Continuous endotracheal tube cuff pressure control system protects against ventilator-associated pneumonia.

INTRODUCTION: The use of a system for continuous control of endotracheal tube cuff pressure reduced the incidence of ventilator-associated pneumonia (VAP) in one randomized controlled trial (RCT) with 112 patients but not in another RCT with 142 patients. In several guidelines on the prevention of VAP, the use of a system for continuous or intermittent control of endotracheal cuff pressure is not reviewed. The objective of this study was to compare the incidence of VAP in a large sample of patients (n = 284) treated with either continuous or intermittent control of endotracheal tube cuff pressure. METHODS: We performed a prospective observational study of patients undergoing mechanical ventilation during more than 48 hours in an intensive care unit (ICU) using either continuous or intermittent endotracheal tube cuff pressure control. Multivariate logistic regression analysis (MLRA) and Cox proportional hazard regression analysis were used to predict VAP. The magnitude of the effect was expressed as odds ratio (OR) or hazard ratio (HR), respectively, and 95% confidence interval (CI). RESULTS: We found a lower incidence of VAP with the continuous (n = 150) than with the intermittent (n = 134) pressure control system (22.0% versus 11.2%; p = 0.02). MLRA showed that the continuous pressure control system (OR = 0.45; 95% CI = 0.22-0.89; p = 0.02) and the use of an endotracheal tube incorporating a lumen for subglottic secretion drainage (SSD) (OR = 0.39; 95% CI = 0.19-0.84; p = 0.02) were protective factors against VAP. Cox regression analysis showed that the continuous pressure control system (HR = 0.45; 95% CI = 0.24-0.84; p = 0.01) and the use of an endotracheal tube incorporating a lumen for SSD (HR = 0.29; 95% CI = 0.15-0.56; p < 0.001) were protective factors against VAP. However, the interaction between type of endotracheal cuff pressure control system (continuous or intermittent) and endotracheal tube (with or without SSD) was not statistically significant in MLRA (OR = 0.41; 95% CI = 0.07-2.37; p = 0.32) or in Cox analysis (HR = 0.35; 95% CI = 0.06-1.84; p = 0.21). CONCLUSIONS: The use of a continuous endotracheal cuff pressure control system and/or an endotracheal tube with a lumen for SSD could help to prevent VAP in patients requiring more than 48 hours of mechanical ventilation.

Effect of nitrogen and phosphorus fertilization on the composition of rhizobacterial communities of two Chilean Andisol pastures.

The effect of nitrogen (N) and phosphorus (P) fertilization on composition of rhizobacterial communities of volcanic soils (Andisols) from southern Chile at molecular level is poorly understood. This paper investigates the composition of rhizobacterial communities of two Andisols under pasture after 1- and 6-year applications of N (urea) and P (triple superphosphate). Soil samples were collected from two previously established sites and the composition of rhizobacterial communities was determined by denaturing gradient gel electrophoresis (PCR-DGGE). The difference in the composition and diversity between rhizobacterial communities was assessed by nonmetric multidimensional scaling (MDS) analysis and the Shannon-Wiener index. In Site 1 (fertilized for 1 year), PCR-DGGE targeting 16S rRNA genes and MDS analysis showed that moderate N application (270 kg N ha(-1) year(-1)) without P significantly changed the composition of rhizobacterial communities. However, no significant community changes were observed with P (240 kg P ha(-1) year(-1)) and N-P application (270 kg N ha(-1) year(-1) plus 240 kg P ha(-1) year(-1)). In Site 2 (fertilized for 6 years with P; 400 kg P ha(-1) year(-1)), PCR-DGGE targeting rpoB, nifH, amoA and alkaline phosphatase genes and MDS analysis showed changes in rhizobacterial communities only at the highest rate of N application (600 kg N ha(-1) year(-1)). Quantitative PCR targeting 16S rRNA genes also showed higher abundance of bacteria at higher N application. In samples from both sites, the Shannon-Wiener index did not show significant difference in the diversity of rhizobacterial communities. The changes observed in rhizobacterial communities coincide in N fertilized pastures with lower soil pH and higher pasture yields. This study indicates that N-P application affects the soil bacterial populations at molecular level and needs to be considered when developing fertilizer practices for Chilean pastoral Andisols.

Platelet cytochrome c oxidase activity and quantity in septic patients.

