Can environmental contamination be explained by particular traits associated with patients?

BACKGROUND: Little is known about patient risk factors associated with environmental contamination. AIM: To evaluate the rate of environmental contamination and to investigate individual risk factors. METHODS: A prospective cohort study was conducted. Each day, five rooms occupied by patients were selected. Five critical surfaces were systematically swabbed twice a day before and after cleaning. Clinical characteristics of all patients were collected. Logisitic regression was performed to evaluate the association between environmental contamination and patients' characteristics. FINDINGS: A total of 107 consecutive patients were included and 1052 environmental samples were performed. Nineteen (18%) patients were known previously colonized/infected with a multidrug-resistant organism (MDRO). Respectively, 723 (69%) and 112 (11%) samples grew with ≥1 and >2.5 cfu/cm2 bacteria, resulting in 62 (58%) contaminated rooms. Considering positive samples with at least one pathogenic bacterium, 16 (15%) rooms were contaminated. By univariate and multivariate analysis, no variables analysed were associated with the environmental contamination. Considering contaminated rooms with >2.5 cfu/cm2, three factors were protective for environmental contamination: known MDRO carriers/infected patients (odds ratio: 0.25; 95% confidence interval: 0.09-0.72; P = 0.01), patients with urinary catheter (0.19; 0.04-0.89; P = 0.03) and hospitalization in single room (0.3; 0.15-0.6; P < 0.001). CONCLUSION: This study was conducted in a non-outbreak situation and showed a low rate of environmental contamination with pathogenic bacteria. Only 11% of environmental samples grew with >2.5 cfu/cm2, and they were related to non-pathogenic bacteria. No risk factors associated with environmental contamination were identified.

Enhanced strand break induction of DNA by resonant metal-innershell photoabsorption.

We determined the number of single and double strand breaks (ssb and dsb) in a DNA-chloroterpyridine platinum complex induced by resonant photoabsorption in the L(III) innershell of a platinum atom. The number of ssb and dsb were measured in supercoiled plasmids (AG30) versus the chloroterpyridine platinum concentration, i.e., the ratio of intercalated molecules to the number of phosphate sites in DNA. A significant increase in the number of ssb and dsb was observed when the DNA contained intercalated molecules. This technique is an efficient way to induce ssb and dsb triggered by the atomic Auger effect.

Strand break induction by photoabsorption in DNA-bound molecules.

Dried samples of a DNA-chloroterpyridine platinum complex were irradiated with monochromatic X rays tuned to the photoabsorption resonance of the L(III) inner shell of the platinum atom. The number of single- and double-strand breaks (SSBs and DSBs) triggered by the Auger effect in supercoiled DNA plasmids was measured by the production of circular nicked and linear forms. To probe the specific contribution of the L(III) inner-shell excitation of the platinum atom, photon wavelengths were tuned on the resonance energy (on peak) and below (off peak). The quantum yields of the resonance radiation were typically found to be 11 for the SSBs and 1 for the DSBs. The DSB-to-SSB ratio increased by 20% when switching from off-resonance to on-resonance irradiation.

DNA breakage upon K-shell excitation of phosphorus as a model for direct effects in radiation biology.

Single-strand breaks (SSBs) and double-strand breaks (DSBs) induced in DNA under phosphorus K-shell resonant absorption have been studied using supercoiled plasmids. The kinetics of the production of SSBs and DSBs exhibits a linear and a quadratic dependence, respectively, on photon fluence. Cross sections and quantum yields have been measured. The resonant photoexcitation of the phosphorus atoms was found to increase the DSB/SSB ratio compared to the off-resonance excitation. This enhancement factor can be related to the measured enhancement of the rate of cellular death and gene mutation in yeast under similar experimental conditions reported previously in the literature. Such resonant excitation of a specific atom belonging to DNA turns out to be an elegant method to investigate pure direct effects.

[Autologous transfusion in heart surgery (apropos of 74 patients)]. / Transfusion autologue en chirurgie cardiaque (a propos de 74 patients).

