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Effect of Repositioning Aids and Patient Weight on Biomechanical Stresses When Repositioning Patients in Bed

  • Rivian

Abstract and Figures

Objective The aim of the study was to estimate the risk of injury when repositioning patients of different weight with commonly used repositioning aids. Background Repositioning dependent patients in bed is the most common type of patient handling activity and is associated with high rates of musculoskeletal disorders in healthcare workers. Several studies have evaluated repositioning aids, but typically for a single patient weight and often without estimating risk of injury based on biomechanical analysis. Method Ten nurses performed four repositioning activities on three participants (50, 77, 141 kg) using three repositioning aids (pair of friction-reducing sheets [FRS], turn and position glide sheet, air-assisted transfer device) and a draw sheet. Motion capture, hand forces, and ground reaction forces were recorded. Spine loading was estimated using a dynamic biomechanical model. Results Hand forces and spine compression exceeded recommended limits for most patient weights and repositioning tasks with the draw sheet. FRS and glide sheet reduced these loads but still exceeded recommended limits for all but the 50-kg patient. Only the air-assisted transfer device reduced forces to accepted levels for all patient weights. Physical stresses were relatively low when turning patients. Conclusion Most repositioning aids are insufficient to properly mitigate risk of musculoskeletal injury in healthcare workers. Only the air-assisted transfer device was sufficient to adequately mitigate the risk of injury when moving patients of average or above-average weight. Application To safely move dependent patients, a robust solution requires mechanical lifts and may utilize air-assisted transfer devices for patient transfers.
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Effect of Repositioning Aids and Patient Weight on
Biomechanical Stresses When Repositioning Patients
Neal Wiggermann , Jie Zhou, Hillrom, Batesville, IN, USA, and Nancy McGann,
SCL Health, Broomfield, CO, USA
Address correspondence to Neal Wiggermann, Hillrom,
1069 State Rd. 46, Batesville, IN 47006, USA; e-mail:
neal. wiggermann@ hillrom. com
Vol. 00, No. 0, Month XXXX, pp. 1
DOI:10.1177/0018720 8198 95850
Article reuse guidelines: sagepub. com/ journals-
Copyright © 2020, The Author(s).
Objective: The aim of the study was to estimate the risk
of injury when repositioning patients of different weight with
commonly used repositioning aids.
Background: Repositioning dependent patients in bed is
the most common type of patient handling activity and is asso-
ciated with high rates of musculoskeletal disorders in health-
care workers. Several studies have evaluated repositioning aids,
but typically for a single patient weight and often without esti-
mating risk of injury based on biomechanical analysis.
Method: Ten nurses performed four repositioning activities
on three participants (50, 77, 141 kg) using three repositioning
aids (pair of friction- reducing sheets [FRS], turn and position
glide sheet, air- assisted transfer device) and a draw sheet. Motion
capture, hand forces, and ground reaction forces were record-
ed. Spine loading was estimated using a dynamic biomechanical
Results: Hand forces and spine compression exceeded
recommended limits for most patient weights and reposition-
ing tasks with the draw sheet. FRS and glide sheet reduced
these loads but still exceeded recommended limits for all but
the 50- kg patient. Only the air- assisted transfer device reduced
forces to accepted levels for all patient weights. Physical stress-
es were relatively low when turning patients.
Conclusion: Most repositioning aids are insufficient to
properly mitigate risk of musculoskeletal injury in healthcare
workers. Only the air- assisted transfer device was sufficient to
adequately mitigate the risk of injury when moving patients of
average or above- average weight.
Application: To safely move dependent patients, a robust
solution requires mechanical lifts and may utilize air- assisted
transfer devices for patient transfers.
Keywords: patient handling, patient repositioning, hos-
pital bed, medical devices and technologies, nursing and
nursing systems
Rates of musculoskeletal injuries among
healthcare workers are higher than for almost
all other occupations (Bureau of Labor
Statistics, 2016) and most of these injuries are
attributed to manual handling of patients (Davis
& Kotowski, 2015; Holtermann et al., 2013;
Smedley et al., 2003). Manually lifting patients
exposes workers to forces that are known to
cause risk of back injury, and training in man-
ual lifting techniques does not reduce this risk
(Kraus et al., 2002; Lavender et al., 2007;
Martimo et al., 2008; Warming et al., 2008). By
applying the NIOSH lift equation to postures
adopted during manual patient handling, Waters
et al. (2007) determined at most 35 lbs (156 N)
could be lifted safely. Therefore, when lifting
or mobilizing patients, mechanical lifts are rec-
ommended as the standard of care to protect
healthcare workers from injury.
Of all the patient handling activities that
healthcare workers perform, repositioning
supine patients is most frequent (Poole Wilson
et al., 2015; Vasiliadou et al., 1995). Recent data
from the global risk consulting company AON
suggest that nearly twice as many healthcare
workers are injured when repositioning patients
as compared to transferring patients between
beds or chairs (AON, 2018). These reposition-
ing activities include repositioning patients up
in bed (boosting), laterally repositioning, and
turning. Such activities tend to require more
horizontal pushing and pulling than purely lift-
ing against gravity. Repositioning patients can
also involve rapid jerking motions as caregivers
pull and lift to overcome the starting friction of
the patient against the bed. The NIOSH lifting
equation does not apply to these pushing, pull-
ing, and rapid force exertions. Therefore, when
Month XXXX - Human Factors2
repositioning supine patients, it is unclear under
what circumstances patients can be safely repo-
sitioned manually, or whether aids like friction-
reducing sheets (FRS) or lift equipment are
needed. Understanding when assistive devices
are needed is important so facilities can have the
proper equipment available to allow caregivers
easy access to the tools they need to reposition
their patient safely.
Several studies have estimated spine load-
ing on healthcare workers when performing
the activities required to reposition patients in
bed (Daynard et al., 2001; Schibye et al., 2003;
Skotte et al., 2002; Skotte & Fallentin, 2008).
These studies all consider boosting, lateral repo-
sitioning, and turning. The researchers found
that lateral repositioning and boosting often
exceeded the 3400 N action limit for acceptable
compression forces on the spine (Waters et al.,
1993). However, the studies did not systemati-
cally evaluate assistive devices or interventions
designed to reduce the risk of injury during
patient handling.
Other researchers have evaluated the use of
assistive devices for at least one patient repo-
sitioning activity (i.e., boosting, lateral reposi-
tioning, and turning) or for laterally transferring
a patient between surfaces. In several dierent
experiments, at least one FRS was compared to
a traditional cotton draw sheet for one or two
activities (Baptiste et al., 2006; Bartnik & Rice,
2013; Bohannon, 1999; Fragala & Fragala, 2014;
Fray et al., 2016; Larson, 2015; Lloyd & Baptiste,
2006; McGill & Kavcic, 2005; Theou et al.,
2011; Weiner et al., 2017). Dependent variables
included hand force, estimated spine loads, elec-
tromyography of the arm and shoulder, coecient
of friction measurements, and subjective ratings.
There is general agreement among the studies that
physical demands are lower when using an assis-
tive device such as an FRS to reposition a patient
as compared to using a draw sheet. However, in
most studies dierences among assistive devices
tended not to be signicant. Two studies have
evaluated the turn assist feature common in many
air surfaces available on hospital beds. Turn assist
reduced hand force and spine loads when turning
and laterally repositioning a 63- kg patient and a
123- kg patient (Wiggermann, 2016) and when
turning an 82- kg patient (Budarick et al., 2019).
