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OXFORD
UK
20-22 September 1998
AN EVALUATION OF FOUR OPERATING TABLE MATTRESSES USED
FOR PREVENTING PRESSURE ULCERS
Mr Tom Defloor and Mr J De Schuijimer*
Nursing Sciences, University of Gent, Belgium
*University Hospital of Gent, Gent, Belgium
Purpose
Pressure ulcers develop due to pressure and shearing
forces. The intensity of the pressure and shearing force is determined
by the position of the patient and by the type of operating table mattress.
This research focused on the pressure reducing effects of operating table
mattresses.
Methods
Five different types of mattresses were tested:
a standard operating table mattress, a foam mattress, a gel mattress,
a polyether mattress and a polyurethane mattress. Four different intraoperative
postures, in which patients are frequently positioned during long term
operations, have been evaluated: supine, lateral, fossa and Miles Pauchet
position. The pressure measurement system used was the Ergocheck system.
This system consists of a measuring mat containing 684 air filled sensors
connected with pressure transducers , The pressure measurements were performed
on 36 healthy volunteers (37.5+9.9 years; 25.1+4.9 BMI).
Results
The foam mattress appears to have little or
no pressure reducing effect and is of no use in the prevention of ulcers.
The frequently used gel mattress reduces pressure only in a limited matter
(in supine position 5.6+9.9 mmHg). The effect on pressure ulcer prevention
is therefore minimal. ANOVA and Tukey HSD analysis reveals that the polyurethane
mattress (16.3+7.7 mmHg pressure reduction) and the polyether mattress
(13.7+11.7 mmHg pressure reduction) reduces pressure significantly (p<0.005)
better than the other mattresses.
Pressures are highest in lateral position. All mattresses
generate a significant lower pressure (on average between 10.1 and 18.1
mmHg) in this position than the standard operating table mattress, but
bottoming out effect is still noticed. There is no mattress that significantly
reduces the pressure. Other preventative measures have to be taken.
Conclusion
Not all the anti-decubitus mattresses really
succeed in reducing the interface pressure. The foam and gel mattresses
have no or limited pressure reducing qualities. The polyether mattress
and especially the polyurethane slow foam mattress reduce pressure best
and are preferable in the prevention of pressure ulcers on an operating
table. None of the mattresses tested reduced the pressure sufficiently
in lateral position.
INTERFACE PRESSURE CHARACTERISTICS
OF INTENSIVE CARE PATIENTS NURSED ON SPECIAL BEDS
J T M Weststrate, L den Ouden, H Dannenberg, E Heule,
H A Bruining and R Goosens
Surgical Intensive Care,
University Hospital Rotterdam,
The Netherlands.
Introduction
Most studies that measure the average interface
pressure generated by standard and special pressure reducing mattresses
use healthy young volunteers in a laboratory setting. This despite the
fact that several investigators list that age, bed rest and severe illness
influence the interface pressure due to change of body posture and pressure
reducing capabilities of the skin, Furthermore, daily clinical practice
can differ significantly from a controlled laboratory setting for example
in the management of bed making and the use of extra bedding materials
like incontinent material. Therefore, we conducted a study in which the
interface pressure of intensive care patients on standard and specialised
mattresses were measured.
Materials and Methods
The peak interface pressure (PIP) was measured
in intensive care patients with the Oxford Pressure Monitor (OPM) on six
body locations: the back of the head, shoulder, sacrum, buttocks, trochanter
and heel. Measurements were all carried out in the supine body position
and repeated every two to three days during the patients stay on the unit.
Measurements were carried out on a standard hospital mattress, a special
foam mattress, three kinds of low-air loss mattresses (BioMedx: Sunrise
Medical; Kinair III: KCI; Therapuls: KCI) and an air mattress (First Step;
KCI).
Results
We evaluated 51 patients (35 male and 16 female)
during a period of two months. The average age was 60.2 years (+ 15.7),
the average weight 75kg (+ 12.9) and the average quetelet index 25.1 (+4.5).
The PIP measurements on al locations had a range between 8 and 246 mmHg.
The special foam mattress produced in combination with the patient’s
pillow the lowest mean PIP on the back of the head (45.8 mmHg). This was
significantly different from the mean PIP measured on the Therapuls bed
(62.7 mmHg). The BioMedx mattress produced the lowest mean PIP on the
shoulder (45.6 mmHg) and was significantly different from the mean PIP
measured on the special foam mattress (77.7 mmHg). The Therapuls bed produced
the lowest PIPs on the sacrum (42.2 mmHg) but was only significantly higher
compared with the PIP’s measured on the standard mattress (64.2 mmHg).
The BioMedx mattress produced the lowest PIPs on the buttocks (45.6 mmHg)
but measurements were not significantly different from the PIPs measured
on the other mattresses. In the trochanter area the Therapuls bed produced
the lowest PIPs (41.1 mmHg) but measurements were not significantly different
compared with any other mattress. The Kinair III bed produced the lowest
PIPs on the heel and measurements differed significantly with the standard
mattress, the BioMedx mattress, the First step mattress and the special
foam mattress.
Discussion
This study shows that intensive care patients
produce a mean PIP that is substantially higher compared with the 32 mmHg
borderline that is often taken as standard. This shows that clinical practice
produces different results in this area of research compared with laboratory
tests in which healthy volunteers are used. In the future manufacturers
of special mattresses should be able to produce study results based on
clinical studies or improve their laboratory model.
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