OBJECTIVE: The cytopathic hypoxia theory proposes that there is an impaired cellular oxygen utilization during sepsis. Respiratory complex IV, or cytochrome c oxidase, was only previously studied in muscle biopsies of 16 surviving and 12 nonsurviving septic patients. We hypothesized that higher activities and quantities of this enzyme complex could be associated with septic patient survival. The objective was to evaluate the relationship between cytochrome c oxidase activities and quantities and 6-month survival in a larger series of septic patients using a less invasive method (circulating platelets). DESIGN: Prospective, multicenter, observational study. SETTING: The study was carried out in six Spanish intensive care units. PATIENTS: We included 96 septic patients. INTERVENTIONS: We determined the cytochrome c oxidase activity per citrate synthase activity ratio and cytochrome c oxidase quantity per citrate synthase activity ratio in circulating platelets at the time of diagnosis and related them to 6-month survival. The written informed consent from the family members was obtained. MEASUREMENTS AND MAIN RESULTS: Survivor patients (n = 54) showed higher cytochrome c oxidase activity per citrate synthase activity ratio (p = .04) and cytochrome c oxidase quantity per citrate synthase activity ratio (p = .006) than nonsurvivors (n = 42). Logistic regression analyses confirmed that the cytochrome c oxidase activity per citrate synthase activity ratio (p = .04) and cytochrome c oxidase quantity per citrate synthase activity ratio (p = .02) were independent predictors of 6-month survival. The area under the curve to predict 6-month survival was 0.62 (95% confidence interval 0.51-0.74; p = .04) for the cytochrome c oxidase activity per citrate synthase activity ratio and 0.67 (95% confidence interval 0.56-0.76; p = .003) for the cytochrome c oxidase quantity per citrate synthase activity ratio. A negative correlation was found between the cytochrome c oxidase quantity per citrate synthase activity ratio and Sepsis-Related Organ Failure Assessment score (p = .04). CONCLUSIONS: Platelet cytochrome c oxidase activity and quantity were independent predictors of 6-month survival and could be used as biomarkers of sepsis mortality. This is a rapid, easy, and less invasive protocol to assess mitochondrial function. Patients with lower cytochrome c oxidase activity and quantity could benefit from drugs that improve mitochondrial function.

Lower incidence of catheter-related bloodstream infection in cubital than in femoral artery access.

Data on catheter-related bloodstream infection (CRBSI) in cubital artery access are scarce. Thus, the objective of this study was to compare the incidence of CRBSI in a large series of patients with femoral or cubital artery catheters. We found 11 events of CRBSI in 1085 femoral artery catheters during 6497 days and none in 449 cubital artery catheters during 2709 days. Poisson regression analysis showed a higher incidence of CRBSI in femoral than in cubital artery site access (1.69 vs 0 CRBSI events per 1000 catheter-days; odds ratio 6.41, 95% confidence interval 1.05-infinite; p = 0.02). In conclusion, according to the results of our observational study, cubital artery access could have a lower risk of CRBSI than femoral artery access. However the development of randomized controlled trials is necessary before this conclusion can be definitively established. In addition, it is necessary to consider other potential mechanical complications when decision-making.

Niche Differentiation in the Composition, Predicted Function, and Co-occurrence Networks in Bacterial Communities Associated With Antarctic Vascular Plants.

Climate change directly affecting the Antarctic Peninsula has been reported to induce the successful colonization of ice-free lands by two Antarctic vascular plants (Deschampsia antarctica and Colobanthus quitensis). While studies have revealed the importance of microbiota for plant growth and stress tolerance in temperate climates, the role that plant-associated microbes play in the colonization of ice-free lands remains unknown. Consequently, we used high-throughput DNA sequence analyses to explore the composition, predicted functions, and interactive networks of plant-associated microbial communities among the rhizosphere, endosphere, and phyllosphere niches of D. antarctica and C. quitensis. Here we report a greater number of operational taxonomic units (OTUs), diversity, and richness in the microbial communities from the rhizosphere, relative to endosphere and phyllosphere. While taxonomic assignments showed greater relative abundances of Proteobacteria, Bacteroidetes, and Actinobacteria in plant niches, principal coordinate analysis revealed differences among the bacterial communities from the other compartments examined. More importantly, however, our results showed that most of OTUs were exclusively found in each plant niche. Major predicted functional groups of these microbiota were attributed to heterotrophy, aerobic heterotrophy, fermentation, and nitrate reduction, independent of plant niches or plant species. Co-occurrences network analyses identified 5 (e.g., Microbacteriaceae, Pseudomonaceae, Lactobacillaceae, and Corynebacteriaceae), 23 (e.g., Chitinophagaceae and Sphingomonadaceae) and 7 (e.g., Rhodospirillaceae) putative keystone taxa present in endosphere, phyllosphere, and rhizosphere, respectively. Our results revealed niche differentiation in Antarctic vascular plants, highlighting some putative microbial indicators and keystone taxa in each niche. However, more studies are required to determine the pivotal role that these microbes play in the successful colonization of ice-free lands by Antarctic plants.

