Risk factors for nosocomial pneumonia in critically ill trauma patients

Diagnostic importance of pulmonary interleukin-1beta and interleukin-8 in ventilator-associated pneumonia

Background

Ventilator-associated pneumonia (VAP) is the most commonly fatal nosocomial infection. Clinical diagnosis of VAP remains notoriously inaccurate. The hypothesis was tested that significantly augmented inflammatory markers distinguish VAP from conditions closely mimicking VAP.

Methods

A prospective, observational cohort study was carried out in two university hospital intensive care units recruiting 73 patients with clinically suspected VAP, and a semi-urban primary care practice recruiting a reference group of 21 age- and sex-matched volunteers.

Growth of pathogens at >10⁴ colony-forming units (cfu)/ml of bronchoalveolar lavage fluid (BALF) distinguished VAP from “non-VAP”. Inflammatory mediators were quantified in BALF and serum. Mediators showing significant differences between patients with and without VAP were analysed for diagnostic utility by receiver operator characteristic (ROC) curves.

Results

Seventy-two patients had recoverable lavage—24% had VAP. BALF interleukin-1β (IL-1β), IL-8, granulocyte colony-stimulating factor and macrophage inflammatory protein-1α were significantly higher in the VAP group (all p<0.005). Using a cut-off of 10 pg/ml, BALF IL-1β generated negative likelihood ratios for VAP of 0.09. In patients with BALF IL-1β <10 pg/ml the post-test probability of VAP was 2.8%. Using a cut-off value for IL-8 of 2 ng/ml, the positive likelihood ratio was 5.03. There was no difference in cytokine levels between patients with sterile BALF and those with growth of <10⁴ cfu/ml.

Conclusions

BALF IL-1β and IL-8 are amongst the strongest markers yet identified for accurately demarcating VAP within the larger population of patients with suspected VAP. These findings have potential implications for reduction in unnecessary antibiotic use but require further validation in larger populations.

Late-onset ventilator-associated pneumonia in nontrauma intensive care unit patients

BACKGROUND

Most studies designed to determine the factors associated with the acquisition of late-onset ventilator-associated pneumonia (VAP) were performed in critically ill trauma patients. The impact of enteral nutrition (EN) on the risk of acquiring VAP has been discussed. In this study, we assessed factors associated with late-onset VAP in nontrauma patients and determined whether nutrition provided early was associated with development of late-onset VAP in this population.

METHODS

We performed a prospective observational cohort study in a 21-bed polyvalent intensive care unit in a university hospital.

RESULTS

Three hundred sixty-one intubated adult patients with a duration of mechanical ventilation (MV) of 6 days or more were admitted over a 28-mo period. Late-onset VAP was confirmed in 76 patients (21%) by the presence of at least one microorganism at a concentration >or=10(4) colony-forming units/mL on the bronchoalveolar lavage. Gram-negative bacilli represented 75% and Staphylococcus aureus 21% of recovered organisms. Factors independently associated with late-onset VAP by multivariate analysis included a high simplified acute physiology score II score (odds ratio: 1.021; 95% confidence interval [CI]: 1.005-1.038; P = 0.01), development of acute respiratory distress syndrome during the first 5 days of MV (odds ratio: 1.98; 95% CI: 1.05-3.67; P = 0.04), and size of the endotracheal tube >or=7.5 (odds ratio: 2.06; 95% CI: 1.88-3.90; P = 0.03). EN started within 48 h of MV onset was not associated with a higher risk for late-onset VAP.

CONCLUSION

In our nontrauma patient population, early EN was not associated with development of late-onset VAP. In this population, severity of the disease during the first 5 days of MV seemed to be associated with late-onset VAP. In addition, our results suggest that the risk of late-onset VAP is higher in patients with a tube size >or=7.5 than in patients with a tube size <7.5.

Positive-end expiratory pressure reduces incidence of ventilator-associated pneumonia in nonhypoxemic patients

OBJECTIVE

To analyze the effect on clinical outcomes of prophylactic positive end expiratory pressure in nonhypoxemic ventilated patients.

DESIGN

Multicenter randomized controlled clinical trial.

SETTING

One trauma and two general intensive care units in two university hospitals.

PATIENTS

One hundred thirty-one mechanically ventilated patients with normal chest radiograph and PaO2/FiO2 above 250.

INTERVENTIONS

Patients were randomly allocated to receive mechanical ventilation with 5-8 cm H2O of positive end-expiratory pressure (PEEP) (PEEP group, n = 66) or no-PEEP (control group, n = 65).

MEASUREMENTS AND MAIN RESULTS

Primary end-point variable was hospital mortality. Secondary outcomes included microbiologically confirmed ventilator-associated pneumonia, acute respiratory distress syndrome, barotrauma, atelectasis, and hypoxemia (PaO2/FiO2 <175). Both groups were similar at randomization in demographic characteristics, intensive care unit admission diagnoses, severity of illness, and risk factors for ventilator-associated pneumonia. Hospital mortality rate was similar (p = 0.58) between PEEP (29.7%) and control (25.4%) groups. Ventilator-associated pneumonia was detected in 16 (25.4%) patients in the control group and 6 (9.4%) in the PEEP group (relative risk, 0.37; 95% confidence interval = 0.15-0.84; p = 0.017). The number of patients who developed hypoxemia was significantly higher in the control group (34 of 63 patients, 54%) than in the PEEP group (12 of 64, 19%) (p < 0.001), and the hypoxemia developed after a shorter period (median [interquartile range]) in the control group than in the PEEP group (38 [20-70] hrs vs. 77 [32-164] hrs, p < 0.001). Groups did not significantly differ in incidence of acute respiratory distress syndrome (14% in controls vs. 5% in the PEEP group, p = 0.08), barotrauma (8% vs. 2%, respectively, p = 0.12), or atelectasis (27% vs. 19%, respectively, p = 0.26).

CONCLUSIONS

These findings indicate that application of prophylactic PEEP in nonhypoxemic ventilated patients reduces the number of hypoxemia episodes and the incidence of ventilator-associated pneumonia.

Controversies in mechanical ventilation: when should a tracheotomy be placed?

With the large and increasing population of mechanically ventilated patients, critical care physicians frequently face the dilemma of whether to perform tracheotomy. The decision is a complex one, requiring a detailed understanding of the risks and benefits of both tracheotomy and prolonged translaryngeal intubation (TLI). It also must be individualized, taking into consideration the patient's preferences and expected clinical course. This article reviews the medical literature regarding the benefits and risks of tracheotomy as compared with TLI. The authors then discuss current data regarding the optimal timing for the procedure and propose an algorithm that may aid intensivists in clinical decision making.

Diabetes mellitus as a risk factor for nosocomial pneumonia and associated mortality

BACKGROUND

Patients with diabetes mellitus (DM) are considered to be more susceptible to several types of infections, including community-acquired pneumonia. However, it is not clear whether DM is a risk factor for development of hospital-acquired pneumonia (HAP), an infection with considerable morbidity and mortality worldwide.

METHODS

We searched PubMed for relevant publications that included data on the possible association between DM and HAP. Cohort studies, case-control studies and observational studies were included in this analysis. Two of the authors performed the literature search independently.

