Amputation level assessment using lightguide spectrophotometry

The Effect of Revascularization on Lower Limb Circulation Parameters in Symptomatic Peripheral Arterial Disease

Background: The prevalence of peripheral arterial disease and the number of revascularization procedures performed in symptomatic patients are steadily increasing. However, uncertainties remain regarding hemodynamic monitoring after revascularization and the prediction of clinical outcomes. This study aimed to investigate hemodynamic parameters with a focus on the microvasculature. Methods: This prospective, single-center study included 29 patients (15 with intermittent claudication [IC] and 14 with chronic limb-threatening ischemia [CLTI]). Before and after the revascularization procedure, in addition to the ankle-brachial index (ABI), microperfusion parameters, including microvascular blood flow, capillary oxygen saturation (SO2), and relative hemoglobin content (rHb), were assessed with lightguide spectrophotometry combined with laser Doppler flowmetry using an oxygen-to-see (O2C) device in the horizontal and elevated leg positions. Results: At baseline, SO2 in the elevated leg position was significantly lower in patients with CLTI than in those with IC (p = 0.0189), whereas the other microcirculatory parameters and ABI values were not significantly different. Patients with diabetes mellitus had a higher flow rate than those without in the horizontal leg position (p = 0.0162) but not in the elevated leg position. After successful revascularization, the flow increased immediately and significantly in both positions, whereas SO2, rHb, and the ABI did not. Conclusions: Elevated leg SO2 was significantly lower in CLTI than in clinically compensated peripheral arterial disease, whereas microvascular flow was a suitable surrogate parameter indicating successful revascularization. In studies using surgical or interventional revascularization procedures, noninvasive hemodynamic monitoring of the microcirculation at the foot level might be beneficial.

The impact of class I compression stockings on the peripheral microperfusion of the lower limb: A prospective pilot study

OBJECTIVE

The use of medical compression stockings (MCS) in patients with peripheral arterial disease (PAD) and diabetes is the subject of an ongoing critical debate. While reducing leg edema of various origins by improving venous back flow, there is a concern about additional arterial flow obstruction when compression therapy is applied in pre-existing PAD. The aim of this study is to obtain further information on the use of class I MCS in patients with advanced PAD and to evaluate the framework conditions for a safe application.

METHODS

The total collective (n = 55) of this prospective, clinical cohort study consisted of 24 patients with PAD Fontaine stage IIb and higher studied before revascularization, of whom 16 patients were examined again after revascularization, and 15 healthy participants included for reference. The microperfusion of the lower extremity of all participants was examined in a supine, elevated, and sitting position using the oxygen to see (O2C) method.

RESULTS

The results indicate that leg positioning had the strongest influence on microcirculation (SO2 and flow: p = 0.0001), whereas MCS had no significant effect on the perfusion parameters (SO2: p = 0.9936; flow: p = 0.4967) and did not lead to a deterioration of values into critical ranges.

CONCLUSION

Mild medical compression therapy appears to be feasible even in patients with advanced PAD. Larger studies are warranted to observe any long-term effects, in particular for the treatment of reperfusion edema after revascularization.

Investigation of Different Methods of Intraoperative Graft Perfusion Assessment during Kidney Transplantation for the Prediction of Delayed Graft Function: A Prospective Pilot Trial

Delayed graft function (DGF) after renal transplantation is a relevant clinical problem affecting long-term organ function. The early detection of patients at risk is crucial for postoperative monitoring and treatment algorithms. In this prospective cohort study, allograft perfusion was evaluated intraoperatively in 26 kidney recipients by visual and formal perfusion assessment, duplex sonography, and quantitative microperfusion assessment using O2C spectrometry and ICG fluorescence angiography. The O2C tissue spectrometry device provides a quantitative method of microperfusion assessment that can be employed during kidney transplantation as an easy-to-use and highly sensitive alternative to ICG fluorescence angiography. Intraoperative microvascular flow and velocity in the allograft cortex after reperfusion predicted DGF with a sensitivity of 100% and a specificity of 82%. Threshold values of 57 A.U. for microvascular flow and 13 A.U. for microvascular velocity were identified by an ROC analysis. This study, therefore, confirmed that impairment of microperfusion of the allograft cortex directly after reperfusion was a key indicator for the occurrence of DGF after kidney transplantation. Our results support the combined use of intraoperative duplex sonography, for macrovascular quality control, and quantitative microperfusion assessment, such as O2C spectrometry, for individual risk stratification to guide subsequent postoperative management.