Matrix metalloproteinase-9, -10, and tissue inhibitor of matrix metalloproteinases-1 blood levels as biomarkers of severity and mortality in sepsis.

INTRODUCTION: Matrix metalloproteinases (MMPs) play a role in infectious diseases through extracellular matrix (ECM) degradation, which favors the migration of immune cells from the bloodstream to sites of inflammation. Although higher levels of MMP-9 and tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) have been found in small series of patients with sepsis, MMP-10 levels have not been studied in this setting. The objective of this study was to determine the predictive value of MMP-9, MMP-10, and TIMP-1 on clinical severity and mortality in a large series of patients with severe sepsis. METHODS: This was a multicenter, observational, and prospective study carried out in six Spanish Intensive Care Units. We included 192 (125 surviving and 67 nonsurviving) patients with severe sepsis and 50 age- and sex-matched healthy controls in the study. Serum levels of MMP-9, MMP-10, TIMP-1, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-10 were measured in patients with severe sepsis at the time of diagnosis and in healthy controls. RESULTS: Sepsis patients had higher levels of MMP-10 and TIMP-1, higher MMP-10/TIMP-1 ratios, and lower MMP-9/TIMP-1 ratios than did healthy controls (P < 0.001). An association was found between MMP-9, MMP-10, TIMP-1, and MMP-9/TIMP-1 ratios and parameters of sepsis severity, assessed by the SOFA score, the APACHE-II score, lactic acid, platelet count, and markers of coagulopathy. Nonsurviving sepsis patients had lower levels of MMP-9 (P = 0.037), higher levels of TIMP-1 (P < 0.001), lower MMP-9/TIMP-1 ratio (P = 0.003), higher levels of IL-10 (P < 0.001), and lower TNF-alpha/IL-10 ratio than did surviving patients. An association was found between MMP-9, MMP-10, and TIMP-1 levels, and TNF-alpha and IL-10 levels. The risk of death in sepsis patients with TIMP-1 values greater than 531 ng/ml was 80% higher than that in patients with lower values (RR = 1.80; 95% CI = 1.13 to 2.87;P = 0.01; sensitivity = 0.73; specificity = 0.45). CONCLUSIONS: The novel findings of our study on patients with severe sepsis (to our knowledge, the largest series reporting data about MMP levels in sepsis) are that reduced MMP-9/TIMP-1 ratios and increased MMP-10 levels may be of great pathophysiologic significance in terms of severity and mortality, and that TIMP-1 levels may represent a biomarker to predict the clinical outcome of patients with sepsis.

The use of rifampicin-miconazole-impregnated catheters reduces the incidence of femoral and jugular catheter-related bacteremia.

BACKGROUND: The guidelines of the Centers for Disease Control and Prevention do not recommend the use of an antimicrobial- or antiseptic-impregnated catheter for short-term use. In previous studies, we have found a higher incidence of central venous catheter-related bacteremia among patients with femoral and central jugular accesses than among patients with other venous accesses. OBJECTIVE: The objective of our study was to determine the incidence of central venous catheter-related bacteremia associated with rifampicin-miconazole-impregnated catheters and standard catheters in patients with femoral and central jugular venous accesses. METHODS: This was a cohort study, conducted in the 24-bed polyvalent medical-surgical intensive care unit of a university hospital. We included patients who were admitted to the intensive care unit from 1 June 2006 through 30 September 2007 and who underwent femoral or central jugular venous catheterization. RESULTS: We inserted 184 femoral (73 rifampicin-miconazole-impregnated catheters and 111 standard catheters) and 241 central jugular venous catheters (114 rifampicin-miconazole-impregnated catheters and 127 standard catheters). We found a lower rate of central venous catheter-related bacteremia associated with rifampicin-miconazole-impregnated catheters than with standard catheters among patients with femoral access (0 vs. 8.62 cases per 1000 catheter-days; odds ratio, 0.13; 95% confidence interval, 0.00-0.86; P = .03) and among patients with central internal jugular access (0 vs. 4.93 cases per 1000 catheter-days; odds ratio, 0.13; 95% confidence interval, 0.00-0.93; P = .04). CONCLUSIONS: Rifampicin-minonazole-impregnated catheters are associated with a statistically significant reduction in the incidence of catheter-related bacteremia in patients with short-term catheter use at the central jugular and femoral sites.

Postoperative bleeding in cardiac surgery: the role of tranexamic acid in patients homozygous for the 5G polymorphism of the plasminogen activator inhibitor-1 gene.