RESULTS

We identified 84 studies designed to identify risk factors and predictors of mortality as a result of HAP. Of these, 13 studied patients in the ward or intensive care unit (ICU), 28 studied patients treated in the ICU only, and 44 studied patients with ventilator-associated pneumonia. Only 14 considered the role of DM for this nosocomial complication. The reviewed data suggest that DM is not a risk factor for development of HAP in patients who require ICU treatment. In addition, patients with DM are not at increased risk for development of ventilator-associated pneumonia. Moreover, DM is not a prognostic factor for mortality in patients with HAP based on data from two out of 84 identified studies that provided relevant information.

CONCLUSIONS

There is a relative scarcity of studies examining DM as a potential risk factor for HAP. Our analysis of the available data supports the conclusion that DM is not a risk factor for development of HAP and mortality associated with this nosocomial infection.

Acinetobacter infections: a growing threat for critically ill patients

There has been increasing concern regarding the rise of Acinetobacter infections in critically ill patients. We extracted information regarding the relative frequency of Acinetobacter pneumonia and bacteraemia in intensive-care-unit (ICU) patients and the antimicrobial resistance of Acinetobacter isolates from studies identified in electronic databases. Acinetobacter infections most frequently involve the respiratory tract of intubated patients and Acinetobacter pneumonia has been more common in critically ill patients in Asian (range 4-44%) and European (0-35%) hospitals than in United States hospitals (6-11%). There is also a gradient in Europe regarding the proportion of ICU-acquired pneumonias caused by Acinetobacter with low numbers in Scandinavia, and gradually rising in Central and Southern Europe. A higher proportion of Acinetobacter isolates were resistant to aminoglycosides and piperacillin/tazobactam in Asian and European countries than in the United States. The data suggest that Acinetobacter infections are a growing threat affecting a considerable proportion of critically ill patients, especially in Asia and Europe.

Incidence and risk factors for ventilator-associated pneumonia in a developing country: Where is the difference?

BACKGROUND

Latin America exhibits a wide range of differences, compared to developed nations, in genetic background, health services, and clinical research development. It is valid to hypothesize that the incidence and risk factors for ventilator-associated pneumonia (VAP) in our setting may be substantially different of those reported elsewhere. We conducted a study to determine the incidence and risk factors for VAP in a University Hospital from Medellin, Colombia.

METHODS

Prospective cohort study in three intensive care units (ICU) (surgical/trauma, medical, cardiovascular) in a 550-bed University Hospital. Critically ill patients (n=270) who required at least 48 h of mechanical ventilation (MV) between June 2002 and October 2003 were followed until ICU discharge, VAP diagnosis or death.

RESULTS

Sixty patients (22.2%) developed VAP 5.9+/-3.6 days after admission. The overall incidence of VAP was 29 cases per 1000 ventilator-days. The daily hazard for developing VAP increased until day 8, and then decreased over the duration of stay in the ICU. The only statistically significant factor after multivariable analysis was gender, with being female reducing 57% the risk of pneumonia (hazard ratios (HR): 0.43; 95% confidence intervals (CI): 0.19-0.96).

CONCLUSIONS

The epidemiologic profile of VAP in terms of incidence, length of stay and clinical course resembles the general pattern described everywhere. Surprisingly, we could not identify any potentially modifiable risk factor for VAP. A comprehensive multicenter study is warranted. It should provide deep insight about the specific microbiological, genetic and clinic features of VAP in our setting.

Factors associated with mortality in critically injured trauma patients who require simultaneous cultures

BACKGROUND

In trauma patients surviving their initial injuries, infectious complications and multiple organ failure represent the major causes of death after the first 72 hours. Critically injured trauma patients frequently have bacteria recoverable simultaneously from multiple culture sites; the clinical significance of this event is unknown. The objective of this study was to identify the association between growth patterns of multiple site cultures and mortality among critically injured trauma patients.

METHODS

We performed a retrospective chart review collecting demographic and medical data on admissions to a state-designated Level I trauma center from April 2000 to December 2002. The inclusion criteria were age >17 years, admission to the trauma intensive care unit (TICU), and simultaneous sampling of blood, sputum, and urine in the setting of fever of undetermined origin or alteration in the white blood cell count. Four mutually exclusive groups were developed according to the number of positive culture sites. We used standard statistical analysis and multivariate logistic regression.

RESULTS

During the study period, 3,402 patients were admitted to the trauma service of whom 124 met the inclusion criteria. Eighty percent of these (99) were male, and the average age was 41 years. The median TICU stay was 17 days. The mortality rate was 24.2% (30 nonsurvivors). The survivors and non-survivors were comparable in injury severity score (ISS), initial base deficit, initial hematocrit, initial blood pressure, and hospital length of stay (p > 0.05), whereas age (p = 0.03), female sex (p = 0.04), and TICU stay (p < 0.01) were higher among non-survivors. More non-survivors showed growth of microorganisms in simultaneous blood, sputum, and urine cultures (p = 0.02). By multivariate analysis, adjusting for age, sex, and TICU length of stay, patients with growth of microorganisms in simultaneous cultures (blood, sputum, and urine) had a 3-fold greater mortality rate (OR, 3.20; 95% CI 1.05, 9.73).

CONCLUSIONS

In this group of patients, growth of bacteria in simultaneous cultures was associated with higher mortality-a factor that may be considered a poor prognostic indicator. This factor requires further studies to explore the relation with survival in critically injured patients.

Impact of ventilator-associated pneumonia in patients with severe head injury

BACKGROUND

The impact of ventilator-associated pneumonia (VAP) on outcome seems to vary depending on the critically ill patients we analyze. Our objective, therefore, has been to evaluate the influence of VAP on the mortality and morbidity in patients with severe head injury (Glasgow Coma Scale score </= 8).

METHODS

A prospective, matched, case-control study was conducted in our intensive care unit (ICU) for a 3-year period (1998-2000). Seventy-two patients with severe head injury (HI) who developed VAP were matched with 72 patients with severe HI without VAP. The matching criteria were as follows: age (+/- 5 years); category of HI based on computed tomographic scanning; Acute Physiology and Chronic Health Evaluation II (+/- 4 points) score; Injury Severity Score (+/- 4 points); and duration of mechanical ventilation. VAP was diagnosed on the basis of quantitative microbiologic criteria.

RESULTS

Mortality did not differ significantly between cases and matched control subjects (15 [20.8%] vs. 11 [15.3%], p = 0.54). However, patients with VAP had a significantly longer duration of mechanical ventilation (median, 14 vs. 10 days; p = 0.015) and ICU stay (median, 21 vs. 15.5 days; p = 0.008). The occurrence of multiple organ failure was also significantly more frequent among the case group (33.3% vs. 12.5%, p = 0.004) during the overall ICU stay.

CONCLUSION

VAP does not seem to be associated with a significantly increased risk of death in patients with severe HI, but it may be associated with greater morbidity during the ICU stay.

Impact of the suctioning system (open vs. closed) on the incidence of ventilation-associated pneumonia: Meta-analysis of randomized controlled trials

OBJECTIVE

Ventilation-associated pneumonia (VAP) is a serious complication of patients in intensive care units (ICU) who require mechanical ventilation. The choice of suctioning system (open vs. closed) remains unresolved in evidence-based guidelines. This meta-analysis was carried out to analyze the effect of the type of suctioning system on the incidence of VAP.

