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Biomedical subjects

O Bongard

Publications and source records attributed to O Bongard.

27 records · Page 2Linked to original sources
PubMed1990

Discrepancies between total and nutritional skin microcirculation in patients with peripheral arterial occlusive disease (PAOD).

Clinical observations indicate that a discrepancy may exist between the total and nutritional skin microcirculation in extremities of patients with peripheral arterial occlusive disease (PAOD), which suggests a local maldistribution of blood flow. The present study was performed to investigate how the skin blood flow is locally distributed in the toes of patients with PAOD. The total skin microcirculation was evaluated by laser Doppler fluxmetry (LDF), and the blood flow in the nutritional skin capillaries by dynamic capillaroscopy. This combination was simultaneously used to study the nailfold microcirculation in the big toe of 12 legs of 8 patients with various degrees of PAOD, using 10 legs of 8 healthy subjects as control. Capillary blood cell velocity (CBV) was evaluated by a new computerized videophotometric technique (CapiFlow). It was found that the nutritional blood flow, as evaluated by CBV, was similar in both groups (0.2 vs. 0.25 mm/s, NS), whereas the total blood flow, as evaluated by LDF, was significantly (p less than 0.05) increased in toes of patients with PAOD (11.7 AU) in comparison to normal subjects (2.0 AU). The postocclusive reactive hyperemia was impaired for both CBV (6% vs. 70%, p less than 0.05) and LDF (14% vs. 50%, p less than 0.01) in the PAOD group. The prevalence of flow motion (30% vs. 80%) was significantly (p less than 0.05) lower in patients as compared to controls. It is concluded that the resting blood flow in the skin microcirculation is increased but maldistributed in patients with PAOD. The reactivity of the microcirculation is also impaired in the affected region.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Delayed arterial thrombosis following an apparently trivial low-voltage electric injury.

Vascular damage is a frequent and serious complication following high voltage injuries (greater than 1000 V), but does not seem to have been described with low-voltage current. We report an unusual case with delayed thromboses in the hand arteries of a young, healthy 24 yo man, after a 220 V electric shock. Two weeks after the accident he developed a successively increasing hand ischemia with Raynaud phenomenon, and finally fingertip necroses. Angiography revealed multiple small vessel occlusion. Although systemic fibrinolysis with streptokinase was not initiated until eight weeks after the accident, a partial restitution of the markedly reduced macro- and microcirculation in the fingers was possible. The blood pressure of the ischemic fingers increased from 0 to 40 mmHg, with total relief of symptoms. Concomitantly, a marked improvement of the skin microcirculation could be objectively demonstrated by laser Doppler fluxmetry and dynamic capillaroscopy. Three conclusions can be made 1) low-voltage electric shock can initiate late vascular thromboses, 2) thrombolysis can be effective also weeks after the thromboses have been established, and 3) the improvement of the nutritional circulation in the ischemic areas can be nicely and objectively documented by the two methods described.

Adult↗
PubMed1988

Predicting amputation in severe ischaemia. The value of transcutaneous PO2 measurement.

The predictive value of the pedal transcutaneous oxygen tension (tcPO2) and of the distal systolic blood pressure (SBP) in forecasting the necessity for later amputation has been studied in 26 patients suffering from severe chronic ischaemia of the lower limbs. In all these patients vascular surgery had failed or not been possible, and they were threatened by amputation; they suffered from trophic lesions, or pain at rest, or both. The great toe SBP averaged 10 mmHg (range 0 to 60 mmHg) and the pedal tcPO2 10 mmHg (range 2 to 45 mmHg). After six minutes of oxygen inhalation there was an increase in pedal tcPO2 of 9 mmHg (0 to 50 mmHg). After a follow-up period averaging 7 months (range 10 days to 13 months), 13 patients underwent an amputation and nine (five of whom had been amputated) died. The great toe SBP in the patients who required amputation was initially lower than in those who did not. The pedal tcPO2 also was lower in amputated than in non-amputated patients. There was no amputation in the group showing an increase of at least 10 mmHg after six minutes of oxygen inhalation; and conversely, all patients in whom the pedal tcPO2 increased less than 10 mmHg were amputated. Thus increase in the pedal tcPO2 after oxygen inhalation appears the best criterion for estimating the prognosis of severely ischaemic limbs.

Adult↗
PubMed1985

[The venous-arteriolar reflex].

Cutaneous blood flow (Xenon clearance) and transcutaneous pO2 were simultaneously measured on the foot of normal subjects and patients suffering from severe arterial insufficiency of the lower limbs. When the subject is sitting, cutaneous blood flow decreases, as well in normal subjects than in most patients with arterial insufficiency. However, tc pO2 increases in sitting position, probably because local vasoregulation is abolished by local heating. Increase in tc pO2 in sitting position is higher in patients in whom tc pO2 was very low in lying position. In normal subjects, there is a positive correlation between cutaneous blood flow and tc pO2. This correlation do not exist in patients suffering from severe ischemia; it is likely that Xenon clearance actually measures total cutaneous blood flow, while tc pO2 constitutes an index of nutritional circulation. It is also possible that Xenon clearance is modified by changes in partition coefficient in ischemia areas.

Arterial Occlusive Diseases↗
PubMed1984

Pedal blood flow and transcutaneous PO2 in normal subjects and in patients suffering from severe arterial occlusive disease.