BACKGROUND: Plasminogen activator inhibitor 1 (PAI-1) attenuates the conversion of plasminogen to plasmin. Polymorphisms of the PAI-1 gene are associated with varying PAI-1 levels and risk of prothrombotic events in nonsurgical patients. The purpose of this study, a secondary analysis of a clinical trial, was to investigate whether PAI-1 genotype affects the efficacy of tranexamic acid (TA) in reducing postoperative chest tube blood loss of patients undergoing cardiopulmonary bypass. METHODS: Fifty patients were classified according to PAI-1 genotype (4G/4G, 4G/5G, or 5G/5G). Twenty-four received 2 g TA before and after cardiopulmonary bypass, whereas 26 received placebo. The authors recorded data related to coagulation, fibrinolysis, and bleeding before surgery, at admission to the intensive care unit (0 h), and 4 and 24 h later. RESULTS: In patients not receiving TA, those with the 5G/5G genotype had significantly higher chest tube blood loss and transfusion requirements compared with patients with the other genotypes at all time points. Patients with the 5G/5G genotype receiving TA showed significantly lower blood loss compared with the placebo group. There were no significant differences in blood loss or transfusion requirements between patients with the 4G/4G genotype when TA was used. CONCLUSIONS: Plasminogen activator inhibitor-1 5G/5G homozygotes who did not receive TA showed significantly greater postoperative bleeding than patients with other PAI-1 genotypes. 5G/5G homozygotes who received TA showed the greatest blood-sparing benefit.

Influence of an endotracheal tube with polyurethane cuff and subglottic secretion drainage on pneumonia.

RATIONALE: Subglottic secretion drainage (SSD) appears to be effective in preventing ventilator-associated pneumonia (VAP), primarily by reducing early-onset pneumonia; but it may not prevent late-onset pneumonia. We tested the hypothesis using an endotracheal tube incorporating an ultrathin polyurethane cuff (which reduces channel formation and fluid leakage from the subglottic area), in addition to an SSD lumen, which would reduce the incidence of late-onset VAP. OBJECTIVES: To compare the incidence of VAP, using an endotracheal tube with polyurethane cuff and subglottic secretion drainage (ETT-PUC-SSD) versus a conventional endotracheal tube (ETT-C) with polyvinyl cuff, without subglottic secretion drainage. METHODS: Clinical randomized trial in a 24-bed medical-surgical intensive care unit. Patients expected to require mechanical ventilation for more than 24 hours were randomly assigned to one of two groups: one was ventilated with ETT-PUC-SSD and the other with ETT-C. MEASUREMENTS AND MAIN RESULTS: Tracheal aspirate samples were obtained during endotracheal intubation, then twice per week and finally on extubation. VAP was found in 31 of 140 (22.1%) patients in the ETT-C group and in 11 of 140 (7.9%) in the ETT-PUC-SSD group (P = 0.001). Cox regression analysis showed ETT-C as a risk factor for global VAP (hazard ratio [HR], 3.3; 95% confidence interval [CI], 1.66-6.67; P = 0.001), early-onset VAP (HR, 3.3; 95% CI, 1.19-9.09; P = 0.02), and late-onset VAP (HR, 3.5; 95% CI, 1.34-9.01; P = 0.01). CONCLUSIONS: The use of an endotracheal tube with polyurethane cuff and subglottic secretion drainage helps prevent early- and late-onset VAP. Clinical trial registered with www.clinicaltrials.gov (NCT 00475579).

Internal jugular venous catheter-related bacteremia according to central and posterior accesses.

BACKGROUND: Although there are many studies about central venous catheter-related infection, we have not found any analysis of the incidence of internal jugular venous catheter-related bacteremia associated with different accesses. OBJECTIVE: The objective of this study was to test whether the position of the internal jugular venous catheter, central or posterior, influences the incidence of bacteremia. DESIGN: A cohort study. SETTING: A 12-bed polyvalent medical-surgical intensive care unit (ICU). PATIENTS: Patients admitted to ICU between 1 May 2000 and 30 April 2004 who received one or more internal jugular venous catheters. MEASUREMENTS AND RESULTS: A total of 1,483 patients were admitted to the polyvalent ICU, of whom 1,311 underwent central venous catheterization. A total of 547 patients received 684 internal jugular venous catheters, 169 by posterior and 515 by central access. There were no significant differences between central and posterior access patients in sex, age, APACHE II (14.1 +/- 5.0 vs. 13.9 +/- 5.2, p = 0.40), diagnosis, order of catheter insertion, use of mechanical ventilation, use of antimicrobials, use of total parenteral nutrition or use of pulmonary artery catheter. We found a higher incidence of internal jugular venous catheter-related bacteremia with central (4.8 per 1000 catheter-day) than with posterior (1.2 per 1000 catheter-day) access (odds ratio 3.9; 95% confidence interval 1.1-infinite; p = 0.03). CONCLUSION: Posterior access has a lower incidence of internal jugular venous catheter-related bacteremia than central access in non-severely ill patients (according to the low APACHE II score values of the study patients).