Previous studies of patient repositioning
had a great variety in the types of patients and
caregivers included. Several studies of patient
repositioning have included dierent patient
weights but only some of those have reported
results by patient weight or considered patient
weight as a factor in the analysis (Fray et al.,
2016; Skotte & Fallentin, 2008; Zhuang et al.,
1999). When considering the caregiver, past
studies included as many as 77 caregivers in
an unbalanced experimental design and 12
caregivers in a full factorial design (Fragala &
Fragala, 2014). Several researchers included
individuals without healthcare experience
(Larson, 2015; McGill & Kavcic, 2005; Silvia
et al., 2002). Other studies used only members
of the research team to reposition patients or
mannequins (Bartnik & Rice, 2013; Bohannon,
1999; Fray et al., 2016; Lloyd & Baptiste,
Although the existing body of literature is
useful for understanding how well specic
assistive devices work for certain repositioning
activities, it is still unclear when a patient of a
given weight can be safely repositioned manu-
ally, with a small repositioning aid, or whether
lift equipment is needed. Most of these previ-
ous studies did not perform a biomechanical
assessment of the load on the spine to estimate
risk of injury. Moreover, these studies provide
only a patchwork of limited comparisons of
repositioning aids with disparate methods and
dependent variables. Ergonomists and caregiv-
ers need to understand the relative risk of injury
for all repositioning activities across multiple
patient weights and with all current types of
repositioning aids. Given the widespread use
of repositioning aids, this lack of information
is concerning.
The objective of this study was to compare
the physical stress on caregivers across all repo-
sitioning activities, for multiple patient weights,
and for each common type of repositioning aid.
The results from these combinations of test
conditions will allow caregivers to understand
when repositioning aids are eective and when
manual handling of the patient presents an ele-
vated risk of injury.
Evaluation of PatiEnt REPositioning DEvicEs 3
This laboratory study evaluated healthcare
workers as they repositioned individuals of dif-
fering body weight in hospital beds. The activ-
ities investigated were repositioning up in bed
(boosting), lateral repositioning, lateral transfer
between beds, and turning. During these tasks,
hand forces, ground reaction forces, and pos-
tural data were collected to be used for biome-
chanical modeling.
Ten female “caregiver participants” were
recruited from Southeast Indiana and Southwest
Ohio, who had at least 1 year of experience in
a role where they repositioned patients at least
once per shift. Their mean (standard deviation)
height and weight were 169.8 cm (7.6 cm) and
80.4 kg (16.6 kg), respectively. The caregiver
participants wore their own form- tting clothes
that consisted of knit or spandex workout pants,
T- shirts or tank tops, and athletic shoes. Three
healthy “patient participants” were recruited
to act as completely immobile patients. The
patient participants were a 50- kg female, a 77-
kg female, and a 141- kg male. These individ-
uals participated in all experimental sessions
except for the 77- kg female who was replaced
with an 82- kg female for two sessions because
of scheduling conicts. This research was
approved by Advarra IRB (Cincinnati, OH) and
each participant provided written informed con-
sent (Protocol #201706185).
Three types of repositioning aids were eval-
uated across the dierent patient repositioning
activities. Two Liko HandySheets (Hillrom,
Batesville, IN, USA) were used to represent the
category of the FRS. These sheets were intended
to represent a particularly low- friction type of
FRS and were placed under the patient as a pair
as per manufacturer recommendations to max-
imize their eectiveness. The AirPal (AirPal,
LimePort, PA, USA) was included to represent
the air- assisted repositioning device (AARD).
This device is connected to a blower which
inates the AARD under the patient. Small
perforations on the underside of the device
creates a ow of air which reduces the fric-
tion between the AARD and the bed. The Sage
Turn and Position (TAP) glide sheet (Stryker,
Kalamazoo, MI, USA) was chosen to represent
the category of TAP systems which are used
by caregivers to reposition patients, typically
to ooad parts of the body at risk of pressure
injuries. Whereas the FRS and AARDs are gen-
erally not designed to be left under the patients
and must be installed and removed before and
after use, manufacturers claim that TAP systems
can be left under the patient without increased
risk to pressure injury. The standard cotton
draw sheet which is still most commonly used
to move patients was included as the baseline
condition for all activities.
All trials were performed on the same
Centrella Max hospital bed (Hillrom). Turning
trials were performed with and without the turn
assist on Centrella Max. For the lateral trans-
fer, the patient participant was transferred from
a Centrella bed with a foam mattress to the
Centrella Max, so it would be representative of
a transfer from either a bed or a stretcher with a
foam mattress.
Data Collection
During the trials, hand forces of the caregiver
participant were measured using force gages
congured as described in a previous study
(Wiggermann, 2016). Ground reaction forces
were measured using a force plate (AMTI,
Watertown, MA, USA). Data from an eight-
camera optical motion capture system (Motion
Analysis, Santa Rosa, CA, USA) were recorded
at 60 Hz.
Experimental sessions began by placing 38
motion capture markers in a modied Helen
Hayes conguration on the caregiver partici-
pant (Clark et al., 2016). After the experiment
was explained to the caregiver participant, she
practiced with any repositioning aids that were
dierent from what was typically used on her
job. Caregiver participants performed all tasks
from the patient’s left side of the bed.
The caregiver participant was instructed to
begin the trial with both feet on the force plate
Month XXXX - Human Factors4
and the bed was moved per caregiver instruc-
tions to achieve a realistic relative position
between the caregiver and the patient. For the
boosting trials, the caregiver was permitted to
step o the force plate with her right foot as she
shifted her weight to move the patient up in bed.
If the caregiver participant stepped o the force
plate, a visual inspection of the biomechani-
cal model output was performed to verify that
the relative maximum of spine load occurred
before the caregiver stepped o the force plate,
which was true for all aected trials. Other than
these instructions, the caregiver participant was
encouraged to perform the repositioning task as
she would on the job. The movement adopted
by the caregivers was generally most similar
to the “parallel stepping” method described by
Fray and Holgate (2018), but some torso rota-
tion was also observable in most trials.
Because boosting and lateral transfers are
commonly performed by a pair of caregivers,
the same member of the research team (NW)
assisted the caregiver participant from the oppo-
site side of the bed. Turning and lateral reposi-
tioning trials were performed by the caregiver
participant alone. Before each trial, the care-
giver adjusted the bed to her preferred height
and provided direction to the assistant, if pres-
ent. Caregivers were instructed to adjust the bed
to their preferred height without considering the
height of the assistant. For the transfer trials, the
caregiver also prescribed the height of the bed
from which the patient was being transferred,
typically so that it was a few centimeters higher
than the destination bed.
Patient position was standardized across the
four repositioning activities. For the boosting
trials, the patient participant was centered along
the width of the bed and the head was posi-
tioned at the lowest of two tape marks on the
mattress that were 8 and 38 cm below the head-
end edge of the mattress. When boosting the
patient, the caregiver and the assistant pulled
up the patient so that the head moved from the
lower tape mark to approximately the higher
tape mark, for a travel of approximately 30 cm.
For lateral repositioning, the patient participant
began with the right shoulder approximately 5
cm from the right edge of the bed and the care-
giver pulled the patient until the left shoulder
was approximately 5 cm from the left edge
of the bed. This activity simulated the reposi-
tioning that might often be achieved before a
caregiver turns a patient so that the patient has
room to be rotated. For the lateral transfer tri-
als, the side rails of both beds were lowered and
the beds were pushed together side by side to
minimize the gap between the mattresses. The
patient participant began with the left shoul-
der approximately 10 cm from the edge of the
origin bed and was moved until approximately
centered in the destination bed. Before each
turning trial, the caregiver directed the patient
to assume the position that the caregiver would
typically position a patient before turning in the
clinical setting. Data for the turning trial were
then recorded as the caregiver turned the patient
toward the caregiver using a draw sheet. When
turn assist was used, the caregiver engaged turn
assist on each product either until the actuation
was complete or until she was satised with the
patient position. Each repositioning activity is
illustrated in Figure 1.
