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Scandinavian Journal of Rheumatology
ISSN: 0300-9742 (Print) 1502-7732 (Online) Journal homepage: http://www.tandfonline.com/loi/irhe20
Muscle Tissue Oxygen Pressure in Primary
Fibromyalgia
N. Lund, A. Bengtsson & P. Thorborg
To cite this article: N. Lund, A. Bengtsson & P. Thorborg (1986) Muscle Tissue Oxygen Pressure
in Primary Fibromyalgia, Scandinavian Journal of Rheumatology, 15:2, 165-173
To link to this article: http://dx.doi.org/10.3109/03009748609102084
Published online: 12 Jul 2009.
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Scand
J
Rheumatology 15: 165-173, 1986
Muscle Tissue Oxygen Pressure in Primary Fibromyalgia
N.
LUND,’ A. BENGTSSON’ and P. THORBORG’
‘Department
of
Anesthesiology and 2Departrnent
of
Internal Medicine, Division
of
Rheumatology,
University Hospital,
S-58185
Linkoping, Sweden
Lund,
N.,
Bengtsson,
A.
and Thorborg,
P.
Muscle tissue oxygen pressure in primary
fibromyalgia. (Submitted June 14 and accepted October 10, 1985.) Scand
J
Rheumatology
Trigger points in painful muscle are a characteristic sign in patients with primary fibro-
myalgia. The
MDO
oxygen electrode was used to evaluate oxygenation in the subcutane-
ous
tissue and in trigger points in the trapezius and brachioradial muscles. Ten patients and
8 normal controls were studied. The results in the patients were abnormal, with scattered
.
or
slalom-slope histograms, indicating low tissue oxygenation. The controls were normal,
except in one
case.
The conclusion is that in patients with primary fibromyalgia, the
muscle oxygenation is abnormal
or
low, at least in the trigger point area of the muscles.
Ann Bengtsson, Division
of
Rheumatology, Dept.
of
Internal Medicine, University Hospi-
tal,
S-58185
Linkoping, Sweden.
15:
165-173, 1986.
Primary fibromyalgia (PF) is a non-articular rheumatic disease, also known as ‘fibrositis’,
‘myofascial syndrome’ and ‘muscle rheumatism’. It is predominantly a female disease
characterized by chronic pain and stiffness in skeletal muscles and joints, but without
arthritic manifestations.
A
typical feature is the painful trigger-points in muscles and
tendon insertions (29).
In 1973 Fassbender
&
Wegner published
a
morphologic study on the pathogenesis of PF
(3).
Biopsies from the trapezius muscle were studied with light- and electronmicroscopy.
Among their findings were swollen endothelid cells of the muscle capillaries. They
hypothesized that local hypoxia was a possible cause of the development and symptoms of
the disease. However, there is, no published investigation which has actually proved the
existence
of
muscle hypoxia in PF.
In 1966 Lubbers
&
Kessler described a multipoint oxygen electrode (the MDO elec-
trode, Mehrdraht Dortmund Oberflache) for measuring oxygen pressure fields on organ
surfaces (6). This MDO oxygen electrode has been used extensively in physiological
research (15,
20,
23). Since the development of a disinfection technique (16), the MDO
electrode has also been used in human studies (17, 18, 24). A complete system for
computerized on-line measurements of tissue surface oxygen pressures was later de-
scribed (30).
The purpose of the present study was to elucidate whether or not muscle hypoxia exists
in PF-patients, and to compare the findings in these patients with the results from
a
group
of healthy volunteers.
MATERIAL AND METHODS
Ten patients and 8 healthy volunteers were studied. All patients fulfilled the diagnostic criteria of
Yunus
et al. (Table
I)
(29).
In
the patient group, 9 were female and
1
male, with a mean age of43 years
(range 22-58).
On
average the patients had had symptoms of
PF
for
3
years (range 2-10). There were
no
symptoms
or
signs of any other rheumatological
or
neuromuscular disease that could explain the
symptoms
of
the patients and
no
patient had clinical hypoxia (for example from chronic obstructive
lung disease). Arterial blood samples
for
gas analysis were not taken. The volunteer group consisted
of
healthy females only, with
a
mean age
of
36 years (range 2643).