Comparison of clinical cure rates in adults with ventilator-associated pneumonia treated with intravenous ceftazidime administered by continuous or intermittent infusion: a retrospective, nonrandomized, open-label, historical chart review.

BACKGROUND: Beta-lactam antibiotics are reported to exhibit time-dependent bactericidal activity. However, there are limited data on the clinical efficacy of ceftazidime administered by continuous infusion. OBJECTIVE: The objective of this study was to compare the clinical efficacy of ceftazidime administered by continuous infusion and by intermittent infusion in the treatment of ventilator-associated pneumonia (VAP) caused by gram-negative bacteria. METHODS: This was a retrospective chart review of patients with VAP caused by gram-negative bacteria who were treated with initial empiric ceftazidime therapy in the intensive care unit (ICU) over a 5-year period (from June 2002 to June 2007). The intermittent-infusion group received ceftazidime 2 g infused over 30 minutes every 12 hours; the continuous-infusion group received a ceftazidime loading dose of 1 g over 30 minutes, followed by 2 g infused over 720 minutes every 12 hours. Data extracted from patients' charts included sex, age, severity of the patient's condition at ICU admission (Acute Physiology and Chronic Health Evaluation II [APACHE II] score), diagnosis group, weight, creatinine clearance, MIC of the organism responsible for VAP, and severity of organ dysfunction at the time VAP was suspected (Sepsis-related Organ Failure Assessment [SOFA] score). Each clinical history was reviewed by a group of 6 staff intensivists who were blinded to whether the patient received ceftazidime by continuous or intermittent infusion. The clinical effect of treatment was categorized as cure (complete resolution of all clinical signs and symptoms of pneumonia) or failure (persistence or progression of any sign or symptom of pneumonia). RESULTS: The final sample consisted of 121 patients, of whom 88 (72.7%) were males. The mean (SD) age of the population was 62.87 (9.35) years. The mean APACHE II score on admission to the ICU was 16.08 (2.17), the SOFA score at suspicion of VAP was 8.80 (2.06), and the MIC of the organism responsible for VAP was 2.77 (2.24) microg/mL. There were no significant differences in these and other characteristics at baseline between those who received ceftazidime by continuous infusion (n = 56) and those who received ceftazidime by intermittent infusion (n = 65). On logistic regression analysis, continuous infusion was associated with a greater clinical cure rate than intermittent infusion (50/56 [89.3%] vs 34/65 [52.3%], respectively; odds ratio [OR] = 12.2; 95% CI, 3.47-43.21; P < 0.001). Patients with VAP caused by organisms with an MIC of 8 microg/mL had lower cure rates compared with those with VAP caused by organisms with an MIC < or =2 microg/mL (OR = 0.2; 95% CI, 0.04-0.71; P = 0.02) but not compared with those with an MIC of 4 microg/mL. No significant interaction was found between the type of ceftazidime infusion and the MIC of the causative organism. CONCLUSION: In this small, selected population of adult patients with VAP caused by gram-negative bacteria who were treated in a nonrandomized, open-label manner, ceftazidime administered by continuous infusion had greater clinical efficacy than ceftazidime administered by intermittent infusion.

Tranexamic acid attenuates inflammatory response in cardiopulmonary bypass surgery through blockade of fibrinolysis: a case control study followed by a randomized double-blind controlled trial.

INTRODUCTION: Extracorporeal circulation induces hemostatic alterations that lead to inflammatory response (IR) and postoperative bleeding. Tranexamic acid (TA) reduces fibrinolysis and blood loss after cardiopulmonary bypass (CPB). However, its effects on IR and vasoplegic shock (VS) are not well known and elucidating these effects was the main objective of this study. METHODS: A case control study was carried out to determine factors associated with IR after CPB. Patients undergoing elective CPB surgery were randomly assigned to receive 2 g of TA or placebo (0.9% saline) before and after intervention. We performed an intention-to-treat analysis, comparing the incidence of IR and VS. We also analyzed several biological parameters related to inflammation, coagulation, and fibrinolysis systems. We used SPSS version 12.2 for statistical purposes. RESULTS: In the case control study, 165 patients were studied, 20.6% fulfilled IR criteria, and the use of TA proved to be an independent protective variable (odds ratio 0.38, 95% confidence interval 0.18 to 0.81; P < 0.01). The clinical trial was interrupted. Fifty patients were randomly assigned to receive TA (24) or placebo (26). Incidence of IR was 17% in the TA group versus 42% in the placebo group (P = 0.047). In the TA group, we observed a significant reduction in the incidence of VS (P = 0.003), the use of norepinephrine (P = 0.029), and time on mechanical ventilation (P = 0.018). These patients showed significantly lower D-dimer, plasminogen activator inhibitor 1, and creatine-kinase levels and a trend toward lower levels of soluble tumor necrosis factor receptor and interleukin-6 within the first 24 hours after CPB. CONCLUSION: The use of TA attenuates the development of IR and VS after CPB.

