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Objective To confirm in vivo the hypothesis that hemofiltration with a large pore membrane can achieve significant cytokine clearance.Method We used a well-known animal model of endotoxinic shock (0.5 mg/kg of lipopolysaccharide from Escherichia Coli over a period of 30 mins). Six pigs were hemofiltrated for 3 hours with a large pore membrane (78 Å pore, 80 kDa cut off) (Sureflux FH 70, Nipro, Osaka, Japan). The ultrafiltration rate was 45 ml/kg/min. Samples were taken from arterial, venous line and in the ultrafiltrate at T120 and T240. We measured concentrations of interleukin 6, interleukin 10 and albumin.Results At T120 and T240, the IL-6 clearances were 22 ± 7 and 15 ± 3 ml/min, respectively. The IL-6 sieving coefficients were 0.97 and 0.7 at T120 and T240, respectively. At T120 and T240, the IL-10 clearances were 14 ± 4 and 10 ± 7 ml/min, respectively. The sieving coefficients were 0.63 and 0.45 at T120 and T240, respectively. The concentrations of IL-6 and IL-10 were the same at T0 and T240. At T60 and T240, the plasmatic albumin concentrations were 24 ± 4 g/L and 23 ± 4 g/L, respectively (p = 0.13).Conclusions In this animal model of endotoxinic shock, we confirm the high cytokine clearance observed when hemofiltration is applied to a large pore membrane. The loss of albumin seems negligible. The impact of such clearances on hemodynamic stability and survival remains to be proved.

The aim of this study was to investigate left ventricular contractility and energetic cost of cardiac ejection under conditions of acute increase in aortic compliance.

The problem of the parameter identification of the three-element windkessel model is studied. Minimization by least-square technique - LSQ - in time domain and frequential techniques -FFT - are compared.Continuous pressure and flow curves were recorded in the proximal aorta of an open chest dog.Comparison shows very high correlations between the parameter estimations obtained by LSQ and FFT methods. However, systematic differences appear between the calculated values, but do not seem to endanger physiological interpretation of the results.

In 11 anaesthetised pigs the accuracy of the three-element (WK3) and the four-element (WK4) Windkessel models to describe hemodynamic properties of the pulmonary circulation was compared during six different experimental conditions increasing pulmonary arterial pressure: increase in left atrial pressure, increase in alveolar pressure, increase in pulmonary blood flow, endotoxin shock, mechanical obstruction of left pulmonary artery or histamine infusion. Our results showed that WK4 fitted better the data than did WK3 because values of 1- R 2 decreased from 6 percent (WK3) to 1.4 percent (WK4) when WK4 was used (P < 0.0005). 1- R 2 was an adequate marker of the accuracy of the linear regression used to solve equations of both models. Compliance values estimated by WK4 were decreased by 5 comparatively to WK3 (P = 0.008). However, this difference can be considered as not physiologically relevant. Values of characteristic resistance corresponding to R 1 (L/R 2 C) in WK4 and to R 1 in WK3 were not different (P = 0.22). The relative changes in R 1, R 2, and C observed due to the different experimental conditions were comparable regardless of the model. In conclusion, the conversion of WK3 in WK4 by adding an inductance, whose physiological meaning is not clear, resulted in an increased statistical accuracy of the model, but did not seem to have relevant influence on parameters or their evolution during experimental conditions.

Arterial tissue has been analysed by 31P-, 13C-, 23Na- and 1H-NMR spectroscopyRabbit thoracic aortas were mounted on a system with perfusate circulation and studied in basal conditions. Phosphorus spectra remained stable for hours and showed low levels of phosphocreatine (PCr) compared to skeletal, cardiac or even to nonvascular smooth muscle. Significant levels of sugar-phosphates (SP), phosphodiesters (PDE) were detected, as well as occasionally a peak in the diphosphodiester region Experiments with phosphate-free perfusate demonstrated a very low level of in tracellular inorganic phosphate. As expected from previous data, free ADP levels in tonic arterial tissue were found much higher than in any other muscle.Addition of norepinephrine into the perfusate induced transient decrease in ATF and PCr levels, associated with an increased production of phosphorylated intermediates.At the early stage of renovascular hypertension, aortic energetic pattern was characterized by an increased ADP/ATP ratio.Natural abundant 13C spectra were recorded from dog aortic fragments and showed mainly resonances attributed to fatty components.After addition of a shift-reagent, dysprosium tripolyphosphate, 23Na-NMR allowed separation of intra- and extracellular Na of perfused rabbits aortas.Proton NMR of lyophilized aortic fragments revealed several peaks originating from biologically relevant molecules, lactate, creatine, taurine…These preliminary data demonstrate the feasability of multinuclear NMR spectroscopy of vascular tissue and are suggestive of the potential of the method when it will be combined with monitoring of functional parameters.

