[Fatal outcome of aortic arch syndrome].
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Biomedical subjects
Publications and source records attributed to L Caspary.
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With regard to the increasing use of tcPO2-measurements for the assessment of peripheral arterial occlusive disease, the variability of the method needs more consideration. We studied the reproducibility of tcPO2 measured at 37 degrees C and 44 degrees C, especially under the influence of provocation tests, in 21 patients with severe claudication (ankle artery pressures (AP) 30-100 mmHg) without skin lesions. On 6 days within 2 weeks tcPO2 was recorded on the forefoot at 37 degrees C and 44 degrees C electrode core temperatures a) in supine position, b) in sitting position, c) during O2-breathing, d) during reactive hyperemia (RH). In measurements at 37 degrees C variation coefficients (VC) were high (mean +/- S.D.: 74 +/- 27%) and could not be improved by oxygen inhalation nor by the sitting position. Only during RH, VC decreased significantly to 49 +/- 23%. At 44 degrees C VC were still quite high (mean: 42 +/- 24%) and were inversely correlated with AP. Mean tcPO2 increased under all provocation maneuvers. However, only in the sitting position VC decreased significantly to 18.7 +/- 8.4% (p < 0.001). Single tcPO2 measurements, both at 37 degrees C and 44 degrees C, are of low value in patients with severe claudication. For the evaluation of the individual patient repeated measurements are demanded. Reduced variability may be achieved by measurements at 44 degrees C in a sitting position.
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Transcutaneous oxygen pressure (tcPo2), laser Doppler flux and capillary microscopy have been used to examine the forefoot skin in 5 healthy men and 8 patients with severe peripheral arterial occlusive disease in order to evaluate the dose dependent effects of iloprost on skin microcirculation. Iloprost was infused IV starting at 0.0625 ng.kg-1.min-1 and doubling the dose every 15 min up to 2 ng.kg-1.min-1. While tcPo2 at an electrode core temperature of 44 degrees C decreased in both patients and controls, there was a significant dose dependent increase in tcPo2 (37 degrees C) in the controls from 0.25 ng.kg-1.min-1. In the patients the reaction was variable: it was decreased in two and increased in 6, with a maximum either at 0.25-0.5 ng.kg-1.min-1 (n = 3) or at the highest dose (1.0 or 2.0 ng.kg-1.min-1; n = 3). Mean laser Doppler flux in both groups was increased, although the reaction was not consistent in the patients. Density of forefoot skin capillaries was reduced in 3 patients, and in the others the flow velocity was very low. During infusion of iloprost, both an increase in capillary density and blood cell velocity were observed. The effects were of variable intensity and occurred at varying doses, some appeared early and diminished as the dose was increased, and others were found only at 2 ng.kg-1.min-1. Adverse effects were numerous, extending from harmless skin flushing to mental changes and a quickly reversible attack of angina pectoris.(ABSTRACT TRUNCATED AT 250 WORDS)
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By a spectrophotometrical method, the oxygenation and relative concentration of hemoglobin in the skin of the forefoot was determined in 40 patients with advanced peripheral arterial occlusive disease. While the Hb-saturation at rest was hardly different from normals, leg elevation provoked a marked decrease of both parameters, especially in patients with critical ischemia. In these patients, reactive hyperemia was markedly delayed and impaired. External heat application failed to cause a hyperemic saturation increase in 14 patients and produced a decrease in 8 patients, 6 of whom experienced an infavourable clinical outcome. The method seems specially suited to assess states of severe ischemia.
When measuring transcutaneous oxygen pressure at an electrode core temperature of 37 degrees C autoregulating mechanisms of skin microcirculation can be studied. Because of poor reproducibility of a single PO2 measurement we determined skin surface oxygen pressure fields out of 50 or more PO2 values. At the forefeet and calves of healthy volunteers the histograms were slightly left-shifted with median PO2 of 4 mm Hg. Patients with multilevel arterial occlusive disease and low systolic ankle pressure presented with a disturbed PO2 distribution with very low PO2 values close to zero. About 16% of measurements were above 10 mm Hg. In contrast, diabetics had significantly higher PO2 (median 8 mm Hg) at the forefoot level when compared with healthy volunteers or patients without diabetes.
Quantitative analysis of nailfold capillary morphology was performed in age and sex matched groups of 29 patients with systemic lupus erythematosus (SLE) presenting Raynaud phenomenon (RP), 29 RP negative patients with SLE with the same duration of the disease, and 29 healthy controls. Percentages of tortuous, meandering and bushy capillaries were significantly increased in both groups of patients without influence of RP. Capillary density was lower, mean diameters of the capillary loops were higher in patients, especially when RP was present (at the venular branch in microns, mean +/- SD: controls: 15.0 +/- 2.0, RP negative patients with SLE: 17.6 +/- 3.6, RP positive patients with SLE: 20.5 +/- 6.3). In a subgroup of 13 patients with frequent Raynaud's attacks (more than 1/week), diameters were still higher (22.1 +/- 7.1, p to controls less than 0.0005; p to RP negative patients less than 0.05). In patients with SLE, the prevalence of RP seems not to be associated with the increased number of abnormal capillaries but with capillary enlargement, correlating with the frequency of attacks.
Prostaglandin E1 is offered as a new therapeutic agent in the treatment of severe peripheral arterial occlusive disease. Especially when treating patients with ulcers or gangrene, the oxygen tension of the skin should improve during PGE1 administration. The new technique of assessing skin surface oxygen pressure histograms allows study of the skin microcirculation in vivo. Oxygen histograms were determined on the forefeet of 19 patients with different degrees of disease and different occlusion levels before and during a single intraarterial infusion of PGE1 at a dosage of 1.5 ng/kg body weight/min. Only 9 patients showed improvement during the infusion period. Skin oxygen pressure was increased to a large extent only in patients assumed to suffer from diabetic microangiopathy. The effect of a long-term therapy with PGE1 on skin microcirculation remains to be settled.
Skin microcirculation and regional peripheral resistance were studied in 14 patients with renal anaemia during therapy with recombinant human erythropoietin. Haematocrit was raised from 20.0 to 31.3% after 10-12 weeks of treatment and remained stable over another period of 12 weeks. Antihypertensive treatment had to be intensified in five patients. Regional calf blood flow decreased significantly; accordingly, calculated peripheral vascular resistance was increased by more than 100%. However, transcutaneous oxygen pressure (37 degrees C and 44 degrees C) increased significantly. The pathological vasoconstrictor response of skin capillaries was not influenced. There were no significant differences of any parameter between the patients requiring reinforced antihypertensive therapy and those with stable blood pressure. In conclusion skin oxygenation may be improved by erythropoietin treatment to a large extent despite an increase in calculated total limb vascular resistance.
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