Alternating-pressure mattresses for the prevention of decubitus ulcers: a study of healthy subjects and patients

Alternating-pressure mattresses for the prevention of decubitus ulcers: a study of healthy subjects and patients Klaus- Dieter Neander, Ralf Birkenfeld alternating

INTRODUCTION Alternating-pressure used in hospitals often nurses

who decide

for a particular which

mattresses to prevent

whether

patient,

one to use may

considerations. nurses

It

such

units,

should

their

be restricted

for patients

as many

choice

that

the

in intensive

under-

and consider

evi-

as to its effectiveness.

The

following

underlies

ing the pressure interrupt

intensive

and

are compared igations

theoretical

concept

of these mattresses:

exerted

on tissue

the developmental

here

with

patients,

and

number

test

results

of invest-

out to date.

DESCRIPTION chambers

is thought

OF THE MATTRESS one set of air

and another

eously

deflated

ration

of the air chambers

by a pump as does

set is simultan-

unit. varies

the

The

to the

frequency

(2-

of the air chambers

Some manufacturers

sure to be varied

configua-

according

cycle

The size and shape

not uniform.

to

mattresses

is inflated

5 min).

chang-

mechanism

care

with the limited

carried

manufacturer,

elegant

the function

subjects

is discussed

investigations

In alternating-pressure

care

principles

mattresses

of original

of

by economic

at risk of decubitus

of those

understand

It is

important

lying the use of such equipment dence

regularly ulcers.

or not to use one

though

is therefore

responsible

ulcers,

are

decubitus

pressure

on the basis

is

allow the pres-

but not the frequency.

of decu-

bitus ulcers. It is well known duced

by

that decubitus

prolonged

pressure

following

rule of thumb

entation

of

the

developmental

The probability

bitus

increases

nitude

Various

publications

tissue.

of developing

acting

The repres-

mechanism

with the duration

of the pressure

for example

on

are pro-

gives a simplified

decubitus: ulcer

ulcers

of

a decuand mag-

on the tissue.

confirm

this

al. 1978, Husain,

1953. Staff therefore

attempt

et to

prevent decubitus ulcer formation by influencing the time the patient is subjected to pressure. The

concept

of decubitus

prevention

using

Klaus-Dieter Neander, RN, Leader of the Workgroup of Nursing Researcher Gijttingen, Im Beeke 15,340O Giittingen 1, Germany Ralf Birkenfeld, RN, Member of the Workgroup of Nursing Researcher Gbttingen, Otto-Lauffer-Str. 16a. 3400 Gijttingen 1, Germany

The

study

part

was

was divided intended

into to

two parts.

examine

The

whether

first the

measurement of transcutaneous oxygen pressure (tcPOs), introduced into decubitus research by Seiler

et al, is a useful

measuring

statement

Seiler et al, 1982, 1984, Gadomski

TEST SET-UP

et al,

1983, Schwab,

measured

and

the efficiency the direct

reliable

of pressure

method relief,

1982. Simultaneously, contact

pressure

for Seiler we

on the test

subject to establish the maximum pressure load with inflated air chambers and the extent of relief of this contact are deflated.

pressure The

contact

when

the air chambers

pressure

and

the per-

cutaneous oxygen pressure were measured with and without load over a period of 10 minutes. The

study

included

healthy

test

sub.jects

whose age, height and weight are given in Table 1. This selection of test subjects was intended to 67

68

INTENSIVE

CARE NURSING

Table 1 Data from 10 test subjects

Age

Weight in kg

Height in cm

Body surface area in m

23 21 23 27 23

82 73 75 65 76

191 185 180 178 193

2.1 2.04 1.96 1.85 2.10

E 30

86 78 60

178 181 176

2.08 1.98 1.78

25 26

71 62

180 176

1.92 1.88

anatomical

parameters

create

02’2 H204~~10H’

7mm IJ

that

l

p\-Eloctmdo

02 - Diffusion

Fig. 1. Original plot in a patient in whom tcPOz measurement did not recover after a few minutes. shows the investigator’s control:-the patient’s buttock was raised several times to check that the electrode was correctly located and fixed l

were

as

uniform as possible, so as to obtain reproducible and comparable

in electrically

results.

conductive

media at cathodes

precious

metals at a specific potential.

carried out on intensive care patients who had led on alternating pressure mattresses to prevent

current

which then flows is proportional

decubitus

medium.