Tracheal suction by closed system without daily change versus open system.

BACKGROUND: Tracheal suctioning costs are higher with a closed tracheal suction system (CTSS) than with an open system (OTSS), due to the need for complete daily change as recommended by the manufacturer. However, is it necessary to change the closed system daily? OBJECTIVE: To evaluate the tracheal suctioning costs and incidence of ventilator-associated pneumonia (VAP) using closed system without daily change vs OTSS. DESIGN: Prospective and randomised study. SETTING: An Intensive Care Unit in a university hospital. PATIENTS: Patients requiring mechanical ventilation. INTERVENTIONS: Patients were randomly assigned to CTSS without daily change or OTSS. We used a CTSS that allowed partial or complete change. MEASUREMENTS AND RESULTS: There were no significant differences between both groups of patients (236 with CTSS and 221 with OTSS) in gender, age, diagnosis, APACHE-II score, mortality, number of aspirations per day, percentage of patients who developed VAP (13.9 vs 14.1%) or the number of ventilator-associated pneumonia per 1000 days of mechanical ventilation (14.1 vs 14.6). There were not significant differences in tracheal suctioning costs per patient/day between CTSS vs OTSS (2.3+/-3.7 vs 2.4+/-0.5 Euros; p=0.96); however, when length of mechanical ventilation was lower than 4 days, the cost was higher with CTSS than with OTSS (7.2+/-4.7 vs 1.9+/-0.6 Euros; p<0.001); and when length of mechanical ventilation was higher than 4days, the cost was lower with CTSS than with OTSS (1.6+/-2.8 vs 2.5+/-0.5 Euros; p<0.001). CONCLUSION: CTSS without daily change is the optimal option for patients needing tracheal suction longer than 4 days.

Ventilator-associated pneumonia using a heated humidifier or a heat and moisture exchanger: a randomized controlled trial [ISRCTN88724583].

INTRODUCTION: Some guidelines to prevent ventilator-associated pneumonia (VAP) do not establish a recommendation for the preferential use of either heat and moisture exchangers (HMEs) or heated humidifiers (HHs), while other guidelines clearly advocate the use of HMEs. The aim of this study was to determine the incidence of VAP associated with HHs or HMEs. METHODS: A randomized study was conducted in the intensive care unit of a university hospital involving patients expected to require mechanical ventilation for >5 days. Patients were assigned to two groups; one group received HH and the other group received HME. Tracheal aspirate samples were obtained on endotracheal intubation, then twice a week, and finally on extubation, in order to diagnose VAP. Throat swabs were taken on admission to the intensive care unit, then twice a week, and finally at discharge from the intensive care unit in order to classify VAP as primary endogenous, secondary endogenous, or exogenous. RESULTS: A total of 120 patients were assigned to HMEs (60 patients) and HHs (60 patients); 16 patients received mechanical ventilation for less than five days and were excluded from the analysis. Data analysis of the remaining 104 patients (53 HMEs and 51 HHs) showed no significant differences between groups regarding sex, age, Acute Physiology and Chronic Health Evaluation II score, pre-VAP use of antibiotics, days on mechanical ventilation, and diagnosis group. VAP was found in eight of 51 (15.69%) patients in the HH group and in 21 of 53 (39.62%) patients in the HME group (P = 0.006). The median time free of VAP was 20 days (95% confidence interval, 13.34-26.66) for the HH group and was 42 days (95% confidence interval, 35.62-48.37) for the HME group (P <0.001). Cox regression analysis showed the HME as a risk factor for VAP (hazard rate, 16.2; 95% confidence interval, 4.54-58.04; P < 0.001). CONCLUSION: The patients mechanically ventilated during more than 5 days developed a lower incidence of VAP with a heated humidifier than heat and moisture exchanger.

Arterial catheter-related infection of 2,949 catheters.

