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Is anyone using a TcPO2 machine? If so, I have only found Radiometer as a supplier (approx. £6800 for one modality, £11,000 for two), is anyone else better/cheaper and how reliable is it as a determinant of:
a) Amputation level
b) Healing potetntial?
Any information would be gratefully received, before I have to put in a bid for nearly £7000!
Hi Nicola,
No experience of this kit I'm afraid. I did a small search on it, and it seems to be quoted in most of the abstracts I looked at so it's probably ok :) .
Given that £7000 is not such a lot for a piece of medical hardware, what do you estimate the difference the kit will make to outcomes?
Do you, for example, believe it will provide better outcome-determinant data than a Tekscan vertical loading gait analysis mat, or are you looking to use it to augment modalities already in place?
Possibly I didn't explain myself properly - I was requesting information on the use of this technology with respect to determining the level of ischaemia in diabetic patients, via tissue oxygen perfusion, which would then help to determine healing potential, amputation level and results following vascular intervention, not with respect to muscle function (is this what you thought I meant?)
Either way, as there has been no response, I would suspect that not many people are using it!
And yes, it is relatively inexpensive, but not when you only have £6000 to spend!
Possibly I didn't explain myself properly - I was requesting information on the use of this technology with respect to determining the level of ischaemia in diabetic patients, via tissue oxygen perfusion, which would then help to determine healing potential, amputation level and results following vascular intervention, not with respect to muscle function (is this what you thought I meant?)
Hi Nicola,
I understood that, and looks like it was I who didn't explain myself clearly !
With small lumps of cash being available in our NHS one has, more than ever, to look for "best value".
I wonder(ed) how this equipment compares with force-plates, the use of which are reasonably well documented in the contexts of peripheral vascualr disease and diabetes(Cavanagh et al) when looking at elevated plantar pressures during ambulation?
Regards,
David
I recently attended a national meeting for the launch of the DRAFT SIGN guidelines on Diagnosis and Management of Peripheral Arterial Disease, available for comment via the web site www.sign.ac.uk
can I direct you to 3.3.6 Pulse Oximetry and 3.3.7 Near infra-red spectroscopy with attached references, which may make your decision clearer, I personally have no experience of TcPO2 meausurements but would be interested in what others have to say in non research areas.
regards
Sarann Macphee :p
With respect to load-bearing forces - I am purely thinking of TCPO2 with respect to ischaemia - no neuropathy involved - being lazy and on my way out to get a life - does the Cavanagh research refer to increased plantar forces with respect solely to iscahemia - no neuropathy?
I intend to use this tool only as an indicator of healing potential and anticipated amputation level.......blah, blah, blaaaaahhhh (I'm boring myself now)!
Hand Held TCPO2 machines are available at about $800 US, and are used quite widely in the Physio world to assess pulse rate and tissue perfusion during exercise. These should be quite suitable for a clinic based assessment of lower limb tissue perfusion
Reference value of transcutaneous oxygen measurement in diabetic patients compared with nondiabetic patients.
Meijer VE, Sant HP, Spronk S, Kusters FJ, Hoed PT. J Vasc Surg. 2008 Jun 20. [Epub ahead of print]
Quote:
PURPOSE: This study evaluated the values of transcutaneous oxygen tension (TcPo(2)) measurement in diabetic patients compared with nondiabetic patients and assessed its reproducibility.
METHODS: In 60 diabetic patients (type 1 and type 2 diabetes mellitus) without signs of peripheral arterial disease or neuropathy, we measured TcPo(2) at the chest and foot and compared these measurements with 60 age- and sex-matched nondiabetic patients in a cross-sectional fashion. The reproducibility of TcPo(2) in terms of interobserver variability was also assessed.