In the second

the

of the study

tests were

ulcers. The age, weight and height of

patients

account

part

were

purposely

not

taken

in order to reflect the everyday

into

clinical

concentration

of the oxygen

Stossek (1977) the method

serves to elucidate

situation. The

percutaneous

measured

oxygen

in these patients

pressure

was

over a period of at

least two hours with and without

load, because

transcutaneous

dissolved

to the in the

provides a good description

as follows:

‘A schematic

the interactions

measurement

of

The test

of

diagram

which arise in

of the arterial

par-

tial oxygen pressure (Fig. 1). The electrode heats the skin underneath

and creates

local hyperae-

part one of the study showed that measurement

mia in the subepidermal

of the

the capillary partial oxygen pressure to approach

percutaneous

statements

oxygen

pressure

permits

the arterial

on the effect of pressure relief.

partial

oxygen

creased transepidermal

SELECTION POINTS Measurement cutaneous

capillaries.

pressure

pressure and transwere carried

out at

cathode

(Fig.

1 shows the corresponding The current

the sacrum were those points at which the skin is cushioned by the least subcutaneous fatty tissue

electrochemical partial oxygen

process pressure

and which experience

trode surface.’ Determination

to decubitus

The preferred

measuring

points on

has shown are most prone

ulcers. These prominent

points were

marked and sensors were attached.

FUNDAMENTALS MEASUREMENTS Transcutaneous method based solved oxygen

OF tcP02

are selectively

chem-

which flows in this

is proportional to the prevailing at the elec-

of the transcutaneous

oxygen

pressure with the thermal electrode is used for noninvasive monitoring in newborn children and

measurement is a oxygen on the fact that physically dismolecules

as well as the mem-

brane itself and are reduced at the surface of the ical equation).

the sacrum.

traverse the

capillary fluid gap between the epidermal surface and the electrode membranes

oxygen

so that in-

diffusion of oxygen mole-

cules results. The oxygen molecules

OF MEASURING of the contact

pressure,

This causes

reduced

for monitoring anesthesia in adults. It is also used in intensive care units and in angiology (Huch, 1975; Vermold, 1975; Schickardi, 1975). After calibrating the equipment, the thermal electrode was positioned at the prescribed measuring point on the test subjects and was

lightly

fixed

tcP02

with

an

was measured

adhesive

with

bandage.

The

the test subject

in the

lateral position until a relatively obtained (initial tcPOz:value).

stable

value

was

FUNDAMENTALS OF CONTACTPRESSURE MEASUREMENT The

measuring

study

is used in neurosurgery

dural

brain

monitor, The

instrument

pressure.

with

sensor

brane.

contains

in

required

interface

starting

the and

sensitive

mem-

is

The mattresses

pneumatically The

position

pressure

treated

correction

is

then measured. In the study,

the sensor

was placed

of the test subject

(parallel

trode:)

fixed

and

dage.

The

lightly instrument

test subject during sub,ject

in the

placed

supine

underlying

technical

principle

of other

alternating

pressure

mattresses,

the

that

tresses.

With

ban-

axis in an attempt

to simulate

the

and

with

the

to the right

nursing

tissue.

position.

from

in the same position

position

with

the

the test

sensors

were

of an air cushion.

pressures

ciated

of the

pressure

with

study

showed

that

on the skin was always

a corresponding

drop

cutaneous

oxygen

pressure.

pressures

rose again

as soon

the asso-

in the

However,

per-

oxygen

as the contact

pres-

sure was reduced. Figure ively

high

lease

of pressure

values

between

The ing

pressures

tcP0z

contact

sures brought an average pressure sure

typical

(51-63

the contact

pressure

mmHg)

pressures. about

rose

the

but

of the initial which

value.

oxygen lay only

initial

values

is quite that

by On

pres20 to (Fig.

by on

the contact

were significantly

neous

oxygen

unit.

the

was

the transcuta-

also

measured not

were

were of different

of 2 hours

measured and

with those

not possible.

tcP0, with

in care

height

of the values

was therefore of the

was

carried

the patient

supine

position.