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166
N.
Lund
et al.
Scand
J
Rheumatology
15
-1
-2
-3
-4
-5
-6
-7
Fig.
1.
The MDO oxygen electrode.
1,
Rubber ring to hold
the Teflon membrane.
2,
Teflon membrane.
3,
Lucite ring to
hold the cellophane membrane.
4,
Cellophane membrane.
5,
Ag/AgCI-anode.
6,
Electrolyte solution
(0.2
M KCI).
7,
Glass
nucleus.
8,
Eight platinum wires. Reproduced with kind per-
mission of Acta Anaesth Scand.
Routine laboratory tests including erythrocyte sedimentation rate, hematology count, electrolytes,
creatinine, creatine phosphokinase, thyroid function, rheumatoid factor and antinuclear antibody
were normal in all patients.
A trigger point was defined as a localized area of intense pain on compression of the muscle, often
with radiation of pain, and often
so
painful that the patient jumped
on
palpation. Trigger points are
often found in the trapezius muscle, which was therefore the initial choice for oxygen measurements
(29).
Later in the study both the trapezius and the brachioradial muscles were studied. The reasons for
this were
our
initial findings in the trapezius muscle and the fact that the only normal material
Table
I.
Diagnostic criteria
of
primary jlbromyalgia
(Yunus,
1
981)a
1.
Obligatory criteria:
(a)
Presence of generalized aches and pains
or
prominent stiffness, involving at least three anatomic
sites for at least
3
months.
(b)
Absence of secondary causes, e.g. traumatic, other rheumatologic, infective, endocrine or
malignant.
2.
Major criteria:
Presence
of
at least
5
typical and consistent tender points.
3.
Minor criteria:
(a)
modulation of symptoms by physical activity;
(b)
modulation of symptoms by weather factors;
(c)
aggravations of symptoms by anxiety
or
stress;
(4
poor sleep;
(e)
general fatigue
or
tiredness;
v)
anxiety;
(g)
chronic headache;
(h)
irritable bowel syndrome;
(i)
subjective swelling;
0)
numbness.
PF-patients must satisfy the two obligatory criteria, by definition, as well as the major criterion plus
at least three minor criteria. If the patient has only
3
or
4
tender points, five minor criteria are
suggested.
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Scand
J
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15
Muscle oxygen pressure in primary fibromyalgia
167
available for comparison was
a
group studied in
1980
by Lund and co-workers, who used the
brachioradial muscle
(17).
Measurements of tissue surface oxygen pressure fields were performed with the MDO oxygen
electrode (Fig.
1)
(6,
20,
30).
This electrode is constructed according to the Clark principle and has
eight separate and individually registering measurement points
(1).
Under surgically aseptic condi-
tions and under subcutaneous local anesthesia
(10
ml
0.25%
bupivacaine per measurement site) an
incision was made through the skin over a trigger point located in the trapezius and the brachioradialis
muscles, respectively. Tissue p02 (p,Oz) was also measured in the subcutaneous tissue in some of the
subjects. Thus,
a
disinfected oxygen electrode was initially placed
on
the subcutaneous tissue for
measurements (for a
full
description of methodology and equipment, see Lund,
1979)
(16,
14).
After
the subcutaneous measurements, the fascia
was
opened and the muscle surface was freed with the
utmost care to avoid trauma to the muscle surface
(12,
15).
To obtain a sufficient number of observations
(n>80)
for
statistical evaluation and to enable
construction of the tissue oxygen pressure field histograms, eight oxygen pressure values (one from
each measuring point) were collected every
15
sec
(20).
Usually
120
single oxygen pressures were
collected for
a
histogram, i.e. the total sampling time for one histogram was
210
sec. The oxygen
pressure values were then fed into an
ABC
800
computer (Luxor
AB,
Motala, Sweden) and corrected
for electrode drift, local tissue temperature and air pressure. Histograms were obtained during
spontaneous breathing of ambient
air.
