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APPENDIX C
Appraisal Guide
Conclusions of a Systematic Review with Narrative Synthesis
Citation:
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
Synopsis
What organization or persons produced the systematic review (SR)?
How many persons were involved in conducting the review?
What topic or question did the SR address?
How were potential research reports identified?
What determined if a study was included in the analysis?
How many studies were included in the review?
What research designs were used in the studies?
What were the consistent and important across-studies conclusions?
Credibility
Was the topic clearly defined? Yes No Not clear
Was the search for studies and other
evidence comprehensive and unbiased? Yes No Not clear
Was the screening of citations for
inclusion based on explicit criteria? Yes No Not clear
*Were the included studies assessed
for quality? Yes No Not clear
Were the design characteristics and
findings of the included studies displayed
or discussed in sufficient detail? Yes No Not clear
*Was there a true integration (i.e., synthesis) of the findings—not
merely reporting of findings from
each study individually? Yes No Not clear
*Did the reviewers explore why differences
in findings might have occurred? Yes No Not clear
Did the reviewers distinguish between
conclusions based on consistent findings
from several good studies and those
based on inferior evidence (number or quality)? Yes No Not clear
Which conclusions were supported by
consistent findings from two or more
good or high-quality studies? List
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
Are the conclusions
credible? Yes All Yes Some No
Clinical Significance
*Across studies, is the size of the
treatment or the strength of the
association found or the
meaningfulness of qualitative findings
strong enough to make a difference
in patient outcomes or experiences of care? Yes No Not clear
Are the conclusions relevant to the
care the nurse gives? Yes No Not clear
Are the conclusions
clinically significant? Yes All Yes Some No
Applicability
Does the SR address a problem,
situation, or decision we are addressing in our setting? Yes No Not clear
Are the patients in the studies or a
subgroup of patients in the studies
similar to those we see? Yes No Not clear
What changes, additions, training, or
purchases would be needed to implement
and sustain a clinical protocol based
on these conclusions? Specify and list
____________________________________________________________________________
____________________________________________________________________________
Is what we will have to do to implement
the new protocol realistically achievable
by us (resources, capability, commitment)? Yes No Not clear
How will we know if our patients are
benefiting from our new protocol? Specify
____________________________________________________________________________
____________________________________________________________________________
Are these conclusions
applicable to our setting? Yes All Yes Some No
Should we proceed to design
a protocol incorporating
these conclusions? Yes All Yes Some No
* = Important criteria
Comments
____________________________________________________________________________
____________________________________________________________________________
APP C-2 Brown
Brown APP C-1
How to cite this article
Prado CBC, Machado EAS, Mendes KDS, Silveira RCCP, Galvão CM. Support surfaces for intraoperative
pressure injury prevention: systematic review with meta-analysis. Rev. Latino-Am. Enfermagem. 2021;29:e3493.
[Access
daymonth year
]; Available in:
URL
. DOI: http://dx.doi.org/10.1590/1518-8345.5279.3493
* Paper extracted from doctoral dissertation “Support surfaces
for prevention for pressure ulcer in the intraoperative
period: systematic review with meta-analysis”, presented
to Universidade de São Paulo, Escola de Enfermagem de
Ribeirão Preto, PAHO/WHO Collaborating Centre for Nursing
Research Development, Ribeirão Preto, SP, Brazil.
1 Universidade de Uberaba, Ciências da Saúde, Uberaba,
MG, Brazil.
2 Universidade de São Paulo, Escola de Enfermagem de
Ribeirão Preto, PAHO/WHO Collaborating Centre for Nursing
Research Development, Ribeirão Preto, SP, Brazil.
3 Scholarship holder at the Conselho Nacional de
Desenvolvimento Científico e Tecnológico/Ministério da
Ciência, Tecnologia e Inovações, Brazil.
Support surfaces for intraoperative pressure injury prevention:
systematic review with meta-analysis*
Objective: to evaluate evidence on effectiveness support
surfaces for pressure injury prevention in the intraoperative
period. Method: systematic review. The search for primary
studies was conducted in seven databases. The sample
consisted of 10 studies. The synthesis of the results was carried
out descriptively and through meta-analysis. Results: when
comparing low-tech support surfaces with regular care (standard
surgical table mattress), the meta-analysis showed that there is
no statistically significant difference between the investigated
interventions (Relative Risk = 0.88; 95%CI: 0.30-2.39). The
Higgins inconsistency test indicated considerable heterogeneity
between studies (I2 = 83%). The assessment of the certainty
of the evidence was very low. When comparing high-tech and
low-tech support surfaces, the meta-analysis showed that there
is a statistically significant difference between the interventions
studied, with high-tech being the most effective (Relative Risk
= 0.17; 95%CI: 0.05-0.53). Heterogeneity can be classified
as not important (I2 = 0%). The assessment of certainty of
evidence was moderate. Conclusion: the use of high-tech
support surfaces is an effective measure to prevent pressure
injuries in the intraoperative period.
Descriptors: Perioperative Nursing; Pressure Ulcer; Systematic
Review; Meta-Analysis; Intraoperative Period; Equipment and
Supplies.
Review Article
Rev. Latino-Am. Enfermagem
2021;29:e3493
DOI: 10.1590/1518-8345.5279.3493
www.eerp.usp.br/rlae
Carolina Beatriz Cunha Prado1
https://orcid.org/0000-0002-4570-9502
Elaine Alves Silva Machado1
https://orcid.org/0000-0002-3683-6438
Karina Dal Sasso Mendes2
https://orcid.org/0000-0003-3349-2075
Renata Cristina de Campos Pereira Silveira2
https://orcid.org/0000-0002-2883-3640
Cristina Maria Galvão2,3
https://orcid.org/0000-0002-4141-7107
www.eerp.usp.br/rlae
2 Rev Latino-Am. Enfermagem 2021;29:e3493.
Introduction
Pressure injury (PI) is an adverse event that can
affect the surgical patient. In recently published clinical
guidelines, information based on research results
indicated that the incidence of this type of injury, directly
attributable to the surgical anesthetic procedure, can
range from 4% to 45%(1). This variability of data must
be interpreted with caution, since in the intraoperative
period skin changes due to the appearance of PI may
take a while to manifest, several hours or even three to
five days after surgery. This condition can generate an
underestimated number of this type of injury resulting
from the surgical anesthetic procedure; in addition, it
is commonly attributed to the postoperative period or
confused with burns(1).
