Norbert Vasile

Effects of Positive End-expiratory Pressure and Different Tidal Volumes on Alveolar Recruitment and Hyperinflation

BackgroundThe morphologic effect of positive end-expiratory pressure (PEEP) and of two tidal volumes were studied by computed tomography to determine whether setting the tidal volume (Vt) at the upper inflection point (UIP) of the pressure-volume (P-V) curve of the respiratory system or 10 ml/kg hav

Acute swelling of the limbs: magnetic resonance pictorial review of fascial and muscle signal changes

OBJECTIVEnThis pictorial review analyzes the magnetic resonance (MR) fascial/muscular changes in 69 patients referred as emergencies with acute swelling of the limbs (ASL) from various causes.nnnMETHODS AND MATERIALnA prospective MR imaging (MRI) study of 69 patients referred as emergencies for ASL was performed. Our population consisted of 45 patients with skin and soft-tissue infections (cellulitis and necrotizing fasciitis, and pyomyositis), six patients with soft-tissue inflammatory diseases (dermatomyositis, graft-versus-host disease), 11 patients with acute deep venous thrombosis, three patients with rhabdomyolysis, one patient with acute denervation and three other patients with rare diseases. Hematomas, tumorous or infectious bone involvement and soft-tissue tumors were excluded. All studies included spin echo T1-weighted images and spin echo T2-weighted images. Gadolinium-enhanced spin echo T1-weighted images were obtained when an abscess was suspected on T2-weighted images. Selective fat-saturated T1- and T2-weighted sequences were also used. MRI analysis was performed to obtain a compartmentalized anatomical approach according to the location of signal abnormalities in subcutaneous fat, superficial and deep fascia and muscle.nnnRESULTSnIn all patients with ASL, MRI demonstrated soft-tissue abnormalities involving subcutaneous fat, superficial fascia, deep fascia, or muscle. Although MR findings were non-specific, MRI appears sensitive for detecting subtle fascial and muscle signal changes.nnnCONCLUSIONSnIn skin and soft-tissue infections, MRI can be helpful for therapeutic management by determining the depth of soft-tissue involvement, particularly within fasciae and muscles, which is partly related to the severity of cellulitis with severe systemic manifestations. MRI can also aid the surgeon in diagnosing abscesses. In inflammatory diseases, MRI can determine the best site for biopsy and also monitor therapeutic response.

Magnetic Resonance Imaging of Penile Rupture: Aid to Diagnosis

We report on a patient with atypical clinical findings in whom magnetic resonance imaging confirmed the suspicion of penile rupture. The tear appeared as an obvious discontinuity of the low signal intensity of the tunica albuginea and was associated with a hematoma. We conclude that magnetic resonance imaging is useful for confirming the diagnosis of penile rupture when clinical findings are atypical, indicating surgical repair.

Prevention of thrombotic complications of the nephrotic syndrome by the low-molecular-weight heparin enoxaparin.

The nephrotic syndrome (NS) carries one of the highest risks of thrombotic complications. Consequently, over the last 15 years, some nephrologists have treated patients risk (i.e. those with albuminemia < 20 g/l and membranous nephropathy) with anticoagulants: either subcutaneous heparin (Kakkar protocol) or antivitamin K. Low-molecular-weight heparin (LMWH) has a longer plasma half-life and better bioavailability than standard heparin and can thus be administered as a single daily injection. LMWH also carries a lower risk of hemorrhage. We prospectively studied the safety and efficacy of the LMWH Enoxaparin for preventive anticoagulation in NS. In a preliminary study, 10 adult nephrotic patients with biological markers of thrombosis risk (severe hypoalbuminemia and/or anomalies of the fibrinolytic pathway and/or deficiency in coagulation inhibitors) were given 40 mg (4,000 U) of Enoxaparin daily for at least 3 months; 3 patients were treated for 3 months, 1 for 6 months and 6 for 12 months. Patients were assessed for silent thrombosis, using renal vein Doppler ultrasonography, lower leg vein Doppler ultrasonography and lung ventilation-perfusion scintigraphy, before entry to the trial and subsequently at 3-month intervals. As LWMH caused no obvious side effects and no thrombosis was observed during the pilot study, we then placed 55 adult nephrotic patients free of thrombosis on the same treatment. Patients were seen according to the usual calendar required by their individual illnesses. At each examination, patients were assessed for clinical signs and symptoms of thrombosis and side effects; plasma D-dimer and urinary fibrin-fibrinogen degradation products were also measured at each visit.(ABSTRACT TRUNCATED AT 250 WORDS)