DESIGN

A search of the literature was used to identify randomized controlled trials addressing this question. A meta-analysis was then performed to calculate the relative risk of ventilation-associated pneumonia acquisition with the two suctioning systems.

RESULTS

Nine trials were included, with 648 patients in the open suctioning group and 644 in the closed suctioning group. VAP occurred in 128 (20%) of the open suctioning group and in 120 (19%) in the closed suctioning group (relative risk 0.95).

CONCLUSIONS

At a given pneumonia prevalence of 20% in ICU patients there was no significant advantage for the use of either suctioning system in this meta-analysis. The choice of suctioning system should therefore be based on handling, cost, and individual patient's disease until more data are available.

Massive transfusion as a risk factor for acute lung injury: Association or causation?

One of the most common clinical sequelae of massive transfusion is acute lung injury. In virtually all clinical settings, there is a very strong relationship between transfusion and acute lung injury that remains even after adjusting for potential confounders. Whether the association between transfusion and acute lung injury in these settings is a result of residual confounding or actually reflects a causal relationship is unknown. However, there are several potential mechanisms by which massive transfusion might predispose to lung injury: a) cognate antigen-antibody interactions (classic transfusion-associated lung injury); b) activation of nonspecific immunity through soluble mediators present in transfused blood; c) an increased risk of infection through transfusion-associated immunomodulation leading to sepsis and sepsis-induced lung injury; and d) volume overload in the face of increased permeability of the alveolar capillary membrane. Elucidating the precise causal mechanism operative in patients receiving massive transfusion has more than academic importance; it has direct implications for transfusion policy and practice.

Risk and prognostic factors of ventilator-associated pneumonia in trauma patients

OBJECTIVE

To assess the risk and prognostic factors of ventilator-associated pneumonia in trauma patients, with an emphasis on the inflammatory response.

DESIGN

Case-control study.

SETTING

Trauma intensive care unit.

PATIENTS

Of 190 consecutive mechanically ventilated patients, those with microbiologically confirmed pneumonia (n = 62) were matched with 62 controls without pneumonia.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Clinical, microbiological, and outcome variables were recorded. Cytokines were measured in serum and blind bronchoalveolar lavage specimens at onset of pneumonia. Multivariate analyses of risk and prognostic factors for ventilator-associated pneumonia were done. Increased severity of head and neck injury (odds ratio, 11.9; p < .001) was the only independent predictor of pneumonia. Among patients with pneumonia, serum levels of interleukin-6 (p = .019) and interleukin-8 (p = .036) at onset of pneumonia were higher in nonresponders to treatment. Moreover, serum levels of tumor necrosis factor-alpha (p = .028) and interleukin-6 (p = .007) at onset of pneumonia were higher in nonsurvivors. Mortality in the intensive care unit was 23% in cases and controls. Nonresponse to antimicrobial treatment (odds ratio, 22.2; p = .001) and the use of hyperventilation (p = .021) were independent predictors of mortality in the intensive care unit for patients with pneumonia.

CONCLUSIONS

Severe head and neck trauma is strongly associated with ventilator-associated pneumonia. A higher inflammatory response is associated with nonresponse to treatment and mortality among patients with pneumonia. Although pneumonia did not influence mortality, nonresponse to treatment independently predicted mortality among these patients.

Bench-to-bedside review: early tracheostomy in critically ill trauma patients

A significant proportion of trauma patients require tracheostomy during intensive care unit stay. The timing of this procedure remains a subject of debate. The decision for tracheostomy should take into consideration the risks and benefits of prolonged endotracheal intubation versus tracheostomy. Timing of tracheostomy is also influenced by the indications for the procedure, which include relief of upper airway obstruction, airway access in patients with cervical spine injury, management of retained airway secretions, maintenance of patent airway and airway access for prolonged mechanical ventilation. This review summarizes the potential advantages of tracheostomy versus endotracheal intubation, the different indications for tracheostomy in trauma patients and studies examining early versus late tracheostomy. It also reviews the predictors of prolonged mechanical ventilation, which may guide the decision regarding the timing of tracheostomy.

Review article: proton pump inhibitors and bacterial overgrowth

Proton pump inhibitors are potent drugs producing profound suppression of gastric acid secretion. Consequently, they are highly effective at treating acid-related disorders. There have been concerns that the suppression of gastric acid will alter the bacterial flora of the upper gastrointestinal tract and lead to complications such as cancer, enteric or other infections and malabsorption. Studies have confirmed that proton pump inhibitors do alter the bacterial population but present evidence indicates that this only rarely leads to clinical disease. As with all drugs, proton pump inhibitors should only be used for disorders shown clearly to benefit from the therapy and where the benefits will outweigh the small risks associated with them. Further research to more fully quantify the risk associated with PPI therapy is required.

Ventilator-associated pneumonia in severe traumatic brain injury

INTRODUCTION

Pneumonia is an important cause of morbidity following severe traumatic brain injury (TBI). However, previous studies have been limited by inclusion of specific patient subgroups or by selection bias. The primary objective of this study was to describe the incidence, risk factors for, and outcome of ventilator-associated pneumonia in an unselected population-based cohort of patients with severe TBI. An additional goal was to define the relationship of ventilator-associated pneumonia (VAP) with nonneurological organ dysfunction.

METHODS

A prospective, observational cohort study was performed at Foothills Medical Centre, the sole adult tertiary-care trauma center servicing southern Alberta. All patients with severe TBI requiring ventilation for more than 48 hours between May 1, 2000 and December 30, 2002 were included.

RESULTS

A total of 60 patients (45%) acquired VAP for an incidence density of 42.7/1000 ventilator days. Patients with polytrauma were at higher risk (risk ratio 1.7, 95% confidence interval, 0.9-3.1) for development of VAP than those with isolated head injury. Development of VAP was associated with a significantly greater degree of nonneurological organ system dysfunction. Although VAP was not associated with increased hospital mortality, patients who developed VAP had a longer duration of mechanical ventilation (15 versus 8 days, p < 0.0001), longer intensive care unit (17 versus 9 days, p < 0.0001) and hospital (60 versus 28 days, p = 0.003) lengths of stay, and more often required tracheostomy (35 versus 18%, p = 0.003).

CONCLUSIONS

VAP occurs frequently and is associated with significant morbidity in patients with severe TBI.

Impact of ventilator-associated pneumonia on outcome in patients with COPD

PURPOSES

The aim of this study was to determine the impact of ventilator-associated pneumonia (VAP) on outcome in patients with COPD.

METHODS

Prospective, observational, case-control study conducted in a 30-bed ICU during a 5-year period. All COPD patients who required intubation and mechanical ventilation (MV) for > 48 h were eligible. VAP diagnosis was based on clinical, radiographic, and quantitative microbiologic criteria. Patients with unconfirmed VAP were excluded, as well as patients with ventilator-associated tracheobronchitis without subsequent VAP. Matching (1:1) criteria included MV duration before VAP occurrence, age +/- 5 years, simplified acute physiology score II on ICU admission +/- 5, and ICU admission category. Variables associated with ICU mortality were determined using univariate and multivariate analyses.