Table

from

patients

and

data

relief

over

pressures

and a comparison

vidual

pressure

subjects

intensive

of the test subjects

the

It was also

anesthesiological

the patients

a horizontal

intended

of the study

pressure

Contact

the oxy-

of 10 minutes.

part

of an

that

for determining

healthy

period

show

on the skin.

the

in

over a period

pres-

turning pressure

on percutaneous

suitable

load

Measurement

of the tcPOz

is

also differed

and

so far

based

pressure

In the second

weight

contact

presented

method

measurement

on re-

alternat-

mat-

patient

typical

the parameters in tcP0,

obtained

because

to

completely

relieve

and change

demonstrated was

relat-

returns

with

percutaneous

the (contact-free)

tcPO2

(Fig. 3).

Maximum a reduction

to values

for

pressure

also varied

of 70 to 89%

again

plot

load yields

12 and 26.5 mmHg

release

24O/(,, below 2).

a

The skin contact

thus

mattresses,

results

patients

2 shows

measurement.

differs

left in the longitudinal

of other

gen pressure

part

be the

lower.

effective

mechanical

and

Accordingly,

The

RESULTS first

staff

those

measuring

The

these

an adhesive zeroed

must

because

from turned

For measurement

in the centre

by STAHL

in this overview

elec-

with

remained

the study.

on the skin

produced

separately

to the oxygen

was then

in the lateral

‘Ihe two sensors

Fig. 2. Original plot of tcPOz behaviour on an alternating-pressure mattress (plotted at two speeds). The curve was obtained from a patient and clearly shows that the method of tcP0, measurement reveals the effect of alternating pressure.

the membrane

position.

for this pneumatic

epi-

for a plotter.

is exerted

controlled)

the

for

of a sensor

a pressure

pressure

(photo-optically

held

It consists

an optional

When

available

for measuring

2 shows the

out

lying in indi-

findings

obtained. Measurements who

showed

were

no evidence

carried

out

of decubitus

on patients ulcers

at

the time of measurement and who received no vasoactive substances during the test period. As a

70

INTENSIVE

CARE

Contact

NURSING

pressure

ImmHgl

4 70 -60-50-IJO-30 -20 -10 -10 -20-30 -GO -50 -60 -70-80 -go-100 -1

tcP02 drop ino/o of initial

value

+ Values

obtained

m

Average

maximum

pressures

II

Average

minimum

pressures

from9test

subjects

Fig. 3 rule, these patients

had no fever but had been

urements

were then

taken

generally classified by the intensive care staff as being ‘vulnerable to decubitus ulcers’ on account

hours.

of their restricted movement.

subjects was demonstrated

Measurements

were carried out in all patients

over a period

of 2

A similar pressure effect to that in the healthy i.e. the maximum

in 14 and 21 patients,

pressure load was associated

as follows: first the patient was turned on one side

with a drop in tcPO,,

which again rose upon the

to relieve the skin for 2 hours. Then the electrode

relief of the pressure.

In six patients

was attached padded by fatty tissue. initial value,

to a point on the sacrum which was the thinnest layer of subcutaneous After the tcPOs had stabilized an the patients were laid on the mat-

was no longer detectable after a short period, although the tcPOs electrode was correctly positioned. In these cases the tcP0, did not recover in the remaining test period (Fig. 4).

tress taking care to ensure that the electrode was positioned in the centre of an air cushion. Meas-

Three of these six patients developed a decubitus ulcer; they had been lying immobile for

this change

INTENSIVE

CARE NURSING

Table 2 No.

Age

Sex

Weight height

tcp02 initial

tcpoz change

Contact pressure Remarks

1.

45~

F

96/l 64

Brain abscess, pneumonia

70

34163

90165

2.

62~

M

65/l 70

65

25160

45/l 6

70

38160

6212%

90/l 75

Under pinning COLD, heart failure Bone fracture, suspicion of deep thrombosis of pelvic vein Polytrauma

3.