Assessing the effects of Kampo medicine on human skin texture and microcirculation

In this study, we verified the effectiveness of Kampo medicine by evaluating the changes in the feature values of facial skin texture and microcirculation at two distinct tissue depths (subcutaneous 2 mm and 8 mm). A total of 80 patients who took the Kampo formula participated in this study, and the changes in the feature values of facial skin texture and microcirculation were measured before and after Kampo treatment. The treatment period lasted 6–18 months, according to the doctor’s judgment. The total area of the sulci cutis and the average thickness of the sulci cutis significantly decreased (P < 0.05), and the pixels of the grayscale image increased after Kampo treatment (P < 0.05). Moreover, the blood flow velocity at 8 mm depth significantly increased after Kampo treatment (P < 0.05). In this study, we specifically noted changes in the skin texture and microcirculation after Kampo treatment.

Determination of baseline alveolar mucosa perfusion parameters using laser Doppler flowmetry and tissue spectrophotometry in healthy adults

Objectives: To determine the baseline perfusion parameters of the alveolar mucosa using laser Doppler flowmetry and tissue spectrophotometry (LDF-TS) in healthy adults.Material and methods: Forty-two healthy adult subjects of either sex were tested. The perfusion of the alveolar mucosa was evaluated using a laser Doppler flowmetry and tissue spectrophotometry using O2C 'oxygen to see' device. The measurements encompassed the maxillary and mandibular mucosa at 20 different points.Results: The O2C device is a reliable method for noninvasive measurement of different perfusion parameters of the oral mucosa. The hemoglobin saturation values (So2 in %), as well as relative amount of hemoglobin in arbitrary units (AU) of the maxillary mucosa demonstrated lower values of that in the mandible. The flow value (AU) exhibited a significant difference in the posterior molar region only, while the velocity value (AU) showed a significant difference across all points except for the anterior region.Conclusion: the present study provides a set of brand-new perfusion parameters of the microcirculation of the alveolar mucosa using LDF-TS. The study suggests a variation of the perfusion parameters between the maxilla and the mandible. Differences in the anatomy of the blood supply, the thickness of the mucosa and the cortical bone, may be attributed to this variation. Further studies using different probes and a combination of ultrasonic measurements and SDF imaging will aid in giving a better overview of the perfusion in the oral mucosa.

Soft tissue micro-circulation in the healthy hindfoot: a cross-sectional study with focus on lateral surgical approaches to the calcaneus

PURPOSE

Open reduction and internal fixation (ORIF) using an extended lateral approach combined with plate osteosynthesis represents the current gold standard in calcaneal fracture treatment, but it is associated with a wound complication rate of up to 30%. Literature suggests that micro-circulation is one of the key factors for sufficient wound healing. The aim of this study was to evaluate soft tissue micro-circulation of the hindfoot in healthy volunteers to determine influencing factors and to identify hypoxic or hypoperfused areas in non-trauma situations, with special attention to surgical approaches.

METHODS

Micro-circulation of the lateral hindfoot of 125 participants was non-invasively measured at 2 and 8 mm depths, utilizing a Micro-Lightguide O2C® spectrophotometer. Blood flow (BF [AU]) and oxygen saturation (SO2 [%]) of ten measurement points (MPs) were documented. Demographic factors (age, gender, body mass index [BMI], systolic/diastolic blood pressure, smoking, and pack-years) and regional differences with special regard to surgical approaches (extended lateral approach, Palmer approach, Ollier approach, and a self-modified extended lateral approach) were analyzed.