This experiment tested every feasible com-
bination of repositioning activity, reposition-
ing aid, and patient weight. The TAP sheet was
not tested for lateral transfers because it was
not designed for this purpose, and the 141- kg
patient participant was omitted from some tri-
als to limit the risk of injury to the caregiver
participant. Each condition was replicated twice
for a total of 66 trials per participant (Tables 1
and 2 for all conditions). Trials were random-
ized within patient participant. Caregivers were
encouraged to rest as often as needed but rested
a minimum of 60 s between trials and often lon-
ger if a change of equipment was required. For
all caregiver participants, the entire experimen-
tal session lasted between 6 and 8 hr including
lunch and other rest breaks.
Biomechanical Model
Spine forces at the L5/S1 and muscle forces
as a percentage of maximum voluntary eort
(%MVE) were estimated using the AnyBody
Modeling System (AnyBody Technology,
Aalborg, Denmark). Anybody is a validated
(Bassani et al., 2017) whole- body dynamic
model that scales a custom human model for
Evaluation of PatiEnt REPositioning DEvicEs 5
each participant, estimates kinematic move-
ments, and performs inverse dynamics analysis
(Figure 2) to estimate muscle forces and joint
loads (Damsgaard et al., 2006). Motion capture
marker coordinates, ground reaction force, and
hand forces were all inputs to the model.
Relative to accepted injury thresholds, spine
compression forces were consistently larger
than shear forces, and shear forces were gen-
erally below 500 N. Therefore, the analysis of
spine loading was limited to spine compres-
sion. Similarly, %MVE was greatest for the
elbow exors, so analysis focused on the left
Statistical Analysis
For each repositioning activity, a repeated
measures analyses of variance (ANOVA) was
performed to test for the eects of repositioning
aid and patient weight. Caregiver participant
was included as a random factor. Within repo-
sitioning activity, post hoc comparisons of
repositioning aid and patient weight were per-
formed using Tukey–Kramer tests. An ANOVA
and Tukey–Kramer test was also used to com-
pare activities. All analyses were performed
using Minitab software (v.16, Minitab Inc.,
Pennsylvania, USA), with signicance criteria
set as α < .05.
Peak Compression at L5/S1
Both repositioning aid and patient weight
signicantly aected peak compression at the
L5/S1 (Table 1). Across all activities, the draw
sheet trended toward the greatest compression,
followed by the TAP, FRS, and AARD with the
lowest compression. Higher patient weight was
also associated with greater spine compression
Figure 1. Repositioning activities: (a) boosting, (b) lateral repositioning, (c) lateral
transfer, (d) turning with the turn assist condition. Red arrows indicate the direction of
Month XXXX - Human Factors6
across all activities. All activities signicantly
diered from one another, with the greatest
spine compression for lateral transfers, followed
by boosting, turning, and lateral repositioning.
Post hoc comparisons of peak spine com-
pression among repositioning aids are shown
in Table 1. Peak compression for the AARD
was signicantly less than those for the draw
sheet and TAP across all activities and patient
weights tested. For the remaining comparisons
across devices, statistical signicance varied by
activity and patient weight. For turning, peak
spine compression for turn assist was signi-
cantly less than manual turning for the 141- kg
patient only. Means of peak compression forces
exceeded 3,400 N only when boosting the large
patient with TAP. Additionally, individual tri-
als exceeded 3,400 N for boosting the 77- kg
patient with the draw sheet, TAP, and FRS; and
boosting and laterally repositioning the 141- kg
patient with the FRS; and transferring the 50-
and 77- kg patients with the draw sheet.
Peak Hand Force
Similar to spine compression, both repo-
sitioning aid and patient weight signicantly
aected hand force, and these factors also
trended the same as for spinal compression with
draw sheet, TAP, FRS, and AARD in order of
greatest to least force. A comparison of spine
compression and hand force for the boosting
task is illustrated in Figure 3. For most activities
and patient weights, all repositioning aids were
signicantly dierent from one another. For
turning, hand forces were signicantly lower
TABLE 1: Estimated Peak Spine Compression at the L5/S1 by Repositioning Activity, Repositioning Aid,
and Patient Weight
Peak L5/S1 Compression (N)
Activity Repositioning Aid
50 kg 77 kg 141 kg
Boosting Draw sheet 2,173 (594)a2,665 (755)a
TAP 1,985 (521)ab 2,737 (1,131)a3,736 (1,101)a
FRS 1,817 (532)b2,277 (696)a2,654 (817)b
AARD 1,072 (301)c1,209 (382)b1,747 (521)c
Lateral repositioning Draw sheet 1,569 (529)a1,913 (327)a
TAP 1,218 (315)b1,780 (463)a
FRS 1,122 (366)b1,320 (335)b2,271 (860)a
AARD 849 (257)c853 (188)c1,133 (314)b
Lateral transfer Draw sheet 2,602 (428)a2,974 (601)a
FRS 2,343 (485)b2,409 (490)b
AARD 2,280 (459)b2,318 (473)b
Turning Manual 1,983 (420)a2,100 (467)a2,551 (605)a
Turn assist 1,924 (398)a2,061 (409)a2,244 (484)b
Note. AARD = air- assisted repositioning device; FRS = friction- reducing sheets; TAP = Turn and Position glide
sheet. Values shown are mean (standard deviation). Superscript letters indicate the results of the Tukey multiple
comparison tests. A different letter indicates a significant difference between means within activity and patient.
Evaluation of PatiEnt REPositioning DEvicEs 7
with turn assist for the 50- and 77- kg patients
(Table 2). All activities signicantly diered
from one another, with the greatest hand forces
occurring for lateral repositioning, followed by
lateral transfers, boosting, and turning.
Estimated Muscle Exertion
Muscle forces as %MVE were greatest for
the elbow exors. The %MVE for the left bra-
chialis during the boosting task is shown in
Figure 4. The %MVE trended very closely with
peak hand force.
Interaction of Repositioning Aids and
Patient Weight
A signicant interaction between reposition-
ing aid and patient weight was found for peak
spine compression and hand force for all activ-
ities except turning. The general trend of these
interactions was that increased patient weight
corresponded to a greater increase in spine
TABLE 2: Peak Hand Force by Repositioning Activity, Repositioning Aid, and Patient Weight
Peak Hand Force (N)
Activity Repositioning Aid
50 kg 77 kg 141 kg
Boosting Draw sheet 203.0 (36.2)a287.2 (47.5)a
TAP 188.9 (43.8)a246.9 (64.9)b292.5 (78.6)a
FRS 158.3 (52.2)b206.3 (44.2)c250.1 (51.5)b
AARD 70.8 (22.7)c94.2 (35.9)d158.7 (29.5)c
Lateral repositioning Draw sheet 289.9 (16.2)a445.9 (44.1)a
TAP 215.6 (21.6)b348.0 (31.6)b
FRS 160.0 (24.6)c247.3 (25.1)c408.9 (19.6)a
AARD 96.5 (14.8)d129.5 (20.2)d196.6 (38.2)b
Lateral transfer Draw sheet 288.4 (50.3)a386.9 (37.9)a
FRS 162.6 (34.7)b257.6 (48.5)b
AARD 114.7 (25.5)c175.2 (27.2)c
Turning Manual 70.3 (18.0)a117.4 (15.9)a196.9 (35.6)a
Turn Assist 49.2 (12.0)b102.0 (24.8)b182.4 (30.3)a
Note. AARD = air- assisted repositioning device; FRS = friction- reducing sheets; TAP = Turn and Position glide
sheet. Values shown are mean (standard deviation). Superscript letters indicate the results of the Tukey multiple
comparison tests. A different letter indicates a significant difference between means within activity and patient.
Figure 2. Graphical representation of the kinematic
(left) and inverse dynamic (right) steps of modeling.
Month XXXX - Human Factors8
compression and hand force for the draw sheet
and TAP than for the FRS and AARD.