The present study uses three techniques of autotransfusion in heart surgery under ECC: peroperative and post-ECC transfusion of blood removed after induction of anaesthesia (group I: 25 patients); postoperative transfusion of extravasated thoracic blood (group II: 24 patients) and a combination of the two (group III: 25 patients). Postoperative bleeding was comparable in all groups; A subset likely to haemorrhage made up of patients who had lost more than one litre of blood was isolated and demonstrated a reduction in the number of homologous red cell concentrates needed for the autotransfused population in comparison with the controls (2.4 +/- 2.6 vs 5.7 +/- 3.5 red cell concentrates, p less than 0.05) and was particularly marked in Group II patients who received 1.9 +/- 2.2 homologous red cell concentrates. None of the techniques caused any side-effects. Combination of the two autotransfusion techniques in heart surgery does not secure any additional advantages compared with postoperative autotransfusion alone.

Effects of halothane on human and rat hepatocyte cultures.

The aim of this study was to investigate direct cytotoxicity to human and rat hepatocytes in primary culture from halothane and compare it with that of isoflurane, which is known to be minimally metabolized and less toxic in vivo. Both human and rat parenchymal cells were isolated by the two-step collagenase perfusion method and after attachment to plastic were incubated with either volatile anesthetic for 24 h. All the cultures were maintained in 20% O2 condition and were not induced prior to anesthetic treatment. Temperature, atmosphere conditions, and anesthetic concentrations were kept constant during the study period. Evaluation of cytotoxicity was based on morphologic, biologic (determination of both extracellular and intracellular lactate dehydrogenase activity), and metabolic (protein synthesis and secretion) end points. Protein synthesis and secretion rates were found to be the most sensitive parameters in hepatocyte cultures from both species. Protein synthesis was inhibited by 18% and protein secretion by 50% in the presence of 1 and 1.25 mM halothane, respectively, in human cell cultures (P less than 0.05). With 1.25 mM halothane intracellular lactate dehydrogenase was also decreased; lactate dehydrogenase leakage and morphologic alterations were detected only beyond 5 mM halothane. By contrast, in rat hepatocyte cultures protein secretion was inhibited by 26% and protein synthesis by 20% in the presence of 0.1 and 0.75 mM halothane, respectively, whereas morphologic alterations and a 37% lactate dehydrogenase leakage increase were observed with the concentration of 1 mM (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

[Effects of propofol on intraocular pressure in surgery of strabismus in children]. / Effets du propofol sur la pression intraoculaire dans la chirurgie du strabisme de l'enfant.

Propofol was assessed for eye surgery in 20 children. ASA group I or II, 2-14 year-old, randomly assigned to 2 equal groups. Premedication, analgesia and muscle paralysis were similar in both groups. Group P patients were given an induction dose of 4 mg.kg-1 propofol, followed by an infusion of 15 mg.kg-1.h-1 for the first half hour, and then 10 mg.kg-1.h-1 to maintain anaesthesia. Group C patients were given 10 mg.kg-1 thiopentone for induction and halothane for maintenance. The quality of anaesthesia was assessed by monitoring adverse effects, heart rate, blood pressure, the length of anaesthesia, the delay of the first spontaneous breath and eye opening, and extubation. Intraocular pressure was measured before and 3 min after intubation, and 5 min after extubation. The quality of anaesthetic induction and maintenance were very similar in both groups. Pain occurred more frequently at the injection site with propofol (p less than 0.01). Children in group P recovered more quickly, and extubation was possible much earlier in this group (p less than 0.05). However, restlessness was significantly more frequent in group P (n = 9) than in group C (n = 1) (p less than 0.01). Systolic, diastolic blood pressure and heart rate were significantly lower in group P (p less than 0.05; 0.001; 0.001 respectively). No significant decrease in intraocular pressure in both groups was observed. The use of propofol for eye surgery in children is acceptable, despite some restlessness during recovery.

[Liver transplantation in metastases of carcinoid tumor]. / Transplantation hépatique pour métastases d'une tumeur carcinoïde.

A 30-year-old woman underwent a liver transplantation for metastasis of a carcinoid tumor of the midgut previously resected. Operative manipulation of the liver resulted in arterial hypotension, tachycardia, high pulmonary arterial pressure, oedema of the face and peripheral cyanosis, although the patient was given somatostatin (Modustatine, Clin-Midy) (300 micrograms a hour) prior to the procedure. The improvement of the symptoms was obtained by the increase of somatostatin infusion rate to 750 micrograms a hour associated with dopamine (6 micrograms.kg-1.min-1) and fluid replacement. The diagnosis of carcinoid syndrome is discussed. This unusual observation stresses the difficulty in preventing and/or treating a carcinoid shock. If somatostatin seems to be the treatment of choice of such a syndrome, its role in that case was limited.

