Selective decontamination of the digestive tract. An overview

Topical antibiotic prophylaxis to reduce respiratory tract infections and mortality in adults receiving mechanical ventilation

BACKGROUND

Patients treated with mechanical ventilation in intensive care units (ICUs) have a high risk of developing respiratory tract infections (RTIs). Ventilator-associated pneumonia (VAP) has been estimated to affect 5% to 40% of patients treated with mechanical ventilation for at least 48 hours. The attributable mortality rate of VAP has been estimated at about 9%. Selective digestive decontamination (SDD), which consists of the topical application of non-absorbable antimicrobial agents to the oropharynx and gastroenteric tract during the whole period of mechanical ventilation, is often used to reduce the risk of VAP. A related treatment is selective oropharyngeal decontamination (SOD), in which topical antibiotics are applied to the oropharynx only. This is an update of a review first published in 1997 and updated in 2002, 2004, and 2009.

OBJECTIVES

To assess the effect of topical antibiotic regimens (SDD and SOD), given alone or in combination with systemic antibiotics, to prevent mortality and respiratory infections in patients receiving mechanical ventilation for at least 48 hours in ICUs.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), which contains the Cochrane Acute Respiratory Infections (ARI) Group's Specialised Register, PubMed, and Embase on 5 February 2020. We also searched the WHO ICTRP and ClinicalTrials.gov for ongoing and unpublished studies on 5 February 2020. All searches included non-English language literature. We handsearched references of topic-related systematic reviews and the included studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and cluster-RCTs assessing the efficacy and safety of topical prophylactic antibiotic regimens in adults receiving intensive care and mechanical ventilation. The included studies compared topical plus systemic antibiotics versus placebo or no treatment; topical antibiotics versus no treatment; and topical plus systemic antibiotics versus systemic antibiotics.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included a total of 41 trials involving 11,004 participants (five new studies were added in this update). The minimum duration of mechanical ventilation ranged from 2 (19 studies) to 6 days (one study). Thirteen studies reported the mean length of ICU stay, ranging from 11 to 33 days. The percentage of immunocompromised patients ranged from 0% (10 studies) to 22% (1 study). The reporting quality of the majority of included studies was very poor, so we judged more than 40% of the studies as at unclear risk of selection bias. We judged all studies to be at low risk of performance bias, though 47.6% were open-label, because hospitals usually have standardised infection control programmes, and possible subjective decisions on who should be tested for the presence or absence of RTIs are unlikely in an ICU setting. Regarding detection bias, we judged all included studies as at low risk for the outcome mortality. For the outcome RTIs, we judged all double-blind studies as at low risk of detection bias. We judged five open-label studies as at high risk of detection bias, as the diagnosis of RTI was not based on microbiological exams; we judged the remaining open-label studies as at low risk of detection bias, as a standardised set of diagnostic criteria, including results of microbiological exams, were used. Topical plus systemic antibiotic prophylaxis reduces overall mortality compared with placebo or no treatment (risk ratio (RR) 0.84, 95% confidence interval (CI) 0.73 to 0.96; 18 studies; 5290 participants; high-certainty evidence). Based on an illustrative risk of 303 deaths in 1000 people this equates to 48 (95% CI 15 to 79) fewer deaths with topical plus systemic antibiotic prophylaxis. Topical plus systemic antibiotic prophylaxis probably reduces RTIs (RR 0.43, 95% CI 0.35 to 0.53; 17 studies; 2951 participants; moderate-certainty evidence). Based on an illustrative risk of 417 RTIs in 1000 people this equates to 238 (95% CI 196 to 271) fewer RTIs with topical plus systemic antibiotic prophylaxis. Topical antibiotic prophylaxis probably reduces overall mortality compared with no topical antibiotic prophylaxis (RR 0.96, 95% CI 0.87 to 1.05; 22 studies, 4213 participants; moderate-certainty evidence). Based on an illustrative risk of 290 deaths in 1000 people this equates to 19 (95% CI 37 fewer to 15 more) fewer deaths with topical antibiotic prophylaxis. Topical antibiotic prophylaxis may reduce RTIs (RR 0.57, 95% CI 0.44 to 0.74; 19 studies, 2698 participants; low-certainty evidence). Based on an illustrative risk of 318 RTIs in 1000 people this equates to 137 (95% CI 83 to 178) fewer RTIs with topical antibiotic prophylaxis. Sixteen studies reported adverse events and dropouts due to adverse events, which were poorly reported with sparse data. The certainty of the evidence ranged from low to very low.