In the intraoperative period, the appearance of PI
is related to different factors, which can be classified as
intrinsic to the patient (for example, age, Body Mass Index
and presence of chronic disease), extrinsic (for example,
exposure to pressure, especially in bone prominences,
friction, shear and altered microclimate) and related to
the surgical anesthetic procedure (duration of the surgical
anesthetic procedure, type of surgical position, among
others)(2-4).
In the literature there is evidence of the importance
of using support surfaces for the prevention of PI in the
intraoperative period. These devices can be mattresses,
overlays or specific pads for different parts of the human
body, and they can be made of foam, gel, viscoelastic
polymer, air or fluids(1,5-6). Support surfaces can be
classified into high tech and low tech. The first one is
dynamic, capable of changing the pressure distribution
with or without load applied and powered by an energy
source (for example: alternating pressure overlay). On
the other hand, the low-tech surface is not powered
by electricity and adapts to the shape of the body,
distributing body weight over a large area (for example:
dry viscoelastic overlay)(7). On the other hand, there are
knowledge gaps, which are the most effective support
surfaces for use in the operating room(7-8).
The perioperative nurse has a fundamental role in the
assessment of the patient before the surgical anesthetic
procedure and in the identification of predisposing factors
for the occurrence of skin lesions, including PI. In the
intraoperative period, the planning and implementation of
care for the prevention of PI are crucial for the reduction
of complications associated with this type of injury, such
as: intense pain in the postoperative period, not related
to the surgical site; patient dissatisfaction; the extension
of the length of stay; the increase in the expenses of the
public/private health system(9).
This systematic review was conducted in an attempt
to contribute to the advancement of knowledge about the
problem in question. In addition to providing support for
nurses’ decision-making in clinical practice, with a view
to increasing the quality of care provided and reducing
costs, mainly related to the treatment of PI and the use
of appropriate technology in the operating room. Thus,
the delimited objective was to evaluate the evidence
on effectiveness support surfaces for the prevention of
pressure injuries in the intraoperative period.
Method
Type of study
This is a systematic review of health interventions
and was conducted based on the recommendations of the
Cochrane Collaboration. The following steps were taken:
1) elaboration and registration of the review protocol;
2) delimitation of the review question; 3) definition of
eligibility criteria; 4) search and selection of studies;
5) data collection; 6) synthesis and presentation of
the results of the systematic review(10). The Preferred
Reporting Items for Systematic Review and Meta-Analyses
(PRISMA) checklist guidelines were also adopted to report
the systematic review(11).
The review protocol was registered in the International
Prospective Register of Systematic Reviews (PROSPERO).
The registration number is CRD42019131271 and the
protocol can be accessed at the website (https://www.
crd.york.ac.uk/prospero/display_record.php).
Setting
The systematic review was conducted in the city of
Ribeirão Preto, state of São Paulo, Brazil.
Period
The systematic review took place from January to
November 2020.
Population
The delimited review question was: “what are the
effective support surfaces for the prevention of pressure
injuries in patients during the intraoperative period?”. The
question followed the components of the acronym PICOT
(population, intervention, comparison, outcome and time),
being P = surgical patient; I = tested support surface; C
= standard care (non-use of support surface) or support
surface different from the one tested; O = pressure injury
prevention; T = intraoperative period.
www.eerp.usp.br/rlae
3Prado CBC, Machado EAS, Mendes KDS, Silveira RCCP, Galvão CM.
Selection criteria
In the systematic review, primary studies that met
the components of the PICOT strategy were included, and
those in which the population consisted of patients under
18 years old or volunteers were excluded. Systematic
reviews of the effectiveness of health interventions
advocated by the Cochrane Collaboration traditionally
focus on the inclusion of randomized controlled trials.
However, this organization also discusses the inclusion,
in this type of review, of non-randomized studies of
interventions(10). Given the above and the diversity of
non-randomized study designs, the reviewers delimited
the inclusion of randomized controlled trials and non-
randomized studies, whose authors investigated the
effectiveness of support surfaces in preventing pressure
injuries in the intraoperative period. With regard to non-
randomized studies, studies that in the design presented
at least two comparative groups (for example, a control
group and an intervention group) were selected. It is
also noteworthy that for the selection of primary studies,
limitations of language or period of publication were not
established.
Sample definition
The databases selected for the search of primary
studies were PubMed, Cumulative Index to Nursing and
Allied Health Literature (CINAHL), Cochrane Central
Register of Controlled Trials (CENTRAL), EMBASE,
Scopus, Web of Science, and Latin American and Latin
American Literature Caribbean in Health Sciences
(LILACS).