[Oral contraception and surgery]. / Contraception orale et chirurgie.

PIP: Oral contraceptives (OCs) and surgery are both recognized risk factors for thromboembolism. Observation of a postoperative deep venous thrombosis and pulmonary embolism in a 21-year-old OC user prompted the authors to define the risk of OC use in surgical patients through a review of the literature. The patient had no other relevant risk factors except a moderate smoking habit. Surgery increases risk of thromboembolism because of the postoperative hypercoagulation state with declines in AT III, elevation of fibrinogen and products of degradation of fibrin, decline of plasminogen, and elevation of antiplasmin. The risks are greater in the immobile postsurgical phase and are increased as well by direct vascular lesions during surgery. Estimates of rates of deep venous thrombosis are very variable according to different authors because of the difficulties of diagnosis, heterogeneity of risk factors encountered, and variety of prophylactic methods employed. The most thrombogenic surgery is believed to be that on the legs; 1 literature review produced a range of estimates from 45-70% without prophylaxis and with 2% involving fatal pulmonary emboli. Another study estimated the risk of deep venous thrombosis at 2% for young subjects in good health undergoing minor surgery lasting less than 30 minutes and at 10-40% for subjects over 40 undergoing moderately serious general surgical procedures. No ideal method of prevention has been found that is well accepted by patients, nurses, and physicians. OC use entails multiple physiopathologic modifications including among others alterations of the vascular walls with endothelial proliferation and/or thickening of the media, increased blood viscosity, hyperaggregability of platelets, and increases in certain coagulation factors. Synthetic estrogens play the major role in modifications but progestins diminish venous tone and increase stasis. Large epidemiologic studies in the US and Great Britain found a significantly increased thromboembolic risk in OC users beginning in the 1st month of use and persisting until 3-4 weeks after termination of treatment. Most authors believe that OC use increases the postsurgical risk of thromboembolism by a factor of about 3. More selective choice of OC users, reduced estrogen doses, and better surveillance of users appear to have diminished the risk of thromboembolic disease with OC use. But unfortunately there are no sure predictors of thromboembolic disease. All authors recognize the reversibility of modifications caused by OCs on hemostasis by 4 weeks after termination. If therefore is recommended that OC use be interrupted 1 cycle before surgery.^ieng

[2 cases of the HELLP (Hemolysis Elevated Liver Low Platelet) syndrome]. / A propos de deux observations de "HELLP (Hemolysis Elevated Liver Low Platelet) syndrome".

Recently described by Weinstein, the "HELLP syndrome" is an entity of the pre-toxemic syndrome; its precise physiopathological mechanism, related to a thrombotic micro-angiopathy, is still not clearly established. Therefore, the treatment remains symptomatic, associated with the treatment of the toxemia. Two cases occurring in twin pregnancies are reported.

[Digestive stress hemorrhage. Physiopathology and prevention]. / Les hémorragies digestives de stress. Physiopathologie et prévention.