RESULTS

A total of 1,241 patients were eligible; 181 patients (14%) were excluded, including 133 patients for VAT and 48 patients for unconfirmed VAP. VAP developed in 77 patients (6%), and all were successfully matched. Pseudomonas aeruginosa was the most frequently isolated bacteria (31%). ICU mortality rate (64% vs 28%), duration of MV (24 +/- 15 d vs 13 +/- 11 d [+/- SD]), and ICU stay (26 +/- 17 d vs 15 +/- 13 d) were significantly (< 0.001) higher in case patients than in control patients. VAP was the only variable independently associated with ICU mortality (odds ratio [OR], 7.7; 95% confidence interval [CI], 3.2 to 18.6; p < 0.001). In VAP patients who received corticosteroids during their ICU stay compared with those who did not receive corticosteroids, mortality rate (50% vs 82%; OR, 1.8; 95% CI, 1.2 to 2.7; p = 0.002), duration of MV (21 +/- 14 d vs 27 +/- 16 d, p = 0.043), and ICU stay (22 +/- 16 d vs 31 +/- 18 d, p = 0.006) were significantly lower.

CONCLUSION

VAP is associated with increased mortality rates and longer duration of MV and ICU stay in COPD patients.

The potential dangers of treating head injury patients with corticosteroids

In the past, corticosteroids were given to head-injured patients in order to prevent secondary brain damage, even if clinical trials had been inconclusive and potential risks of complications were of concern. Recently, CRASH, a large, multi-centre study on short-term, high-dose corticosteroid treatment in head trauma, was interrupted after enrolling > 10,000 patients because corticosteroid treatment was associated with significantly higher mortality within two weeks. Participating clinicians were not requested to judge the causes of death, but rates of infections and gastrointestinal haemorrhages did not differ between treated patients and controls. Other potential corticosteroid complications include metabolic derangements (particularly hyperglycaemia), adrenal insufficiency and critical illness myopathy. Furthermore, experimental data suggest that corticosteroids may have some harmful effects on neural tissue. In this review, the potential risks of treating head-injured patients with corticosteroids are examined.

Outcomes in a pediatric intensive care unit before and after the implementation of a nutrition support team

BACKGROUND

We evaluated the effect of parenteral nutrition (PN) and enteral nutrition (EN) on in-pediatric intensive care unit (PICU) mortality before and after a continuous education program in nutrition support that leads to implementation of a nutrition support team (NST).

METHODS

We used a historical cohort study of infants hospitalized for >72 hours at the PICU from 1992 to 2003. Five periods were selected (P1 to P5), considering the modifications incorporated into the program: P1, without intervention; P2, basic themes and original articles discussion; P3, clinical and nursing staff participation; P4, clinical visits; P5, NST. The samples were compared in terms of sex, age, admitting service (ie, medical vs surgical), prognostic index of mortality, length of stay (LOS), duration of mechanical ventilation, in-PICU mortality rate, and percentage of time receiving EN and PN for each patient. Bi- and multivariate analyses were performed. Statistical significance was set at 0.05 level.

RESULTS

Progressive increase was observed in EN use (p = .0001), median values for which were 25% in P1 and rose to 67% by P5 in medical patients; there was no significant difference in surgical patients. A reduction was observed in PN use; in P1 medians were 73% and 69% for medical and surgical patients respectively, and decreased to 0% in P5 for both groups (p = .0001). There was significant reduction in-PICU mortality rate during P4 and P5 among medical patients (p < .001). The risk of death was 83% lower in patients that received EN for >50% of LOS (odds ratio, 0.17; confidence interval, 0.066-0.412; p = .000).

CONCLUSIONS

The program motivated an increase in EN and a decrease in PN use, mainly after implementation of NST and reduced in-PICU mortality rate.

Pneumonia-induced sepsis and gut injury: effects of a poly-(ADP-ribose) polymerase inhibitor

BACKGROUND

Pseudomonas aeruginosa is commonly associated with nosocomial pneumonia. Ileal mucosal injury may be induced by severe lung infection. During septic shock, peroxynitrite-mediated DNA strand-breaks activate the enzyme poly-(ADP)-ribose polymerase (PARP) resulting in cellular energetic suppression and cell dysfunction. The aim of this study was to determine whether gut injury could be demonstrated in sepsis induced by P. aeruginosa and the effects of a PARP inhibitor (PJ34) on the associated gut injury.

MATERIALS AND METHODS

After baseline measurements, 20 rabbits were randomized into three groups: Sham (n = 5): transtracheally inoculated (TI) with 2 ml of phosphate buffer solution (PBS); P. aeruginosa + saline (n = 8), TI with 4 x 10(12) CFU/ml of P. aeruginosa in 2 ml/kg of PBS + i.v. saline; and P. aeruginosa + PJ34 (n = 7), TI with 4 x 10(12) CFU/ml of P. aeruginosa and i.v. treatment with PJ34.

RESULTS

P. aeruginosa caused a hyperdynamic response with increased blood flow also in the superior mesenteric artery. No significant differences were found in luminal gut lactate concentrations or PCO(2)-gap between groups. Histological specimens showed moderate or diffuse alveolar infiltrate in the P. aeruginosa + saline group (6/8) and in the P. aeruginosa + PJ34 group (6/7). Gut wet-to-dry weight ratio was significantly higher in the P. aeruginosa + saline group than in Shams (7.5 +/- 0.8 versus 6.4 +/- 0.7, P < 0.05) and significantly lower in the P. aeruginosa + PJ34 group (6.1 + 0.5, P < 0.05 versus the other groups). Blood cultures were positive in 1/5 (Sham), 8/8 (P. aeruginosa + saline group) and 4/7 (P. aeruginosa + PJ34 group) (RR 0.57 CI 95% 0.30-1.08).

CONCLUSIONS

Pharmacological inhibition of PARP reduces gut inflammation and may limit bacterial translocation.

Is early enteral nutrition a risk factor for gastric intolerance and pneumonia?

BACKGROUND

Early enteral nutrition (EN) after injury reduces septic complications, but upper digestive intolerance (UDI) occurring immediately post-trauma is a risk factor for pneumonia. Our study aimed to determine whether early intragastric feeding may lead to gastric intolerance and subsequent pneumonia in ventilated multiply injured patients.

METHODS

This prospective study involved two groups of patients randomized either to immediate intragastric EN, or to delayed intragastric EN started later than 24 h after admission. UDI was diagnosed when gastric residual volume, measured with a 50-ml syringe after stopping the feeding for 2 h, exceeded 200 ml at least at two consecutive measurements, and/or when vomiting occurred.

RESULTS

Out of 52 patients, 27 were included in the early EN group, and 25 in the delayed-EN group. On day 4, the early EN group received a greater amount of feeding because of intolerance problems occurring in the delayed-EN group (1175 +/- 485 ml vs. 803 +/- 545 ml). Twenty-five subjects--33% of the early EN patients and 64% of the delayed-EN patients--met the criteria for pneumonia (P = 0.050). On average, patients with pneumonia were older, more severely injured, and therefore required more ventilator days and a longer stay in the intensive care unit than patients without pneumonia.

CONCLUSIONS

If properly administered, early enteral nutrition can decrease the incidence of upper intestinal intolerance and nosocomial pneumonia in patients with multiple injuries.

Gargling with povidone-iodine reduces the transport of bacteria during oral intubation

PURPOSE

Nosocomial pneumonia remains a common complication in patients undergoing endotracheal intubation. This study examined the transport of bacteria into the trachea during endotracheal intubation, and evaluated the effects of gargling with povidone-iodine on bacterial contamination of the tip of the intubation tube.

