Nicotine induced haemodynamic changes during cigarette smoking and nicotine gum chewing: a placebo controlled study in young healthy volunteers.

Because cigarette smoking is a definite risk for the development of cardiovascular disease and nicotine induced vasoconstriction may be a possible pathogenetic factor the haemodynamic effects of smoking cigarettes with high or low nicotine content were compared with those induced by chewing nicotine gum in a placebo controlled, crossover study in six healthy volunteers. The three stimuli induced similar increases in heart rate (about 20%) and systolic blood pressure (about 7%) and a decrease in digital blood flow. Although the mean haemodynamic changes parallelled the mean plasma nicotine concentration increases, no correlation was found between them when the individual values were considered. It is concluded that the nicotine induced haemodynamic changes probably occur as a result of the (local) release of vasoactive mediators such as adrenaline or noradrenaline after a threshold plasma nicotine concentration has been reached. Such a threshold may explain the large interindividual variability in susceptibility to smoking induced cardiovascular diseases.

Diagnosis of deep vein thrombosis by combination of Doppler ultrasound flow examination and strain gauge plethysmography. An alternative to venography only in particular conditions despite improved accuracy of the Doppler method.

Doppler ultrasound flow examination, strain gauge plethysmography and contrast venography were performed in 160 lower limbs of 80 in-patients. Deep vein thrombosis (DVT) was suspected in 87 limbs. Using measurement of venous stop-flow pressure, the Doppler method hae an overall sensitivity of 83%. By combined use of Doppler and Plethysmography, sensitivity was increased to 96%. Specificity was 62% and 51%, respectively. With a positive and a negative predictive value of 80% and 73%, respectively, the combination of both non-invasive method cannot reliably replace venography in the diagnosis of DTV, although all (40/40) thromboses proximal to or involving the popliteal segment were detected by either Doppler and Plethysmography or both. After exclusion of 14 patients (18%) suffering from conditions known to alter the results of these non-invasive methods, the positive predictive value of abnormal findings in both Doppler and Plethysmography was increased to 94% for suspected limbs, whilst negative predictive value of both negative Doppler and Plethysmography was 90%, allowing the avoidance of venography in these patients.

Measurement of plasma D-dimer for diagnosis of deep venous thrombosis.

Venography was performed on fifty-six patients suspected of having deep venous thrombosis (DVT) of the legs. The accuracy of the D-dimer measurement in plasma using two latex tests and an enzyme-linked immunosorbent assay (ELISA) was compared with that of usual determination of total fibrin(ogen) degradation products (FDPs) in serum with respect to the presence of DVT. The three D-dimer tests were clearly superior to the FDP assay, but only the ELISA could accurately rule out the diagnosis of DVT with a predictive value of 100% when plasma D-dimer level was less than 200 micrograms/L. However, this test cannot be used for positive diagnosis (false positive rate of 69%). Thus, plasma D-dimer measurement with ELISA allows identification of patients in whom further investigation by means of more specific tests (venography or plethysmography) is indicated in order to establish the diagnosis of DVT. In contrast to this, sensitivity of the two latex tests studied was low (60 and 76%, respectively), which makes them unsuitable for emergency screening. In addition, the potential of D-dimer dosage for diagnosis of DVT in hospitalized patients is hampered by the presence of associated conditions that are responsible for elevated plasma levels in most cases.

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.

Prevention of postoperative deep vein thrombosis by one daily injection of low molecular weight heparin and dihydroergotamine.

201 patients aged over 40 years undergoing abdominal surgery were divided randomly into two groups. Each patient received two subcutaneous injections daily: the first group received a morning injection of 1500 aPTT U of low molecular weight heparin combined with 0.5 mg dihydroergotamine (LMH/DHE) and an evening injection of placebo; the second group received morning and evening injections of 2500 IU standard heparin combined with 0.5 mg dihydroergotamine(H/DHE). 25 patients were withdrawn during the course of the trial, 13 in the LMH/DHE group and 12 in the H/DHE group. There was no significant difference between the two groups with regard to age, sex, body weight or history of thromboembolism. 125I-labelled fibrinogen test was routinely used to detect deep vein thrombosis (DVT), which was confirmed by phlebography. Ventilation-perfusion scanning was performed in patients in whom pulmonary embolism was suspected on clinical grounds. DVT occurred in 6 patients in the LMH/DHE group (6.9%) and in 7 patients in the H/DHE group (7.9%). Pulmonary embolism occurred in one patient in each group. The only noteworthy haemorrhagic incident was a haematoma of the abdominal wall in one patient (LMH/DHE). It was concluded that a single daily injection of 1500 aPTT U low molecular weight heparin combined with DHE is as effective and as well tolerated as two injections daily of 2500 IU standard heparin combined with DHE.

