Methodology of management of dredging operations II. Applications

This paper presents the new methodology of management of dredging operations. Derived partly from existing methodologies (OECD, PNUE, AIPCN), it aims to be more comprehensive, mixing the qualities and the complementarities of previous methodologies. The application of the methodology has been carried out on the site of the Port of Dunkirk (FRANCE). Thus, a characterization of the sediments of this site has allowed a zoning of the Port to be established in to zones of probable homogeneity of sediments. Moreover, sources of pollution have been identified, with an aim of prevention. Ways of waste improvement have also been developed, to answer regional needs, from a point of view of competitive and territorial intelligence. Their development has required a mutualisation of resources between professionals, research centres and local communities, according to principles of industrial ecology. Lastly, a tool of MultiCriteria Decision-Making Aid (M.C.D.M.A.) has been used to determine the most relevant scenario (or alternative, or action) for a dredging operation intended by the Port of Dunkirk. These applications have confirmed the relevance of this methodology for the management of dredging operations.

Methodology of management of dredging operations I. Conceptual developments

This article presents a new methodology for the management of dredging operations. Partly derived from existing methodologies (OECD, UNEP, AIPCN), its aim is to be more complete, by integrating the qualities and complementarities of former methodologies. Moreover, it was carried out in a context of sustainable development. Indeed, it supports, according to a framework of industrial ecology, the development and the implementation of solutions of waste improvement of dredged materials, in order to minimize the environmental impact of dredging. It also uses a tool of MultiCriteria Decision-Making Aid (M.C.D.M.A.), in order to integrate local characteristics. In addition, this tool, called DRAGSED, allows to a dialogue to be established between all the parties concerned with a dredging project (harbour's authorities, industrialists, municipalities, administrations, populations, associations,...). Thus, the implementation of this methodology enables consensus to be reached for the dredging solution retained. It also proposes an environmental follow-up, which will allow an evaluation during its application.

Clinical characteristics at initial presentation and impact of dual therapy on the outcome of bacteremic Streptococcus pneumoniae pneumonia in adults

BACKGROUND

Approximately 10% of patients hospitalized with community-acquired pneumonia (CAP) are bacteremic. Bacteremic Streptococcus pneumoniae pneumonia (BSPP) is the number one cause of mortality, representing up to 70% of all CAP deaths. In fact, all CAP guidelines have identified this issue as one of the most important issues when establishing their recommendations.

OBJECTIVE

To assess the impact of dual antibiotic therapy in patients with BSPP.

PATIENTS AND METHODS

All cases of BSPP in patients 18 years of age and older who were hospitalized from 1995 to 2000 were retrospectively analyzed. The standard initial therapeutic regimen used was cefuroxime with or without a macrolide from 1995 to 1997, and ceftriaxone and azithromycin or clarithromycin from 1998 to 2000. During the 1995 to 1997 period, only 16% of the patients initially received a macrolide, whereas all patients in the 1998 to 2000 period received a macrolide at admission.

RESULTS

Ninety-five patients (49 men, 46 women) with a mean age of 63 years (range 20 to 98 years) were included in the present study. The mean pneumonia severity index at admission was 113 for the monotherapy cohort and 114 for the dual therapy group. At admission, 30.5% of patients had a leukocyte count greater than 20 109/L, 11.5% had a systolic blood pressure less than 90 mmHg, 44.2% had a respiratory rate greater than 30 breaths/min and 33.6% had nausea/vomiting, necessitating some form of therapy or preventing the patient from eating. In addition, 16.8% had no fever at admission. Overall, 72.5% became afebrile within 48 h. Fifteen (15.8%) patients died (four within the first 72 h). The mortality rate was significantly higher in the monotherapy group (11 of 42 patients; 25.6%) than in the dual therapy cohort (four of 53 patients; 7.5%) (OR 0.23; 95% CI 0.07 to 0.74). Antibiotic resistance was not associated with increased mortality.

CONCLUSION

The combination of ceftriaxone plus a macrolide significantly reduced the mortality rate compared with monotherapy (cefuroxime) in patients with CAP that have the highest mortality rate.

Transitory or permanent regular wide QRS complex tachycardia induced by atrial stimulation in patients without apparent heart disease. Significance

OBJECTIVES

The purpose of the study was to evaluate the frequency of transitory or permanent bundle branch block (BBB) associated with a paroxysmal tachycardia induced by atrial stimulation in patients without heart disease and its significance.

