Comparison of intensive-care-unit-acquired infections and their outcomes among patients over and under 80 years of age.

BACKGROUND: Patients aged >80 years represent a growing population admitted to intensive care units (ICUs). However, little is known about ICU-acquired infection (IAI) in this population, and the rate of invasive procedures is increasing. AIM: To evaluate the frequency and effects of IAI in elderly (≥80 years) and younger patients. METHODS: Retrospective evaluation of consecutive patients hospitalized for three days or more over a three-year period in an 18-bed ICU in an academic medical centre. FINDINGS: Elderly patients represented 18.9% of the study population. At admission, the mean number of organ dysfunctions was similar in elderly and younger patients. The use of invasive procedures was also similar in elderly and younger patients, as follows: invasive mechanical ventilation for more than two days, 67.4% vs 55%; central venous catheterization, 56.9% vs 51.4%; and renal replacement therapy, 17.6% vs 17.8%, respectively. The frequency of IAI was 16.5% in elderly patients and 13.9% in younger patients (P = 0.28), with 20.5 vs 18.9 IAI episodes per 1000 ICU-days, respectively (P = 0.2). A Cox model identified central venous catheterization and invasive mechanical ventilation for more than two days as independent risk factors for IAI. The associations between IAI and prolonged ICU stay, increased nursing workload, and ICU and hospital mortality rates were similar in elderly and younger patients. CONCLUSIONS: The frequency of IAI was similar in elderly and younger patients, as were the associations between IAI and length of ICU stay, nursing workload and ICU mortality in an ICU with a high rate of invasive procedures.

Mediastinitis due to Gram-negative bacteria is associated with increased mortality.

The aim of this study was to describe the features of a large cohort of patients with postoperative mediastinitis, with particular regard to Gram-negative bacteria (GNB), and assess their outcome. This bicentric retrospective cohort included all patients who were hospitalized in the Intensive Care Unit with mediastinitis after cardiac surgery during a 9-year period. Three hundred and nine patients developed a mediastinitis with a mean age of 65 years and a mean standard Euroscore of six points. Ninety-one patients (29.4%) developed a GNB mediastinitis (GNBm). Of the 364 pathogens involved, 103 GNB were identified. GNBm were more frequently polymicrobial (44% versus 3.2%; p <0.001). Being female was the sole independent risk factor of GNBm in multivariate analysis. Initial antimicrobial therapy was significantly more frequently inappropriate with GNBm compared with other microorganisms (24.6% versus 1.9%; p <0.001). Independent risk factors for inappropriateness of initial antimicrobial treatment were GNBm (OR = 8.58, 95%CI 2.53-29.02, p 0.0006), and polymicrobial mediastinitis (OR = 4.52, 95%CI 1.68-12.12, p 0.0028). GNBm were associated with more drainage failure, secondary infection, need for prolonged mechanical ventilation and/or use of vasopressors. Thirty-day hospital mortality was significantly higher with GNBm (31.9 % versus 17.0%; p 0.004). GNBm was identified as an independent risk factor of hospital mortality (OR = 2.31, 95%CI 1.16-4.61, p 0.0179).

Dynamical spin structure factor for the anisotropic spin-1/2 Heisenberg chain.

The longitudinal spin structure factor for the XXZ-chain at small wave vector q is obtained using Bethe ansatz, field theory methods, and the density matrix renormalization group. It consists of a peak with a peculiar, non-Lorentzian shape and a high-frequency tail. We show that the width of the peak is proportional to q2 for finite magnetic field compared to q3 for a zero field. For the tail we derive an analytic formula without any adjustable parameters and demonstrate that the integrability of the model directly affects the line shape.

Concordance of antibiotic prophylaxis, direct Gram staining and protected brush specimen culture results for postoperative patients with suspected pneumonia.

BACKGROUND AND OBJECTIVES: Antibiotic therapy alters the diagnostic value of protected brush specimens. With protected brush specimens alone, diagnosing pneumonia requires 24 or 48 h. Addition of direct Gram staining shortens this delay. Antibiotic prophylaxis, recommended after major surgery, may influence the contribution of Gram staining to diagnosing postoperative pneumonia. METHODS: During a 1-yr period, we retrospectively studied all patients on mechanical ventilation suspected of having postoperative pneumonia who had undergone fibreoptic bronchoscopy with protected brush specimens. Postoperative pneumonia was diagnosed when quantitative protected brush specimens culture results yielded 103 colony-forming units mL-1. RESULTS: Fifty patients were clinically suspected of having postoperative pneumonia after cardiac (n=42), vascular (n=5) or thoracic (n=3) surgery. Eleven (22%) samples were obtained during antibiotic prophylaxis. Twenty-two (44%) episodes were microbiologically proven. Gram-stain sensitivity was 95.5%, with 82.1% specificity, 80.7% positive-predictive value and 95.8% negative-predictive value. Concordance between direct Gram-stain-identified pathogens and Gram stain of cultured pathogens was significantly less frequent during antibiotic prophylaxis (63.6%) than afterwards (94.9%) (P<0.05). CONCLUSION: Antibiotic prophylaxis diminished the diagnostic value of Gram staining of protected brush specimens. When protected brush specimens was performed during antibiotic prophylaxis, Gram staining accurately enabled early exclusion of postoperative pneumonia because of its excellent negative-predictive value. After antibiotic prophylaxis, Gram staining permitted early diagnosis of postoperative pneumonia identification of the responsible pathogen.