A normal histogram is Gaussian in shape with a mean usually between
1.3
kPa
(10
mmHg) and
4.7
kPa
(35
mmHg) when measured
on
skeletal muscle
(9,
17.20).
Abnormal histograms are of two types:
one
looks
like a slalom slope and usually begins at the origin.
In
the other the registered values are
widely scattered, though
a
scattered histogram may have the same mean p,Oz-value as a normal
histogram. The slalom slope type indicates impaired tissue oxygenation, whereas the exact meaning
of the scattered type is still under discussion
(18,
20).
Statistical
methods
Comparisons between pOz group means were made using paired t-test
(13).
A parametric test, e.g.
Student’s t-test, can be applied to oxygen pressure histograms only when all histograms included are
of the normal type. Statistically significant differences were determined at the levels indicated in text.
All
mean values are given
f
standard deviation (SD).
A histogram is described by its mean, standard deviation, skewness, kurtosis and distribution type.
A statistical method for testing one histogram against another must be independent of the mean
values, as the mean does not necessarily change from one measuring situation to another, even
though a definite biological change may have taken place
(20).
Changes in distribution types were
tested with the non-parametric two-sample Kolmogorov-Smirnov test
(13)
as modified by Odman
&
Lund
(30).
which provides an analysis independent
of
the mean and enables one to calculate the
significance level at which the hypothesis of equal distributions can be rejected.
RESULTS
Measurements in the subcutaneous (fat) tissue superficial to the trapezius muscle were
made in
7
patients and
6
control subjects. The results are given in Table
11.
One patient
histogram and one control histogram are shown in Fig.
2.
The total mean tissue pO2 in the
patients
(6.0
kPa
=
45
mmHg) was significantly lower than that in the controls
(8.7
kPa
=
65
mmHg), with
p<O.Ol.
Most
of
the histograms in this tissue were of the normal type,
with only
one
clearly abnormal histogram among the patients.
The trapezius muscle oxygen pressure results are given in Table
111.
Scattered histo-
grams,
one example shown in Fig.
3,
were obtained in all patients except one who had a
slalom slope histogram.
In
the control group, standard deviations were small and
all
histograms were normally bell-shaped; one example is shown in Fig.
3.
Brachioradial muscle oxygen pressures were measured in
4
patients and
5
controls; the
results are presented in Table
IV.
A
typical histogram is shown in Fig.
4.
The findings in
this muscle paralleled those in the trapezius, i.e. in the patient group
3
out of
4
histograms
were abnormal, while in the control group only
1
of
5
was abnormal. One histogram in the
patient group was
of
an intermediate type close to normal, and one histogram in the
control group
was
frankly scattered.
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Scand
J
Rheumatology
15
168
N.
Lund
et
al.
PATIENT
no8
CONTROL
no8
i
p0"2
k
Pa
10
20
30
40
50
60
70
SO
mmHg
Fig.
2.
Histograms registered in the subcutaneous tissue. The histogram from the control is normal,
the histogram from the patient begins to scatter. Abbreviations:
N,
number of observations;
pro2,
tissue oxygen pressure. The arrow at the abscissa indicates the mean tissue oxygen pressure.
Table
11.
Subcutaneous tissue oxygen pressure
in
kPa
Case
Subjects
no.
plOza SD
S
K
HDT
PF
patients
1 4.3 (32)b 0.36 0.17 -1.12
N
3 8.5
(64)
0.62 -0.04
-
1.38
N
5
8.9 (67) 0.25 -0.04 -0.56
N
6 6.1 (46) 0.37 -0.59 -0.09
N
7
5.5
(41) 0.99 -0.26
-
1.29
sc
8 4.2 (31) 0.56
-0.14
-1.47
N/Sc
9 4.6 (35) 0.48 -0.57
-
1.26
N
Mean
Controls
6.0 (45) 1.97
1
8.3
(62)
0.32 0.03
-0.50
N
2 7.7
(58)
0.85 0.38 -0.54
N
4 9.5 (71) 0.80 -0.22 -1.41
NISc
5 9.8 (74) 0.39 -0.02 -0.56
N
7 8.8
(66)
0.52 -0.09 -0.90
N
8 8.5
(64)
0.42 0.69 0.43
N
Mean
8.7 (65) 0.78
Abbreviations: plOz, mean tissue oxygen pressure;
SD,
standard deviation;
S,
skewness;
K,
kurtosis; HDT, histogram distribution type
(N
=
normal,
L
=
low ski-slope, Sc
=
scattered).