This study compared biomechanical stresses
on the body for dierent patient reposition-
ing activities, repositioning aids, and patient
weights. Spinal compression, hand forces, and
estimated muscle exertion all increased with
patient weight. Physical stresses were greatest
for the draw sheet followed by the TAP and
FRS, and were lowest for the AARD. The draw
sheet, TAP, and FRS exceeded recommended
pull forces for many test conditions, suggest-
ing that AARD or lift equipment is needed to
address the risk of injury when repositioning
For spine loading, only boosting the
141- kg patient with TAP exceeded the
NIOSH- recommended 3,400 N limit (Waters
et al., 1993). Although boosting and transfer-
ring the 141- kg patient with a draw sheet were
not tested, these conditions would also likely
exceed 3,400 N based on the trends in the
Based on Snook and Ciriello (1991), peak
hand forces acceptable to 75% and 90% of the
female population are 255 and 216 N, respec-
tively, when pulling 2.1 m at waist height every
30 min. These peak hand force limits were
exceeded for many patient weights, reposi-
tioning activities, and repositioning aids. The
AARD was the only repositioning aid to reduce
peak hand forces below the psychophysical
guidelines for all patient weights and reposi-
tioning activities tested.
Relative to recommended limits, peak hand
forces were consistently higher than spine
Figure 3. Mean of peak spinal compression (a) and peak hand force (b) for the boosting
activity. Dotted line indicates the 3,400 N NIOSH limit (a) and 255 N psychophysical limit
(b). Error bars depict standard error.
Figure 4. Mean of left brachialis activity as a proportion of maximal strength (a) and peak
hand force (b) for the boosting activity. Dotted line indicates the 255 N psychophysical
limit. Error bars depict standard error.
Evaluation of PatiEnt REPositioning DEvicEs 9
compression. There were no test conditions for
which spine compression was greater than peak
hand forces when compared as a proportion of
the recommended guidelines. For the boost-
ing activity as an example, Figure 3 compares
spine compression relative to the NIOSH’s
3,400 N limit and peak hand forces relative to
the Snook guidelines. Although these guide-
lines were developed using dierent methods,
this comparison shows how peak hand forces
appear to be the primary limitation to safely
repositioning the patient. The horizontal nature
of the hand forces applied by the caregiver par-
ticipants when repositioning likely explains the
low spine compression values relative to hand
forces. Accordingly, for the repositioning activ-
ities included in this study, repositioning aids
should be selected based on force exposures at
the hands.
Figure 5 illustrates the peak hand forces
measured in the current study as compared to
the psychophysical requirements. The compar-
isons in this gure are based on assumptions of
posture and frequency used to select psycho-
physical limits from Snook and Ciriello (1991).
The estimates of accommodation based on
patient weight also assume a linear relationship
between the weights tested in the current
study, and should be interpreted with caution.
Although the exact thresholds in this gure are
sensitive to these assumptions, they generally
illustrate that with the exception of the AARD,
most repositioning aids fail to properly mitigate
physical stresses on caregivers across patient
weights and repositioning activities.
The work methods used by Snook and
Ciriello (1991) to determine psychophysical
limits dier from the physical exertions of the
caregiver participants in the current study. The
hand forces in the current study were primarily
horizontal, but some vertical force component
was applied to overcome the starting friction
when moving the patient. Nevertheless, the
psychophysical guidelines provide the best
comparison for estimating risk of injury to
healthcare workers.
Although these psychophysical limits are
not a direct estimate of biomechanical load,
musculoskeletal disorders have been shown
to increase when physical demands exceeded
forces acceptable to 75% of the working popu-
lation (Herrin et al., 1986). In the current study,
estimated muscle forces as %MVE revealed
that particularly the elbow exors were near
Figure 5. Guidelines for selecting repositioning aids based on patient weight. Hand forces measured in the
current study are compared to psychophysical guidelines by Snook and Ciriello (1991). Green shading indicates
hand forces less than pull forces acceptable to 90% of females. Red indicates forces greater than pull forces
acceptable to 75% of females. Yellow accommodates 75% but not 90%. *Actual patient weights tested in the
study; all other ranges are estimates. The black vertical lines between colors represent an interpolation of the
hand forces between test conditions that corresponds to the psychophysical threshold.
Month XXXX - Human Factors10
maximal eort when hand forces exceeded
psychophysical guidelines. When the human
body cannot accomplish a task due to either
movement or strength limitations, a compen-
sation pattern manifests to fulll the task.
Compensation strategies frequently employ the
use of momentum, abnormal muscle recruit-
ment, and adjacent joint movement. This often
increases the risk of injury, especially in the
shoulder complex, which is primarily stabi-
lized by muscle alone (Paine & Voight, 2013).
Muscles recruited to assist in compensatory
strategies are typically not designed for such
tasks, creating strains. Momentum stretches
muscles and tendons beyond their safe range,
and adjacent joints often become hypermobile
creating inammation and tissue damage. These
ndings are particularly relevant considering
that rates of shoulder injuries are second only to
back injuries in caregivers (Davis & Kotowski,
Spine compression values from the current
study were similar to those of the research group
of Skotte and Fallentin (2008) that also used a
dynamic biomechanical model with an optimi-
zation algorithm for estimating muscle recruit-
ment. Spinal compression from the current
study of 2,665 and 2,100 N when boosting and
turning a 77- kg patient with a draw sheet was
very similar to the respective estimates of 2,616
and 2,044 N by Skotte and Fallentin (2008).
However, the current study estimated 1,913 N
when laterally repositioning the 77- kg patient
with a draw sheet which is much less than the
3,167 N from Skotte and Fallentin (2008). It is
possible these studies had methodological dif-
ferences such as the height of the bed or dis-
tance of repositioning which were not described
by Skotte and Fallentin (2008). The spinal com-
pression estimates in the current study appear
to be lower than an electromyography- assisted
model. For the only comparable task evaluated
by Marras et al. (1999), boosting a 50- kg patient
with a draw sheet resulted in 3,861 N when
averaging caregivers working on both sides
of the bed compared to 2,173 N in the current
study for the 50- kg patient.
Of the literature that reported hand forces
when repositioning patients, Bartnik and Rice
(2013) evaluated hand forces in a manner most
similar to the current study. When boosting 29
individuals with a mean mass of 66 kg, a single
caregiver produced a mean hand force of 222
N using a draw sheet (Bartnik & Rice, 2013)
which is similar to the 203 and 287 N for the
50- and 77- kg patients from the current study.
Similar to the current study, Lloyd and Baptiste
(2006) measured hand force for a single inves-
tigator performing a lateral transfer of a man-
nequin and found the greatest forces for a draw
sheet, followed by models of FRS, and the least
force for two AARDs.
Repositioning aids appeared to reduce phys-
ical stress commensurate with their friction
reduction, which is logical because the forces
required to reposition patients were primarily
horizontal. The AARD resulted in the lowest
friction because of the cushion of air it gener-
ates between the AARD and the bedsheet. The
pair of low- friction sheets for the FRS product
had resulted in considerably lower friction than
the single TAP sheet. Friction is also a function
of normal force, which increases with patient
weight and explains why physical stresses were
greater when moving heavier patients.
This was the rst study to provide a broad
comparison of dierent repositioning aids for
various patient weights across several repo-
sitioning activities. However, the study nec-
essarily included only the most representative
repositioning aids and three patient weights.
This study only considered spine compres-
sion loads, estimated muscle activity, and hand
loads. For the activities studied, hand forces
appear to be the greatest indicator of risk of
injury. Although pull forces are associated
with injury, this causal relationship is not as
well established as for lifting and back injury.
The hand forces associated with repositioning
patients may partially explain the high inci-
dence of shoulder and neck injury in healthcare
workers, but a lack of strong shoulder biome-
chanical models that explain the mechanism
for injury limits the ability to develop tolerance
thresholds for shoulder injury.