METHODS

In the gargling group, patients gargled with 25 mL of povidone-iodine (2.5 mg.mL(-1)). In the control group, patients gargled with 25 mL of tap water. Before tracheal intubation, microorganisms were obtained from the posterior wall of the patient's pharynx using sterile cotton swabs. After anesthesia, all patients were extubated and bacteria contaminating the tip of the tracheal tube were sampled and cultured.

RESULTS

Before orotracheal intubation, all 19 patients who gargled with tap water (control group) had bacterial colonization on the posterior walls of the pharynx. This group included five patients who had methicillin-resistant staphylococcus aureus (MRSA) in their nasal cavity preoperatively and MRSA was also detected in the pharynx of four patients. Bacterial colonization was observed in all 19 patients who gargled with povidone-iodine (gargling group) and four patients carried MRSA in their nasal cavity, although no MRSA was detected in the pharynx. In the control group, all the patients had bacterial colonization at the tip of the tube after extubation. Additionally, MRSA was detected in two of the four patients. In the gargling group, povidone-iodine eradicated general bacteria and MRSA colonies in the pharynx before intubation and at the tip of the tube after extubation.

CONCLUSION

Gargling with povidone-iodine before oral intubation reduces the transport of bacteria into the trachea.

Respiratory nosocomial infections in the medical intensive care unit

Intensive care unit (ICU)-acquired lower respiratory tract infections include acute tracheobronchitis and hospital-acquired and ventilator-associated pneumonia (VAP). Nosocomial pneumonia is the second most common hospital-acquired infection and the leading cause of death in hospital-acquired infections. The mortality rate in VAP ranges from 24% to 76% in several studies. ICU ventilated patients with VAP have a 2- to 10-fold higher risk of death than patients without it. Early oropharyngeal colonization is pivotal in the etiopathogenesis of VAP. The knowledge of risk factors for VAP is important in developing effective preventive programs. Once the physician decides to treat a suspected episode of ICU-acquired pneumonia, some issues should be kept on mind: first, the adequacy of the initial empiric antibiotic therapy; second, the modification of initial inadequate therapy according to microbiological results; third, the benefit of combination therapy; and finally, the duration of the antimicrobial treatment. Additionally, a protocolized work-up to identify the causes of non-response to treatment is mandatory. All these issues are discussed in depth in this article.

Optimum sedation and analgesia in critical illness: we need to keep trying

Many studies have documented patients' distressing recollections of the intensive care unit (ICU). The study by van de Leur and colleagues, conducted in a group of surgical ICU patients with moderate severity of sickness, found that the frequency of such unpleasant memories was increased in those able to recall factual information about their stay in the ICU. The study did not include sedation scoring but it did use a simple tool to assess factual recall. This tool appeared reliable and could be easily applied in any ICU. Previous work strongly suggests that abolishing memory of ICU by using deep sedation would not be an appropriate response to these findings. Rather, we need to work on strategies that reduce distress by improving analgesia, reducing noxious stimuli (if possible) and, potentially, using pharmacology to produce a calm patient with minimal sedation. Achieving the latter is rarely possible today but it might become possible with future drug development.

Nosocomial lung infections in adult intensive care units

Nosocomial respiratory tract infections are the leading type of nosocomial infections. Despite the development of new antibiotic therapies, they are associated with an increased morbidity and mortality. Patients with comorbidities are especially predisposed to acquire these infections, as are patients exposed to respiratory therapy. Aspiration of colonized secretions from the oropharynx is the main mechanism of infection development. Barrier techniques to reduce aspiration and antimicrobial agents to alter bacterial flora are important in preventing pneumonia episodes. The initial institution of an adequate antibiotic regimen is a determinant of outcome. Nosocomial pneumonias are often difficult to treat due to antibiotic-resistant bacteria. Antibiotic policies are crucial in avoiding a progression in antibiotic resistance.

Do proton pump inhibitors increase the incidence of nosocomial pneumonia and related infectious complications when compared with histamine-2 receptor antagonists in critically ill trauma patients?

BACKGROUND

Proton pump inhibitors (PPI) may increase the risk of nosocomial pneumonia caused by profound irreversible gastric acid suppression. The study purpose was to characterize differences in nosocomial pneumonia and related infections in trauma patients administered either histamine2-receptor antagonists (H2RA) or PPI.

METHODS

Observational evaluation of consecutive critically ill adult trauma patients administered either omeprazole or famotidine during a 22-month period. Nosocomial infection was evaluated daily based on published CDC definitions.

RESULTS

Eighty of 269 patients fulfilled study criteria. The PPI group (n = 40) exhibited increased baseline risk for infection, demonstrated by higher ISS (p = 0.020), more chest tube placements (p = 0.031), and increased chest trauma (p = 0.025). Overall number of patients infected per group included 33% and 40% of patients administered PPI and H2RA, respectively (p = 0.64). Despite baseline differences, the incidence of nosocomial infection was similar (p = 0.87), and extrapolation of pneumonia based on 1000 patient days revealed a ratio 51.7 vs 52.2 in the PPI vs H2RA groups, respectively, which was not significant (p = 0.99).

CONCLUSIONS

Proton pump inhibitor administration does not increase risk of nosocomial pneumonia or other nosocomial infections compared with H2RA therapy in the critically ill trauma patient.

Early Tracheostomy versus Prolonged Endotracheal Intubation in Severe Head Injury

BACKGROUND

To see if early tracheostomy (fifth day) reduces duration of mechanical ventilation, ICU stay, incidence of pneumonia and mortality in comparison with prolonged intubation (PI) in patients with head injury.

METHODS

Patients were prospectively included in this study if they met the following criteria: isolated head injury, Glasgow coma scale (GCS) score < or =8 on first and fifth day, with cerebral contusion on CT scan. On the fifth day, randomization was done in two groups: early tracheostomy group (T group, n = 31) and prolonged endotracheal intubation group (I group, n = 31). We evaluated total time of mechanical ventilation, ICU stay, pneumonia incidence and mortality. Complications related to each technique were noted. Analysis of data were performed using Yates and Kruskall Walis tests. p < 0.05 was considered significant.

RESULTS

The two groups were comparable in term of age, sex, and Simplified Acute Physiologic Score (SAPS). The mean time of mechanical ventilatory support was shorter in T group (14.5 +/- 7.3) versus I group (17.5 +/- 10.6) (p = 0.02). After pneumonia was diagnosed, mechanical ventilatory time was 6 +/- 4.7 days for ET group versus 11.7 +/- 6.7 days for PEI group (p = 0.01). There was no difference in frequency of pneumonia or mortality between the two groups.

CONCLUSION

In severe head injury early tracheostomy decreases total days of mechanical ventilation or mechanical ventilation time after development of pneumonia.

Costs and risk factors for ventilator-associated pneumonia in a Turkish university hospital's intensive care unit: a case-control study

Background

Ventilator-associated pneumonia (VAP) which is an important part of all nosocomial infections in intensive care unit (ICU) is a serious illness with substantial morbidity and mortality, and increases costs of hospital care. We aimed to evaluate costs and risk factors for VAP in adult ICU.