-
Values in parentheses
are
mmHg.
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PO
30
40
rnrnHg
90
30
40
60
(10
70
SO
mrnHg
Fig.
3.
Histograms registered in the trapezius muscle. The histogram distribution types are statistical-
ly
different, with
p<O.OOI.
Abbreviations: see Fig.
2.
Table
111.
Trapezius
muscle
oxygen pressure in
kPa
Abbreviations: see Table
11.
Values in parentheses are mmHg. The total mean is not given, since the
PF-patients and the controls have different HDT. See further under Methods
Case
Subjects
no.
P,02
SD
S
K
HDT
PF patients
1
5.9
(44)
2 1.4
(11)
3 1.5
(11)
4 3.8 (29)
5 7.2 (54)
6 3.7 (28)
7 2.3 (17)
8 2.0
(15)
9
5.5
(41)
10 6.3 (47)
Controls
1
7.1 (53)
2 3.0 (23)
3
5.5
(41)
4 5.3
(40)
5 9.4 (71)
6 3.2 (24)
7 3.4 (26)
8 6.7
(50)
0.89
0.37
1.29
1.04
2.25
1.23
0.95
1.80
1.62
2.34
0.65
0.91
0.69
0.56
0.78
0.53
0.53
0.41
0.07
0.75
0.16
0.84
-0.57
-0.97
-0.65
0.57
1.03
-0.05
-0.02
0.71
-0.34
-0.29
0.84
-0.10
0.34
-0.76
-0.61
-0.45
-0.66
-1.20
-0.72
0.55
-0.67
-
1.54
-0.20
-1.24
-0.48
0.46
0.03
V.
76
-0.54
0.64
-0.16
1.09
sc
L
sc
sc
sc
sc
LISC
sc
sc
sc
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Scand
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15
170
N.
Lund et
a!.
N
CONTROL
no
7
N
PATIENT
no9
30
e0
10
30
PO
10
0
o
10
PO
30
40
mmHg
10
PO
30
40
mmHp
Fig.
4.
Histograms registered in the brachioradial muscle. The histogram distribution types are
statistically different, with
p~0.001.
Abbreviations: see Fig.
2.
Statistical testing of the subcutaneous tissue histogram distribution types showed no
differences between patients and the control group. However, testing of histogram distri-
bution types in the trapezius and the brachioradial muscles, respectively, showed statisti-
cal significance ranging from
p<O.O5
to
p<0.001.
DISCUSSION
Several factors are thought to interact to produce the PF-syndrome, e.g. overload,
disturbed sleep and psychogenic factors,
all
possibly causing muscle tension or spasm
(27).
Table
1V.
Brachioradial
muscle
oxygen pressure
in
kPa
Abbreviations: see Table
11.
Values in parentheses are mmHg. The total mean is not given, since the
PF-patients and the controls have different HDT. See further under Methods
Case
Subjects
no.
P,02 SD
S
K
HDT
PF patients
7
3.7 (28) 0.87
8 6.9 (52) 1.16
9 2.3 (17) 1.82
10
8.7 (66) 0.90
Controls
4 6.3 (47) 0.56
5
10.5 (79) 0.53
6 3.7
(28)
1.13
7 3.9 (29) 0.49
8 2.7 (20)
0.64
0.76
-0.22
0.25
-0.05
0.33
0.21
-0.28
0.82
-0.20
-0.93
-0.68
-
1.67
-
1.29
2.06
-0.63
-1.41
-0.65
1.23
Sc/N
sc
sc
sc
N
N
sc
N
N
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Scand
J
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15
In addition to these factors, Fassbender
&
Wegner hypothesized that hypoxia was an
essential and causative factor in the PF-syndrome
(3).
With the development of the MDO-electrode it has become possible to measure tissue
oxygen pressures with
a
high degree of accuracy
(6, 14, 20).
