Strategy of antibiotic rotation: long-term effect on incidence and susceptibilities of Gram-negative bacilli responsible for ventilator-associated pneumonia

OBJECTIVE: To evaluate the long-term effect of a program of rotating antibiotics on the incidence of ventilator-associated pneumonia and the susceptibilities of Gram-negative bacilli responsible for ventilator-associated pneumonia. DESIGN: Prospective program for the surveillance of antibiotic susceptibilities of microorganisms responsible for ventilator-associated pneumonia. SETTING: Academic, university-based, medical intensive care unit (16 beds). SUBJECTS: 2,856 mechanically ventilated patients. INTERVENTIONS: A new program of antibiotic use was introduced at the end of 1996 that involved the rotation of antibiotics in empirical and therapeutic use of the treatment of ventilator-associated pneumonia. The rotation concerned the beta-lactam and aminoglycoside classes, with a rotation interval of 1 month. The use of antibiotics was monitored monthly. No preference was given to any particular antibiotic. In a previous study, the period before the introduction of this protocol (1995-1996) was compared with the period 2 yrs after (1997-1998): The results indicated a decreased incidence of ventilator-associated pneumonia, a lower incidence of potentially resistant Gram-negative bacilli, and increased sensitivities of Gram-negative bacilli, especially Pseudomonas aeruginosa and Burkholderia cepacia. After 1998, we decided to continue a routine for this rotation. The long-term effect of this program was studied by comparing the incidence of Gram-negative bacilli responsible for ventilator-associated pneumonia and their susceptibilities obtained in a third period: 1999-2001. The long-term effect (5 yrs) of such a strategy-2-yr protocol period (1997-1998) and 3-yr routine period (1999-2001)-could be evaluated. MEASUREMENTS AND MAIN RESULTS: During the 7-yr study period, 2,856 patients were mechanically ventilated for >48 hrs. The incidence of ventilator-associated pneumonia remained significantly lower in period 3 (1999-2001): 23% (period 1, 1995-1996) vs. 15.7% (period 2, 1997-1998) vs. 16.3% (period 3, 1999-2001; p =.002). Late-onset ventilator-associated pneumonia occurred in 86.6% and 94% of cases, respectively, in periods 1 and 3 (p =.02). The decrease of the incidence of early-onset ventilator-associated pneumonia was statistically significant during the 7-yr study period: 13% vs. 9% vs. 5.9% (p =.02). Combined with a higher incidence of late-onset ventilator-associated pneumonia, the incidence of potentially resistant Gram-negative bacilli increased in period 3: 42.2% vs. 34.5% vs. 41.7% (nonsignificant), except for B. cepacia: 11.7% vs. 7.4% vs. 3.7% (p =.005). Nevertheless, the potential antibiotic-resistant Gram-negative bacilli were more sensitive to most of the beta-lactams, especially piperacillin-tazobactam and cefepime. CONCLUSIONS: Rotation of antibiotics could help to avoid ventilator-associated pneumonia. It could greatly improve the susceptibilities of the potentially antibiotic-resistant Gram-negative bacilli responsible for late-onset ventilator-associated pneumonia. This program could be applied in routine with good results 5 yrs after its introduction. Further studies, especially multiple-center trials, are necessary to confirm this result and better define the rotation type and intervals.     

Delayed diagnosis in pediatric blunt trauma

OBJECTIVE: Identification of injuries of a traumatized patient is a mandate for the emergency department (ED) and the trauma team. Delayed diagnosis of injury in trauma patients leads to increased morbidity, mortality, dissatisfaction, and risk of litigation. Comparing children admitted for blunt trauma, with and without delay, this study examines risk factors for delayed diagnosis. METHODS: Delays in diagnosis from 1991 to 1996 were identified during prospective collection of trauma registry data. Controls were randomly selected from the trauma registry. Charts from both groups were retrospectively reviewed. RESULTS: Fifty-eight patients had 65 delays in diagnosis. Significant independent delay variables included: female, motor vehicle crash (MVC)-related mechanism, altered consciousness, higher injury severity score, and multiple injuries (P < 0.05). Trauma team activation, documentation of tertiary survey, and length of hospitalization were greater in patients with delay injuries (P < 0.05). Logistic regression identified MVC-related mechanism, female, facial, and extremity injuries as a combination of predictors. CONCLUSIONS: Delays occurred in 1% of patients. Trauma team care itself did not protect all patients from delay. Injury severity at presentation alone is not an adequate predictor of delayed diagnosis in the pediatric patient. A combination of variables was identified as negative predictors of delay. Further study is needed to validate these criteria, and determine if earlier diagnosis would effect quality.     