Before performing the final searches of the
primary studies in the selected databases, several
combinations were performed using the controlled
descriptors, keywords and the Boolean operators AND
and OR, this was done in order to identify the largest
possible number of publications. For this step, the
combinations adopted the five components of the PICOT
strategy. However, it was observed that the removal of
P and C elements allowed the increase of the search
amplitude. Thus, the combination I AND O AND T was
used, and in four databases, PubMed, CENTRAL, Web
of Science and Scopus, the controlled descriptors were
delimited from the Medical Subject Headings (MeSH)
and the search strategies adopted were: I – “Equipment
and Supplies”[Mesh] OR “Supplies and Equipment”
OR “Apparatus and Instruments” OR “Instruments
and Apparatus” OR “Supplies” OR “Inventories” OR
“Inventory” OR “Medical Devices” OR “Medical Device”
OR “Device, Medical” OR “Devices, Medical” OR “Devices”
OR “Device” OR “Equipment” OR “support surface” OR
“foam mattress” OR “gel mattress” OR “visco-elastic
polyether foam mattress” OR “visco-elastic polyurethane
mattress” OR “polymers” OR “mattress” OR “foam”
OR “viscoelastic” OR “pillows polyurethane foam” OR
“rubber foam” OR “pillows” OR “cushion” OR “overlay”
OR “pad” OR “Dry viscoelastic Polymer”; O – “Pressure
Ulcer”[Mesh] OR “Pressure Ulcers” OR “Ulcer, Pressure”
OR “Ulcers, Pressure” OR “Bedsore” OR “Bedsores” OR
“Pressure Sore” OR “Pressure Sores” OR “Sore, Pressure”
OR “Sores, Pressure” OR “Bed Sores” OR “Bed Sore” OR
“Sore, Bed” OR “Sores, Bed” OR “Decubitus Ulcer” OR
“Decubitus Ulcers” OR “Ulcer, Decubitus” OR “Ulcers,
Decubitus” OR “Interface pressure” OR “Pressure ulcer
Prevention and control” OR “intraoperative pressure
injuries” OR “intraoperatively acquired pressure ulcer”
OR “Wounds and Injuries”[Mesh] and T – “Intraoperative
Period”[Mesh] OR “Intraoperative Periods” OR “Period,
Intraoperative” OR “Periods, Intraoperative”. In the other
databases, CINAHL, EMBASE and LILACS, the search
strategies used were similar, however the controlled
descriptors used were in accordance with the base
vocabulary, namely: CINAHL Headings, Emtree and
Descriptors in Health Sciences (DeCS).
At the end of the search for primary studies in all
selected databases, the results were exported to EndNote
Basic (desktop version) for the removal of duplicates(12).
Then, all citations from the reference manager were
imported into the Rayyan technology platform of the Qatar
Computing Research Institute (QCRI), specifically aimed
at the study selection phase among reviewers. Thus,
allowing the blinding between these and the monitoring
of the selection process by the main researcher. This
platform can be accessed through an electronic address
(https://rayyan.qcri.org/welcome) or as an application
for smartphones(13).
Titles and abstracts of primary studies identified
in the databases and imported from EndNote Basic
to the Rayyan platform were independently assessed
by two reviewers to determine which studies met the
aforementioned eligibility criteria. The reading of the
primary studies, in full, was also carried out independently
by two reviewers. In those cases where there was
disagreement between reviewers, a third reviewer was
consulted to solve the question.
The search and selection of primary studies that were
included in the review sample took place from February to
April 2020. Through a manual search, the main reviewer
tried to identify, in the reference list of each study included
in the review, other studies that could answer the guiding
question. However, no study was selected.
www.eerp.usp.br/rlae
4 Rev Latino-Am. Enfermagem 2021;29:e3493.
Data collection
A standard form was developed to collect data from
the studies included in the systematic review. The script
items were: authors; study title; year of publication;
journal name; goal; sample; inclusion and exclusion
criteria for the investigated population; randomization;
blinding; type of anesthesia and duration; type of
surgery and duration; intervention/experimental group;
group control; number of patients who had pressure
injury at the end of the study; statistical analysis; main
results; conclusion. Data collection was again carried
out by two reviewers, independently, in May and June
2020. To solve items and/or information that presented
divergences, meetings were scheduled between
reviewers for discussion and resolution of divergent
aspects until consensus.
Data analysis
To analyze the risk of bias of the randomized
controlled trials included in the review (n=6), the
free tool named Revised Cochrane risk-of-bias tool
for randomized trials (RoB 2), which is proposed by
the Cochrane Collaboration(10) was adopted. This tool
has five domains, namely: bias resulting from the
randomization process; bias due to deviations from
intended interventions; bias from missing outcome data;
bias from the measurement of the outcome; bias from
the selection of the reported result. Such analysis was
performed by two reviewers, independently. Through
meetings, the results of each evaluated study and the
doubts were discussed until the reviewers reached
consensus.
To assess the methodological quality of the non-
randomized studies (n=4), the quasi-experimental study
tool proposed by the Joanna Briggs Institute (JBI) was
used. The tool is called JBI Critical Appraisal Checklist
for Quasi-Experimental Studies, and is composed of
nine questions. For each question, the reviewer answers
yes, no, unclear or not applicable. The questions are
aimed at assessing the study’s internal validity and
risk of bias (selection of participants, conduction and
analysis of results)(14). In this analysis, two reviewers
also independently assessed the four studies. Then, a
meeting was held to discuss doubts and final evaluation
of the research. The adopted tool does not have a scoring
system for the general evaluation of the study.
The summary of the review results was carried
out in descriptive form and through meta-analysis.
To perform the meta-analysis, randomized controlled
trials were grouped according to the support surfaces
investigated by the researchers. The delimited meta-
analysis analysis model was the random effect, using
the software Review Manager (RevMan) version 5.3 of
the Cochrane Collaboration.
The assessment of the certainty of the evidence
was performed using the Grading of Recommendations
Assessment, Development and Evaluation (GRADE). This
assessment is performed for each outcome analyzed. In
this review, the outcome is the development of pressure
injury related to the use of support surfaces using the
evidence available in the literature. The certainty of the
evidence can be assessed as high (strong confidence
that the true effect is close to that estimated), moderate
(moderate confidence in the estimated effect), low (limited
confidence in the effect estimate) and very low (very
limited confidence in the estimate of the effect)(15). The
assessment of the certainty of the evidence was performed
using the GRADEpro software (https://www.gradepro.org).
Results
In Figure 1, the detailed flowchart of the selection
process of the primary studies included in the systematic
review is presented. Thus, the review sample consisted
of 10 studies, with six randomized controlled trials and
four non-randomized studies.