Studies performed with
needle-type electrodes had drawbacks: the needle compressed the tissue, the relation of
the needle to the vascular bed was unknown
(19, 25, 28).
In order to avoid these
drawbacks, Lubbers
&
Kessler developed an electrode (MDO) with eight individually
registering points, to be used on tissue surface
(6,
8).
This technique is non-traumatic to
the tissue and the weight of the electrode
so
light that pressure ischemia is not induced
(7,
30).
Measuring at
8
points simultaneously avoids the problem of the relationship of the
electrode to the vascular bed
(20).
Tissue oxygenation is constantly varying with changes
in local capillary blood flow, hemoglobin oxygen affinity and metabolism
(4, 21, 23).
The
sum of these variations is thus registered with the electrode, and in order to describe the
dynamically varying oxygen pressure field, at least
80
individual oxygen pressures must be
registered
(14, 20).
The catchment zone of each measuring point is hemispherical and
reaches approximately
20
pm into the tissue
(24).
Studies initially performed in different
animals
(8,
15, 26)
and later in humans
(2, 5, 14, 17, 24)
have led to the recognition of three
basic types of oxygen pressure histogram; the normal Gaussian-shaped type, and
2
abnormal types. One consists of only low values (the slalom slope type) close to the origin,
clearly indicating tissue hypoxia. The other type shows
a
scattering of oxygen values along
the x-axis (Fig.
3).
The meaning
of
a
scattered histogram has, as yet, not been finally
defined, though maldistribution of capillary blood flow has been hypothesized. However,
neither the slalom slope type nor scattered histograms have been found in any normal
situation
(2, 5,
9,
15, 17, 18, 20, 23, 24).
In hypoxemia or hyperoxemia, histograms either
change immediately to the slalom slope type or first to the scattered type and then to the
slalom slope type
(2, 5, 17, 18).
To
minimize trauma to the patient, no arterial blood samples were taken for blood gas
analysis, though no signs of clinical hypoxemia (cyanosis, dyspnea, tachycardia, etc.)
were seen. Had the subjects been hypoxic (or even hyperoxic, e.g. through an increase of
the inspired oxygen fraction), this would have led to either type of abnormal histogram.
Local anesthetics are myotoxic agents. Great care was therefore taken to inject the
anesthetic only into the superficial subcutaneous tissue. That bupivacaine injected in this
way does not influence microcirculatory flow in the underlying muscle has previously been
shown
(15).
Thus the local anesthetic should not have affected the muscle measurements.
Whether it had any effect on the subcutaneous measurements is impossible to ascertain,
though in the present study the findings showed a consistently normal pattern. Thus,
addition of the histograms and testing of mean values with the t-test was permitted. The
histograms obtained in the patient group were centered around lower mean values,
SO
much
so
that the two groups were differed statistically with
pcO.01.
Subcutaneous tissue
pO2 has never before been studied with the MDO-electrode, but studies with implanted
Silastic catheters and subcutaneous gas pockets have shown oxygen pressures at the same
level as those obtained in the controls in this study
(1
1,
22).
The results from the trapezius
muscle and the brachioradial muscle parallel one another in that we almost exclusively
found abnormal histograms in the patients and normal in the controls.
Oxygen pressure fields in the trapezius muscle have never been studied before. Howev-
er, there are
a
few published studies on humans utilizing the brachioradial muscle
(17, 18).
A
comparison of the results of the measurements in the brachioradial muscle in the
controls of the present study, versus those obtained by Lund et
al.
in healthy volunteers
revealed no statistically significant differences
(17).
Furthermore, the results from the
trapezius muscle measurements in the control group in this study did not differ from either
Muscle
oxygen pressure in primary fibromyalgia 171
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172
N.
Lund
et
al.
Scand
J
Rheumatology
15
the brachioradial controls or the earlier brachioradial group studied by Lund et
al.
(17).
Thus the findings in the trapezius and the brachioradial muscles of the PF-patients indicate
an abnormal oxygenation, possibly due to morphological or functional changes affecting
the microvessels in the trigger points. The significantly lower total mean oxygen pressure
in the subcutaneous tissue of the patients, although not hypoxic, might indicate that PF
also affects tissues other than skeletal muscle.