The system for measuring hand force was
specially designed to minimize the eect on
posture, but a 7- cm spacing between the sen-
sors and the attachment to the sheet likely had
a small eect. All trials studied the caregiver
Evaluation of PatiEnt REPositioning DEvicEs 11
while performing care on the patient’s left side
of the bed and it is reasonable to expect there
could be small dierences in posture or force
generation when caregivers stand on the oppo-
site side of the bed. The current study aimed
to evaluate repositioning activities as they are
commonly performed, but researchers have
shown that alternative methods such as pulling
from the head of the bed can reduce pull forces
(Fray & Holgate, 2018).
These ndings provide a general indication
of which interventions might be suitable for
which patient weights, but practitioners should
exercise caution if using these results to estab-
lish policy. Two patients of the same weight
may require dierent forces to reposition based
on body habitus or amount of deformable soft
body tissue. The recommendations in Figure 5
draw on guidelines that considered worker pop-
ulations that might be younger, thinner, and
healthier than the population of caregivers in
many healthcare facilities. Furthermore, these
repositioning activities might require more
dynamic forces than Snook and Ciriello (1991)
and may occur in a more stressful work envi-
ronment which could increase muscle coact-
ivation (Marras et al., 2000). Based on these
considerations, the comparisons to psychophys-
ical thresholds and the results in Figure 5 may
not be suciently conservative to protect all
healthcare workers.
This study did not evaluate the physical stresses
required to place the repositioning aids under the
patients, but the relatively low forces associated
with turning the patient suggest that placing repo-
sitioning aids can be installed safely. These results
are consistent with previous studies of patient
turning (Budarick et al., 2019; Wiggermann,
2016). Alternatively, using an electromyography-
assisted model Nagavarapu et al. (2017) identied
spine compression forces that exceeded 3,400 N
when applying slings under certain parameters.
However, these risks were mitigated when the
bed was elevated to knuckle height of the care-
giver or higher. Consistent with previous studies
(Budarick et al., 2019; Wiggermann, 2016), turn
assist tended to reduce the physical stresses on
caregivers and may be particularly appropriate
for turning heavier patients or reducing cumu-
lative load on caregivers. Turn assist has also
been suggested for use in lateral repositioning to
reduce pull force (Wiggermann, 2016). Integrated
features such as turn assist serve as an example
of interventions that are compatible with care-
giver workow and may be sustainably adopted
because they require few extra steps.
The results of the current study clearly indi-
cate that of the systems studied, the AARD
is the only repositioning aid that is eective
at mitigating risk of injury for most patient
weights and repositioning activities. Because its
thickness can contribute to the risk of pressure
injuries if left under a patient, the AARD must
be placed under the patient before repositioning
and removed after each use. The AARD also
requires the connection of an external blower
which must be retrieved and disinfected by
healthcare workers. The inclusion of the AARD
for the boosting and lateral repositioning activ-
ities demonstrates dierences in forces across
products, but in practice the AARD is unlikely
to be used for boosting and lateral repositioning
because of the diculty of placing and remov-
ing the product from under the patient. In fact,
to turn the patient to place the AARD, a lateral
reposition might rst be required to make space
for the turn. These extra steps and the additional
cumulative workload should be considered
when identifying suitable applications for the
In practice, a repositioning sheet together
with a mechanical overhead lift can provide
the most robust option for repositioning activ-
ities with the least impact to caregiver work-
ow. The repositioning sheet can be used to
boost, laterally reposition, transfer, and turn the
patient; and because its fabric is thin enough
and breathable it can be left under the patient
without signicant impact to risk of pressure
injury (Nelson et al., 2014). By not having to
place the sheet under the patient, much greater
compliance to safe patient handling protocols
can be achieved. Furthermore, the mechanical
lifting equipment can be used for other safe
patient handling practices that include seated
transfers from bed, toileting, and gait training.
For these reasons, the use of lift equipment has
been recommended by professional groups such
as the American Nurses Association (2013) and
the Facility Guidelines Institute (Cohen et al.,
Month XXXX - Human Factors12
2010), as well as the National Institute for
Occupational Safety and Health (2013).
When manually repositioning patients with
a draw sheet, spine compression and hand
forces exceeded recommended limits for many
patient weights and repositioning activities.
Repositioning aids reduced physical stresses,
but the TAP and FRS did not adequately miti-
gate the risk of injury across all patient weights.
Spine forces and hand forces did not exceed
recommended limits when using the AARD for
the patient weights tested. However, placing
and removing the AARD from under the patient
may increase the cumulative workload on care-
givers. Patient weight should be considered
when determining which repositioning aids to
use. These ndings reinforce recommendations
for using mechanical lift equipment, which
should be considered as a robust alternative to
repositioning aids that can safely accommodate
all patients regardless of weight.
FRS and “TAP” sheets reduce physical stresses
on healthcare workers when repositioning
patients, but these devices are insucient to
properly mitigate risk of musculoskeletal injury
for most patient weights.
For the repositioning activities tested, psycho-
physically developed guidelines for pull force
were exceeded more often than the recommended
limits for spine loading.
To safely move dependent patients, a robust solu-
tion requires mechanical lifts and may utilize air-
assisted transfer devices.
Neal Wiggermann h t t p s : / / o r c i d . o r g / 0 0 0 0 -
0 0 0 2 - 5 8 0 3 - 4 3 9 9
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Neal Wiggermann is a specialist research scientist
in Human Factors and Ergonomics at Hill- Rom. He
received his PhD in industrial and operations engi-
neering from the University of Michigan in 2011.
Jie Zhou is an advanced research scientist at Hill- Rom.
He received his PhD in ergonomics and biomechanics
from the University of California, Davis, in 2018.
Nancy McGann is a system manager of Ergonomics
and Safe Patient Handling at SCL Health. She received
a BS in Physical Therapy from Boston University in
Date received: August 2, 2019
Date accepted: November 25, 2019
... However, patient repositioning in bed (boosting task) can take place without lifting the patient, and friction reducing devices can be used in different transfer situations to reduce the physical load on nursing staff (Larson et al., 2018;Koppelaar et al., 2012;Bartnik and Rice 2013;Elnitsky et al., 2014;Weiner et al., 2017;Wiggermann et al., 2021). The use of patient handling devices can pose risks, but nursing professionals can implement patient handling programs in ways that are safe both for staff and for patients (Elnitsky et al., 2014). ...
... Friction is a function of the normal force, which increases with patient weight and explains why physical stress is greater when moving heavier patients. Wiggermann et al. (2021) conducted a study in which nurses performed four repositioning activities, namely boosting, lateral repositioning, lateral transfer and turning for patients weighing 50 kg, 77 kg and 141 kg. Repositioning aids appear to reduce physical stress commensurate with their friction reduction, which is logical because the forces required in repositioning patients were primarily horizontal. ...
... Repositioning aids appear to reduce physical stress commensurate with their friction reduction, which is logical because the forces required in repositioning patients were primarily horizontal. The results show that only air-assisted transfer devices reduced compressive forces in the lumbar spine in boosting tasks to accepted levels of 3400 N (Wiggermann et al., 2021). ...
Repositioning patients in bed (boosting) is a common daily task of health care workers. Our aim was to measure the physical load on nurses in a patient handling situation where a supine patient is repositioned toward the head of the bed. The study was conducted in a laboratory setting. Assistive devices used in boosting were a cotton draw sheet on top of a fitted draw sheet in bed (regular sheet) and a cotton draw sheet on top of a slide film, which was in double sheet condition. Ground reaction forces (GRF) and perceived physical load (Borg CR10 scale) were measured in two experienced nurses who repositioned two voluntary test persons weighing 90 kg and 125 kg. The boosting tasks (n = 16) were performed on both sides of the bed and measured in both nurses. The lowest rate of perceived exertion and the lowest requirement of force were measured when the slide film was used. Difference between peak and baseline of resultant ground reaction force was used to describe the force needed in boosting. The peak force needed in boosting was on average 38.1% less with slide film compared to regular sheet, and the impulse of force was on average 40.6% less. Friction-reducing assistive devices can decrease the force needed in boosting heavy patients. The results of our study can be used in workplace training programs aiming to enhance ergonomics and reduce the physical load of nurses and caregivers who perform boosting tasks many times a day in their work.