RESULTS

The SO2 assessments at 2- and 8-mm depths revealed higher values in males (p = 0.043; p = 0.025). There was a correlation between higher age and lower 2 mm BF (p = 0.044). Smoking history and number of pack-years did not predict micro-circulation. BF at the 2 mm depth was highest in the regions of Palmer and Ollier approach (p < 0.001). The MP at the distal calcaneal tuberosity showed significantly higher values regarding all parameters (SO2 (2 mm), p < 0.001; SO2 (8 mm), p = 0.001; BF (2 mm), p < 0.001; BF (8 mm), p < 0.001), compared to the surrounding area.

CONCLUSIONS

In non-trauma situations, young males were associated with better micro-circulatory supply of the lateral hindfoot. There was a trend for higher blood flow in regions of the Palmer and Ollier approach. The distal calcaneal tuberosity was clearly superior in all micro-circulatory parameters when compared to the surrounding area.

Noninvasive measurements of tissue perfusion in critical limb ischemia

Critical limb ischemia (CLI) remains a challenge for an interdisciplinary therapeutic team due to chronic nonhealing wounds. Against this background, there is a necessity of quality control after revascularization. Beside the isolated evaluation of the macrocirculation by Ankle-Brachial or Toe-Brachial Index measurements, the microcirculation as an additional important factor of wound healing often remains underestimated. The following article gives an overview about the current investigation methods for noninvasive perfusion control of the CLI patient. Therefore, transcutaneous oxygen pressure (tcpO₂), the “oxygen-to-see” method which is a combination of white light tissue spectrometry and laser-Doppler flowmetry, fluorescence angiography with indocyanine green, and multispectral optoacoustic tomography will be described.

Optical Measurement of Tissue Oxygen Saturation

Advances in opto-electronic systems have meant that optical spectroscopy can now be used for noninvasive measurements in tissue in patients. A number of techniques have evolved over the last 15 years that make use of the characteristic differences in the absorption spectrum of deoxygenated and oxygenated hemoglobin to measure oxygen saturation. This article summarizes, in particular, those techniques that may prove to be applicable to measurements relating to lower extremity wounds. A short introduction is given about existing electrode methods before describing applications of near infrared and visible wavelength spectroscopy to measurements in tissue. The advantages and limitations of these methods are discussed. An example of an area where tissue spectroscopy is now in routine clinical use for tissue healing viability assessment is presented.

A pilot study of a new spectrophotometry device to measure tissue oxygen saturation

Tissue oxygen saturation (SO2) measurements have the potential for far wider use than at present but are limited by device availability and portability for many potential applications. A device based on a small, low-cost general-purpose spectrophotometer (the Harrison device) might facilitate wider use. The aim of this study was to compare the Harrison device with a commercial instrument, the LEA O2C.Measurements were carried out on the forearm and finger of 20 healthy volunteers, using a blood pressure cuff on the upper arm to induce different levels of oxygenation. Repeatability of both devices was assessed, and the Bland-Altman method was used to assess agreement between them.The devices showed agreement in overall tracking of changes in SO2. Test-retest agreement for the Harrison device was worse than for O2C, with SD repeatability of 10.6% (forearm) or 18.6% (finger). There was no overall bias between devices, but mean (SD) difference of 1.2 (11.8%) (forearm) or 4.4 (11.5%) (finger) were outside of a clinically acceptable range.Disagreements were attributed to the stability of the Harrison probe and the natural SO2 variations across the skin surface increasing the random error. Therefore, though not equivalent to the LEA O2C, a probe redesign and averaged measurements may help establish the Harrison device as a low cost alternative.