INTRODUCTION: Which particular arterial catheter site is associated with a higher risk of infection remains controversial. The Centers for Disease Control and Prevention guidelines of 1996 and the latest guidelines of 2002 make no recommendation about which site or sites minimize the risk of catheter-related infection. The objective of the present study was to analyze the incidence of catheter-related local infection (CRLI) and catheter-related bloodstream infection (CRBSI) of arterial catheters according to different access sites. METHODS: We performed a prospective observational study of all consecutive patients admitted to the 24 bed medical and surgical intensive care unit of a 650 bed university hospital during three years (1 May 2000 to 30 April 2003). RESULTS: A total of 2,018 patients was admitted to the intensive care unit during the study period. The number of arterial catheters, the number of days of arterial catheterization, the number of CRLIs and the number of CRBSIs were as follows: total, 2,949, 17,057, 20 and 10; radial, 2,088, 12,007, 9 and 3; brachial, 112, 649, 0 and 0; dorsalis pedis, 131, 754, 0 and 0; and femoral, 618, 3,647, 11 and 7. The CRLI incidence was significantly higher for femoral access (3.02/1,000 catheter-days) than for radial access (0.75/1,000 catheter-days) (odds ratio, 1.5; 95% confidence interval, 1.10-2.13; P = 0.01). The CRBSI incidence was significantly higher for femoral access (1.92/1,000 catheter-days) than for radial access (0.25/1,000 catheter-days) (odds ratio, 1.9; 95% confidence interval, 1.15-3.41; P = 0.009). CONCLUSION: Our results suggest that a femoral site increases the risk of arterial catheter-related infection.

Chlorhexidine-silver sulfadiazine-impregnated venous catheters are efficient even at subclavian sites without tracheostomy.

BACKGROUND: Chlorhexidine-silver sulfadiazine (CHSS)-impregnated catheters have been found to decrease the risk of catheter-related bloodstream infection (CRBSI) and central venous catheter (CVC)-related costs. However, there are no published data about cost-effectiveness of the use of CHSS-impregnated catheters in subclavian venous access without the presence of tracheostomy (thus, with a very low risk of CRBSI). That was the objective of this study. METHODS: This was a retrospective study of patients admitted to a mixed intensive care unit who underwent placement of subclavian venous catheters without the presence of tracheostomy. RESULTS: Patients with standard catheters (n = 747) showed a higher CRBSI incidence density (0.95 vs 0/1,000 catheter-days; P = .02) and higher CVC-related cost per day ($3.78 ± $7.43 vs $3.31 ± $2.72; P < .001) than patients with a CHSS-impregnated catheter (n = 879). Exact logistic regression analysis showed that catheter duration (P = .02) and the type of catheter used (P = .01) were associated with the risk of CRBSI. Kaplan-Meier method showed that CHSS-impregnated catheters were associated with more prolonged CRBSI-free time than standard catheters (log-rank = 9.76; P = .002). Poisson regression analysis showed that CHSS-impregnated catheters were associated with a lower central venous catheter-related cost per day than standard catheters (odds ratio, 0.87; 95% confidence interval, 0.001-0.903; P < .001). CONCLUSIONS: The use of CHSS-impregnated catheters is an effective and efficient measure for the prevention of CRBSI even at subclavian venous access sites without the presence of tracheostomy.

Chlorhexidine-silver sulfadiazine- or rifampicin-miconazole-impregnated venous catheters decrease the risk of catheter-related bloodstream infection similarly.

BACKGROUND: The objective of this study was to compare the incidence of catheter-related bloodstream infection (CRBSI) with the use of second-generation chlorhexidine-silver sulfadiazine (CHSS)-impregnated catheters, rifampicin-miconazole (RM)-impregnated catheters, and standard catheters. METHODS: Retrospective study of patients admitted to an intensive care unit who received CHSS, RM, or standard catheters in femoral venous access. RESULTS: We diagnosed 18 CRBSIs in 245 patients with standard catheters in 2,061 days, zero CRBSI in 169 patients with CHSS-impregnated catheters in 1,489 days, and zero CRBSI in 227 patients with RM-impregnated catheters in 2,009 days. Patients with standard catheters compared with CHSS- and RM-impregnated catheters showed a higher rate of CRBSI (7.3%, 0%, and 0%, respectively; P < .001) and higher incidence density of CRBSI (8.7, 0, and 0 per 1,000 catheter days, respectively; P < .001). We found in the exact Poisson regression that standard catheters were associated with a higher CRBSI incidence than CHSS-impregnated catheters (P < .001) and RM-impregnated catheters (P < .001), controlling for catheter duration. We found in survival analysis that standard catheters were associated with a lower CRBSI-free time than CHSS-impregnated catheters (P < .001) and RM-impregnated catheters (P < .001). CONCLUSION: We found that CHSS- and RM-impregnated catheters decreased similarly the risk of CRBSI.

Central venous catheter-related infection in a prospective and observational study of 2,595 catheters.