... Work-Related Musculoskeletal Disorders (WMSDs) are common among health sector workers and this has been reinstated in several studies, reporting a one-year prevalence of WMSDs of more than 70% (Heidari et al., 2019;Tang et al., 2022;Yang et al., 2019). Previous studies have shown that the use of patient handling aids such as air-assisted devices, slide boards, friction-reducing sheets may reduce the risk of WMSDs (Al-Qaisi et al., 2020;Hwang et al., 2019;Wiggermann et al., 2020). In another study, an automated device, Careful Patient Mover (C-Pam), allowed the nurse to transfer a patient single-handedly (Wang and Kasagami, 2008). ...
... To obtain the hand forces in lateral transfer for direct analysis or as inputs to obtain the biomechanical load through a human musculoskeletal model, previous studies used the load cells mounted on the transfer sheets (Hwang et al., 2019;Wiggermann et al., 2020;Zhou and Wiggermann, 2021). However, these load cell set-ups were only applicable to the pulling but not pushing mode. ...
... All the lateral hand forces reported were only in the pulling mode and no measurement has been made on the pushing mode due to the impracticality of making the load cell be in contact with the patient (Hwang et al., 2019;Wiggermann et al., 2020;Zhou and Wiggermann, 2021). Previous patient transfer studies using REBA were based on the estimated constant hand force (Davison et al., 2021;Iridiastadi et al., 2020). ...
Full-text available
Bed to stretcher patient transfer by nurses involves significant manual force at various postures and could lead to work-related musculoskeletal disorders (WMSDs). Motorized Patient Transfer Device (MPTD) is a newly available patient transfer intervention and its WMSDs risk have not yet been studied. The existing REBA assessment is unable to track the continuous load changes and to represent the actual load applied. The load cell set-ups in previous studies were unable to obtain the hand forces of lateral pushing. This study aimed (1) to identify and compare the hand forces for all the subtasks involved in sliding board and MPTD using the data from force plates and IMUs; (2) to evaluate the REBA score by using both instantaneous measured force and constant estimated force settings within a cycle of patient transfer task; and (3) to evaluate the WMSDs risk of the sliding board and MPTD. Seven nurses carried out all the tasks using the MPTD and the sliding board. Postural angles and external forces from the nurses were measured using Inertial Measurement Units (IMUs) and force plates, respectively, as the inputs for the automated REBA system. The hand force was comparatively higher for the subtasks of the lateral pushing (302.64 ± 136.45N) and lateral pulling (359.67 ± 150.14N) compared to the rest of the subtasks. The constant estimated force notably underestimated the REBA score for the lateral pushing by 1.76 points (95% Confidence Interval; CI [1.42, 2.10], p < 0.001). MPTD significantly reduced the mean peak REBA score by 4.21 (95% CI [3.77, 4.65], p < 0.001) and external force acting on the nurses by 180.41N (95% CI [111.68, 249.14], p < 0.001) compared to the sliding board. These findings proved that MPTD can reduce the WMSDs risk, pushing, and pulling force for the patient transfer. Relevance to the industry: MPTD should be implemented in the hospital for the lateral transfer instead of using the sliding board. Its main benefit is eliminating the strenuous subtasks of lateral pushing and pulling. It can handle any type of patient such as bedridden, dependent, big size or overweight patient.
... Nurses and caregivers experienced lower back pain (LBP) as a result of patient handling motions to assist in wheelchair or bed transfer and repositioning [1][2][3][4]. Therefore, previous studies provided assistive tools and devices to reduce lumbar loads while handling patients [4][5][6][7][8]. Schibye et al. reported that using a sliding sheet could reduce compressive forces at L4/ L5 compared with self-righting motions [5]. ...
... Schibye et al. reported that using a sliding sheet could reduce compressive forces at L4/ L5 compared with self-righting motions [5]. Additionally, assistive beds with automatic turn functions contributed to preventing lumbar loads during repositioning and turning patients on a bed [6][7][8]. Iridiastadi et al. found that a lifting machine could reduce compressive and shear forces on the vertebra during patient handling motion for transfer [9]. These findings suggest that these assistive devices and tools can prevent LBP due to patient handling motions. ...
... Powered drives integrated into stretchers can reduce maneuvering forces (e.g., Kotowski et al. 2022, Wiggermann 2017. However, while the interventions named may reduce the physical stresses on workers, interventions such as friction reducing sheets and team lifting do not always sufficiently mitigate the risk of injury based on body weight and work postures adopted (Wiggermann et al. 2021). ...
The COVID-19 pandemic has taken many lives in the last two years. Handling high volumes of decedents within and beyond a hospital’s environment has put healthcare- and deathcare-workers at an increased health risk throughout this pandemic. However, systematic research about manual handling of the dead either at the hospital, morgue, funeral home, or in situations of mass fatalities is still in infancy. This session aims to educate ergonomics and safety professionals on the importance of understanding the risk factors associated with handling the decedents, design issues of body bags, effects of PPE, routine versus mass fatality handling of the decedents, and participatory ergonomics. This session will also examine the feasibility of translating the past and current research on the handling of live patients to the handling of patients postmortem. Finally, psychosocial risks due to handling the deceased within the pandemic environment that might influence these workers’ risk of musculoskeletal injuries will be deliberated.
... The frequently affected body parts in work-related MSDs of nursing assistants were the back (associated with 53% of MSDs), the shoulder (13%), the leg (6%) and the arm (3%) (BLS 2018b). Unsurprisingly, in an experimental and modeling study, where the hand forces and low-back compression forces were measured and calculated during four repositioning tasks (i.e., boosting, lateral repositioning, lateral transfer and turning), both hand forces and low-back loads exceeded the recommended limits in many situations (Wiggermann et al. 2020). To design exoskeletons that could provide assistances at multiple joints and body parts, exoskeleton developers may also need to pay attention to some high-risk patient handling tasks. ...
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Musculoskeletal Disorders (MSDs) remain a major concern for workers in the healthcare industry. Healthcare workers are at high risk of work-related MSDs mainly caused by overexertion from manually handling patients. Exoskeletons may be a useful tool to help reduce the risk of MSDs during patient handling. As a review study, we surveyed articles focusing on applying exoskeletons to patient handling tasks specifically. We also reviewed relevant government databases and other studies related to Safe Patient Handling and Mobility (SPHM) programs and exoskeleton applications in general. The exoskeletons specifically designed for patient handling were found to be sparse. To have a better understanding of the needs and challenges of developing and using exoskeletons for reducing risks of work-related MSDs in healthcare workers during patient handling, this critical review (1) provided an overview of the existing issues and projected future burdens related to work-related MSDs during patient handling tasks, (2) recognized current and potential roles and applications of existing exoskeletons, and (3) identified challenges and needs for future exoskeleton products. In conclusion, we do not expect exoskeletons to replace the existing SPHM programs, but rather play a complementary role to these multi-pronged programs. We expect that emerging exoskeleton products can be introduced to uncontrolled or specialized healthcare environments. There are various expectations and requirements for an exoskeleton used in different healthcare settings. Additionally, introducing certain types of exoskeletons for patients to assist them during treatment and rehabilitation may help reduce the MSD risks to the healthcare workers.
... Like slide sheets, these devices have been found to decrease spinal loads (Fray, Michael, Hignett 2015). Another study compared spinal compression and peak hand forces during repositioning tasks of patients at multiple weights (50kg, 77kg, 141kg) using different friction reducing aides (Wiggermann, Zhou, & McGann 2021). Air assist devices were found to be the most effective in lowering spine compression and peak hand forces below injury thresholds, especially as patient weight increased. ...