In Figure 2, the descriptive synthesis of the primary
studies was presented. The following data were indicated:
authors and year of publication of the research; sample;
support surfaces tested in the intervention and control
groups; number of PI in each group; the incidences of
the analyzed outcome. Missing data were not described
by the authors of the included studies.
www.eerp.usp.br/rlae
5Prado CBC, Machado EAS, Mendes KDS, Silveira RCCP, Galvão CM.
Source: Moher, et al.(11)
*CENTRAL = Cochrane Central Register of Controlled Trials; †LILACS = Latin American and Caribbean Literature in Health Sciences; ‡CINAHL = Cumulative
Index to Nursing and Allied Health Literature; §PI = Pressure injury
Figure 1 – Flowchart of the selection process of primary studies included in the systematic review adapted from Preferred
Reporting Items for Systematic Review and Meta-Analyses (PRISMA). Ribeirão Preto, SP, Brazil, 2020
Study Sample IG*/support surface/Technology type CG†/support surface/technology type PI‡
IG*
PI‡
CG†
Nixon, et al.
(1998)(16) n=416 n=205/dry viscoelastic polymer pad/
low tech
n=211/standard surgical table mattress/regular
care
22
I§=11%
(22/205)
43
I§=20%
(43/211)
Aronovitch, et
al. (1999)(17) n=217 n=112/alternating pressure system/
high technology n=105/dry viscoelastic polymer overlay/low tech 0
7
I§=8.75%
(7/105)
Schultz, et al.
(1999)(18) n=413 n=206/ special foam cover for
operating room/low tech mattress
n=207/gel pads, egg box foam mattress and
“foam donuts”/low tech
55
I§=26.6%
(55/206)
34
I§=16.4%
(34/207)
Russell;
Lichtenstein
(2000)(19)
n=198 n=98/multi-cell pulsatile dynamic
mattress system/high-tech n=100/dry viscoelastic polymer pad/low tech
2
I§=2.2%
(2/98)
7
I§=7.7%
(7/100)
Feuchtinger, et
al. (2006)(20)
n=175
I§=14.3%
n=85/4 cm thermoactivated
viscoelastic foam cover/low tech
n=90/standard surgical table mattress/regular
care
15
I§=17.6%
(15/85)
10
I§=11.1%
(10/90)
(continues on the next page…)
www.eerp.usp.br/rlae
6 Rev Latino-Am. Enfermagem 2021;29:e3493.
Study Sample IG*/support surface/Technology type CG†/support surface/technology type PI‡
IG*
PI‡
CG†
Huang, et al.
(2018)(21)
n=120
I§=8.3%
n=60/alternating air cushion positioned
under the head/high tech n=60/gel pad positioned under the head/low tech
1
I§=1.7%
(1/60)
9
I§=15%
(9/60)
Non-
randomized
study
Hoshowsky;
Schramm
(1994)(22)
n=505
n=85/PI‡
I§=16.8%
Group 1: SFM|| versus FGM¶ (n=91)
Group 2: VEO** above de SFM|| versus
FGM (n=92)
Group 3: SFM|| versus VEO** above
FGM (n=62)
Group 4: VEO** above SFM|| versus
VEO** above FGM¶ (n=113)
Group 5- SFM|| versus VEO** above
SFM (n = 73)
Group 6- FGM¶ versus VEO** above
FGM¶ (n = 74)
_ _ _
Wu, et al.
(2011)(23)
n=30
I§=7.5%
n=30/high density foam pad/low tech n=30/viscoelastic polymer pad/low tech
6
I§=10%
(6/30)
2
I§=5%
(2/30)
Joseph, et al.
(2019)(24) n=392 n=100/low profile alternating pressure
overlay/high tech
n=292/standard surgical table mattress/regular
care
0
I§=0%
(0/100)
18
I§=6%
(18/292)
Ezeamuzie, et
al. (2019)(25) n=212 n=104/low profile alternating pressure
overlay/high tech n=108/standard gel polymer mattress/low-tech
1
I§=0.96%
(1/104)
7
I§=6.5%
(7/108)
*IG = Intervention group; †CG = Control group; ‡PI = Pressure injury; §I = Incidence; ||SFM = Standard surgical table mattress (regular care); ¶FGM = Two-
inch thick foam and surgical table gel mattress coated with nylon fabric (low tech); **VEO = Dry viscoelastic polymer overlay (low tech)
Figure 2 – Characterization of primary studies included in the systematic review. Ribeirão Preto, SP, Brazil, 2020
Figure 3 shows the result of the risk of bias assessment using the RoB 2 tool, which was presented for each of
the six randomized controlled trials included in the systematic review.
Study R
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iz
at
io
n
pr
oc
es
s
D
ev
ia
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ns
fr
om
in
te
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en
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iss
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e
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at
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ea
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en
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es
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ve
ra
ll
B
ia
s
Nixon, et al. (1998)(16) Low risk
Aronovitch, et al. (1999)(17) Some concerns
Schultz, et al. (1999)(18) High risk
Russell; Lichtenstein (2000)(19)
Feuchtinger, et al. (2006)(20)
Huang, et al. (2018)(21)
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
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+
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+
+
+
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Figure 3 – Risk of bias assessment of randomized controlled trials in each domain of the Revised Cochrane risk-of-bias
tool for randomized trials (RoB 2). Ribeirão Preto, SP, Brazil, 2020
www.eerp.usp.br/rlae
7Prado CBC, Machado EAS, Mendes KDS, Silveira RCCP, Galvão CM.
Of the six randomized controlled trials, 66.7% (n=4)
were considered to be at low risk of bias and 33.3%
(n=2) were considered to be at high risk of bias. In two
studies(17,19) the bias domain in the measurement of results
was evaluated as being of high risk, since there was no
information about blinding of the result evaluators, that
is, the evaluator could know which was the participant’s
group and perform less rigorous evaluation for patients
in the experimental group regarding the outcome, in
this case, the development of PI. In one study(19) the
bias domain in the selection of reported outcome was
also assessed as high risk, that is, researchers reported
outcome measures selectively favorable to the intervention
of the experimental group.