INTRODUCTION: Central venous catheterization is commonly used in critically ill patients and may cause different complications, including infection. Although there are many studies about CVC-related infection, very few have analyzed it in detail. The objective of this study was to analyze the incidence of catheter-related local infection (CRLI) and catheter-related bloodstream infection (CRBSI) with central venous catheters (CVCs) according to different access sites. METHODS: This is a prospective and observational study, conducted in a 24-bed medical surgical intensive care unit of a 650-bed university hospital. All consecutive patients admitted to the ICU during 3 years (1 May 2000 and 30 April 2003) were included. RESULTS: The study included 2,018 patients. The number of CVCs and days of catheterization duration were: global, 2,595 and 18,999; subclavian, 917 and 8,239; jugular, 1,390 and 8,361; femoral, 288 and 2,399. CRLI incidence density was statistically higher for femoral than for jugular (15.83 versus 7.65, p < 0.001) and subclavian (15.83 versus 1.57, p < 0.001) accesses, and higher for jugular than for subclavian access (7.65 versus 1.57, p < 0.001). CRBSI incidence density was statistically higher for femoral than for jugular (8.34 versus 2.99, p = 0.002) and subclavian (8.34 versus 0.97, p < 0.001) accesses, and higher for jugular than for subclavian access (2.99 versus 0.97, p = 0.005). CONCLUSION: Our results suggest that the order for punction, to minimize the CVC-related infection risk, should be subclavian (first order), jugular (second order) and femoral vein (third order).

Efficiency of chlorhexidine-silver sulfadiazine-impregnated venous catheters at subclavian sites.

BACKGROUND: Cost-effectiveness analyses show that chlorhexidine-silver sulfadiazine (CHSS)-impregnated catheters reduce catheter-related bloodstream infection (CRBSI) and central venous catheter (CVC)-related costs. However, no studies have reported the efficiency of CHSS-impregnated catheters for venous access when the risk of CRBSI is low; for example, at the subclavian site. This study determined the cost of a CVC, diagnosis of CRBSI, and antimicrobial agents to treat CRBSI; we did not consider the cost of increased hospital stay. METHODS: This retrospective study included patients admitted to the intensive care unit at Hospital Universitario de Canarias (Tenerife, Spain) who had a subclavian venous catheter. RESULTS: Patients with CHSS catheters (n = 353) had a lower incidence density of CRBSI (2.12 vs 0 out of 1,000 catheter-days; P = .02) and lower CVC-related cost per catheter-day (3.35 ± 3.75 vs 3.94 ± 9.95; P = .002) than those with standard catheters (n = 518). CHSS-impregnated catheters were associated with a lower risk of CRBSI (exact logistic regression) (odds ratio, 0.10; 95% confidence interval, -∞ to 0.667; P = .008) than standard catheters when controlling for catheter duration. CHSS-impregnated catheters were also associated with a lower CVC-related cost per catheter day than standard catheters (Poisson regression) (odds ratio, 0.85; 95% confidence interval, 0.001-0.873; P < .001). CONCLUSIONS: CHSS-impregnated catheters may be efficient in preventing CRBSI in patients with subclavian venous access.

Periodically changing ventilator circuits is not necessary to prevent ventilator-associated pneumonia when a heat and moisture exchanger is used.

OBJECTIVE: To analyze the efficacy of periodically changing ventilator circuits for decreasing the rate of ventilator-associated pneumonia when a heat and moisture exchanger (HME) is used for humidification. The Centers for Disease Control and Prevention recommended not changing the circuits periodically. DESIGN: Randomized, controlled trial conducted between April 2001 and August 2002. SETTING: A 24-bed, medical-surgical intensive care unit in a 650-bed, tertiary-care hospital. PATIENTS: All patients requiring mechanical ventilation during more than 72 hours from April 2001 to August 2002. INTERVENTIONS: Patients were randomized into two groups: (1) ventilation with change of ventilator circuits every 48 hours and (2) ventilation with no change of circuits. Throat swabs were taken on admission and twice weekly until discharge to classify pneumonia as endogenous or exogenous. RESULTS: Three hundred four patients (143 from group 1 and 161 from group 2) with similar characteristics (age, gender, Acute Physiology and Chronic Health Evaluation II score, diagnostic group, and mortality) were analyzed. There was no significant difference in the rate of pneumonia between the groups (23.1% vs 23.0% and 15.5 vs 14.8 per 1,000 ventilator-days). There was no significant difference in the incidence of exogenous pneumonia per 1,000 days of mechanical ventilation (1.71 vs 1.25). There was no difference in the distribution of microorganisms causing pneumonia. CONCLUSIONS: Circuit change using an HME for humidification does not decrease pneumonia and represents an unnecessary cost.