Among other factors, the tissue oxygen pressure depends on capillary blood flow and
metabolism
(4,
21).
Blood flow in fibromyotic muscles was studied by Klemp et
al.
(10).
They injected '33Xenon,
0.1
ml, into trigger points in the trapezius muscle. They found no
significant changes in local blood flow in the fibromyotic group compared with a normal
group. However, the results from the '33Xenon-clearance technique and the MDO elec-
trode cannot be compared. Lund et al. also tried to relate the capillary flow changes
(measured with '33Xenon and "Cr-EDTA) induced by changes in arterial PO*
to
changes
in tissue oxygen pressure fields
(17, 18).
No correlations were found, since the MDO-
electrode measurement volume is extremely small, and even the small volume of tracers
used
(0.03
ml) was approximately
lo6
times greater than the electrode catchment volume
(17).
Thus, tissue pOz measurements have a much higher power of resolution than
'33Xenon-clearance and therefore these two methods need not correlate. Furthermore,
with the greater tissue volume measured with the '33Xenon technique, local maldistribu-
tion of flow may remain undetected, whereas it can be seen in the abnormal oxygen
histograms.
TO
conclude,
we
have found evidence of abnormal tissue oxygenation in muscle with
trigger points in patients with
PF
as measured with the MDO oxygen electrode. Studies
employing modern techniques elucidating the tissue metabolic state of the trigger points
may confirm these findings.
ACKNOWLEDGEMENT
This study was supported by the Swedish Medical Research Council
(05956),
the Ostergotland County
Council
(14/83, 122/83),
the Tore Nilson Foundation
(83/94)
and the Lions' Research Fund. We are
greatly indebted to Lars-Ake Malmqvist and Anita Forsman for expert technical help, and to Peter
COX,
M.D., for scrutinizing the English language
of
this article.
REFERENCES
1.
2.
3.
4.
5.
6.
7.
8.
9.
Clark
Jr,
L. C.: Monitor and control of blood and tissue oxygen tensions. Trans Am SOC Artif
Intern Organs
2:41, 1956.
Ehrly, A. M.: (ed) Messung des Gewebesauerstoffdruckes bei Patienten. Baden-Baden: Verlag
Gerhard Witzstrock,
1981.
Fassbender,
H.
G.
&
Wegner, K.: Morphologie und Pathogenese des Weichteilrheumatismus.
Z
Rheumaforschg
32: 355, 1973.
Granger,
H.
J.,
Goodman, A. N.
&
Cook, B.
H.:
Metabolic models of microciculatory regulation.
Federation
Proc
34:2025, 1975.
Hauss,
J.,
Schonleben, K.
&
Spiegel, H.4.: Therapiekontrolle durch ubenvachung des Gewebe-
pO2. Bern: Verlag
Hans
Huber,
1982.
Kessler, M.
&
Lubbers,
D.
W.: Aufbau und Anwendungsmoglichkeit verschiedener p02-electro-
den. Ptliigers Arch
291:R82, 1966.
Kessler, M.: Normal and critical 02-supply of the liver.
In
Oxygen Transport in Blood and
Tissue. (ed. D. W. Lubbers, U. C. Luft,
G.
Thews
&
E.
Witzleb) p.
242.
Stuttgart: Georg Thieme
Verlag,
1968.
Kessler,
M.
&
Grunewald,
W.:
Possibilities of measuring oxygen pressure fields in tissue by
multiwire platinum electrodes.
Progr
Respir Res
3: 147, 1969.
Kessler,
M.,
Hoper,
J.
&
Krumme, B. A.: Monitoring of tissue perfusion and cellular function.
Anesthesiology
45:
184, 1976.
Downloaded by [T&F Internal Users], [Rachel Andrews] at 06:29 05 February 2016
Scand
J
Rheumatology
I5
Muscle oxygen pressure in primary fibromyalgia
173
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
Klemp,
P.,
Nielsen,
H.
V., Korsghd, J.