75y

F

95/l 70

4.

70~

F

75

27161

54126

5.

82y

M

70/l 65

Acute.abdomen

70

28159

60114

6.

54~

F

68/l 70

Pneumonia

64

O/58

64/l 2

7.

6Oy

M

811177

CCT (craniocerebral trauma)

89

26160

56130

8.

69y

F

70/l 54

72

3OJ67

50131

9,

21 y M

87/l 76

Polytrauma

89

1O/80

64128

10.

84~

F

93/l 72

Wertheim’s

62

21 I54

68120

11.

21 y M

63/l 77

70

34168

50/l 6

12.

56~

M

70/l 80

68

24162

49114

13.

60~

F

64/l 72

RSF Ift, bone fracture Lobectomy, susp. of ARDS Neck dissection

72

40/64

51113

14.

28~

F

60/l 73

Polytrauma

94

52179

44/l 8

15.

71 y

F

821170

RSF, CCT 2”, COLD

84

20/61

64/l 6

16.

68~

M

65/l 70

90

34/72

60132

17.

24~

M

50/l 72

CCT 2”‘ bone fracture, susp. of cerv. spine fracture Polytrauma

94

39180

54/l 8

18.

60~

F

72/l 68

78

20164

60/l 2

19.

29y

M

69/l 73

Polytrauma

94

30186

56123

20.

31 y

F

65/l 74

Susp. of aspiration

92

31 I75

60/l 7

21.

84~

F

60/l 76

Polytrauma

84

21 I60

64133

Diagnosis

After approx. 15 minutes change in tcP0, can no longer be detected; tcPO* levels settled at a constant of about 10 Measuring time 2 hours, change constant After approx. 10 minutes tcP0, no longer detected; tcP02 settled at a constant of about 2-O; decubitus after 2 days After approx. 5 minutes change in tcP0, no longer detected; tcP0, levels settled at a constant of 10. Decubitus after 2 days! Measuring time 2 hours, change constant Measuring time 2 hours, change constant Measuring time 2 hours, change constant Measuring time 2 hours, change constant After approx. 20 minutes, change in tcP0, no longer detected; tcPOz settled at a constant of 15. Decubitus after 3 days! After approx. 15 minutes change in operation tcPOz no longer detected; tcP0, settled at a constant of 20 Measuring time 2 hours, change constant Measuring time 2 hours, change constant. Decubitus after 4 days! Measuring time 2 hours, change constant Measuring time 2 hours, change constant After approx. 36 minutes, change in tcP0, no longer detected; tcP0, settled at constant of 21 Measuring time 2 hours, change constant Measuring constant Measuring constant Measuring constant Measuring constant Measuring constant

time 2 hours, change time 2 hours, change time 2 hours, change time 2 hours, change time 2 hours, change

Patients 5 and 12 each received 300 mg dopamine over 24 hours. Patient 6 had a rectal temperature of 38.6X at the time of measurement. All patients received heparin (low dose). Patient 3 Measurement was carried out on day 1; alternating-pressure mattress was removed on day 2, DIA 1 Patient 72 Measurement was carried out on day 2; alternating-pressure mattress was removed afterwards, DIA 2 Patient 9 Measurement was carried out on day 2; alternating-pressure mattress was removed afterwards, DIA 3aDecubitus on day 3; DIA 3b-Decubitus on day?

71

detected.

He recorded

115 mmHg

beneath

Bedford three

pounds),

weight

classes:

them

(up

pounds)

to

and

This

revealed

that

position

was identical

varied

whereas

with

the contact

in other

the weight

121

heavy

in the supine

all 20 test subjects, pressure

pres-

dividing

light

(120-145

(> 145 pounds).

of up to

alternating

in 20 test subjects,

medium

pressure

pressures

(196 1) investigated

sure mattresses into

contact the sacrum.

for

positions

the

of the test sub-

ject. In

Fig. 4

animal

experiments

also observed longer

than

three

patients

2 days They

on the

the

mattress

not develop

the next

mattress.

did not, on average,

on did

vidual

2 days

8 days.