METHODS

Esophageal atrial stimulation was performed in 447 patients suspected to have supraventricular tachycardias (SVT). Sustained regular tachycardia was induced in all of them but three, either in control state (75%) or after administering isoproterenol. In 346 patients, only narrow complex SVTs were induced (77%); in 259 of them, the reentry occurred in the AV node and in remaining patients within a concealed accessory pathway. In 62 patients, a transitory functional BBB was recorded at the onset of the tachycardia (14%). In 33 of them, the reentry occurred in the AV node and in the remaining 29 patients within a concealed accessory pathway. In 36 patients (8%), a permanently wide QRS complex tachycardia was induced. Three patients had also inducible narrow complex SVT. Atrial pacing induced a BBB similar to the aberrancy in tachycardia in 22 patients: the reentry occurred in the AV node in 17 patients, within a concealed accessory pathway in three patients and in a Mahaim bundle in two patients. In other patients, QRS complex remained normal during atrial pacing: all 14 patients had a ventricular tachycardia (VT), either a verapamil-sensitive VT (n = 7) or catecholamine-sensitive VT (n = 4) or bundle branch reentry (n = 3). Followed from 2 to 12 years, the prognosis of these patients was excellent.

CONCLUSION

Transitory BBB at the onset of an SVT is noted in 14% of the population, is more frequent in patients with accessory pathway reentrant tachycardia, but is helpful for this diagnosis in only 12% of cases. A regular tachycardia with permanent left or right bundle branch morphology induced by atrial stimulation in a patient without heart disease and without BBB during atrial pacing is due to a VT even if this patient has also narrow complex tachycardias. This mechanism does not affect the excellent prognosis of this population.

Vesicles and particles of sodium bis(2-ethylhexyl) phosphate in binary and ternary systems

Vesicles were identified in aqueous solution of pure sodium bis(2-ethylhexyl) phosphate, a short branched chain surfactant. Superficial tension measurements show that the vesicles appear above a molality of 0.02 (0.69 %w). These aggregates are equilibrium structures. The "packing parameter' theory established by Israelachvili et al. allows the prediction of the occurrence of such vesicles. If an organic solvent, such as xylene or ethylhexanoate, is added to the binary system, a different type of aggregate appears, the size of which is determined by several methods including electron microscopy and light scattering. Interfacial tension measurements show that these aggregates would be expected to form above a molality of 0.02. According to our experimental results, the microstructure of these aggregates can be described as micelles and/or vesicles, swollen or not.

[Bidirectional ventricular tachycardia (arguments in favor of reentry)]

Bidirectional ventricular tachycardia, defined as the rapid alternation of the QRS complexes with successive opposing axial deviation, is a rare arrhythmia. In the rare cases which have undergone endocavitary investigations, an infrahisian origin has generally been proved. However, the mechanism of these tachycardias remains poorly understood and is discussed with respect to a new case. Bidirectional tachycardia occurred in a 79 year old woman with previous diaphragmatic and anterior wall infarction. It was a wide QRS tachycardia at 180/min with a succession of ventriculogrammes of opposing axis in the frontal plane and permanent right bundle branch block over the right precordium. The two types of tachycardia were observed, monomorphic type A or Type B or a combination of the two realising an A-B bidirectional tachycardia. The origin of these episodes, which occurred on a background of atrial tachycardia at about 100/min, was ventricular as shown by the absence of a His potential before the ventricular complexes in tachycardia. The presence of ventricular extrasystoles with relatively fixed coupling intervals, and the results of endocavitary investigation were suggestive of a reentry phenomenon ventricular extrastimuli were capable of transforming the bidirectional into monomorphic tachycardia and vice versa; this suggests that A was at times the origin of a reentry B, but protected by A, tachycardia B could be sustained. In the light of previously reported cases with documented endocavitary investigation and this new case, it seems possible to talk in terms of true "bidirectional ventricular tachycardia", a tachycardia whose mechanism is obscure but certainly not univocal.

[The myocardiopathies of hereditary neuro-muscular diseases]

This joint work has studied the cardiomyopathies occurring in hereditary neuro-muscular disorders (270 cases). The Duchenne type of disorder (74 cases) was responsible for asystole (4 cases), for cardiomegaly, and especially for abnormalities of the ECG (59 cases)--Q waves and large R waves in V1 and V6. The cardiomyopathy was of the hypokinetic type, with histological evidence of degeneration of the myocardial fibres. Dystrophia myotonica of Steinart (23 cases) caused conductive disorders (17 cases) which were either atrioventricular or intra-ventricular or both. Studies of the His pathway confirmed that these abnormalities were more diffuse in 5 cases. The main histological feature was interstitial fibrosis. There was a high risk of sudden death; ECG follow-up should be close. Friedreich's disease (20 cases) in its complete form led to later development of obstructive cardiomyopathy, with a systolic ejection murmur, cardiomegaly, and abnormalities of the ECG--left ventricular hypertrophy in the vertical axis, right ventricular and septal hypertrophy, repolarisation disorders similar to those found in coronary artery disease. Histology showed hypertrophy with degeneration of the myocardial fibres and interstitial fibrosis. This complete form was rare (7 cases out of 20); on the other hand, ECG abnormalites were very common (16 cases out of 20). The authors have tried to study the relationships between primary cardiomyopathies (50 cases) and peripheral neuromuscular disorders. 17 of the 39 peripheral muscle biopsies were abnormal, but a well-defined muscular dystrophy could not be found in them.