hospital (14.5 vs. 11.2 days,
P=0.006); in addition there was a notable trend towards decreased inpatient cost per patient
($44,302 vs. $41,142, P=0.262).19 Schweikert et al. were able to demonstrate that patients
who had undergone early mobilization had a greater rate of return to independent functional
status at hospital discharge (59% vs. 35%, P=0.02).20 These studies have demonstrated the
ability to increase mobilization, improve physical function, and decrease ICU resource
utilization within a relatively short period of time with an appropriate change in routine
clinical practice.12

Unfortunately, there exist significant barriers to the implementation of an early mobility
program. The most significant and pervasive of these barriers is cultural—the perception that
the critically ill patient cannot tolerate physical activity. This barrier, however, is
rapidly dissolving with the mounting evidence noted above. The demonstrated benefits of early
mobility have prompted increasing numbers of institutions to develop their own early mobility
protocols and attempt their implementation. Once the cultural barriers are overcome, however,
additional barriers appear. Thus, implementation has been slow and spotty. In a multisite
study, only 27% of patients with acute lung injury received any form of physical therapy in
the ICU, with treatments occurring only 6% of those days.22 These barriers involved: 1)
providing safety guarantees, 2) accommodating staffing models, and 3) finding the right
hardware. With regard to safety guarantees, there exist legitimate fears regarding possible
harm to the patient in the process of mobilization, either secondary to patient falls, or
unintentional removal of lines, feeding or drainage tubes, or endotracheal tubes. Safe
mechanical support is needed for the patient, to the point of full body-weight support. The
staffing model is also critical: the mobilization of one ventilated patient requires, in
addition to a physical therapist, at least three staff members to move medical equipment
while the patient walks.11, 21 Although on a given day, within a 20-bed ICU, only two
patients might qualify for assisted walking, and would require only four 15-minute periods
from a 5-member mobility team per day, the logistics of assembling that team from the ICU
staff are often prohibitive. Finally with regard to finding appropriate hardware, the
management and transport of medical equipment alongside the walking patient is not easily
addressed with rolling poles and carts. The current standard of care for walking a
mechanically ventilated patient consists of a wheeled walker held onto by the patient, the
patient supported with a gait belt held from behind by a physical therapist, and 4-5 staff
persons in attendance to guide the patient, roll the equipment, and be ready to "pick up"
should the patient fall.

As an alternative to the front-wheeled walker, the Rifton Gait Trainer has been introduced
into clinical practice. This device provides greater inherent safety features via a pelvic
harness that keeps the patient from falling, even if their legs should give out while
walking. In addition, there is a chest piece to keep patients from tipping forward or
backward, and there are higher handholds to help patients mobilize more easily. The Rifton
Gait Trainer addresses two of the three above listed barriers by providing more inherent
safety features through better hardware, and it may also help decrease the number of staff
required to mobilize patients.

Purpose The following sections describe a 10-week pilot study for a randomized non-blinded
controlled clinical trial to assess whether use of the Rifton Gait Trainer will improve the
incidence of mobilization of critically ill ventilator dependent patients in the intensive
care units (ICUs) and improve important patient outcomes. The pilot study is designed to
assess the feasibility and logistics of doing a study of this nature in the ICU; it will also
provide the means to obtain estimates of outcome effect sizes, number of repeated measures,
time between repeated measures, and intra-subject and intra-unit correlations, to be used for
sample size calculations for a multi-center study.

Subjects Approximately forty subjects will be randomized to use either the RGT or the FWW,
with enrollment spanning a period of approximately 10 weeks. Patients will be deemed eligible
to ambulate based on their daily mobility score, as calculated according to the Early
Mobility Protocol. Mobility scores are first determined based on level of consciousness. The
unconscious patient has the lowest mobility level, Level 1. Patients who are conscious but
have a low RASS score (-2) are considered a Level 2. Conscious patients are considered to be
Level 3 or 4. Level 4 patients are those patients who have proven that they can master all
the activities outlined for Level 3 mobility; that is, they can dangle at the bedside and
stand and pivot to a chair. Level 4 activities are separated from Level 3 activities only by
the ability to walk in the hallway.

Informed consent will occur prior to randomization. Randomization will occur when patients
have been on the ventilator > 2 days and have mobility scores eligible for walking.
Randomization will be assigned on a 1:1 ratio to either the RGT or FWW. Patients will be
randomized using a web-based system called CREDIT.

Data Analysis A future study will be considered feasible if we are able to enroll 60% of
eligible patients, have records for 90% of eligible ambulation days, and at least 85% of
required data fields are completed as designed. Analysis will be based on intention-to-treat;
that is, regardless of which walker is actually used, the patient will be analyzed in the
group to which he or she was randomized.

The primary outcome measure, how many times the patient is mobilized each day, will be
compared between devices using a hierarchical generalized linear model with number of times
the patient is mobilized each day as the dependent variable, device, unit and day and an
interaction of device with day as the independent variables, and subject as the random effect
in the model. Most likely, ordinal regression will be used with 0, 1, 2 or more times as the
definition of outcome. If there are too few occurrences of 2 or more, we will convert to a
logistic model. If one device is better than the other, we would expect the odds of being
mobilized at a higher level with RGT is significantly different from the odds of being
mobilized with FWW. We will also test for the interaction of device with time.

Sources

Inclusion Criteria:

- >18 years of age

- On the ventilator for > 48 hours

- Mobility score > 3

Exclusion Criteria:

- > 220 lbs

- Limb amputees

- Prisoners

- Pregnant women