The

lie longer

without

being

a decubitus

Table

other than

moved.

ulcer

3 summarizes

during the indi-

values.

In the seventh

patient

the tcPOs

demonstrated

as a function

pressure

a period

patient

over

change

of change

of 2 hours.

lay on this mattress

in contact

Although

for less than

was removed

after measurement

the

was

every

veloped

turned

a decubitus

2 hours,

ulcer on the fourth

the

2 days,

the mattress patient

was

and he de-

day.

positioning

of paralysed

Redfern

et al

pressures

of up

39.6 mmHg

In a review ulcers

problems assessment

addressed Kosiak even

after

mattresses

of their

pressure

effectiveness

the alternating subjects

had

4 hours damage

developed

muscle

pressure could

be

IS:/,

injury

Berelying

on

of the test ulcer.

96%

With of

the

pressure

mattress

A significantly

of patients a decubitus rejected

also established

the size of the air chamber

ulcers.

with

and

the risk

higher

previously

when

they

alternating

perintact

lay on a

small air chambers.

We were able to confirm practical

after

a decubitus

tresses for both prophylaxis own

of decubitus

mattress

the author

with relatively

cek therefore

of

a decubitus.

between

(28%)

a mean

mattresses,

2 weeks

skin

In the same survey

skin developed

use of alternating to skin and

that

developed

patients

mattress

that

contact

with

the sacrum.

pressure

pre-existing

mattresses

in only a few publications. (1961) demonstrated in animals

demonstrated

antidecubitus

minor

have

been

18 days,

(1973)

cek ( 1975) reported

of decubitus

of alternating

dogs for 20 and

of the development

on various

centage and

et al (1967)

7 and 5 days after

to 73 mmHg,

beneath

of the alternating

The

ulcers

respectively.

a connection

DISCUSSION

Spence

decubitus

pressure

Beremat-

and therapy. these findings

investigations.

Table 3 After the patients had been transferred from the mattress into a bed with an antidecubitus mattress they were regularly turned every 2 hours

Patient

Weight

No.

(kg)

Height (cm)

Age (years)

Use of (hours)

tcP0, change

Decubitus?

1 3 4 9 10 12 15

96 95 90 87 93 70 82

164 170 175 176 172 180 160

45 75 70 21 84 56 71

15 248 60 56 16 >48 40

No No No No No Yes No

No Yes Yes Yes No Yes No

Decubitus

in our ulcers

INTENSIVE

were

by no means

extended

rare

periods

tresses.

These

in patients

investigations

percutaneous

oxygen

blood

supply

to the skin)

under

conditions

it is obvious, about

recovery

patients

had

1

makes this

of

behaviour

Whether since

of the

test

anyway,

decubitus

ulcers.

sure

appear

docz

worthv

that

hours

on the

However,

a

patients

who

lay

no

study

in this

diff‘er markedly.

and

the

1

patient’s

veloping

the

the

three

Datients

be

did

1

not

own

movements

nor

was

major

time

inter-

1

were Nor

A

clinically

did those

differ

de-

in age

from

those who did not. In a comparison

in the table

of the individual

patient

ing. At tcP0,

No.

recovery

over

the

than

48 hours

decubitus

although

There

lain

less

he develooed

a

was no apparent

e$ana-

tion for this development. It seems patients

justifiable

in

whom

to assume tcP0,

that

recovery

detected

and who lay on the mattress

48 hours

would

bitus

ulcer

sequently, on alternating

the

have developed

longer

use of the mattress.

more

than

a decu-

of the patients

mattresses

not

for less than

certainly

pressure

three

was

with

28%

on a mat-

aid, the value seriously

the

of such

into question.

were

developing a decubitus ulcer (3 patients) actually develop a decubitus ulcer.