The assessment of the methodological quality of the
non-randomized studies (n=4) was performed using the
JBI Critical Appraisal Checklist for Quasi-Experimental
Studies, as already mentioned, this tool does not have
a scoring system. Thus, of the nine questions that make
up the checklist, in two studies(24-25), eight questions
received the answer “yes” in the assessment carried
out by the reviewers; in one study(22), seven questions
received “yes”; and in the other research(23), five
questions received “yes”, and in the evaluation, three
questions received the answer “not applicable”, since
the questions were related to follow-up and comparison
between the control and experimental groups. In this
study, the support surfaces were tested on the same
patient, and the high-density foam pad was tested under
the right chest and the right iliac crest (experimental
intervention), and the viscoelastic polymer pad was
tested under the left chest and the left iliac crest (control
intervention).
In the meta-analysis, only randomized controlled
trials with similar characteristics regarding the surfaces
tested in the intervention and control groups were
included. As already mentioned, the outcome considered
to assess the effectiveness of the support surfaces was
the development of pressure injury in the intervention
and control groups. In Figure 4, two meta-analyses were
presented. The first considers clinical trials in which the
authors tested low-tech support surfaces in comparison
with usual care (standard surgical table mattress) (Figure
4 A.1). In the second meta-analysis, the clinical trials in
which researchers investigated high-tech support surfaces
compared to low-tech support surfaces are considered
(Figure 4 A.2). The Relative Risk (RR) was indicated in
the last column of the forest plots.
Figure 4 – Forest plots from meta-analyses addressing pressure injury prevention interventions. Ribeirão Preto, SP,
Brazil, 2020
In Figure 4 A.1, when comparing low-tech support
surfaces with usual care (standard surgical table
mattress), the interpretation of the meta-analysis
indicates that there is no statistically significant
difference between the investigated interventions (RR
= 0, 88; 95%CI: 0.30-2.39). On the other hand, in
Figure 4 A.2, when comparing high-tech and low-tech
support surfaces, the interpretation of the meta-analysis
shows that there is a statistically significant difference
between the investigated interventions, with the high-
tech ones being the most effective (RR = 0.17; 95%CI:
0.05-0.53).
(A.1) Low Tech versus Usual Care (Standard Surgical Table Mattress)
(A.2) High Tech versus Low Tech
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8 Rev Latino-Am. Enfermagem 2021;29:e3493.
In Figure 4 A.1, the Higgins inconsistency statistical
test (I2) indicated considerable heterogeneity between
studies (I2 = 83%). On the other hand, on Figure 4
(A.2), heterogeneity can be classified as unimportant
(I2 = 0%).
In Table 1, the assessment of certainty of evidence
by the GRADE system was presented. As explained above,
this assessment is performed for each outcome, in the
case of this review, the development of pressure injury.
Thus, when comparing low-tech support surfaces with
usual care, the certainty of the evidence was very low
(very limited confidence in the estimation of the effect),
as it presented very serious inconsistency, that is,
considerable heterogeneity (I2 = 83%). Furthermore, the
imprecision was also rated as very severe due to variation
in the effect estimate. When comparing high-tech and low-
tech support surfaces, the certainty of the evidence was
moderate (moderate confidence in the estimated effect),
since two randomized controlled trials were evaluated at
high risk of bias.
Table 1 – Synthesis of the assessment of the certainty of evidence, according to the Grading of Recommendations
Assessment, Development and Evaluation (GRADE). Ribeirão Preto, SP, Brazil, 2020
Certainty of evidence Number of
patients Effect
Number
of study
Type of
study
Risk of
bias Inconsistency Indirect
evidence Imprecision Other
considerations I* C† Relative
(95% CI‡)
Absolute
(95%
CI‡)
Certainty
Incidence of Pressure Injury/Low Technology versus Standard Surgical Table Mattress
2 RCT§ not
serious very serious|| not
serious
very
serious¶| none 37/290
(12.8%)
53/301
(17.6%)
not
estimable
20 plus
per
1,000
(from
140
minus
to 180
plus)
⃝⃝⃝
Very low
Incidence of Pressure Injury/High Tech versus Low Tech
3 RCT§ serious** not serious not
serious not serious none 3/270
(1.1%)
23/265
(8.7%)
RR†† =
0.17
(0.05 to
0.53)
72 minus
per
1,000
(from 82
minus
to 41
minus)
⃝
Moderate
*I = Intervention; †C = Control; ‡CI = Confidence interval; §RCT = Randomized controlled trial; ||The justification for the assessment is that the Higgins
inconsistency test (I2=83%) indicated considerable heterogeneity between studies; ¶|The justification for the assessment is that the effect estimate varies
greatly; **The justification for the assessment is that two randomized controlled trials were considered to be at high risk of bias; ††RR = Relative risk
Discussion
To make the discussion of the evidenced results
easier, three categories were defined (the first one
comparing low-tech support surfaces with regular care,
that is, standard surgical table mattress), in addition,
two randomized controlled trials were grouped(16,20). In a
study(20) the results led to the interruption of the research,
since the patients in the intervention group (overlay of
thermoactive viscoelastic foam of 4 cm) had a higher
number of PI, although the difference between the groups
was not statistically significant. In another study(16), the
results showed that the use of a dry viscoelastic polymer
pad was more effective in preventing PI compared to
regular care (OR=0.46; 95%CI: 0.26-0.82; p=0.01).
In a quasi-experimental study carried out in Brazil,
the authors evaluated the interface pressure of support
surfaces in bony prominences, at specific points (occipital,
subscapular, sacral and calcaneal regions) in 20 healthy
volunteers in supine position on a surgical table. Seven
different combinations were evaluated, namely: standard
surgical table mattress without overlaying; the viscoelastic
polymer overlay; three overlays of 5 cm thick sealed foam
at densities 28, 33 and 45 kg/m3; two overlays of soft
foam 5 cm thick and densities 28 and 18 kg/m3. The mean
interface pressure of the viscoelastic polymer overlay was
higher compared to the other surfaces tested, including
the standard surgical table mattress (p<0.001)(5).