Surgery for ischemic colitis: outcome and risk factors for in-hospital mortality

PURPOSE

Surgery for ischemic colitis is associated with high perioperative morbidity and mortality, but the risk factors for mortality and major surgical complications are unclear.

METHODS

In this retrospective single institution cohort study of all patients undergoing colorectal surgery for histologically proven ischemic colitis between 2004 and 2010, we evaluated surgical outcomes and risk factors for in-hospital mortality and major surgical complications.

RESULTS

For the 100 patients included in the study, in-hospital mortality was 54 %; major surgical complications, defined as anastomotic leakage or rectal stump and stoma complications, occurred in 16 %. In the multivariable analysis, hospital death was more likely in patients with right-sided (odds ratio [OR] 3.8; 95 % confidence interval [CI] 1.2, 12; P = 0.022) or pan-colonic ischemia (OR 11; 95 % CI 2.8, 39; P < 0.001), both relative to left-sided ischemia. Decreased preoperative pH level (OR 2.5 per 0.1 decrease; 95 % CI 1.5, 4.1; P < 0.001) and prior cardiac or aortic surgery (OR 2.4; 95 % CI 0.82, 6.8; P = 0.109) were further important risk factors for in-hospital mortality. Major postoperative surgical complications were more likely in patients with ischemic alterations at the resection margin of the histological specimen (OR 3.7; 95 % CI 1.2, 11; P = 0.022).

CONCLUSIONS

Colonic resection for ischemic colitis is associated with high in-hospital mortality, especially in patients with right-sided or pan-colonic ischemia. In patients developing acidosis, early laparotomy is essential. Since resection margins' affection seems to be underestimated upon surgery, resections should be performed wide enough within healthy tissue.

Impact of diabetes and peripheral arterial occlusive disease on the functional microcirculation at the plantar foot

BACKGROUND

Plastic and reconstructive surgeons are commonly faced with chronic ulcerations and consecutive wound infections of the feet as complications in patients with diabetes and/or peripheral arterial occlusive disease (PAOD). Microcirculatory changes seem to play an important role. However, the evaluation of functional changes in the soft tissue microcirculation at the plantar foot using combined Laser-Doppler and Photospectrometry System has not yet been performed in patients with DM or PAOD.

METHODS

A prospective, controlled cohort study was designed consisting of a total of 107 subjects allocated to 1 of 3 groups-group A: healthy subjects (57% males, 63.3 y); group B: patients with diabetes mellitus (DM) (53% males, 59.4 y); and group C: patients with PAOD (81% males, 66.1 y). Microcirculatory data were assessed using a combined Laser-Doppler and Photospectrometry System.

RESULTS

Global cutaneous oxygen saturation microcirculation at the plantar foot of healthy individuals was 8.4% higher than in patients with DM and 8.1% higher than in patients with PAOD (both P = 0.033). Patients with diabetes did not show significant differences in global cutaneous blood flow when compared with either healthy subjects or patients suffering from PAOD.

CONCLUSIONS

Functional microcirculation at the plantar foot differs between healthy subjects and patients suffering from diabetes or PAOD of the same age. Patients with either diabetes or PAOD demonstrate deteriorated cutaneous oxygen saturation with equivalent blood perfusion at the plantar foot. More clinical studies have to be conducted to evaluate therapeutical methods that might ameliorate cutaneous oxygen saturation within diabetic foot disease and PAOD.

Blood viscosity and the expression of inflammatory and adhesion markers in homozygous sickle cell disease subjects with chronic leg ulcers

OBJECTIVE

To determine differences in TNF-α, IL-1β, IL-10, sICAM-1 concentrations, leg hypoxia and whole blood viscosity (WBV) at shear rates of 46 sec(-1) and 230 sec(-1) in persons with homozygous S sickle cell disease (SCD) with and without chronic leg ulceration and in AA genotype controls.