RESULTS: Diabetic patients had a mean +/- SD TcPo(2) value at the foot of 50.02 +/- 8.92 mm Hg, which was significantly lower compared with 56.04 +/- 8.80 mm Hg in nondiabetic patients (P < .001). At the chest wall, values for TcPo(2) were 51.77 +/- 11.15 mm Hg, and 58.22 +/- 12.47 mm Hg for diabetic patients and nondiabetic patients, respectively (P = .003). Regression analysis showed that TcPo(2)was significantly associated with diabetes mellitus (coefficient = -0.258; P = .004), and with having a first-degree relative with diabetes mellitus (coefficient = -0.265; P = .003). Furthermore, the interobserver variability showed a substantial correlation for both measurements at the chest (P < .001; r = 0.654; intraclass correlation coefficient [ICC] = 0.79) and at the dorsum of the foot (P < .001; r = 0.426; ICC = 0.60).
CONCLUSION: Diabetic patients without signs of peripheral disease or neuropathy had significantly lower TcPo(2) values compared with age- and sex-matched nondiabetic patients. The influence of the examiner on the variance in TcPo(2) measurements was relatively small. We advocate the use of TcPo(2) measurement in diabetic patients to detect subclinical microvascular impairment as an additional tool to assess peripheral vascular disease.
Hand Held TCPO2 machines are available at about $800 US, and are used quite widely in the Physio world to assess pulse rate and tissue perfusion during exercise. These should be quite suitable for a clinic based assessment of lower limb tissue perfusion
Stephen
Do you have a product name or source for these units?
LL
__________________
***************************************** Remember, it's just a foot.
Pulse oximetry index: a simple arterial assessment for patients with venous disease. J Wound Care. 2008 Jun;17(6):253-4, 256-8, 260
Bianchi J, Zamiri M, Loney M, McIntosh H, Dawe RS, Douglas WS
Quote:
OBJECTIVE: To provide additional safety data comparing ankle brachial pressure index (ABPI) and pulse oximetry (Lanarkshire Oximetry Index, LOI) as measures of arterial circulation in patients with venous disease of the leg.
METHOD: A total of 107 (195 legs) attending hospital leg ulcer clinics participated in this prospective open study. We attempted to measure brachial and foot arterial pressures in all patients using both the handheld Doppler method (ABPI) and pulse oximeter method (LOI). Features of patients with limbs in which either the ABPI or LOI could not be assessed were documented. ABPI and LOI values were compared, and agreement between the two assessment methods was assessed.
RESULTS: We found the LOI measurement to be a simpler technique than Doppler ABPI measurement, with an endpoint less prone to the subjective variability associated with the Doppler method. Of the 195 legs assessed,we obtained LOI in 10 in which an ABPI could not be recorded. LOI could not be recorded in only one leg. There was a linear association (p<0.001) and fair agreement (kappa=0.303) between LOI and ABPI in the 184 legs in which both ratios could be measured. There was no evident tendency for LOI to read either low or high compared with ABPI.
CONCLUSION: Pulse oximetry LOI is a simple alternative to Doppler ABPI in the screening of patients for arterial disease that could be a contraindication to, or require modification of, compression therapy. It can be measured in some legs that cannot be assessed by Doppler ultrasound.
I am thinking of buying a Nellcor N100e Pulse Oximeter seeing this thread has been going since 2004 have any of you been using an Oximeter in this time?
I am just wanting to use it for basic vascular assessment (seen one at a very good price second hand), but would like your informed thoughts!!!!!!!!
Transcutaneous oximetry in clinical practice: consensus statements from an expert panel based on evidence.
Fife CE, Smart DR, Sheffield PJ, Hopf HW, Hawkins G, Clarke D. Undersea Hyperb Med. 2009 Jan-Feb;36(1):43-53.