[Subclavian and axillary arteritis in Horton's disease and rhizomelic pseudopolyarthritis. 10 cases]. / Artérites sous-clavières et axillaires au cours de la maladie de Horton et de la pseudopolyarthrite rhizomélique. 10 observations.

Ten patients aged from 60 to 73 years presenting with Horton's disease or polymyalgia rheumatica had arteritis of the upper limbs. Asymptomatic abolition of pulse in the upper limbs (1 case) or claudication at rest or exercise (9 cases) and/or Raynaud's phenomenon (5 cases) preceded (4 cases) or accompanied (1 case) the discovery of giant cell arteritis, or complicated the reduction or discontinuation of corticosteroid therapy. Diagnosis rested on the regular association of an inflammatory syndrome with multiple arterial tapered stenoses and/or arterial thrombosis in the post-vertebral subclavian, axillary or brachial arteries and, chiefly, on the demonstration (in 7 cases) of a giant cell granuloma at biopsy of the temporal artery. Corticosteroid therapy (1 mg/kg/24 h in 8 cases and 0.5 mg/kg/24 h in 2 cases) initially combined with anticoagulants in 4 cases resulted in rapid regression of ischaemic and systemic signs in all patients, thus avoiding surgical revascularization of the upper limbs.

[Transcutaneous measurement of the partial pressure of the oxygen. Theoretical bases and hemodynamic significance]. / Mesure transcutanée de la pression partielle d'oxygène. Bases théoriques et signification hémodynamique.

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.

[The venous-arteriolar reflex]. / Le réflexe veino-artériolaire.

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.

[Determination of the amputation level by transcutaneous PO2 measurement and distal arterial systolic pressure]. / Détermination du niveau d'amputation par la mesure transcutanée de la PO2 et la pression artérielle systolique distale.

Transcutaneous oxygen partial pressure measurement (TcPO2) using a polarographic probe heating the skin at 44 degrees C provides informations about the capacity of blood to supply skin with oxygen. As oxygen is necessary for tissue survival, TcPO2 could constitute an adequate parameter for the determination of an amputation level. Among 67 amputations performed between 1983 and, 1984, we included in this study 34 patients (35 amputations), in whom TcPO2 was preoperatively measured (24 males, 10 females, mean age 67 years, range 19-86 years). Twenty two were diabetics. Twenty patients suffered from severe ischemia (stage Fontaine 4); 13 patients suffered from chronic diabetic lesions or/and osteomyelitis and two patients suffered from frostbite. The follow-up period lasted until operative wound was healed or a more proximal amputation was undertaken (mean 2.5 months, range 15 days to 10 months). Five operative wounds did not heal, so that a more proximal amputation was undertaken. TcPO2 was below 20 mm Hg in 3 of these 5 patients. TcPO2 was above 20 mm Hg in 24 among 30 patients in whom operative wound healed. When TcPO2 is above 20 mm Hg, the probability of operative wound healing is 92%. When TcPO2 is below 20 mm Hg, the risk of a more proximal amputation is 33%. Distal systolic blood pressure has no predictive value. It is concluded than when TcPO2 is above 20 mm Hg, the probability of healing of operative wound is clinically acceptable. When TcPO2 is below 20 mm Hg, 1 of 3 patients will be reamputated at a more proximal level, but healing does occur in 66% of patients.

[Prospective evaluation of specialized consultations in a geriatric university hospital]. / Evaluation prospective des consultations spécialisées dans un hôpital universitaire de gériatrie.

In a prospective study carried out over a 3 month period we analysed the views of consultants and residents taking part in 771 consultations to patients admitted to the Geriatric University Hospital of Geneva with the help of visual analogue scales. 27 medical subspecialties were involved. Both consultants and residents agreed that most of the consultations were useful for the elderly patient and for postgraduate teaching and learning. But the residents thought that consultations were more important for the patients' welfare than for the residents' education. Residents showed a tendency to underestimate crucial aspects of geriatric medicine (in particular the autonomy of the elderly patient) in preference to more "classical" medical preoccupations (diagnosis and treatment). Consultants were aware of the specificity of geriatric pathology but restricted their teaching during the intervention to what was requested by the resident.