DESIGN

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METHODS

fifty-five age-matched participants were recruited into the study: 31 SS subjects without leg ulcers (SSn), 24 SS subjects with leg ulcers (SSu) and 18 AA controls. Haematological indices were measured using an AC.Tron Coulter Counter. Quantification of inflammatory, anti-inflammatory and adhesion molecules was performed by ELISA. Measurement of whole blood viscosity was done using a Wells Brookfield cone-plate viscometer. Quantification of microvascular tissue oxygenation was done by Visible Lightguide spectrophotometry.

RESULTS

TNF-α and whole blood viscosity at 46 sec(-1) and 230 sec(-1) (1.75, 2.02 vs. 0.83, 1.26, p<0.05) were significantly greater in sickle cell disease subjects than in controls. There were no differences in plasma concentration of sICAM-1, IL-1β and IL-10 between SCD subjects and controls. IL-1β (median, IQR: 0.96, 1.7 vs. 0, 0.87; p<0.01) and sICAM-1 (226.5, 156.48 vs. 107.63, 121.5, p<0.005) were significantly greater in SSu group compared with SSn. However there were no differences in TNF-α (2, 3.98 vs. 0, 2.66) and IL-10 (13.34, 5.95 vs. 11.92, 2.99) concentrations between SSu and SSn. WBV in the SSu group at 46 sec(-1) and at 230 Sec 1 were 1.9 (95%CI; 1.2, 3.1) and 2.3 (1.2, 4.4) times greater than in the SSn group. There were no differences in the degree of tissue hypoxia as determined by lightguide spectrophotometry.

CONCLUSION

Inflammatory, adhesion markers and WBV may be associated with leg ulceration in sickle cell disease by way of inflammation-mediated vasoocclusion/vasoconstriction. Impaired skin oxygenation does not appear to be associated with chronic ulcers in these subjects with sickle cell disease.

Micro-lightguide spectrophotometry for tissue perfusion in ischemic limbs

OBJECTIVE

To validate micro-lightguide spectrophotometry (O2C) in patients with lower limb ischemia and to compare results with those obtained from toe blood pressure.

METHODS

We prospectively examined 59 patients, 24 of whom complained of claudication, 31 had critical ischemia, and four were asymptomatic. Diabetes was present in 19 (32%) patients. Saturation (SO(2)) and flow measured with O2C were determined with the limb in the horizontal position followed by a 55-cm elevation. Toe pressures were determined in the horizontal position only. In addition, 13 patients were examined before and, on average, 3 days after revascularization.

RESULTS

Median SO(2) was 62% (25%-75% percentile: 37%-75%) with the limb in the horizontal position and 16% (3%-41%) with the limb elevated. Comparing the individual toe pressures with SO(2) values measured in the horizontal position and elevated position revealed a significant correlation (r(s) = 0.40; P < .01 and r(s) = 0.56; P < .01, respectively). A low SO(2) (ie, <40% in the horizontal position and <20% in the elevated position) was highly predictive of a toe pressure of 40 mm Hg or less. In the horizontal position, the positive predictive value was 100%, whereas the negative predictive value was 47%. The similar figures in the elevated position were a positive predictive value of 97% and a negative predictive value of 68%. Postoperatively, SO(2) increased significantly from 27% (P25%-75%: 11%-75%) to 79% (68%-87%) in the horizontal position (P = .008) and from 14% (P25%-75%: 2%-39%) to 55% (30%-73%) in the elevated position (P = .011), respectively. Looking at the individual 13 cases in which revascularization was performed, three patients had a partial reconstruction (ie, superficial femoral artery occlusion distal to a central reconstruction or reconstruction to a popliteal blind segment). These patients had significantly lower postoperative SO(2) as well as toe pressure compared with the 10 patients with unobstructed flow to the foot.

CONCLUSIONS

O2C was easy to use, fast, and painless. The most useful finding was the high predictive value of a low saturation and the rise in O2C values after successful revascularization.