Quote:
Transcutaneous oximetry (PtcO2) is finding increasing application as a diagnostic tool to assess the peri-wound oxygen tension of wounds, ulcers, and skin flaps. It must be remembered that PtcO2 measures the oxygen partial pressure in adjacent areas of a wound and does not represent the actual partial pressure of oxygen within the wound, which is extremely difficult to perform. To provide clinical practice guidelines, an expert panel was convened with participants drawn from the transcutaneous oximetry workshop held on June 13, 2007, in Maui, Hawaii. Important consensus statements were (a) tissue hypoxia is defined as a PtcO2 <40 mm Hg; (b) in patients without vascular disease, PtcO2 values on the extremity increase to a value >100 mm Hg when breathing 100% oxygen under normobaric pressures; (c) patients with critical limb ischemia (ankle systolic pressure of < or =50 mm Hg or toe systolic pressure of < or =30 mm Hg) breathing air will usually have a PtcO2 <30 mm Hg; (d) low PtcO2 values obtained while breathing normobaric air can be caused by a diffusion barrier; (e) a PtcO2 <40 mm Hg obtained while breathing normobaric air is associated with a reduced likelihood of amputation healing; (f) if the baseline PtcO2 increases <10 mm Hg while breathing 100% normobaric oxygen, this is at least 68% accurate in predicting failure of healing post-amputation; (g) an increase in PtcO2 to >40 mm Hg during normobaric air breathing after revascularization is usually associated with subsequent healing, although the increase in PtcO2 may be delayed; (h) PtcO2 obtained while breathing normobaric air can assist in identifying which patients will not heal spontaneously.
I work on a multidisciplinary diabetic foot and ulcer team and we use the TCP02 machine fairly regularly as the ankle brachial indexes are often questionable in diabetic patients and the arterial duplex dopplers are often opperator dependant. It is often a quick way of determining whether to go ahead with extensive wound care or do vascular intervention first. We feel confident using the machine given the research available but it is important that the operator undergoes training first as placing the sensors in inappropriate areas can lead to incorrect readings
Helen
Quote:
Originally Posted by nicpod1
Hi David,
Possibly I didn't explain myself properly - I was requesting information on the use of this technology with respect to determining the level of ischaemia in diabetic patients, via tissue oxygen perfusion, which would then help to determine healing potential, amputation level and results following vascular intervention, not with respect to muscle function (is this what you thought I meant?)
Either way, as there has been no response, I would suspect that not many people are using it!
And yes, it is relatively inexpensive, but not when you only have £6000 to spend!
Hello,
I am working in a Limb Salvage Clinic in Mexico, we use a 4 channel TCPO2 machine with excellent results for determining amputation level and pronostics. Be careful you guys with pulse oximetry, this is not the same, we are talking about oxigen tension, not photocromatic levels of hemoglobin with pulse oximetry. The incovinient is just the price of the equipment and the replacements, this are costly but worth of it, if the patients has ischaemic limb, and needs to know how will he do after surgery.
Increased Transcutaneous Oxygen Tension in the Skin Dorsum Over the Foot in Patients With Diabetic Foot Disease in Response to the Topical Use of an Emulsion of Hyperoxygenated Fatty Acids.
Lázaro-Martínez JL, Sánchez-Ríos JP, García-Morales E, Cecilia-Matilla A, Segovia-Gómez T. Int J Low Extrem Wounds. 2009 Oct 13. [Epub ahead of print]
Quote:
The aim of this study was to examine changes in the skin over the feet of patients with diabetic foot syndrome after local application of a product containing hyperoxygenated fatty acids (HOFAs) by measuring transcutaneous oxygen. In 64 patients, transcutaneous oxygen pressure (TcPo2) was measured on days 0, 7, 30, 60, and 90 of the study. Foot skin dryness, shedding, and skin color were also assessed using a clinical score.The patients were grouped on the basis of initial levels of transcutaneous oxygen; group 1 comprised patients with TcPo2 >30 mm Hg and group 2 comprised patients with TcPo2 <30 mm Hg on the skin over the dorsum of the feet. Increases in local oxygenation values were observed at a local level in group 2 patients after 30 days of treatment. Skin trophism showed clinical improvement in all patients and these observations may be attributed to improved local microcirculation
TcPO2 usage in surgery and wound care
!
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