Uterovaginal fistula after laparoscopic excision of uterosacral endometriotic nodule

A uterovaginal fistula was reported after an uneventful laparoscopic excision of a left uterosacral endometriotic nodule in a young woman. Indirect thermal injury to the left ureter by the bipolar grasping forceps was the main cause of the injury. Contributing factors are analyzed and preventive measures pertinent to this case are discussed.     

Proteomics as the Tool to Search for Lung Disease Markers in Bronchoalveolar Lavage

Most lung disorders are known to be associated to considerable modifications of surfactant composition. Numerous of these abnormalities have been exploited in the past to diagnose lung diseases, allowing proper treatment and follow-up. Diagnosis was then based on phospholipid content, surface tension and cytological features of the epithelial lining fluid (ELF), sampled by bronchoalveolar lavage (BAL) during fiberoscopic bronchoscopy. Today, it appears that the protein content of ELF displays a remarkably high complexity, not only due to the wide variety of the proteins it contains but also because of the great diversity of their cellular origins. The significance of the use of proteome analysis of BAL fluid for the search for new lung disease marker proteins and for their simultaneous display and analysis in patients suffering from lung disorders has been examined.     

Chest pain in children. Follow-up of patients previously reported

During a 1-year period, 407 children with chest pain were seen in the Emergency Department of Children's Hospital of Philadelphia. Analysis of the clinical data of these children was reported previously. The authors successfully followed 149 of these children for 6 months or more, and 51 for 2 years or more. These patients returned for an average of 3.4 visits during the follow-up period. Thirty-four percent of the initial diagnoses were altered. Usually, during the follow-up period, the authors concluded that chest pain resulted from nonorganic causes. A new organic etiology was uncovered in only 12 of 149 cases. Only 1 child was found to have a heart abnormality (mitral valve prolapse), and 3 were found to have asthma. Chest pain did not resolve during the follow-up period in 43 percent of those followed. Children with chest pain should have follow-up care because of the persistence of symptoms, but serious disease is unlikely to be found over time.     

Rapid development of tolerance to sub-anaesthetic dose of ketamine: an oculomotor study in macaque monkeys

Background  

Ketamine, a non-competitive N-methyl-d-aspartic acid antagonist, has been widely used for anaesthetic purposes. At sub-anaesthetic dosage, it induces a dissociative state similar to schizophrenia. The discovery of this effect on dissociative state has led to its use as a pharmacological model of schizophrenia and has also been responsible for its illegal use as a recreational drug. Whereas the former has provided invaluable information, the latter has demonstrated that repeated administration of ketamine induces tolerance. Surprisingly, a review of the relevant literature shows that tolerance to sub-anaesthetic doses of ketamine is largely unreported in neuropharmacological studies.     

Measurement of both left ventricular function and regional myocardial perfusion with 133Xe in dogs

A technique to measure left ventricular (LV) function and myocardial perfusion was validated in 12 dogs. ¹³³Xe in saline was injected into the left atrium (LA) or LV and two data sets were obtained using gamma camera imaging: 1) A first pass gated scan for LV function; followed by 2) Sequential images for regional myocardial perfusion. LV ejection fraction and wall motion measurements from the ¹³³Xe blood pool images were compared to ejection fraction (r=0.88, P<0.01) and wall motion (r=0.83, P<0.01) data from ^99mTc labeled blood pool scans. The perfusion measurements obtained with the ¹³³Xe method were compared to microsphere data (r=0.79, P<0.01). Measurements after LV ¹³³Xe injection were similar to data following LA injection. Thus, quantitative assessment of global LV function, regional wall motion and myocardial perfusion is possible with LA or LV ¹³³Xe injection and gamma camera imaging.     

PROPERDIN FACTOR D: CHARACTERIZATION OF ITS ACTIVE SITE AND ISOLATION OF THE PRECURSOR FORM

The activity of properdin factor D was measured by the generation of the hemolytically active cellular intermediate, EAC43B(D), bearing the C3b-dependent alternate pathway C3 convertase. Treatment of factor D with DFP prevented formation of EAC43B(D); thus, a serine esterase is essential for the generation of the alternate pathway C3 convertase, a situation analogous to the role of C1 in the formation of the classical C3 convertase, C42. The definition of factor D as a serine esterase prompted a search for its proenzyme form, and resulted in the chromatographic isolation from plasma of a single peak of trypsin-inducible factor D activity, distinct from activated factor D. Analytical gel filtration indicated an apparent mol wt of 25,000. This protein from which trypsin elaborated factor D activity, as assessed by the formation of EAC43B(D), the generation of the CoVF-dependent C3 convertase, and the cleavage of factor B in the presence of C3b, was designated "precursor factor D." The DFP resistance of precursor factor D, and the susceptibility of its trypsin-activated form to inactivation by DFP is analogous to the behavior of other plasma serine esterases, including C1.