&
Crone, P.: Blood flow in fibromyotic muscles. Scand J
Rehab Med
14:81, 1982.
van Liew,
H.
D.: Tissue pOz and pC0, estimation with rat subcutaneous gas pockets. J Appl
Physiol
17:851, 1962.
Lindbom, L, Tuma, R., Rutili, G.
&
Arfors, K-E.: Microvascular response of the tenuissimus
muscle to manipulative trauma. Bib1 Anat
15:506, 1977.
Lindgren, B. W.: Statistical Theory. The Macmillan Company: New York,
1976.
Lund, N.: Studies
on
skeletal muscle surface oxygen pressure fields. PhD thesis, Linkoping
University Medical Dissertations. Sweden,
71, 1979.
Lund, N., Odman,
S.
&
Lewis,
D.
H.:
Skeletal muscle oxygen pressure fields in rats. Acta
Anaesth Scand
24: 155, 1980.
Lund, N., Cardell, B., Tomell, B-M.
&
Odman,
S.:
A technique for disinfection of the MDO
oxygen electrode. Acta Anaesth Scand
24:265, 1980.
Lund,
N.,
Jorfeldt, L.
&
Lewis, D. H.: Skeletal muscle oxygen pressure fields in healthy human
volunteers. Acta Anaesth Scand
24: 272, 1980.
Lund, N., Jorfeldt, L., Lewis,
D.
H.
&
Odman,
S.:
Skeletal muscle oxygen pressure fields in
artificially ventilated critically ill patients. Act Anaesth Scand
24: 347, 1980.
Lund, N.: Skeletal and cardiac muscle oxygenation. Adv Exp Med Biol [in press.]
Lubbers, D.
W.:
Quantitative measurement and description of oxygen supply to the tissue.
In
Oxygen and Physiological Function (ed.
F. F.
Jobsis), p.
254.
Professional Information Library,
Dallas,
1977.
Morff, R. J.
&
Granger,
H.
J.: Autoregulation of blood flow within individual arterioles in the rat
cremaster muscle. Circ Res
51:43, 1982.
Niinikoski, J.
&
Hunt, T. K.: Measurement of wound oxygen with implanted silastic tube.
Surgery
71:22, 1972.
Nylander, E., Lund, N.
&
Wranne, B.: Effect of increased blood oxygen affinity
on
skeletal
muscle surface oxygen pressure fields. J Appl Physiol54:99,
1983.
Schonleben, K., Krumme, B. A., Bunte,
H.
&
Kessler,
M.:
Kontrolle der Intensivbehandlung
durch Messung von Mikrozirkulation und 02-Versorgung. Langenbecks Arch Chir, suppl.
72,
1976.
Silver,
I.
A.: The measurement of oxygen tension in tissues. Intern Anesth Clin
4:
135, 1966.
Sinagowitz, E., Rahmer,
H.,
Rink, R., Gomandt,
L.
&
Kessler, M.: Local oxygen supply in
intra-abdominal organs and in skeletal muscle during hemorrhagic shock. Adv Exp Med Biol
37A:505, 1973.
Smythe,
H.
A,: Nonarticular rheumatism and psychogenic musculo-skeletal syndromes.
In
Arthritis and Allied Conditions, ninth edition (ed. D. J. McCarty), p.
881.
Philadelphia: Lea
&
Febiger,
1979.
Whalen, W.
J.,
Nair,
P.
&
Ganfield, R. A.: Measurements of oxygen tension in tissues with
a
micro oxygen electrode. Microvasc Res
5:254, 1973.
Yunus, M., Masi, A.
T.,
Calabro, J. J., Miller, K. A.
&
Feigenbaum,
S.
L.: Primary fibromyalgia
(fibrositis): clinical study of
50
patients with matched normal controls. Sem Arthr Rheum
11:
151,
1981.
Odman,
S.
&
Lund, N.: Data acquisition and information processing in MDO oxygen electrode
measurements
of
tissue oxygen pressure. Acta Anaesth Scand
24: 161, 1980.
Downloaded by [T&F Internal Users], [Rachel Andrews] at 06:29 05 February 2016
