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Biomedical subjects

H Rieger

Publications and source records attributed to H Rieger.

At least 73 records · Page 4Linked to original sources
PubMed1993

[Results of dorsal pelvic ring stabilization].

Complete disruptions of the posterior pelvic ring are rotationally and vertically unstable [type C according to the Tile/AO (ASIF) classification (1991)]. Usually operative treatment is required. The data on 24 patients over a 5-year period were analyzed. Thirteen patients were female (54.2%) and 11 male (45.8%); the average age was 32.8 years. Multiple trauma was present in 20 patients (83.3%). In most cases operative stabilization of the posterior pelvic ring was performed by lag screws from the ilium into the body of the sacrum. The mortality in this series was 16.7% (4 patients). One patient had a thrombosis of the femoral and pelvic veins. In 2 patients we had to perform a second operative procedure because of lag screws that had not been precisely placed or had dislocated. Two incisions healed secondarily. On the postoperative radiographs in 3 patients a slight deformity of the pelvic ring was visible; in another patient the reduction of the injured hemipelvis was not sufficient. The 20 survivors had a clinical and radiological examination on average 27.5 months after their injury. Eleven patients were without pain, while 9 complained of low back pain. Gait disturbances were found in 8 patients; in 2 of them this was due to associated injuries. Five patients were unable to work. Eight patients had neurological deficits, some of them minor. Additional complications were impotence (3 patients), urinary (2 patients) or fecal incontinence (1 patient), and dystocia requiring a cesarean section (1 woman) [multiple entries].(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

[Technical concepts of retrograde venous perfusion with fluorescein].

Regional intravenous drug application has been suggested to increase peripheral tissue concentrations in severe arterial insufficiency. Within this study basic operational characteristics of the retrograde venous perfusion technique (RVP) were evaluated in 10 patients with intermittent claudication. Fluorescein was used to visualize the intracutaneous distribution of the injected fluid. Subjects were divided into 2 groups. The "cocktail-group" received 100 ml of a homogenous fluorescein dilution. To compare the effect of injecting a small sample, 45 ml of unstained solution were given before and after 10 ml of concentrated dye ("fraction-group"). Photographic recording of skin fluorescence distal to the arterial tourniquet revealed a rapid and complete staining of the lower leg including the toes in the cocktail-group. In the fraction-group, however, skin fluorescence appeared markedly delayed and, more over, did not spread down to the toes in 2 cases. In conclusion, drugs can be applied by RVP provided that they are dissolved in a sufficient amount of fluid of 100 ml at least.

Chemotherapy, Cancer, Regional Perfusion↗
PubMed1993

[Regional drug-induced sympathicolysis in patients with arterial occlusive disease].

Regional drug-induced sympathectomy is a modification of Bier's block technique. By applying this method skin perfusion in patients with occlusions of lower leg arteries or functional disturbance of peripheral circulation can be improved. Under optimal technical conditions effects of regional and surgical sympathectomy are comparable. Fluorescence angiography can be applied to assess the effectiveness of drug-induced as well as surgical sympathectomy.

Arterial Occlusive Diseases↗
PubMed1992

Validation of Doppler measurement of pressure gradients across peripheral model arterial stenosis.

Hemodynamic assessment of aortoiliac occlusive disease is necessary for successful arterial reconstruction of the legs. Various methods have been proposed, and the "pull through" intraarterial pressure measurement method is accepted as the best standard. The pressure readings, however, seemed to depend on the intraluminal position of the catheter. To explain these observations and make a comparison between the Doppler method and the pull through method, we have studied centerline velocity changes at the stenosis throat by Doppler ultrasonography, and axial and lateral pressure gradients by use of pressure transducers mounted 10 mm and 40 mm downstream of short (4 mm) axisymmetric sharp-edged model stenoses having cross-sectional reduced areas of 64%, 84%, 91%, and 96%. Axial manometric pressures measured 10 mm beyond the throat of 84% stenosis were more than twice as high as the lateral pressures. No significant difference was observed between axial and lateral pressures measured 40 mm downstream from the throat. This pressure distribution has important clinical relevance. Mean and peak pressure gradients for both the Doppler method and manometric measurements were compared. Measurements with Doppler method and manometric measurements indicated that mean pressure gradients (r = 0.98; SEE = +/- 2.4 mm Hg) correlate better than peak pressure gradients (r = 0.90; SEE = +/- 16.5 mm Hg). Doppler gradients were higher than manometer gradients. Overestimation was 13% for mean pressure gradients and ranged from 10% to 150% for peak pressure gradients. Explanation for the difference between mean Doppler and catheter gradient may be the pressure recovery occurring in the relaminarized poststenotic regions.

Arterial Occlusive Diseases↗
PubMed1992

Influence of clinical findings, positional manoeuvres, and systolic ankle arterial pressure on transcutaneous oxygen tension in peripheral arterial occlusive disease.

The mutual effects of systolic ankle arterial pressures, positional manoeuvres, and calf artery occlusions on transcutaneous oxygen partial pressures (tcpO2) were studied in 388 legs of 258 patients with peripheral arterial occlusive disease (PAOD). The tcpO2-vs-perfusion pressure relationship could be satisfactorily fitted by a non-linear regression model deduced from the tcpO2 theory. Flow-insensitive ranges of tcpO2-vs-flow hyperbolas were reduced by both leg lowering and moving the electrode towards proximal measuring sites. Lower tcpO2 values were found in case of occluded compared to patent calf arteries at ankle arterial pressure indices below 0.4. The tcpO2 positional variability increased with worsening hemodynamic compensation and was most pronounced in critical limb ischaemia (ischaemic rest pain, non-healing ulcerations). According to a retrospective analysis, a critical ischaemia could be assumed if supine and sitting tcpO2-values exceed neither 10 nor 45 mmHg, respectively.