The second category (high-tech support surfaces
versus low-tech surfaces) included three randomized
controlled trials(17,19,21) and two non-randomized
studies(24-25). In all studies, the high-tech surfaces
tested were alternating pressure devices from different
manufacturers. In two randomized controlled trials(17,19),
the MicroPulse® System alternating air overlay
(MicroPulse, Inc., Portage, Michigan, USA) was tested.
www.eerp.usp.br/rlae
9Prado CBC, Machado EAS, Mendes KDS, Silveira RCCP, Galvão CM.
In non-randomized studies(24-25), low-profile alternating
pressure overlap was investigated (Dabir Micropressure
Operating Table Surface®, Dabir Surfaces, Chicago, Illinois,
USA). In a randomized controlled trial(21), the surface
tested was an alternating air cushion from the Chinese
manufacturer WeXuan Co.
In four studies, the results showed the superiority
of a high-tech support surface in relation to low-tech
surfaces in the prevention of PI in the intraoperative
period(17,21,24-25). In a randomized controlled trial(19), the
experimental group (high-tech support surface) had
a lower incidence of PI (2/98) than the control group
(7/100), however, there was no statistically significant
difference between the groups (p=0.172).
In conducting the two non-randomized studies
included in the review, there are similarities in terms
of research design, population and tested support
surfaces(24-25). In both, in the experimental group, low-
profile alternating pressure overlay was tested. This
overlay incorporates hundreds of supporting nodules
arranged in rows that periodically inflate with air, so the
patient’s weight is distributed over small nodal points of
alternating contact. Alternate rows are interconnected
so that the overlay has two areas that are alternately
inflated. Inflation/deflation of the rows is computer
controlled and provides temporary localized relief of
micropressure in areas of the body lying above deflated
nodules. The overlay was placed on top of the standard
operating table mattress, before starting the surgery.
The operating room is considered as a place of risk
for the development of PI, due to strict restrictions specific
to the environment, namely: the inability to reposition
the patient during the anesthetic surgical procedure for
pressure relief and the need of permanence on a stable
support surface, generally implying the use of a relatively
rigid padding material, resulting in the exposure of the
body to tissue deformation conditions. In this context, low-
profile alternating pressure overlay was designed for use
in surgery, which brought technological advances in a field
in which contemporary technology is generally poor(26).
In the last category (comparison between low-tech
support surfaces) two non-randomized studies(22-23) and
one randomized controlled trial were included(18). In a
non-randomized study(22), two operating table mattresses
and an overlay of dry viscoelastic combined in different
ways were tested with the participation of 505 patients
(divided into six groups). Regarding PI development, dry
viscoelastic polymer overlay was more effective than foam
and gel or standard mattresses.
In the other non-randomized study(23), two support
surfaces were tested on the same patient, and on the
right side a high-density foam pad (32 kg/m3), 50%
resilience and 10 cm thickness was applied (chest and iliac
crest) and on the left side the viscoelastic polymer pillow
(Action®, model 40700; Action, Hagerstown, Maryland,
USA), two-cm-thick, also on the chest and iliac crest.
Mean pressures and peak pressures were significantly
lower at the points evaluated with the viscoelastic polymer
pad, compared to the points tested with the high-density
foam pad. However, the results did not show a statistically
significant difference in the incidence of pressure injury
between the two support surfaces tested (OR=0.47, 95%
CI, 0.11-1.99).
In the randomized controlled trial(18), also included in
this category, patients in the control group used devices
according to the criteria of each nurse. Options included
gel pads, egg box foam mattress and “foam donuts”
for heels and elbows. The patients in the intervention
group were placed on a special foam cover with a 25%
indentation force (IF) of 30 pounds and a density of
1.3 (specification considered ideal). The number of
participants in the experimental group (55/206) showed
significantly higher occurrence of PI than those in the
control group (34/207) (p=0.0111), indicating that the
special foam surface that was tested was not effective in
preventing this type of injury.
The standard surgical table mattress is usually made
of two-inch (5.08 cm) elastic foam and covered with black
vinyl fabric. Despite its excellent stability, there is evidence
that this type of surface contributes to the development
of PI. On the other hand, mattresses made with high-
specification foam can reduce the development of this
type of injury. Thus, the multi-layer smooth surfaces
allow the patient to sink into the underlayer and wrap
around the body to increase the contact area by up to
60%. Such properties help to distribute pressure over
a larger area. Bi-elastic layers also reduce skin creases
and shear forces(27).
The support surface must have the best
characteristics to provide effective pressure redistribution,
which are: lowest mean interface pressure, lowest peak
interface pressure and highest skin contact area. Based on
these assumptions, researchers conducted a comparative
descriptive study with volunteers to investigate four types
of support surfaces, with the aim of identifying the most
effective surface for pressure redistribution in prolonged
surgical procedures. The surfaces tested were: a) standard
surgical table surface, made of three-layer viscoelastic
foam; b) static air-inflated seat cushion that was used
under the sacral area and placed on the standard surgical
table surface; c) two-layer surgical table surface, with
the upper layer of gel and the lower layer of high-density
foam; d) surgical surface for simulating fluid immersion.
The results indicated that, although all surfaces had similar
mean interface pressures, the air-inflated static seat
cushion had the best pressure redistribution properties
www.eerp.usp.br/rlae
10 Rev Latino-Am. Enfermagem 2021;29:e3493.
in the sacral region, compared to the other surfaces
tested(28).
The results of the systematic review showed that
high-tech support surfaces are more effective than
low-tech ones (evidence through meta-analysis) in the
intraoperative period. These results have implications
for clinical practice, since the implementation of this
technology requires a high financial investment from
the health service, that is, a reality that is probably
distant in developing countries. On the other hand, when
comparing low-tech support surfaces with regular care,
the assessment of the certainty of the evidence was very
low, indicating that conducting further research is likely
to change the estimate of the effect. In short, conducting
well-designed randomized controlled trials, testing low-
tech support surfaces, may contribute to decision-making
by perioperative nurses in clinical practice, especially
in developing countries. The evidence generated may
help this professional in planning and implementing
effective support surfaces for the prevention of PI in the
intraoperative period.