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Introduction In April 2020, novel coronavirus SARS-Co-V-2 (COVID-19) produced an ongoing mass fatality event in New York. This overwhelmed hospital morgues necessitating emergent expansion of capacity in the form of refrigerated trucks, trailers, and shipping containers referred to as body collection points (BCPs). The risks for musculoskeletal injury during routine and mass fatality mortuary operations and experiences of decedent handlers throughout the "first wave" of COVID-19 are presented along with mitigation strategies Methods Awareness of the high rates of musculoskeletal injury among health care workers due to ergonomic exposures from patient handling, including heavy and repetitive manual lifting, prompted safety walkthroughs of mortuary operations at multiple hospitals within a health system in New York State by workforce safety specialists. Site visits sought to identify ergonomic exposures and ameliorate risk for injury associated with decedent handling by implementing engineering, work practice, and administrative controls. Results Musculoskeletal exposures included manual lifting of decedents to high and low surfaces, non-neutral postures, maneuvering of heavy equipment, and push/pull forces associated with the transport of decedents Discussion Risk mitigation strategies through participatory ergonomics, education on body mechanics, development of novel handling techniques implementing friction-reducing aides, procurement of specialized equipment, optimizing BCP design, and facilitation of communication between hospital and system-wide departments are presented along with lessons learned. After-action review of health system workers' compensation data found over four thousand lost workdays due to decedent handling related incidents, which illuminates the magnitude of musculoskeletal injury risk to decedent handlers.
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Purpose The high prevalence of musculoskeletal disorders (MSDs) among healthcare workers is partly attributed to the low adoption of patient transfer assistive devices. This study aimed to evaluate the nurses’ perceived workload, technology acceptance, and emotional states during the use of the sliding board (SB) and mechanical intervention in the form of a Motorised Patient Transfer Device (MPTD). Methods The SB and MPTD activities were performed by seven nurses on a simulated patient. The nurses’ facial expressions were recorded during the trial. The NASA Task Load Index and technology acceptance questionnaire were also assessed. Results The MPTD significantly reduced the mean overall NASA-TLX score by 68.7% (p = 0.004) and increased the overall acceptance score (median = 8.30) by 21.2% (p = 0.016) when compared to the SB (median = 6.85). All the subjects reported positive feelings towards MPTD. However, facial expression analysis showed that the nurses had a significantly higher peak density of fear while using MPTD (p = 0.016). Besides, there was no improvement in the negative valence and contempt emotion compared to the SB. Conclusion Overall, nurses showed positive perceptions and acceptance of MPTD even when they experienced negative emotions. • IMPLICATIONS FOR REHABILITATION • The Motorised Patient Transfer Device (MPTD) reduced the perceived workload of nurses and showed a higher acceptance level compared to the commonly used baseline device (SB). • Factors that attributed to the nurses’ negative emotions can be used to improve technology and patient transfer processes. • More training should be given to familiarise the health practitioners with the new assistive device to reduce their fear of technology.
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Objetivo: Trata-se de uma revisão sistemática de artigos que estudam as estratégias de pronação dos últimos 5 anos em unidades de terapia intensiva. Métodos: Foram observados poucos artigos que tratem desse tema, totalizando 4 estudos de um total de 143 extraídos das bases de dados da PUBMED; SCOPUS; WEB OF SCIENCE; EMBASE. Resultados: Os estudos demonstram estratégias semelhantes usadas no planejamento da técnica por profissionais que realizam a pronação, é possível perceber também a concordância de que a pronação em pacientes com síndromes respiratórias internados em unidades de terapia intensiva pode ser um procedimento que atue na redução do tempo de internação e/ou as taxas de mortalidade, além de poder evitar complicações graves. Conclusão: Por tanto é necessário salientar a importância de estudos sobre o tema.
Aim: This study aimed to evaluate the efficacy of patient transfer assistive devices in reducing the risk of work-related musculoskeletal disorders (WMSDs) among nurses. Review method: PubMed, Scopus, Google Scholar, and the Cochrane Database of Systematic Reviews were searched to identify studies with a quantitative assessment of the efficacy of patient transfer assistive devices on the incidence and injury claims of WMSDs as compared to the manual lifting of patients. A health impact analysis of the pre-post intervention of assistive device implementation was performed. The percentage of the reduction of forces, incidence of WMSDs, number of missed workdays, and injury compensation claims were calculated, pooled, and presented as boxplots. Results: A total of 25 studies met the inclusion criteria. The best post-intervention outcomes of assistive devices deployment in the health care setting included a reduction in the WMSDs incidence by 59.8%, missed workdays by 90.0%, and workers' compensation claims by 95.0%. Additionally, hand force declined by 71% (p < 0.05) and 70% (p < 0.05) with the use of air-assisted devices and ceiling lifts respectively. Conclusions: Overall, the evidence suggests that patient transfer assistive devices, notably ceiling lifts and air-assisted devices, are effective in reducing the risk of WMSDs among nurses.
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Current evidence demonstrates why turning and positioning patients in bed presents a serious occupational risk of musculoskeletal disorders for caregivers. Results of the laboratory study investigating a new method of turning and positioning patients in bed are presented. The study was designed to evaluate how this new method reduced the risk of occupational musculoskeletal disorders to caregivers and may improve outcomes for patients.
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Objective: This study investigated the effects of hospital bed features on the biomechanical stresses experienced by nurses when turning and laterally repositioning patients. Turn Assist, a common feature in ICU beds that helps to rotate patients, and side rail orientation were evaluated. Background: Manual patient handling is a risk factor for musculoskeletal injury, and turning patients is one of the most common patient handling activities. No known studies have evaluated bed attributes such as the Turn Assist feature and side rail orientation that may affect the stresses experienced by the nurse. Method: Nine female nurses laterally repositioned and turned a 63-kg and 123-kg subject on an ICU bed while motion capture, ground reaction forces, and hand force data were recorded. Loading of the spine and shoulder was modeled using 3D Static Strength Prediction Program (3DSSPP). Results: Spine compression and shear forces did not exceed recommended limits when turning or laterally repositioning. However, the mean pull forces required to manually laterally reposition even the 63-kg subject was 340 Newtons, more than 50% greater than limits established in psychophysical testing. Turn Assist considerably reduced spine loading and pull forces for both turning and laterally repositioning. Lowering side rails reduced spinal compression by 11% when turning patients. Conclusion: Laterally repositioning patients as part of turning may pose an injury risk to caregivers. Turn Assist reduces physical loading on nurses when turning and repositioning patients. Application: Caregivers should consider using Turn Assist and other aids such as mechanical lifts or sliding sheets especially when turning patients requires lateral repositioning.
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Background. Musculoskeletal disorders have continued to plague nurses in hospitals and long-term care facilities. Low back and shoulder injuries are the most prevalent, frequently linked to patient handling activities. Exposure to patient handling has been predominantly quantified by subjective responses of nurses. Objective. To directly observe handling of patients and other medical equipment for nurses during a 12-hour work shift. Methods. Twenty nurses working in three different intensive care units at a Midwest teaching hospital were directly observed during 12-hour day shifts. Direct observation included documenting frequency and type of handling performed and whether lift assist devices were utilized. Two additional surveys were completed by nurses to assess current pain levels and perceptions of lifting being performed. The observed lifting was compared to the perceived lifting with simple inference statistics. Results. Nurses have a high prevalence of manually lifting patients and medical devices but limited use of lifting assist devices. Nurses handled patients 69 times per shift and medical equipment 6 times per shift, but less than 3% utilized a lift assist device. Nurses suffered from high levels of pain at the end of the shift, with the highest prevalence in the lower back, lower legs, and feet/ankles (all above 60%).