Hospital-acquired pneumonia: methicillin resistance and intensive care unit admission.

Although epidemiologic investigations of hospital-acquired pneumonia have certain intrinsic limitations because of the heterogeneity of the study populations, the difficulties in making a clinical diagnosis of nosocomial pneumonia, and the need for better microbiologic assays, recent studies have provided new and important data concerning the role of Staphylococcus aureus in this disease. This pathogen has now been identified as the most frequent cause of nosocomial pneumonia in hospitals in both Europe and the United States among patients in general hospital units as well as in the intensive care unit (ICU). Patients who have been treated with mechanical ventilation are at especially high risk for S. aureus pneumonia. The incidence of nosocomial pneumonia related to methicillin-resistant S. aureus (MRSA) has increased in recent years in many countries, especially among patients in the ICU. Because hospitalized patients with suspected nosocomial pneumonia often have many risk factors for MRSA infection, it seems advisable to include coverage of MRSA in the initial therapeutic regimen for these patients until MRSA infection is excluded.

Determination of total effective vascular compliance in patients with sepsis syndrome.

Changes in capacitance vessels have important consequences on cardiac filling pressure and fluid volume distribution in patients with sepsis syndrome. Vascular compliance may be evaluated from the slope of the relationship between changes in total blood volume (deltaTBV) and changes in central venous pressure (deltaCVP) during acute volume expansion (450 ml of gelatin fluid over 6 min), i.e., from the deltaTBV/deltaCVP ratio. The mean ratio (ml x mm Hg-1 x kg-1) was 2.03 +/- 0.21 in control subjects, 1.43 +/- 0.25 in mechanically ventilated patients without sepsis syndrome, and 0.94 +/- 0.24 in mechanically ventilated patients with sepsis syndrome (p < 0.0001 versus the other two groups). Based on echocardiographic determinations, cardiac performance was constantly found within the normal range (cardiac output ranged from 5.6 +/- 1.2 to 6.7 +/- 2.0 L/min in nonseptic patients from 6.8 +/- 1.9 to 7.8 +/- 2.2 in septic patients). Effective compliance of the total vascular bed is therefore reduced in patients with sepsis syndrome, independently of the hemodynamic modifications due to mechanical ventilation.

Bone mineral density of the skull in premenopausal women.

Dual-energy X-ray absorptiometry (DXA) of the head has received little attention. We used DXA to measure bone mineral density (BMD) of the entire skull including the mandible (BMDHead) and BMD of the cranial vault (BMDVault) in 91 normal young women. We also measured BMD of the total body (BMDTotal body), proximal femur ("total femur"), and lumbar vertebrae (L1-L4). BMD (g/cm2; mean +/- SE) was 1.032 +/- 0.011 for L1-L4, 0.995 +/- 0.011 for total femur, and 2.283 +/- 0.028 for BMDVault (cranial vault) and the mean body weight of all subjects was 59.8 kg. Correlation between BMD Vault and BMDHead was -0.004 g/cm2 suggesting that these two measurements of bone mass of the skull were similar. To determine the correlation between the different variables after accounting for external sources of variation, partial correlation derived from multiple regression was determined. Correlations between BMD at the various locations and with BMDTotal body were moderate to strong. Although small in magnitude, the partial correlations of body weight with BMDTotal body, total femur, and L1-L4 were of equal value in predicting BMDTotal body and further, BMDVault was not influenced by body weight. Including body weight in multiple regression in addition to total femur or L1-L4 removed the extraneous variation due to body weight, and predictions of MBDTotal body were as reliable as when BMDVault was based on goodness of fit tests (P = 0.314). The techniques used to measure BMD of the cranial vault is a relatively new variation of DXA technology. The precision was as good as other measurements of bone mass of the entire skull (including the mandible). Because the cranial vault is less sensitive to mechanical influences, it may be a region where response to therapy could be evaluated. The cranial vault may be a useful area to study certain heritable diseases that affect the skeleton, skeletal artifact, or evaluation of oral bone loss.