Methods

This is a-three year retrospective case-control study. The data were collected between 01 January 2000 and 31 December 2002. During the study period, 132 patients were diagnosed as nosocomial pneumonia of 731 adult medical-surgical ICU patients. Of these only 37 VAP patients were assessed, and multiple nosocomially infected patients were excluded from the study. Sixty non-infected ICU patients were chosen as control patients.

Results

Median length of stay in ICU in patients with VAP and without were 8.0 (IQR: 6.5) and 2.5 (IQR: 2.0) days respectively (P < 0.0001). Respiratory failure (OR, 11.8; 95%, CI, 2.2–62.5; P < 0.004), coma in admission (Glasgow coma scale < 9) (OR, 17.2; 95% CI, 2.7–107.7; P < 0.002), depressed consciousness (OR, 8.8; 95% CI, 2.9–62.5; P < 0.02), enteral feeding (OR, 5.3; 95% CI, 1.0–27.3; P = 0.044) and length of stay (OR, 1.3; 95% CI, 1.0–1.7; P < 0.04) were found as important risk factors. Most commonly isolated microorganism was methicillin resistant Staphylococcus aureus (30.4%). Mortality rates were higher in patients with VAP (70.3%) than the control patients (35.5%) (P < 0.003). Mean cost of patients with and without VAP were 2832.2+/-1329.0 and 868.5+/-428.0 US Dollars respectively (P < 0.0001).

Conclusion

Respiratory failure, coma, depressed consciousness, enteral feeding and length of stay are independent risk factors for developing VAP. The cost of VAP is approximately five-fold higher than non-infected patients.

Low caloric intake is associated with nosocomial bloodstream infections in patients in the medical intensive care unit

OBJECTIVE

To determine whether caloric intake is associated with risk of nosocomial bloodstream infection in critically ill medical patients.

DESIGN

Prospective cohort study.

SETTING

Urban, academic medical intensive care unit.

PATIENTS

Patients were 138 adult patients who did not take food by mouth for > or =96 hrs after medical intensive care unit admission.

MEASUREMENTS

Daily caloric intake was recorded for each patient. Participants subsequently were grouped into one of four categories of caloric intake: <25%, 25-49%, 50-74%, and > or =75% of average daily recommended calories based on the American College of Chest Physicians guidelines. Simplified Acute Physiology Score II and serum albumin were measured on medical intensive care unit admission. Serum glucose (average value and maximum value each day) and route of feeding (enteral, parenteral, or both) were collected daily. Nosocomial bloodstream infections were identified by infection control surveillance methods.

MAIN RESULTS

The overall mean (+/-sd) daily caloric intake for all study participants was 49.4 +/- 29.3% of American College of Chest Physicians guidelines. Nosocomial bloodstream infection occurred in 31 (22.4%) participants. Bivariate Cox analysis revealed that receiving > or =25% of recommended calories compared with <25% was associated with significantly lower risk of bloodstream infection (relative hazard, 0.24; 95% confidence interval, 0.10-0.60). Simplified Acute Physiology Score II also was associated with risk of nosocomial bloodstream infection (relative hazard, 1.27; 95% confidence interval, 1.01-1.60). Average daily serum glucose, admission serum albumin, time to initiating nutritional support, and route of nutrition did not affect risk of bloodstream infection. After adjustment for Simplified Acute Physiology Score II in a multivariable analysis, receiving > or =25% of recommended calories was associated with a significantly lower risk of bloodstream infection (relative hazard, 0.27; 95% confidence interval, 0.11-0.68).

CONCLUSIONS

In the context of reducing risk of nosocomial bloodstream infections, failing to provide > or =25% of the recommended calories may be harmful. Higher caloric goals may be necessary to achieve other clinically important outcomes.

Patterns of microbiology in intra-abdominal packing for trauma

INTRODUCTION

This study tracks the microbiology of packs and infections in damage-control trauma patients to determine whether the packs cause infections.

METHODS

The peritoneum and abdominal packs were cultured in patients who survived to re-operation. The study recorded all positive cultures, pack count, packing duration, number of operations, and infections.

RESULTS

Thirty-five patients were studied. Twenty-eight patients survived; seven died. Packs were cultured in 29 patients. Data for 291 cultures collected. Pack cultures were positive in 20 patients and negative in nine. Positive pack cultures grew skin and gut flora. Twenty-one patients had infections, 14 did not. Organisms from positive pack cultures did not contribute to subsequent infections or mortality. Microbes and sites of infections were consistent with SICU patients.

CONCLUSIONS

Intra-abdominal packs are contaminated with skin and gut flora. These contaminants, however, do not contribute to subsequent infections. Pathogens from subsequent infections were typical for ICU infections.

Antibiotic prophylaxis strategies in the prevention of ventilator-associated pneumonia

Ventilator-associated pneumonia (VAP) is defined as a nosocomial pneumonia occurring > 48 h after endotracheal intubation. VAP may occur very early after intubation and it is usually defined as early-onset pneumonia, which occurs during the first 4 days. The occurrence of VAP is associated with an increase in morbidity and mortality. The pathogenesis of VAP often results from aspiration of colonised secretions in injured patients and this colonisation of the upper airway acts as a main risk factor in the development of pneumonia. It has been hypothesised that the bacterial inoculum may be decreased through the administration of systemic antibiotic prophylaxis. Antibiotic prophylaxis strategies to prevent VAP can be administered over an extended period to cover all microorganisms using selective digestive decontamination regimens, or in a short-term course of no more than 24 h. Probably, the second strategy is the most useful in the prevention of VAP because it has a lower impact on the emergence of bacterial resistance. This manuscript aims to review current opinions regarding antibiotic prophylaxis strategies in the prevention of VAP.

Caloric intake in medical ICU patients: consistency of care with guidelines and relationship to clinical outcomes

STUDY OBJECTIVES

To assess the consistency of caloric intake with American College of Chest Physicians (ACCP) recommendations for critically ill patients and to evaluate the relationship of caloric intake with clinical outcomes.

DESIGN

Prospective cohort study.

SETTING

Adult ICUs at two teaching hospitals.

PARTICIPANTS

Patients with an ICU length of stay of at least 96 h.

MEASUREMENTS AND RESULTS

On ICU admission, severity of illness (ie, simplified acute physiology score II) and markers of nutritional status (ie, serum albumin level and body mass index) were recorded. The route of feeding (ie, enteral or parenteral), actual caloric intake (ie, percentage of ACCP recommendations: 0 to 32% [tertile I]; 33 to 65% [tertile II]; >/==" BORDER="0"> 66% [tertile III]), and evidence of GI intolerance (ie, gastric aspirate levels, >/==" BORDER="0"> 100 mL) were recorded daily. The following outcomes were assessed: status on hospital discharge (alive vs dead); spontaneous ventilation before ICU discharge (yes vs no); and ICU discharge without developing nosocomial sepsis (yes vs no). The average caloric intake among 187 participants was 50.6% of the ACCP targets and was similar in both hospitals. Caloric intake was inversely related to the mean number of gastric aspirates >/==" BORDER="0"> 100 mL/d (Spearman rho = -0.04; p = 0.06), but not to severity of illness, nutritional status, or route of feeding. After accounting for the number of gastric aspirates >/==" BORDER="0"> 100 mL, severity of illness, nutritional status, and route of feeding, tertile II of caloric intake (vs tertile I) was associated with a significantly greater likelihood of achieving spontaneous ventilation prior to ICU discharge. Tertile III of caloric intake (vs tertile I) was associated with a significantly lower likelihood of both hospital discharge alive and spontaneous ventilation prior to ICU discharge.