Modified spectrometry (O2C device) of intraoperative microperfusion predicts organ function after kidney transplantation: a pilot study

BACKGROUND

Delayed graft function (DGF) is defined as posttransplantation dialysis within 1 week, which might be associated with impaired long-term graft survival. The aim of our pilot study was to establish the ability of intraoperative spectrometry of allograft microperfusion to predict DGF.

METHODS

Twenty human kidney allografts transplanted from deceased donors were evaluated intraoperatively after reperfusion using modified organ spectrometry (O2C device). We examined hemoglobin oxygen saturation, intravascular amount of hemoglobin, and microperfusion flow/velocity.

RESULTS

Retrospectively, 10/20 (50%) allografts with measurable impairment of cortical hemoglobin oxygen saturation and microperfusion flow/velocity developed DGF. Retrospectively, we found that if the intravascular amount of hemoglobin was increased upon intraoperative measurement, the kidney was prone to develop DGF.

CONCLUSIONS

Spectrometry data predicted DGF. Our results supported the thesis that impaired microperfusion is the key to DGF and might be related to postcapillary endothelial damage or intravascular sludge.

Intraoperative measurement of colonic oxygenation during bowel resection

Recently lightguide spectrophotometry (LGS) has been investigated for assessing bowel mucosal oxygenation and may prove helpful in the diagnosis of bowel ischaemia. This pilot study explores the use of LGS and laser Doppler flowmetry (LDF) to measure SO2 and perfusion in the bowel during key stages of colon surgery. SO2 and perfusion in the mucosal and serosal layers of the rectum, sigmoid and descending colon were measured in 7 patients by LGS (Whitland Research, UK) and LDF (Moor Instruments, UK) respectively at four stages (baseline, after mobilisation of the sigmoid, after ligation of the inferior mesenteric artery (IMA) and after complete devascularisation of the sigmoid). The sigmoid mucosal SO2 and LDF values were significantly lower than the baseline after the ligation of IMA and devascularisation. Mean (SD) baseline sigmoid mucosal SO2 (73%) decreased to 55% after ligation of IMA and to 39% after complete devascularisation. The sigmoid serosal SO2 did not show any change after ligation of IMA and showed only 7% decrease after devascularisation. There was no difference in baseline SO2 and LDF values in different parts of the bowel but the mean mucosal baseline SO2 (75%) was significantly lower than that in the serosa (87%). In conclusion, mucosal SO2 measurements can accurately diagnose bowel ischaemia but serosal SO2 does not reflect mucosal ischaemia.

Assessment of oxygenation and perfusion in the tongue and oral mucosa by visible spectrophotometry and laser Doppler flowmetry in healthy subjects

Use of Visible Light Spectrophotometry (VLS) and Laser Doppler Flowmetry (LDF) is currently being studied by the authors to assess the viability of tissue margins in colon resection and to assess mucosal oxygenation in the colon. Thus, as a preliminary study it was necessary to evaluate whether there is any systematic inter-probe variability of the measurements by VLS and LDF. The oral mucosa was used as a model.

METHODS

SO2 with VLS (Whitland Research RM200) and blood flow with LDF (Moor Instruments DRT4) were measured at 10 sites each on the tongue and oral mucosa of 10 healthy volunteers at 0, 6 and 24 hours using 3 different probes for VLS and 2 probes for LDF.

RESULTS

The results showed that the SO2 measurements by VLS using the different probes on the tongue and mucosa were significantly correlated (P < 0.05). SO2 values at 6 hours were significantly higher than at 0 and 24 hours (P < 0.05) in all but one case. SO2 measurements were not correlated with LDF. LDF measurements by the 2 probes were correlated significantly (P < 0.05) but the standard deviations were very large.

CONCLUSIONS

SO2 measurements on the oral mucosa are reproducible. Due to the large variations in LDF, VLS is likely to be the more clinically useful tool for identifying mucosal ischaemia.