Compounds with phosphodiesterase inhibitory activity stimulate myocardial contractility by increasing the intracellular cyclic AMP concentrations. They can also increase Ca2+ entry and inhibit Ca2+ sequestration by the sarcoplasmic reticulum. Xanthines produce bronchodilation with associated venous and arteriolar dilation. However, their use is limited by their positive chronotropic effect and other side effects at high plasma levels. New phosphodiesterase inhibitors have been perfected: they are more specific with little chronotropic effect.Increasing the sensitivity of the myofilaments to Ca2+, and other unclear mechanisms may be involved in the inotropic action of these drugs.These new promising active compounds are described and discussed. They augment cardiac performance and improve regional distribution of blood flow and symptoms.However, their influence on the long-term outcome of severe heart failure has yet to be determined.

The haemodynamic effects of an optimal dose of dobutamine (DUo) (6.7 ± 4.2 μg kg-1 min-1) and the combination of this optimal dose minus 2.5 μg kg-1 min-1 of dobutamine (DU) plus dopamine 2.5 μg kg-1 min-1 (DA) were studied in a first group of 12 consecutive patients with acute myocardial infarction (AMI) and cardiac failure (CF). DUo decreased pulmonary wedge pressure from 23.5 to 16 mm Hg (P < 0.01), systemic vascular resistance from 1 774 to 1 417 dynes s cm-5 (P < 0.01). DUo increased cardiac output from 3.21 to 4.55 litres/min (P < 0.01) and urinary flow (UF) from 20 to 68 ml/h (P < 0.01). Heart rate and blood pressure did not change significantly. DUo - DU + DA significantly increased UF from 68 to 107 ml/h (P < 0.05) while the other parameters remained unchanged with respect to DUo. The positive effect of DA on UF was confirmed in a second group of 12 consecutive patients by comparing the successive effects of DA + DUo and DUo + DU: all previously described parameters remained unchanged except UF which decreased from 107 to 65 (P < 0.01). We conclude that in patients with CF and Ami, association of DA and DUo is useful in obtaining both inotropic and diuretic effects.

The dopamine α- and β-adrenoceptor dose-response curves are investigated in four patients who are exempt from cardiovascular disease.A dose-related increase in CO, HR and SV is observed with infusion rates of up to 3 μg kg-1 min-1.With concentrations > 10 μg kg-1 min-1, both BP and SVR increase. Low-dose dopamine infusion < 3 μg kg-1 min-1 is investigated in ten other patients. With this infusion rate, a selective renal vasodilation is induced without peripheral or cardiac β-adrenoceptor activation. Dopamine is responsible for an increase in diuresis FENa, GFR and RBF. These properties are indicated in renal failure, and when haemodynamic support is required in cardiac failure, if an infusion rate of up to 10 μg kg-1 min-1 is able to reverse cardiac insufficiency.

In anaesthetized dogs, low dose endotoxin perfusion (250 ng kg-1 min-1 during 20 min) resulted, after a delay of 15-40 min, in a decrease of mean arterial pressure (from 127 to 106 mm Hg), a transient increase in cardiac output (from 2.2 to 2.9 L/min), a fall of systemic vascular resistance (from 60 to 41 mm Hg L-1 min-1) and an increase in heart rate (from 109 to 156/min). This haemodynamic pattern is similar to the so called "hyperdynamic" initial phase of clinical septic shock.RésuméChez le chien anesthésié, la perfusion de faibles doses d'endotoxine (250 ng/kg, pendant 20 min), provoque, avec une latence de 15 à 40 min, une diminution de la pression artérielle moyenne (de 127 à 106 mm Hg), une augmentation transitoire du debit cardiaque (de 2.2 à 2.9 L/min), une chute de la résistance périphérique (de 69 à 41 mm Hg L-1 min-1) et une élévation de la fréquence cardiaque (de 109 à 156/min). Cette configuration hémodynamique rappelle celle de la phase initiale du choc septique chez l'homme (choc dit «hyperdynamique»).

To the best of our knowledge, no case of ether-induced acute respiratory distress syndrome (ARDS) has been published as yet. A 36-year-old female developed pneumonitis which showed all the characteristics of a chemical-associated ARDS due to intravenous self-administration of ether: the hemodynamic investigation demonstrated a normal blood flow pattern with low left-heart filling pressure while the anteroposterior roentgenogram evidenced disseminated bilateral lung edema. Advanced symptomatic respiratory support including inhaled nitric oxide and steroidal anti-inflammatory use was the treatment of choice.

Conclusion The ratio of mean aortic pressure and mean aortic flow does not completely describe the mechanical properties of the arterial system. Using the impedance spectrum, a shift of the resistances to the small vessels was observed while total resistance and arterial tonus were unchanged during the application of Peep.