Adult↗
PubMed1992

Redistribution of skin blood flow during leg dependency in peripheral arterial occlusive disease.

A disturbed autoregulation of cutaneous blood flow in legs with peripheral arterial occlusive disease (PAOD) has previously been demonstrated for circumscribed skin areas. In the present study, posturally-induced changes of skin perfusion distribution along ischaemic limbs were investigated topographically in 35 PAOD patients by means of fluorescein perfusography. Among the 68 legs studied, 7 had patent arteries and 61 could be assigned to FONTAINE stages I to IV. Limbs with peripheral skin lesions (stage IV) were further differentiated according to either healing (stage IV+) or non-healing (stage IV-) on conservative treatment. Sitting-up always led to prolonged calf as well as foot fluorescein appearance times (AT) except for legs in stage III or IV- disease. In the latter two groups, decreased sitting as compared to supine AT foot-to-calf ratios indicated a relative shift of dye delivery from proximal towards distal skin regions during posture. In contrast, this measure of blood flow redistribution did not change in the other groups. The redirection of fluorescein influx was significantly correlated with the systolic arterial pressure ankle-to-arm ratios. In conclusion, besides small perfusion pressure increases or passive microvessel distension, a shift of the peripheral resistance ratios may contribute to the improved blood supply of ischaemic skin regions during leg dependency. An arteriolar vasoparalysis does not regularly exist in limbs with skin lesions not primarily originating from ischaemia (stage IV+).

Adult↗
PubMed1992

A comparative analysis of transcutaneous oximetry (tcPO2) during oxygen inhalation and leg dependency in severe peripheral arterial occlusive disease.

Transcutaneous oximetry (tcPO2) performed during either oxygen inhalation or leg dependency was intra-individually compared in 64 patients suffering from a peripheral arterial occlusive disease, with and without critical limb ischemia. Among the 81 extremities investigated, 29 had a moderate peripheral arterial occlusive disease (6 in stage I, 23 in stage II) and 52 were initially affected by rest pain or ulceration (stage III/IV). Thirty-seven legs out of the latter improved under conservative treatment. In the remaining 15 limbs, vascular surgery or an amputation became necessary. The tcPO2 was measured at the forefoot with the patient in supine and sitting positions while breathing room air and in the supine position while inhaling 100% oxygen. In limbs with a tcPO2 below 15 mm Hg of patients in the supine position breathing room air, leg dependency generally provoked larger tcPO2 increases than oxygen inhalation. This difference between oxygen inhalation while supine and room air breathing leg dependency tcPO2 values exhibited an approximately linear correlation with the resting tcPO2. Responses of tcPO2 to leg dependency and oxygen inhalation seemed to reflect different mechanisms, that is, microvascular flow redistribution and supine perfusion reserve, respectively. The best discrimination of critical limb ischemia was observed for the tcPO2 of patients breathing room air while in the supine position, which was not surpassed by either the oxygen inhalation or the leg dependency test. Satisfactory results were achieved by combining limits for, first, supine (10 mm Hg) and sitting (45 mm Hg) tcPO2, as well as, second, ankle arterial pressure (60 mm Hg) and supine tcPO2 (10 mm Hg).

Adult↗
PubMed1992

Spontaneous oscillations of laser Doppler skin blood flux in peripheral arterial occlusive disease.

In the present study, local temporal fluctuations of skin perfusion were non-invasively measured at the forefoot and calf in 374 limbs of 226 patients with peripheral arterial occlusive disease (PAOD) by means of Laser-Doppler-Flowmetry (LDF). Within the scope of a purely descriptive evaluation, each recording was classified according to four previously defined LDF oscillation types named 'aperiodical', 'sinoidal', 'missing waves', and 'small waves'. The prevalences of these curve patterns distinctly varied with both the macrohemodynamic compensation and clinical severity of PAOD. While type 'aperiodical' predominated in case of a normal or only slightly affected circulation, type 'sinoidal' accumulated in legs with marginal collateralization. In contrast, 'missing waves' and 'small waves' mainly occurred in feet affected by severe PAOD. Which pathophysiological mechanisms are responsible for the different LDF oscillation types still remains to be clarified. Retrospectively, in case of a confirmed PAOD, the diagnosis of critical limb ischemia could not be established and wound healing could not be predicted by means of LDF pattern analysis.

Adult↗
PubMed1992

[Changes in systemic fibrinolysis and blood coagulation parameters in local thrombolysis with tissue plasminogen activator (rt-PA)].

During the local fibrinolysis with rt-PA (2.5 mg/h) systemic plasminogen and alpha 2-antiplasmin activities slightly decrease, but the fibrinolytic system is compensated during the whole treatment. The d-dimer plasma levels increase dependently on the mass of thrombus. Despite the administration of high doses of heparin during the fibrinolysis thrombin is formed, measured as thrombin-antithrombin III complex (TAT).

Blood Coagulation↗