Prediction Of Surgical Site Infections After Major Surgery Using Visible And Near-Infrared Spectroscopy

Final results of an investigation into whether oxygen saturation of tissues (StO2, measured by spectrophotometry) could predict surgical site infections (SSI) after major abdominal surgery are presented. StO2 was measured on the arm and wound site pre-operatively and then at 12, 24 and 48 hours post-operatively. A Whitland Research RM200 was employed as the visible lightguide spectrophotometer. StO2 measurements using this machine were designated SSO2 (skin SO2). A Hutchinson Inspectra Model 325 was used for the near infrared spectroscopy (NIS) measurements. StO2 measurements using this machine were designated MSO2 (muscle SO2). Of 59 patients (38 males, 21 females), 42 healed uneventfully and 17 developed SSI. The overall infection rate was 28.8%. No significant differences were seen in wound SSO2 between outcome groups at any stage. At 12 hours there was a significant difference between the two groups with respect to mean wound MSO2 (A = 58.3 +/- 21.6%, B = 42.2 +/- 16.6%, p = 0.005, 95% confidence interval = 5.26, 26.98). A receiver operating characteristic curve showed that when a wound MSO2 of 53% was chosen as the threshold to classify potential infection a sensitivity of 71% and a specificity 73% (chi-squared test, p = 0.002) was achieved. The use of the near-infrared spectrophotometry as a tool to predict wound infections should be further evaluated and advocated.

Amputation level viability in critical limb ischaemia: setting new standards

We have previously demonstrated the successful use of skin oxygen saturation (SO2) measurements to predict the healing viability in lower limb amputations for critical limb ischaemia. The measurements are quick and easy to perform, but the instrument that has been used to date is now obsolete and a new, lightweight, portable instrument has recently been introduced. However, fundamental differences between the two instruments could influence the criteria used for determining amputation level viability. The purpose of this study was to compare the in vivo measurements using the two instruments in order to validate amputation level viability criteria using the RM200. Skin SO2 measurements were carried out on critically ischaemic lower limbs of patients, and on the forearms of normal volunteers during before, during and after a 5 minute period of tourniquet ischaemia. A linear correlation (r2 = 0.91) was found between the values obtained from the two instruments within the range of interest (0 to 40% SO2). Differences between the instruments lay within 1 standard deviation of the mean, demonstrating a high degree of agreement between the two methods. The RM200 is thus an acceptable replacement for the MCPD instrument for amputation level viability assessments.

Optical Measurements of Tissue Oxygen Saturation in Lower Limb Wound Healing

This review has highlighted the role of oxygen in wound healing and in the mechanism of preventing infection. Optical measurements of tissue SO2 in wounds can provide valuable information, not only about the inflammatory state of the wound, but also about healing potential in ulcers and critical limb ischaemia. The technique is fast, non-invasive and can be used without the necessity for contact with the skin.

Disruption of skin perfusion following longitudinal groin incision for infrainguinal bypass surgery

OBJECTIVE

The objective of our study was to investigate whether such an incision results in a reduction in blood flow, and therefore haemoglobin oxygen saturation, across the wound.

DESIGN

Microvascular oxygenation was measured with lightguide spectrophotometry in 21 patients undergoing femoropopliteal or femorodistal bypass procedures. A series of measurements were made in the groin, medial and lateral to the surface marking of the femoral artery. The mean oxygen saturation on each side was calculated, and the contra-lateral groin was used as a control. The measurements were repeated at 2 and 7 days postop.

RESULTS

Oxygen saturation in the skin of the operated groins was increased significantly from baseline at 2 days postop (f = 25.80, p < 0.001) and had begun to return to normal by day 7. The rise was more marked on the lateral side of the wound than on the medial (f = 12.32, p < 0.001). There was no such difference in the control groins. All wounds healed at 10 days.

CONCLUSIONS

These results show a significant difference in skin oxygenation between the lateral and medial sides of the groin following longitudinal incision. This may contribute to the relatively high incidence of postoperative infection in these wounds.