Lesions of the gastroduodenal mucosa are seen very early on in virtually 100% of patients suffering from organ failure. Bleeding, even if it is only occult, defines acute stress-induced gastrointestinal tract bleeding (SGIB). The rates of SGIB vary according to the inclusion criteria: 13 to 100% microscopic SGIB, 2.3 to 9.5% haemorrhage with blood transfusion and/or shock. Gastrointestinal bleeding does not really influence the death rate of patients with SGIB (0 to 5% increase). Damage to the gastric mucosa may be due to an intraluminal aggression, and/or decreased mucosal and mural defence mechanisms. H+ ions and bile salts are mostly responsible for the former. Physiological quantities of H+ ions may be sufficient, as their abnormal diffusion into the gastric mucosa will reduce the mucosal pH (pHm), which is itself sensitive to microcirculatory modifications and systemic acidosis. There is a good correlation between bleeding and pHm. Bile salts are involved because of the usual increase in frequency and volume of gastric biliary reflux due to stress. Surfactant, mucosal alkaline layer and the microcirculation are all involved in gastric protection. The PGE2 synthetized by the gastric mucosa have a favourable influence on these 3 mechanisms. Changes in microcirculation and hypoxia are the predominant factors involved in stress-induced mucosal damage. The prevention of SGIB relies on the treatment of risk factors, a reduction of intraluminal aggression, and the support and/or stimulation of gastric defence mechanisms. Antacids and anti-H2 drugs aim to neutralize most of the H+ ions, being more efficient than placebo in increasing gastric pH greater than 4, although anti-H2 agents are responsible of a greater number of failures. The non-homogenous character of the patient groups studied and the diagnostic methods, as well as the increasing lack of placebo groups in the published studies make the interpretation of the results rather risky. Antacids and anti-H2 drugs are more efficient than placebo, and equally efficient, in preventing overt SGIB. Efficiency is increased by giving anti-H2 drugs continuously, and antacids hourly. Other agents are thought to protect mucosal cells, probably increasing mucosal defences. Amongst them are the prostaglandins, the most interesting of which are still being investigated, and sucralfate. The latter molecule is as efficient as antacids and anti-H2 drugs, and does not alter gastric pH, so reducing the number of nosocomial pneumonias. Its reduced cost and easy administration make it, at the present time, the treatment of choice of SGIB. The few rare contraindications of sucralfate will justify the infusion of anti-H2 drugs in those patients at risk.

[Spontaneous rupture of an adenoma of the liver during pregnancy]. / Rupture spontanée d'un adénome du foie pendant la grossesse.

Must often reporting to an hepatic subcapsular hemorrhage with pre or true eclampsia, Spontaneous rupture of adenoma of the liver during pregnancy is unusual entity. Very exceptionally cases of rupture of anatomic hepatic lesion underlying had been reported. About a new case, diagnosis, physiopathologic and management problems are approached.

[Post-traumatic pneumatocele and hemato-pneumatocele of the lung. Apropos of 3 cases]. / Pneumatocèles et hémato-pneumatocèles post-traumatiques du poumon. A propos de 3 observations.

Pneumatocele and haemato-pneumatocele are air or air/fluid cavitary lesions which develop in the lung parenchyma after thoracic trauma. The formation of this lesion requires a direct violent impact on the pliable lung wall which explains its frequency in young adults. They are preferentially localised in the lung bases. The importance of associated lesions often marks the pneumatocele. Though rarely described, its frequency is certainly underestimated. If haemoptysis is the most frequent clinical sign it is the chest x-ray which demonstrates the early abnormality in the form of a rounded translucent image with a fine contour and variable diameter. The existence of a fluid level suggests the presence of blood (haemato-pneumatocele). The differential diagnosis with a localised pneumothorax, a diaphragmatic hernia and a pre-existing cystic lesion is easy as a rule but an evacuated pulmonary haematoma may lead to the discussion, especially as the mechanism of their formation may be the same. In isolation their clinical implications are minimal, their evolution favourable and after several weeks with a restitution of the integrity of the pulmonary parenchyma the absence of therapeutic intervention is justified.

[Prolonged intravenous infusion of morphine. Pharmacokinetic study]. / Perfusion intraveineuse prolongée de morphine. Etude pharmacocinétique.

Critically ill patients require optimal pain control without undesirable side-effects. Continuous intravenous morphine infusion is often chosen instead of the conventional intermittent administration. In the present study, the pharmacokinetic characteristics of morphine were studied in five subjects receiving a constant rate intravenous infusion with the attainment of a steady state. The plasma levels were compared with values derived from bolus intravenous administration in five other patients. The concentrations of unchanged morphine were determined in serum using high performance liquid chromatography with an electrochemical detector. The decay of plasma concentrations after a single dose fitted a triexponential function consistent with a three compartment pharmacokinetic model. Postinfusion plasma concentrations fitted a two compartment model. Derived values (mean +/- SEM) of total body clearance were significantly different between groups (p less than 0.05), while mean values of terminal elimination half-life (t 1/2 Kel) were similar. It was concluded that values of total distribution volume were significantly different. The extent of morphine distribution varied more than twofold between the two groups of patients. This was interpreted as a consequence of an important underestimation in the extent of distribution tissues after administration of a single dose.