Conlying

at risk

References Bedford P D et al 1961 The alternating pressure mattress. Gerontologica Clinica 69-82 ” Berecek K H 1975 Treatment ofdecubitus ulcers. Nurs Clinics ofNorth America 10: 171-210 Brunstler T et al 1987 Skin surface pcO? monitoring in newborn infants in shock. Effect ofhypotension and electrode temperature Pediatrics 100: 454-457 Gadomski M et al 1978 Prophylaxe und Therapie des Dekubitalgeschwurs Med Klin 73 (46): 1633.-1639 Huch A, Huch R 1975 Klinische und physiologische Aspektr der transcutanen Sauerstoffmessung in der Perinatalmedizin 2 Geburth Perinat 179: 235-249 Husain T 1953 Experimental study ofsome pressure effects on tissues with reference to the bed-sore problem. Journal of Patholoev and Bacterioioev 66: 347 Kosiak M 19Kl Etiology ofdecibitus ulcers. Arch Phys Med & Rehabilitation 42 (1): 19-29 Neander K1 D. Birkenfeld R 1988 Der EinfluD verschirdener Lagerungshilfen zur Dekubitusprophylaxe a&den Auflagedruck und den percutanen. Sauerstoffdruck DKZ 4A !6), 443352 Refern S J et al 1973 Local pressures with ten types of oatient-suunort svstems. Lancet 278-280 Rdinecke H et al 1977 Der Oxymeter, ein neues Gerat zur kontinuierlichen transcutanen Messung des Sauerstoffpartialdrucks im arteriellen. Blut .4naesthesist 26: 361-368 Schickardi D 1975 Unblutige und kontinuierliche Sauerstoffuberwachung mit einer transkutanen. Sauerstoffelektrode Anasth Prax 11:63-66 Schwab T H 1982 SauerstoffsnannunP im Hautareal uber dem OS sacrum und Trochanter m;or in Abhangigkeit von Korperunterlage und Beschaffenheit der Korperunterlage Ein Beitrag yur Pathogenese und Prophylaxe van Dekubitalulcera Inauguraldissertation 2

Base1

strik-

in this patient

he had

on the mattress.

ulcer.

parameters

12 is particularly was found

test period,

must be called

.a

was in good con-

patients ulcer

of

it may

at sDecific

in this resgect.

a decubitus

48 de-

on the mat-

However,

pronounced,

all

unremarkable

than

mattress

while

vals. The skin of all the patients dition,

of pres-

did not take account

undertaken

”

relatively

It is note-

48 hours

resDect

The

more

reoositioninc

were

lav/ longer v

than

in

a few developed

ulcer,

less

movement.

that

a role

questionable,

pressure

decubitus

tress did not. This

were

who

of

explained.

the duration

alternating

patient’s

the cause

to be significant.

Datients

veloped

,

plays

only

in

brings This

subjects

but

of

ulcer

recover

svstem.

appears

a quarter

pressure;

clearly

weight

development

most

assumed

be

patient’s

a mattress

All

I

than

a decubitus

tress used as a prophylactic

circulation. and

more

developed

the

longer

circulatorv unlikely

however,

the

are patients

cutaneous

cannot

the

overweight

the

no

If, patients

that

contact there

mat-

hence

can generally

that

influences

decubitus

(and

pressure

a stable

drug

revealed

pressure

however,

alternating

lay for

pressure

of alternating

whom

who

on alternating

73

CARE NURSING

of

or did

Seiler W 0 et al 1982 DekubituspNeue Aspekte zur Dekubitusproblematik in der Geriatric Hospitalis 52 Sonderdruck Seiler W 0 et al 1983 Decubitus Ulcer Prevention. A new investigative method using tramcutaneous oxygen tension measurement. Tournal of the American Geriatrics Societv 31: 786-789 Seiler W 0 et al 1984 Dekubitus-Neue Forschungsmethode in der De kubituspatholgenese Hospitalis 54: 319-326 Spence W R et al 1962 Gel Support for Prevention of Decubitus ulcers. Arch of .phys Med & Rehab 48 (6): 283288. Spiegel H U et al 1984 Lokale Gewebe-poP-Messung in der experimentellen Angiologie Periodica Angiologica 5: 148 ff Stossek K 1977 Transcutane Sauerstoffmessung Methodik und klinische Anwendung Berlin Vermold H et al 1975 Kritische Anmerkungen zur transcutanen PO,-Messung bei Risikoneugeborencn Mschr Kinderheilk 123: 45%560