Objective: To quantify differences in physical workload afforded by turn-assist surfaces relative to manual patient turns, and between nursing caregivers (turn-away vs. turn-toward) while performing partnered patient turning. Background: Nurse caregivers experience an increased risk of musculoskeletal injuries at the back or shoulders when performing patient-handling activities. Use of turn-assist surfaces can reduce the physical burden and risk on caregivers. Method: Whole-body motion capture and hand force measures were collected from 25 caregivers (17 female) while performing partnered manual and technology-facilitated turns. Shoulder and low back angles and L4/L5 joint contact forces were calculated at the instant of peak hand force application for both caregivers. Results: Hand force requirements for the turn-away caregiver were 93% of the estimated maximum acceptable force when performing a manual turn. Use of a turn-assist surface eliminated hand forces required to initiate the patient turn for the turn-away caregiver, where their role was reduced to inserting appropriate wedging behind the patient once the facilitated turn was complete. This reduced shoulder moments by 21.3 Nm for the turn-away caregiver, a reduction in exposure from 70% of maximum shoulder strength capacity to 15%. Spine compression exposures were reduced by 302.1 N for the turn-toward caregiver when using a turn-assist surface. Conclusion: Use of a turn-assist surface reduced peak hand force and shoulder-related exposures for turning away and reduced spine-related exposures for turning toward. Application: Turn-assist devices should be recommended to decrease the risk of musculoskeletal disorder hazards for both caregivers when performing a partnered patient turn.
Background: This study investigated the effects of 3 different types of slide sheets upon hand forces while sliding a patient up in bed. Methods: The sheets used included the reusable Arjo Maxislide, the McAuley disposable sheet, and a standard cotton sheet. Hand forces were measured from 38 male and female participants as they slid a 'patient' up in bed. A repeated measures ANOVA with 5 levels to the repeated factor (number of sheets and sheet type) was used, along with post-hoc repeated measures contrasts to compare differences between each condition. Results: A significant reduction in required force occurred when using the friction reducing sheets as compared to the cotton sheets when used according to manufacturer recommendations, as well as a reduction in one of the single friction reducing sheet categories compared to the cotton. However, it is important to note that there was still substantial force being placed on the participants. Conclusions: This study illustrates the importance of using friction reducing slide sheets while engaging in manual patient handling. Future research should investigate the forces involved with other friction reducing materials and methods as well as the possibility of combining said materials and methods.
In the panorama of available musculoskeletal modeling software, AnyBody software is a commercial tool that provides a full body musculoskeletal model which is increasingly exploited by numerous researchers worldwide. In this regard, model validation becomes essential to guarantee the suitability of the model in representing the simulated system. When focusing on lumbar spine, the previous works aimed at validating the AnyBody model in computing the intervertebral loads held several limitations, and a comprehensive validation is to be considered as lacking. The present study was aimed at extensively validating the suitability of the AnyBody model in computing lumbar spine loads at L4L5 level. The intersegmental loads were calculated during twelve specific exercise tasks designed to accurately replicate the conditions during which Wilke et al. (2001) measured in vivo the L4L5 intradiscal pressure. Motion capture data of one volunteer subject were acquired during the execution of the tasks and then imported into AnyBody to set model kinematics. Two different approaches in computing intradiscal pressure from the intersegmental load were evaluated. Lumbopelvic rhythm was compared with reference in vivo measurements to assess the accuracy of the lumbopelvic kinematics. Positive agreement was confirmed between the calculated pressures and the in vivo measurements, thus demonstrating the suitability of the AnyBody model. Specific caution needs to be taken only when considering postures characterized by large lateral displacements. Minor discrepancy was found assessing lumbopelvic rhythm. The present findings promote the AnyBody model as an appropriate tool to non-invasively evaluate the lumbar loads at L4L5 in physiological activities.
This study investigated the forces required while performing the common patient handling task of moving a patient up in bed using traditional cotton sheets or friction-reducing slide sheets. Twenty-nine healthy adult participants 18 to 36 years of age were recruited as “patients.” Hand forces and lumbar compression and shear forces were calculated on the “caregiver” when performing the repositioning task. Significant differences in lumbar compression and lumbar sagittal shear forces at L4-L5 and at L5-S1 were found among the three sheet types. No difference in peak sum hand force was found between the slide sheets; however, the traditional cotton sheet created the greatest force at the hands and every sheet exceeded the recommended summative hand force of 35 pounds. As such, sliding patients up in bed may contribute to increased risk of musculoskeletal injuries in caregivers.
Repositioning of passive patients in bed creates health risks to the nursing personnel. Therefore, appropriate assistive devices should be used. Our aim was to find the optimal assistive device for reducing musculoskeletal load while moving a passive patient in bed. Torso kinematic inputs evaluated by the Lumbar Motion Monitor (LMM) and perceived load (Borg scale) were measured in female nurses performing 27 patient transfers [represented by a mannequin weighing 55 (12 nurses), 65 (24 nurses) and 75 kg (12 nurses) in bed] using a regular sheet, a sliding sheet and a carrier. The lowest rates of perceived exertion were found when the sliding sheet and/or carrier were used, for all tasks (p ≤ 0.009). According to the predicted risk for Low Back Disorder (LBD) based on the LMM inputs, negligible differences between assistive devices were found. In a 75 kg mannequin, the participants were able to perform all tasks only by using a sliding sheet. Utilizing sliding sheets is an advantageous technique in comparison to traditional cotton sheets and even carriers.
Fundamental movement skills are considered the basic building blocks for movement and provide the foundation for specialized and sport-specific movement skills required for participation in a variety of physical activities. However, kinematic analyses of fundamental movement has not been performed. The aims of this study were to, (1) characterise the relationship between facets of fundamental movement and, (2) characterise the relationship between overall integrated acceleration and three-dimensional kinematic variables whilst performing fundamental movement skills. Eleven participants (10±0.8y, 1.41±0.07m, 33.4±8.6kg, body mass index; 16.4±3.1kg.m2) took part in this study, had anthropometric variables recorded and performed a series of fundamental movement tasks, whilst wearing a tri-axial accelerometer and were recorded using a three-dimensional motion capture system. Maximum shoulder external rotation (°) and maximum shoulder internal rotation velocity (°.s-1) (r=0.86, p<0.001), mediolateral centre of mass range (cm) and centre of mass coefficient of variation (%) (r=0.83, p<0.001), maximum stride angle (°) in the jog and walk (r=0.74, p=0.01) and maximum sprint stride angle and maximum shoulder internal rotation velocity (°.s-1) (r=0.67, p<0.02) were significantly correlated. Maximum sprint stride angle (hip: r=0.96, p<0.001, ankle: r=0.97, p<0.001) and maximum internal rotation velocity (ankle: r=0.6, p=0.05) were significantly correlated to overall integrated acceleration. Overall integrated acceleration was comparable between participants (CV: 10.5), whereas three-dimensional variables varied by up to 65%.Although overall integrated acceleration was comparable between participants, three-dimensional variables were much more varied. Indicating that although overall activity may be correspondent, the characteristics of a child’s movement may be highly varied.
The biomechanical loading on the lumbar spine was assessed as 12 female nurses applied and removed slings under two patients of differing weights (54 and 100 kg), using two work methods, and while working at three bed heights (56, 71, 93 cm). Three-dimensional spine loads at the L2/L3, L3/L4, L4/L5 and L5/S1 disc levels were measured using a validated EMG-assisted biomechanical model. Anterior/posterior (A/P) shear loading at the L5/S1 level consistently exceeded the tolerance threshold limit for disc failure. The peak compression values exceeded the 3400 N tolerance threshold for several participants when placing the sling under the 100-kg patient. In general, working from both sides of the bed generated slightly higher A/P shear loading than the one-sided method. Raising the bed significantly decreased compression and A/P shear forces. Therefore, raising the bed to at least the nurse’s knuckle height is recommended when applying and removing patient slings. Practitioners Summary: We investigated the spine loading associated with placing and removing slings used for the mechanised lifting of patients. Peak compression and anterior shear forces exceeded recognised thresholds when placing slings underneath heavier patients. Raising the bed to at least knuckle level helps mitigate these spinal loads.