TRÀIISCUTA}IEOUS OXYGEN TENSTON IN THE ASSESSMEI{T
OF LOTIIER LIMB ISCIIAEMIÀ AIID ULCERÀTION
Francis G. Quígley, M.B.B.S
Submitted
of Master Adelaide.
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The work described was performed within the Department of Surgery of the Uníversity of Adelaide.
in of
January , 1989 for t.he degree Surgery in the University of
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TitIe
Tab1e of Contents
Summary
Declaration
Acknowledgements
CIIAPTER 1
Introduction
Literature Revíew
Transcutaneous Oxygen Tension
Factors affecting tcPOz 1. Heating of EPidermis 2. glood flow
Pressure Resistance
3. Oxygen Carrying CaPacitY
Application of tcPOz t,o disease
Summary
Clinical assessment of blood supply
Measurement of distal blood pressure
Measurement of blood flow Isotope Clearance Methods Diabetes and Hypertension Venous Disease
Summary
1
2 4
CIIÀPTER 2
CTIAPTER 3
Transcutaneous Oxygen Tension Lower Limb Ischaemia.
Introduction
Patients and Methods Results
50 50 52 52 57 59 60 61
and Isotope Measurements in Introduction
Patients
Materials and Methods
Transcutaneous Oxygen TensÍon
Isotope Clearance Doppler Ultrasound Photoplethysmography
Statistics
Transcutaneous oxygen tension
SPP and SVR
Factors affecting tcPOz
62 62 63 63 64 65
Discussion 66
CIIAPTER 4
Transcutaneous oxygen tensÍon in venous disease.
Introduction
Patients and Methods
Results DÍscussion
CIIAPTER 5
tcPOz
tcPOz in lower limb ischaemia tcPOz in venous disease
Bibliography
Appendix
69 69 70 72
75 76 77
79 108
STJMMARY
The measurement of transcutaneous oxygen tension (tcPOz) is thought to be an indicator of tissue oxygen supply and in normal circumstances tissue oxygen tension and tcPOz may reflect arterial oxygen content. In the absence of a systemic
impairment to oxygen delivery, a low tcPOz may reflect local impairment in blood flow due to a proximal large vessel occlu- sÍon or stenosis or to an increased rigidity of the small
vessels which would prevent the increase in blood flow that occurs by vasodilatation in response to appropriate stimuli.
A diffusion barrier to oxygen, as is thought to be present in
venous insufficiency, might also cause a decrease in tcPOz.
The hypothesis tested in this study was that tissue oxygen-
ation as measured by tcPOz was influenced by both large vessel occlusive disease (measured by skín perfusion pressure,
SPP, using a radioisotope washout method) and by micro- angiopathy (measured by skin vascular resistance, SVR, using a radioisotope method also). Two hundred and twenty two limbs
were studied, approximately half of which had foot lesions that were clinically ischaemic in origin. The results showed
that SPP and SVR were both significant independent predictors of tcPOz.
The presence of a diffusion barrier to oxygen due to peri- capillary deposition of fibrin is thought to contribute to
venous ulceration. TcPOz levels in patÍents with mild and severe venous disease were compared with those in normal subjects. Patients with severe venous disease demonstrated
Iower tcpOz levels than normal or patients with mild venous disease. The measurement of tcPOz most affected by the presence of severe venous disease was the peak post ischaemic
response. The finding of subnormal tcPOz levels in severe venous disease supports the hypothesis that a diffusion block to oxygen exists in severe venous disease.
ACKNOWLEDGEMEIi|lf S
I wish to take this opportunity to thank those who have given
me support over the past two years.
I would not have been able to complete the large number of clinical investígations without the assistance of Mrs. Tracy pearl who was also responsible for the illustrations and art- work that appear within.
I thank Lynne
script as weII year.
Irwin
always ment.
Spyksma for as numerous
the skilled typing of this manu- other smaller tasks during the
Faris, under whose supervision this work was done, was
avaitable for advice, timely reminders and encourage-
The Royal Àdelaide Hospital Research Foundation provided the
opportunity for me to undertake this project through a Dawes,
Curren, Hughes Research Fellowship.
I most of aII thank Miche1e, without whose support I could not have taken this opportunity and who had to put up with the ínconvenience this work sometimes caused.