CONCLUSIONS

Study participants were underfed relative to ACCP targets. These targets, however, may overestimate needs, since moderate caloric intake (ie, 33 to 65% of ACCP targets; approximately 9 to 18 kcal/kg per day) was associated with better outcomes than higher levels of caloric intake.

Nosocomial infections in adult intensive-care units

Nosocomial infections affect about 30% of patients in intensive-care units and are associated with substantial morbidity and mortality. Several risk factors have been identified, including the use of catheters and other invasive equipment, and certain groups of patients-eg, those with trauma or burns-are recognised as being more susceptible to nosocomial infection than others. Awareness of these factors and adherence to simple preventive measures, such as adequate hand hygiene, can limit the burden of disease. Management of nosocomial infection relies on adequate and appropriate antibiotic therapy, which should be selected after discussion with infectious-disease specialists and adapted as microbiological data become available.

Emergence of resistant microbes in critical care units is transient, despite an unrestricted formulary and multiple antibiotic trials

BACKGROUND

Antimicrobial resistance is a growing problem in the intensive care setting. This study was designed to evaluate the trends in bacterial prevalence and changes in antibiotic resistance at a large university hospital over the past decade. Antimicrobial resistance data were compared among the surgical intensive care unit (SICU), medical intensive care unit (MICU), and burn unit (BNU).

MATERIALS AND METHODS

A large database was created using hospital-wide data from 1989 to 2000. A retrospective analysis of the evolution of organism prevalence, antibiotic resistance, and response to study protocols was evaluated. The formulary was relatively unrestricted. All positive cultures were examined, focusing on wound, blood, and sputum cultures. Six primary antibiotics were targeted specifically to follow resistance patterns.

RESULTS

There were 847 identified positive wound cultures, 2,862 positive sputum cultures, and 2,252 positive blood cultures. The incidence of gram-positive and gram-negative organisms changed little in the SICU and BNU; however, there was a large increase in gram-positive organisms and yeast in the MICU over the past 5 years. Anaerobic bacteria and yeast were nearly nonexistent pathogens in the SICU and BNU. The resistance pattern of most organisms changed little following the introduction of a new antibiotic. However, the effectiveness of study antibiotics after formal clinical study periods decreased dramatically, albeit transiently.

CONCLUSION

Hospital-wide antibiotic resistance data may be misleading and may not reflect individual critical care units throughout the hospital. Bacterial flora, including resistant organisms, changed little over 10 years, despite an unrestricted formulary. The emergence of resistant and opportunistic organisms is related to antibiotic usage and can vary significantly over time. This suggests that a policy of administering limited duration, narrow spectrum antibiotics may reduce drug resistance.

Enteral feeding

In this review, topics with scientific strength, topical interest, and controversy were selected. Over the past 50 years, malnutrition has become increasingly recognized as a cause of increased morbidity and mortality in hospital patients. From 1970 to 1980, parenteral nutrition was advocated as the most appropriate form of nutritional therapy for hospital patients. Since then, parenteral nutrition has been replaced by enteral nutrition as the best way of delivering nutrients to hospital patients. The timing of enteral nutrition has been debated. Should it be instituted early, within the first 24 hours? In addition, enteral nutrition containing immune-enhancing nutrients such as arginine, omega-3 fatty acids, glutamine, and nucleotides has been advocated for critically ill patients. The relative merits of enteral versus total parenteral nutrition continue to be debated. Questions about possible complications related to enteral nutrition have been raised. Patients are at risk of nosocomial pneumonia from aspiration and at risk of bowel ischemia because enteral nutrition increases intestinal oxygen consumption. Steroids are often used to treat Crohn disease, but because of undesirable side effects, various techniques have been used to reduce steroid dependency. Enteral nutrition has been advocated as a way of reducing steroid dependency. Finally, enteral nutrition is routinely used to feed demented patients and those in a vegetative state. It is not clear whether this practice alters outcome or quality of life.

Prevention of infection in the intensive care unit: current advances and opportunities for the future

Recent studies have contributed to our understanding of the risk factors and the impact of nosocomial infections in the ICU, allowing a more rational approach to the prevention of such infections. Ventilator-associated pneumonia, bloodstream infections, and outbreaks all occur in the presence of artificial devices. High antibiotic pressure, prolonged hospitalization, and the presence of comorbidities facilitate the selection of multiresistant strains in the ICU setting. In clinical practice, prevention is the more effective investment to reduce costs. Potential measures of control should focus on the patient, the microorganisms, and the device. A number of recent studies addressing these issues have been published and will be reviewed in this article.

Tolerability of bolus versus continuous gastric feeding in brain-injured patients

Brain injured patients may exhibit altered gastric emptying; thus, some believe post-pyloric feeding to be tolerated better than gastric feeding. Reliable post-pylorus access can be difficult to obtain, so gastric feeding remains the preferred route for administering nutrition. Feeding intolerance may be associated with increased complications and costs. We sought to compare bolus (B) versus continuous (C) gastric feeding in brain injured patients. This retrospective cohort study was carried out at a neurological/neurosurgical intensive care unit at a Level 1 trauma and tertiary referral center. Our subjects were 152 consecutive patients over two years. Use of B or C feedings was based on clinicians' preferences. Abdominal examination and gastric residuals (> 75 mL over four hours) defined feeding intolerance (FI). Putative risks for FI were compared between the groups. Demographic characteristics were similar between groups B (n = 86) and C (n = 66). Feeding intolerance occurred more often in group B than in group C (60.5% vs. 37.9%, p = 0.009). Group C patients achieved 75% of nutritional goals faster than group B patients (median 3.3 vs. 4.6 days; p = 0.03). Prokinetic agent use was similar between the groups and did not reduce the time to achieve nutritional goals. There was a trend towards a reduction in the incidence of infections in group C (p = 0.05). Independent predictors of FI included: sucralfate (OR 2.3), propofol (OR 2.1), pentobarbital (OR 3.9) or paralytic (OR 3) use; older age (OR 5); days receiving mechanical ventilation (OR 1.2); and admission diagnosis of either intracerebral hemorrhage (OR 2.2) or ischemic stroke (OR 1.9). Continuous gastric feeding is better tolerated than B feedings in patients with acute brain injuries. Use of prokinetic agents did not affect time to achievement of nutritional goals. Use of common medications including sucralfate and propofol were associated with FI.

Biofilm Formation on Tracheostomy Tubes

An increased awareness of biofilms and their mechanisms has led to a better understanding of bacterial infections that occur following the placement of tracheostomy tubes and other implanted devices and prostheses. One aspect of biofilm formation that is still subject to debate is whether the specific material that is used to manufacture a tube has any bearing in the incidence of infection. We conducted a test of four different tube materials—polyvinyl chloride, silicone, stainless steel, and sterling silver—to ascertain how bacterial biofilms form on tracheostomy tubes and to determine if there is a material-dependent difference in biofilm formation. Scanning electron microscopy demonstrated that Pseudomonas aeruginosa and Staphylococcus epidermidis both formed bacterial biofilms on tracheostomy tubes in vitro. We also found that there was no difference in susceptibility to biofilm formation among the four tube materials tested.