Intraarticular tolerability and kinetics of gadolinium tetra-azacyclododecane tetraacetic acid

RATIONALE AND OBJECTIVESnWe assessed the tolerability and the intraarticular kinetics of gadolinium tetra-azacyclododecane tetraacetic acid (Gd-DOTA) using magnetic resonance (MR) imaging.nnnMETHODSnTwelve of 18 dogs received an intraarticular injection of Gd-DOTA solution. Pathologic examination of all joints was performed with assessment of Gd-DOTA bone absorption. Effects of Gd-DOTA on chondrocyte viability and proliferation in vitro were determined using cultures of rabbit chondrocytes. Four dogs underwent MR imaging of the stifle joint before and after intraarticular injection of 0.8 ml Gd-DOTA at a concentration of 2 mmol/l (300 mOsm/l). Intraarticular kinetics of Gd-DOTA were determined from quantitative measurements using repeated sagittal spin-echo T1-weighted images.nnnRESULTSnNo microscopic changes of the joints or Gd-DOTA bone absorption were detected. No cytotoxicity for chondrocytes was observed at a concentration of 5 mmol/l, but a decreased cell count was observed at a high concentration (50 mmol/l). The intraarticular Gd-DOTA concentration decreased with time according to a logarithmic curve with an intraarticular half-life of 103-152 min (M = 127 min).nnnCONCLUSIONnGd-DOTA is a safe intraarticular contrast agent with a long half-life in the joint cavity.

Mri of Intralesional Hemolysis in Focal Nodular Hyperplasia of the Liver

A case of Kasabach-Merritt syndrome caused by focal nodular hyperplasia of the liver is presented with atypical magnetic resonance findings due to intratumoral hemosiderin deposition. The high sensitivity of magnetic resonance imaging for iron served to identify the site of hemolysis in this patient with Kasabach-Merritt syndrome.

Effects of Positive End-Expiratory Pressure and Different Tidal Volumes on Alveolar Recruitment and Hyperinflation

Background The morphologic effect of positive end-expiratory pressure (PEEP) and of two tidal volumes were studied by computed tomography to determine whether setting the tidal volume (Vt) at the upper inflection point (UIP) of the pressure-volume (P-V) curve of the respiratory system or 10 ml/kg have different effects on hyperinflation and alveolar recruitment. Methods Alveolar recruitment and hyperinflation were quantified by computed tomography in nine patients with the acute respiratory distress syndrome (ARDS). First, end expiration was compared without PEEP and with PEEP set at the lower inflection point of the P-V curve; second, at end inspiration above PEEP, a reduced Vt set at the UIP (rVt) and a standard 10 ml/kg Vt (Vt) ending above the UIP were compared. Three lung zones were defined from computed tomographic densities: hyperdense, normal, and hyperinflated zones. Results Positive end-expiratory pressure induced a significant decrease in hyperdensities (from 46.8 +/- 18% to 38 +/- 15.1% of zero end-expiratory pressure (ZEEP) area; P < 0.02) with a concomitant increase in normal zones (from 47.3 +/- 20.9% to 56.5 +/- 13.2% of the ZEEP area; P < 0.05), and a significant increase in hyperinflation (from 8.1 +/- 5.9% to 17.8 +/- 12.7% of ZEEP area; P < 0.01). At end inspiration, a significant increase in hyperinflated areas was observed with Vt compared with rVt (33.4 +/- 17.8 vs. 26.8 +/- 17.3% of ZEEP area; P < 0.05), whereas no significant difference was observed for both normal and hyperdense zones. Conclusions end-expiratory pressure promotes alveolar recruitment; increasing Vt above the UIP seems to predominantly increase hyperinflation.