Despite the extensive search carried out in seven
databases, as well as the absence of time and language
limitations, the identification of a small number of
randomized controlled trials can be considered a
limitation, since this type of study is the most suitable
for investigating the effectiveness of health interventions.
In addition to this aspect, the researchers delimited the
inclusion of primary studies indexed in the selected
databases, that is, the non-inclusion of gray literature;
this was due to the difficulty of accessing and handling
this type of material. This decision can also be considered
as a limitation.
Conclusion
The results of the meta-analysis conducted indicated
that when comparing low-tech support surfaces with
regular care, there was no statistically significant
difference. Furthermore, the considerable heterogeneity
between the studies and the very low certainty of the
evidence is highlighted, indicating that the conduct of other
researches is likely to change the estimate of the effect.
When comparing high-tech and low-tech support
surfaces, there was a statistically significant difference
between the investigated interventions, with high-tech
being the most effective. Furthermore, it is noteworthy
that heterogeneity can be classified as not important
and the assessment of the certainty of the evidence was
moderate.
Based on the above, it is recommended to conduct
well-designed randomized controlled trials to investigate
support surfaces for the prevention of pressure injuries
in the intraoperative period, considering the cost-
effectiveness of the technology.
References
1. Emily Haesler, editor. Prevention and treatment
of pressure ulcers/injuries: clinical practice guideline
[Internet]. [place unknown]: European Pressure Ulcer
Advisory Panel; National Pressure Injury Advisory Panel;
Pan Pacific Pressure Injury Aliance; 2019 [cited 2021
Mar 07]. 408 p. Available from: https://www.epuap.org/
download/11182/
2. Engels D, Austin M, McNichol L, Fencl J, Gupta S, Kazi H.
Pressure ulcers: factors contributing to their development
in the OR. AORN J. 2016;103(3):271-81. doi: http://doi.
org/10.1016/j.aorn.2016.01.008
3. Xiong C, Gao X, Ma Q, Yang Y, Wang Z, Yu W, et
al. Risk factors of intraoperative pressure injuries in
patients undergoing digestive surgery: a retrospective
study. J Clin Nurs. 2019;28(7-8):1148-55. doi: http://
doi.org/10.1111/jocn.14712
4. Yoshimura M, Ohura N, Santamaria N, Watanabe Y,
Akizuki T, Gefen A. High body mass index is a strong
predictor of intraoperative acquired pressure injury in
spinal surgery patients when prophylactic film dressings
are applied: a retrospective analysis prior to the BOSS
trial. Int Wound J. 2020;17(3):660-9. doi: http://doi.
org/10.1111/iwj.13287
5. Oliveira KF, Pires OS, De-Mattia AL, Barichello E,
Galvão CM, Araújo CA, et al. Influence of support
surfaces on the distribution of body interface pressure
in surgical positioning. Rev. Latino-Am. Enfermagem.
2018;26:e3083. doi: http://doi.org/10.1590/1518-
8345.2692.3083
6. Karg P, Ranganathan VK, Churilla M, Brienza D. Sacral
skin blood flow response to alternating pressure operating
room overlay. J Tissue Viability. 2019;28(2):75-80. doi:
http://doi.org/10.1016/j.jtv.2019.03.001
7. McInnes E, Jammali-Blasi A, Bell-Syer SE, Dumville
JC, Middleton V, Cullum N. Support surfaces for
pressure ulcer prevention. Cochrane Database
Syst Rev. 2015(9):CD001735. doi: http://doi.
org/10.1002/14651858.CD001735.pub5
8. Oliveira KF, Nascimento KG, Nicolussi AC, Chavaglia
SRR, Araújo CA, Barbosa MH. Support surfaces in the
prevention of pressure ulcers in surgical patients: an
integrative review. Int J Nurs Pract. 2017;23(4):e12553.
doi: http://doi.org/10.1111/ijn.12553
9. Khong BPC, Goh BC, Phang LY, David T. Operating
room nurses’ self-reported knowledge and attitude
on perioperative pressure injury. Int Wound J.
2020;17(2):455-65. doi: http://doi.org/10.1111/
iwj.13295
www.eerp.usp.br/rlae
11Prado CBC, Machado EAS, Mendes KDS, Silveira RCCP, Galvão CM.
10. Higgins JPT, Thomas J, editors. Cochrane handbook
for systematic reviews of interventions. 2nd ed. Hoboken:
Wiley Blackwell; 2019. 694 p.
11. Moher D, Liberati A, Tetzlaff J, Altman DG, PRISMA
Group. Preferred reporting items for systematic reviews
and meta-analyses: the PRISMA statement. PLoS Med.
2009;6(7):e1000097. doi: https://doi.org/10.1371/
journal.pmed.1000097
12. Mendes KDS, Silveira RCCP, Galvão CM. Uso de
gerenciador de referências bibliográficas na seleção
dos estudos primários em revisão integrativa. Texto
Contexto Enferm. 2019;28:e20170204. doi: http://doi.
org/10.1590/1980-265x-tce-2017-0204
13. Ouzzani M, Hammady H, Fedorowicz Z, Elmagarmid
A. Rayyan – a web and mobile app for systematic reviews.
Syst Rev. 2016;5(1):210. doi: http://doi.org/10.1186/
s13643-016-0384-4
14. Tufanaru C, Munn Z, Aromataris E, Campbell J, Hopp
L. Systematic reviews of effectiveness. In: Aromataris
E, Munn Z, editors. JBI Manual for evidence synthesis.
Adelaide: Joanna Briggs Institute; 2020. p. 71-133.
