06 Feb 09
Posted in Infection, Mechanical ventilation at 0:45 by Laci
By Caruso, S Denari, SA Ruiz, SE Demarzo, D Deheinzelin
Critical Care Medicine 2009;37:32-38
To compare the incidence of ventilator-associated pneumonia (VAP) with or without isotonic saline instillation before tracheal suctioning. As a secondary objective, we compared the incidence of endotracheal tube occlusion and atelectasis.
Design
Randomized clinical trial.
Setting and patients
The study was conducted in a medical surgical intensive care unit of an oncologic hospital. We selected consecutive patients needing mechanical ventilation for >72 hrs. Patients were allocated into two groups: a saline group that received instillation of 8 mL of saline before tracheal suctioning and a control group which did not. VAP was diagnosed based on clinical suspicion and confirmed by bronchoalveolar lavage quantitative culture. The incidence of atelectasis on daily chest radiography and endotracheal tube occlusions were recorded. The sample size was calculated to a power of 80% and a type I error probability of 5%.
Measurements and main results
One hundred thirty patients were assigned to the saline group and 132 to the control group. The baseline demographic variables were similar between groups. The rate of clinically suspected VAP was similar in both groups. The incidence of microbiological proven VAP was significantly lower in the saline group (23.5% × 10.8%; p = 0.008) (incidence density/1.000 days of ventilation 21.22 × 9.62; p < 0.01). Using the Kaplan-Meier curve analysis, the proportion of patients remaining without VAP was higher in the saline group (p = 0.02, log-rank test). The relative risk reduction of VAP in the saline instillation group was 54% (95% confidence interval, 18%-74%) and the number needed to treat was eight (95% confidence interval, 5-27). The incidence of atelectases and endotracheal tube occlusion were similar between groups.
Conclusions
Instillation of isotonic saline before tracheal suctioning decreases the incidence of microbiological proven VAP.
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21 Jan 09
Posted in Infection at 0:11 by Laci
By T Watanabea, S Watanabea, K Shinyab, J Hyun Kima, M Hattaa and Y Kawaokaa
PNAS 2008; (online before print)
The 1918 influenza pandemic was the most devastating outbreak of infectious disease in human history, accounting for about 50 million deaths worldwide. In addition to a significant number of cases of secondary bacterial pneumonia, this highly pathogenic strain of influenza A virus caused fatal primary viral pneumonia. To identify the viral gene(s) chiefly responsible for the high virulence of the 1918 virus, we generated a series of reassortants between the 1918 virus and a contemporary human H1N1 virus (A/Kawasaki/173/2001; K173) using reverse genetics. We then assessed their virulence properties in ferrets, a model closely resembling humans in terms of sensitivity to influenza virus infection and pattern of spread after intranasal inoculation. Substitution of single genes from the 1918 virus in the genetic background of K173 virus did not markedly alter the pattern of infection. That is, the reassortants grew well in nasal turbinates, but only sporadically (if at all) in the trachea and lungs. One exception was the 1918PB1/K173 reassortant, which replicated efficiently in lung tissues as well as the upper respiratory tract. A reassortant virus expressing the 1918 viral RNA polymerase complex (PA, PB1, and PB2) and nucleoprotein showed virulence properties in the upper and lower respiratory tracts of ferrets that closely resembled those of wild-type 1918 virus. Our findings strongly implicate the viral RNA polymerase complex as a major determinant of the pathogenicity of the 1918 pandemic virus. This new insight may aid in identifying virulence factors in future pandemic viruses that could be targeted with antiviral compounds.
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01 Jan 09
Posted in Critical Care, Infection at 0:55 by Laci
By M G A de Smet, J A J W Kluytmans, B S Cooper, E M Mascini, R F J Benus, T S van der Werf et al
NEJM 2009;360:20-31
Selective digestive tract decontamination (SDD) and selective oropharyngeal decontamination (SOD) are infection-prevention measures used in the treatment of some patients in intensive care, but reported effects on patient outcome are conflicting.
Methods
We evaluated the effectiveness of SDD and SOD in a crossover study using cluster randomization in 13 intensive care units (ICUs), all in the Netherlands. Patients with an expected duration of intubation of more than 48 hours or an expected ICU stay of more than 72 hours were eligible. In each ICU, three regimens (SDD, SOD, and standard care) were applied in random order over the course of 6 months. Mortality at day 28 was the primary end point. SDD consisted of 4 days of intravenous cefotaxime and topical application of tobramycin, colistin, and amphotericin B in the oropharynx and stomach. SOD consisted of oropharyngeal application only of the same antibiotics. Monthly point-prevalence studies were performed to analyze antibiotic resistance.
Results
A total of 5939 patients were enrolled in the study, with 1990 assigned to standard care, 1904 to SOD, and 2045 to SDD; crude mortality in the groups at day 28 was 27.5%, 26.6%, and 26.9%, respectively. In a random-effects logistic-regression model with age, sex, Acute Physiology and Chronic Health Evaluation (APACHE II) score, intubation status, and medical specialty used as covariates, odds ratios for death at day 28 in the SOD and SDD groups, as compared with the standard-care group, were 0.86 (95% confidence interval [CI], 0.74 to 0.99) and 0.83 (95% CI, 0.72 to 0.97), respectively.
Conclusions
In an ICU population in which the mortality rate associated with standard care was 27.5% at day 28, the rate was reduced by an estimated 3.5 percentage points with SDD and by 2.9 percentage points with SOD
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01 Apr 08
Posted in Infection, Steroid at 19:29 by Laci
By J de Gans, D van de Beek for the European Dexamethasone in Adulthood Bacterial Meningitis Study Investigators
NEJM 2002;347:1549-1556
Mortality and morbidity rates are high among adults with acute bacterial meningitis, especially those with pneumococcal meningitis. In studies of bacterial meningitis in animals, adjuvant treatment with corticosteroids has beneficial effects.
Methods
We conducted a prospective, randomized, double-blind, multicenter trial of adjuvant treatment with dexamethasone, as compared with placebo, in adults with acute bacterial meningitis. Dexamethasone (10 mg) or placebo was administered 15 to 20 minutes before or with the first dose of antibiotic and was given every 6 hours for four days. The primary outcome measure was the score on the Glasgow Outcome Scale at eight weeks (a score of 5, indicating a favorable outcome, vs. a score of 1 to 4, indicating an unfavorable outcome). A subgroup analysis according to the causative organism was performed. Analyses were performed on an intention-to-treat basis.
Results
A total of 301 patients were randomly assigned to a treatment group: 157 to the dexamethasone group and 144 to the placebo group. The base-line characteristics of the two groups were similar. Treatment with dexamethasone was associated with a reduction in the risk of an unfavorable outcome (relative risk, 0.59; 95 percent confidence interval, 0.37 to 0.94; P=0.03). Treatment with dexamethasone was also associated with a reduction in mortality (relative risk of death, 0.48; 95 percent confidence interval, 0.24 to 0.96; P=0.04). Among the patients with pneumococcal meningitis, there were unfavorable outcomes in 26 percent of the dexamethasone group, as compared with 52 percent of the placebo group (relative risk, 0.50; 95 percent confidence interval, 0.30 to 0.83; P=0.006). Gastrointestinal bleeding occurred in two patients in the dexamethasone group and in five patients in the placebo group.
Conclusions
Early treatment with dexamethasone improves the outcome in adults with acute bacterial meningitis and does not increase the risk of gastrointestinal bleeding.
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