[Mitral surgery: prognostic and survival factors. Value of the French score]. / Chirurgie mitrale: facteurs de pronostic et de survie. Intérêt du score "français".

OBJECTIVES: Conservative mitral surgery is the preferred treatment for mitral regurgitation whatever the etiology. Morbidity and mortality figures, both during hospitalization and after long-term follow-up, are better than for mitral valve replacement. This difference could result from a selection bias or express a specific effect of conservative mitral surgery on survival. In addition, concerns about cost-containment justify rigorous analysis of treatment quality. The "French" score can be used for preoperative assessment of individual and population operative risk and for inter-institution comparisons. Its value for assessing overall survival is unknown. METHODS: Using the French score, we compared the clinical features and laboratory data in 100 patients who underwent conservative mitral valve surgery and in 35 patients who had valve replacement. We looked for independent factors predicting overall survival. RESULTS: Overall survival tended to be better after conservative mitral surgery, reaching 86% at 4 years versus 72% after replacement (p = 0.08). The populations were different as the valve replacement group included more women, was more symptomatic (p = 0.022), had heart failure more often (p = 0.003) and tended to have a higher French score (p = 0.06). Inversely, the hemodynamic and echocardiographic parameters were not different between the two groups. DISCUSSION: Independent factors predicting late mortality were preoperative heart failure and the French score. The type of mitral surgery did not have any predictive value. CONCLUSION: In addition to its value for assessing operative risk, the French score appears to be useful for predicting overall survival after mitral surgery.

[Coxiella burnetti endocarditis on bioprosthesis. Apropos of a case]. / Endocardite à Coxiella burnetti sur bioprothèse. A propos d'un cas.

A patient with two bioprostheses was admitted to hospital with pyrexia and a small vegetation on the aortic bioprosthesis visible only on transoesophageal echocardiography without aortic incompetence. Blood cultures were negative. Serology to Coxiella burnetti was positive at high dilution and confirmed the diagnosis of infectious endocarditis. Medical therapy with doxycycline and chloroquine was instaured without surgery. A Coxiella burnetti infection should be systematically searched for in all cases of endocarditis with negative blood cultures. The features of this infection, particularly the aetiological circumstances, diagnosis, history and treatment are reviewed.

[Cardiac surgery in chronic hemodialysed patients: immediate and long-term results]. / Chirurgie cardiaque chez l'hémodialysé chronique: résultats immédiats et à long terme.

Between 1979 and 1993, 50 patients (33 men and 17 women) receiving chronic haemodialysis, underwent 53 cardiac surgical procedures in the department. The mean age was 56 +/- 13 years. The average duration of preoperative dialysis was 82 +/- 63 months. The average duration of cardiac symptoms before surgery was 35 +/- 52 months. Twenty-seven patients (54%) were in NYHA functional classes III or IV before surgery. Sixteen patients (32%) had preoperative left ventricular ejection fractions of less than 0.40. Twelve patients (24%) were emergency referrals. Twenty-nine patients underwent isolated coronary bypass surgery, 13 patients underwent isolated aortic valvular replacement which had to be repeated in one case, 3 patients underwent mitral valve replacement, which had to be repeated in 2 cases, and 5 patients underwent combined surgery. The average aortic clamping time was 75 +/- 32 minutes, the average cardio-pulmonary bypass time was 125 +/- 50 minutes. The surgical revascularisation of the coronary patients was incomplete in 37% of cases because of the severity of the underlying coronary artery disease. The average postoperative bleeding was 800 +/- 650 ml; 29 patients (58%) were transfused with an average of 4.3 +/- 3 units of blood. The global early mortality was 9 patients (18%); 10% in coronary bypass, 7% in aortic valve replacement and 50% in patients with more complex procedures. The causes of death were cardiac (n = 4), sepsis (n = 2) and multiple organ failure (n = 3). The morbidity was 39%, mainly due to low cardiac output.(ABSTRACT TRUNCATED AT 250 WORDS)

Naphtyl methyl imidazoline (NMI) membranes interactions: NMR study and evaluation of possible radioprotective consequences.

The interactions of the radioprotective molecule Naphtyl methyl imidazoline (NMI) with membranes have been studied using biophysical and biochemical methods. 1H, 2H and 31P-NMR methods showed a strong interaction with the deep part of the layer of model membranes inducing the formation of a new membrane compartment. These properties are not involved in the radioprotection effect of NMI which is more probably due to its vasoconstrictive properties.