15. Ministério da Saúde (BR). Secretaria de Ciência,
Tecnologia e Insumos Estratégicos. Departamento de
Ciência e Tecnologia. Diretrizes metodológicas: Sistema
GRADE – manual de graduação da qualidade da evidência
e força de recomendação para tomada de decisão em
saúde. Brasília: Ministério da Saúde; 2014. 74 p.
16. Nixon J, McElvenny D, Mason S, Brown J, Bond S. A
sequential randomised controlled trial comparing a dry
visco-elastic polymer pad and standard operating table
mattress in the prevention of postoperative pressure
sores. Int J Nurs Stud. 1998;35(4):193-203. doi: http://
doi.org/10.1016/s0020-7489(98)00023-6
17. Aronovitch SA, Wilber M, Slezak S, Martin T, Utter D.
A comparative study of an alternating air mattress for the
prevention of pressure ulcers in surgical patients. Ostomy
Wound Manage. 1999;45(3):34-44.
18. Schultz A, Bien M, Dumond K, Brown K, Myers A.
Etiology and incidence of pressure ulcers in surgical
patients. AORN J. 1999;70(3):434-49. doi: http://doi.
org/10.1016/s0001-2092(06)62325-9
19. Russell JA, Lichtenstein SL. Randomized controlled
trial to determine the safety and efficacy of a multi-cell
pulsating dynamic mattress system in the prevention of
pressure ulcers in patients undergoing cardiovascular
surgery. Ostomy Wound Manage. 2000;46(2):46-55.
20. Feuchtingern J, Bie R, Dassen T, Halfens R. A 4-cm
thermoactive viscoelastic foam pad on the operating room
table to prevent pressure ulcer during cardiac surgery. J
Clin Nurs. 2006;15(2):162-7. doi: http://doi.org/10.1111/
j.1365-2702.2006.01293.x
21. Huang W, Zhu Y, Qu H. Use of an alternating inflatable
head pad in patients undergoing open heart surgery. Med
Sci Monit. 2018;24:970-6. doi: http://doi.org/10.12659/
MSM.906018
22. Hoshowsky VM, Schramm CA. Intraoperative pressure
sore prevention: an analysis of bedding materials.
Res Nurs Health. 1994;17(5): 333-9. doi: http://doi.
org/10.1002/nur.4770170504
23. Wu T, Wang ST, Lin PC, Liu CL, Chao YFC. Effects of
using a high-density foam pad versus a viscoelastic polymer
pad on the incidence of pressure ulcer development during
spinal surgery. Biol Res Nurs. 2011;13(4):419-24. doi:
http://doi.org/10.1177/1099800410392772
24. Joseph J, McLaughlin D, Darian V, Hayes L,
Siddiqui A. Alternating pressure overlay for prevention
of intraoperative pressure injury. J Wound Ostomy
Continence Nurs. 2019;46(1):13-7. doi: http://doi.
org/10.1097/WON.0000000000000497
25. Ezeamuzie O, Darian V, Katiyar U, Siddiqui A.
Intraoperative use of low-profile alternating pressure
mattress for prevention of hospital acquired pressure
injury. Perioper Care Oper Room Manag. 2019;17:1-4.
doi: http://doi.org/10.1016/j.pcorm.2019.100080
26. Gefen A. Minimising the risk for pressure ulcers in the
operating room using a specialised low-profile alternating
pressure overlay. Wounds Int [Internet]. 2020 [cited
2021 May 25];11(2):10-6. Available from: https://www.
woundsinternational.com/resources/details/minimising-
the-risk-for-pressure-ulcers-in-the-operating-room-using-
a-specialised-low-profile-alternating-pressure-overlay
27. Scott SM. Perioperative pressure injuries: protocols
and evidence-based programs for reducing risk [Internet].
2016 [cited 2020 Nov 25]. Available from: https://www.
psqh.com/analysis/perioperative-pressure-injuries-
protocols-and-evidence-based-programs-for-reducing-
risk/
28. Kirkland-Walsh H, Teleten O, Wilson M, Raingruber B.
Pressure mapping comparison of four OR surfaces. AORN
J. 2015;102(1): 61.e1-9. doi: http://doi.org/10.1016/j.
aorn.2015.05.012
Authors’ Contribution:
Study concept and design: Carolina Beatriz Cunha
Prado, Cristina Maria Galvão. Obtaining data: Carolina
Beatriz Cunha Prado, Elaine Alves Silva Machado, Karina
Dal Sasso Mendes, Cristina Maria Galvão. Data analysis
and interpretation: Carolina Beatriz Cunha Prado,
Elaine Alves Silva Machado, Karina Dal Sasso Mendes,
Renata Cristina de Campos Pereira Silveira, Cristina
Maria Galvão. Statistical analysis: Carolina Beatriz
Cunha Prado, Renata Cristina de Campos Pereira Silveira,
Cristina Maria Galvão. Drafting the manuscript: Carolina
Beatriz Cunha Prado, Elaine Alves Silva Machado, Karina
www.eerp.usp.br/rlae
12 Rev Latino-Am. Enfermagem 2021;29:e3493.
Received: Mar 7th 2021
Accepted: Jul 10th 2021
Copyright © 2021 Revista Latino-Americana de Enfermagem
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Corresponding author:
Cristina Maria Galvão
E-mail: [email protected]
https://orcid.org/0000-0002-4141-7107
Associate Editor:
Maria Lúcia Zanetti
Dal Sasso Mendes, Renata Cristina de Campos Pereira
Silveira, Cristina Maria Galvão. Critical review of the
manuscript as to its relevant intellectual content:
Carolina Beatriz Cunha Prado, Elaine Alves Silva Machado,
Karina Dal Sasso Mendes, Renata Cristina de Campos
Pereira Silveira, Cristina Maria Galvão.
All authors approved the final version of the text.
Conflict of interest: the authors have declared that
there is no conflict of interest.
© 2021. This work is published under
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the ProQuest Terms and Conditions, you may use this content in accordance
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