Pedal transcutaneous partial pressure of oxygen (tcPO2) has been measured by polarographic method, heating the skin at 44 degrees C. In 50 normal subjects, mean tcPO2 measured 54.5 +/- 7 mmHg. Among 43 patients suffering from chronic ischaemia of lower limbs, mean tcPO2 measured 40.8 +/- 8 mmHg in patients with from claudication and 16.1 +/- 15 mmHg in patients suffering from rest pain and/or gangrene. The variability of repeated tcPO2 measurements, expressed as 1 SD of the mean, was 4.5 mmHg in normal subjects and 2.9 mmHg in patients. The relationships between pedal subcutaneous blood flow measured in xenon-133 clearance method and pedal tcPO2 have been studied in nine normal subjects and in five patients suffering from severe chronic ischaemia of lower limbs (rest pain and/or gangrene). There was a positive correlation between blood flow and tcPO2 in normal subjects (r = 0.77, P less than 0.001). In patients suffering from severe ischaemia, there was no correlation between these two parameters, but measured blood flow was sometimes very high in areas where tcPO2 was low. It is likely that 133Xe clearance method considerably overestimates local blood flow in these patients, because there is considerably less fat in subcutaneous tissue of chronic severely ischaemic areas. Thus, partition coefficient should be determined in each patient. However, tcPO2 may constitute an index of nutritional circulation, while 133Xe clearance actually measures total subcutaneous blood flow.

Adolescent↗
PubMed1984

[Transcutaneous measurement of the partial pressure of the oxygen. Theoretical bases and hemodynamic significance].

Transcutaneous measurement using a modified Clark type electrode actually measures the amount of oxygen diffusing through the skin, i.e. the transcutaneous oxygen flow (tc O2). The latter depends on arterial partial oxygen pressure, local blood flow, diffusion of oxygen in tissues and local oxygen consumption. In this study, tc O2, cutaneous blood flow (133-xenon) and pedal systolic blood pressure were measured simultaneously on the foot. In normal subjects, there was a good correlation between tc O2, perfusion pressure (r = 0.89) and local blood flow (r = 0.77). Tc O2 passively depends on perfusion pressure, because local heating induced an inhibition of vasomotricity. In patients with severe ischemia (stages 3 and 4), there was a lack of correlation between local blood flow measured by 133-xenon clearance and tc O2. This may be explained by variations of partition coefficient from patient to patient, which introduce a bias in blood flow calculation. Furthermore, tc O2 may constitute an index of nutritional blood flow, while 133-xenon clearance measures total blood flow.

Blood Gas Analysis↗
PubMedDate not supplied

Effects of percutaneous transluminal angioplasty on skin microcirculation in patients with disabling peripheral arterial occlusive disease.

Percutaneous transluminal angioplasty (PTA) provokes a huge trauma to the arterial wall and potentially liberates fragments of atherosclerotic material that may impair the microcirculation downstream. Incidence and clinical relevance of such embolisms are not known. This study was aimed at investigating the changes of the skin microcirculation in patients with peripheral arterial occlusive disease undergoing PTA of the lower limbs. Pedal transcutaneous oxygen tension (tcpO2) and nailfold skin microcirculation were measured in 21 patients with disabling peripheral arterial occlusive disease before and after PTA. Sixteen matched patients undergoing arteriography alone were used as controls. The skin microcirculation was investigated at the nailfold of the great toe by the combination of laser Doppler fluxmetry and dynamic capillaroscopy. PTA was successful in all patients. The tcpO2 decreased immediately after PTA (delta tcpO2 = -5 mm Hg; p < 0.004), whereas it tended to increase (delta tcpO2 = 1 mm Hg; NS) following arteriography as compared with baseline values. By contrast, blood flow increased in both groups, predominantly for the total circulation in the PTA group and for nutritional circulation (p < 0.0017) in the arteriography group, respectively. Consequently, the 'nutritional index', i.e., the index of nutritional versus total microcirculation, was decreased following PTA, particularly following mechanical recanalization (p < 0.02), but did not change in the controls. The changes of this 'nutritional index' and those of the tcpO2 were positively correlated (r = 0.4, p = 0.023).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMedDate not supplied

Altered skin microcirculation in patients with systemic lupus erythematosus.

Although microvasculitis is one of the more common manifestations of systemic lupus erythematosus, there is no data on the hemodynamics of the skin microcirculation in such patients. The combination of dynamic capillaroscopy measuring capillary blood cell velocity (CBV) and laser Doppler fluxmetry (LDF) was used to simultaneously evaluate the nutritional and the total skin microcirculation in the fingers of 24 consecutive patients with SLE, using normal matched subjects as controls. The nutritional skin flow, as assessed by the CBV, was significantly impaired in patients, as compared with controls, both at rest (p = 0.001) and during postocclusive reactive hyperemia (p = 0.006). By contrast, no differences were observed in total skin microcirculation, as assessed by LDF (n.s.). There was no significant correlation between hemodynamic parameters and the presence of Raynaud's phenomenon, morphological capillary changes or anticardiolipine antibodies. There was no correlation between the magnitude of the alteration of the capillary blood flow and capillary morphological abnormalities, suggesting that the microvascular damage might be caused by different pathophysiological mechanisms.

Adolescent↗