Nosocomial pneumonia

PURPOSE OF REVIEW

Despite abundant literature on the management of nosocomial pneumonia, a number of aspects, from diagnosis to the therapy of nosocomial pneumonia, are still controversial. This review focuses on recent advances that can aid in the day-to-day care of these critically ill patients.

RECENT FINDINGS

The risk factors for nosocomial pneumonia in specific subsets of trauma, postoperative and burn injury patients have been identified, with emphasis on the type of pneumonia developing in these populations - early or late onset nosocomial pneumonia. Resolution of nosocomial pneumonia, in terms of improvement of clinical parameters such as oxygenation, fever, leukocytosis and bacterial eradication, has been reported, and these data can lead to a better understanding of the natural course of the disease. The importance of initial, accurate empiric therapy in improving mortality in nosocomial pneumonia has been reinforced by multiple studies. Newer techniques to study colonization and the routes of spread of pathogenic organisms in the intensive care unit are adding to our understanding of how pneumonia develops, the role of infection control measures and the types of strategies that are needed for prevention. Oral decontamination is showing promise as a technique to prevent ventilator-associated pneumonia, and noninvasive ventilation has been shown to be useful in various etiologies of respiratory failure, with the beneficial effect of reducing the incidence of ventilator-associated pneumonia and its associated mortality. The implementation of protocolized treatment guidelines and antibiotic rotation policies are emerging as useful tools for reducing the frequency of antibiotic resistance and the impact of nosocomial pneumonia.

SUMMARY

There is a better understanding of nosocomial pneumonia risk factors, mechanisms of bacterial colonization, and resolution of illness, with exciting developments in prevention and treatment emerging, and these data can help us achieve more effective management of this complex illness.

Influence on outcome of ventilator-associated pneumonia in multiple trauma patients with head trauma treated with selected digestive decontamination

OBJECTIVE

Ventilator-associated pneumonia is said to be associated with an increased mortality or a prolonged intensive care unit stay. In multiple trauma, the use of selective digestive decontamination has been reported to decrease morbidity and mortality associated with pneumonia. We performed a study to evaluate the attributable morbidity and mortality of ventilator-associated pneumonia in multiple trauma patients with head trauma treated with selective digestive decontamination.

DESIGN

Prospective, matched-paired, case-control study.

SETTING

Intensive care unit at a tertiary university hospital.

PATIENTS

During a 6-yr period, 324 consecutive multiple trauma patients with head trauma requiring mechanical ventilation for >48 hrs were prospectively followed for the development of VAP. Case-control matching criteria were as follows: 1) age difference within 5 yrs, 2) Glasgow coma scale within five categories, 3) injury severity score within 5 points, 4) APACHE II score within 5 points, 5) ventilation of control patients for at least as long as the cases. The selective digestive decontamination regimen was used in all patients (cases and controls): polymixin E, gentamicin, and amphotericin B. Systemic cefazolin (1 g three times a day) was given for the first 3 days of intensive care unit stay.

MEASUREMENTS AND MAIN RESULTS

Analysis was performed on 58 pairs that were matched with 100% of success The most common isolates recovered were Staphylococcus aureus (39%) and Haemophilus influenzae (22%). High-risk pathogens were rarely isolated: Pseudomonas aeruginosa (5.1%), Acinetobacter species (8.6%), and methicillin-resistant S. aureus (6.7%). The duration of mechanical ventilation and intensive care unit stay were increased in case patients (11.6 +/- 1.7 and 22.7 +/- 2.9 days, respectively) compared with control patients (9.4 +/- 1.3 and 16.8 +/- 2.9 days, respectively; p <.0006). Mortality was similar in both case (17%) and control (24%) patients.

CONCLUSION

Ventilator-associated pneumonia did not seem to increase mortality of multiple trauma patients with head trauma who received selective digestive decontamination. Whether or not this conclusion applied to trauma patients not receiving selective digestive decontamination should be evaluated in further studies.

Infection in the chronically critically ill: unique risk profile in a newly defined population

Although CCI is defined as prolonged ventilatory failure with tracheotomy stemming from preceding critical illness, the contention that multisystem debilities impact on most CCI patients' care and recovery is a central thesis of this volume. Perhaps reflecting the combined debilities inherent in CCI, infectious complications take their toll in morbidity, mortality, and persistent ventilatory insufficiency. Enhanced susceptibility to infection results from a potent admixture of barrier breakdown, exposure to virulent and resistant nosocomial pathogens, and postulated "immune exhaustion" that stems from the combined impact of comorbidities and the sequellae of critical illness. Strategies to improve outcome in CCI-related infection include standard measures of support especially nutrition, reducing environmental inoculum through pulmonary hygiene measures, skin care, and limiting barrier breaches, and appropriate antimicrobials directed at likely pathogens. Future stratification of patient risk on the basis of immune phenotype or genotype and potential immunomodulatory prophylaxis may be around the corner, as new prospects in the pharmaceutical armamentarium are presently undergoing testing.

Nosocomial and ventilator-associated pneumonias: developing country perspective

Nosocomial pneumonias are recognized as an important cause of morbidity and mortality in industrialized nations. Emerging data show that they play a similar role in the developing world. A host of extrinsic and intrinsic factors predispose individuals to the development of pneumonias, and a modification of some of these factors provides a low cost solution to prevention of pneumonias. The ideal modality for microbiologic diagnosis of pneumonia remains to be determined. Recent data suggest that there is no difference in outcome when noninvasive techniques are compared with invasive techniques. Antimicrobial resistance is a rapidly increasing problem globally, and combating this with appropriate antibiotic policies, close surveillance, and physician education is essential.

Hospital-acquired infections following the 1999 Marmara earthquake

In this study, medical records of all casualties admitted to our hospital following the Marmara earthquake, which struck northwest Turkey and resulted in the destruction of several towns in the Marmara region, were evaluated retrospectively. The time buried under the rubble, demographic data, type of medical and surgical therapies performed, type of injury and data on infection were analysed. Between 17 August and 25 September 1999, 630 trauma victims were received at our hospital and 532 (84%) of them were hospitalized. The mean age of hospitalized patients (312 males, 220 females) was 32 years (2-90 years). Two hundred and twenty patients were hospitalized for more than 48 h. Forty-one of them (18.6%) had 43 hospital-acquired infection (HAI) episodes, which were mostly wound infections (46.5%). A total of 143 culture specimens was collected and 48 yielded the following potential pathogens: 15 Acinetobacter baumanii (31.2%), nine Staphylococcus aureus (18.7%), seven Pseudomonas aeruginosa (14.6%), six Escherichia coli (12.5%), six Klebsiella pneumoniae (12.5%), two Stenotrophomonas maltophilia (4.2%) and three various Pseudomonas spp. (6.3%). All S. aureus strains were found to be resistant to methicillin in vitro. Two strains of A. baumannii and one P. aeruginosa were found to be resistant to all antimicrobials including carbapenems. Fifty-three victims died (10%) and 36 of those died during the first 48 h because of severe injuries and multi-organ failure. After 48 h of hospitalization, the mortality rate was significantly higher in those patients with HAI (14/41) than those without (3/179) (34.1% vs. 1.7%, P<0.05). In conclusion, trauma is the significant factor associated with HAI and a high incidence of Acinetobacter strains was responsible for HAI in trauma patients.