AUTHORS' CONCLUSIONS

Treatments based on topical prophylaxis probably reduce respiratory infections, but not mortality, in adult patients receiving mechanical ventilation for at least 48 hours, whereas a combination of topical and systemic prophylactic antibiotics reduces both overall mortality and RTIs. However, we cannot rule out that the systemic component of the combined treatment provides a relevant contribution in the observed reduction of mortality. No conclusion can be drawn about adverse events as they were poorly reported with sparse data.

Aspiration and the Risk of Ventilator-Associated Pneumonia

Ventilator-associated pneumonia (VAP) is a major concern in the intensive care unit. It is estimated that the risk of developing VAP may be as high as 1% per ventilated day, and the attributable mortality approaches 50% in some series. A growing body of evidence implicates the role of microaspiration of contaminated oropharyngeal and perhaps gastroesophageal secretions into the airways as an integral step in the pathogenesis of VAP. In patients who have been intubated and mechanically ventilated for >72 hours, the majority of VAP is caused by enteric gram-negative organisms, presumably of gastrointestinal origin. As a result, strategies designed to minimize the risk of these contaminated secretions into the normally sterile airways are of paramount importance in terms of VAP prevention. This review highlights the important etiological role of the gut in the development of VAP and also discusses the evidence behind interventions that may modulate the risk of both aspiration and subsequent VAP.

Reduction of the intestinal endotoxin pool by three different SDD regimens in human volunteers

Aerobic Gram-negative bacilli (AGNB) carried in the gut by healthy individuals generate 1 mg of 'physiological' endotoxin per g of faeces. Successful eradication of AGNB from the gut would be expected to lead to a lowering of the intestinal endotoxin pool. This prompted us to evaluate the reduction of intestinal endotoxin in 6 healthy volunteers who each received 3 different oral antibiotic regimens. Regimen 1 was polymyxin E (600 mg/day), regimen 2 polymyxin E (400 mg/day) combined with tobramycin (320 mg/day) and regimen 3 pefloxacin (800 mg/day). Each regimen was separated by an antibiotic free period of 3 months. A faecal sample (minimally 2 g) was obtained from each volunteer, before treatment began and afterwards 3 times a week on alternating days (Monday, Wednesday, Friday) for 3 weeks. Each volunteer produced 30 samples, 10 each per oral antibiotic. The samples were serially diluted in nutrient broth for the colony count of AGNB, whilst endotoxin was measured using the classical Limulus amoebocyte lysate micro-assay. The base-line value of faecal AGNB was 10 3-4 colony forming units/g of faeces. All samples obtained on day 3 following antibiotic intake were negative for AGNB, and remained negative during antibiotic intake. The AGNB free carrier state was associated with a reduction in gut endotoxin. The reduction was approximately 10 ng (1 log) for polymyxin E and pefloxacin, whilst the combination of polymyxin/tobramycin significantly reduced the intestinal endotoxin concentrations from 1 mg to 100 ng in the gut; a reduction of 104. Although AGNB were killed by the three regimens, the 'free' endotoxin left in the gut was effectively neutralised by the combination polymyxin/tobramycin only. From a clinical point of view, gut-derived endotoxaemia may play a role in the systemic inflammatory response syndrome and hence the outcome, in critically ill intensive care patients. This study supports other work which indicates that mortality is significantly reduced in only those intensive care patients who received oral polymyxin/tobramycin.

Inapparent Outbreaks of Ventilator-Associated Pneumonia An Ecologic Analysis of Prevention and Cohort Studies

Objective:

To compare ventilator-associated pneumonia (VAP) rates and patterns of isolates across studies of antibiotic and non-antibiotic methods for preventing VAP.

Design:

With the use of 42 cohort study groups as the reference standard, the prevalence of VAP was modeled in two linear regressions: one with the control groups and the other with the intervention groups of 96 VAP prevention studies. The proportion of patients admitted with trauma and the VAP diagnostic criteria were used as ecologic correlates. Also, the patterns of pathogenic isolates were available for 117 groups.

Results:

In the first regression model, the VAP rates for the control groups of antibiotic-based prevention studies were at least 18 (CI95, 12 to 24) per 100 patients higher than those in the cohort study groups (P< .001). By contrast, comparisons of cohort study groups with all other control and intervention groups in the first and second regression models yielded differences that were less than 6 per 100 and not significant (P> .05). For control groups with VAP rates greater than 35%, the patterns of VAP isolates, such as the proportion ofStaphylococcus aureus,more closely resembled those in the corresponding intervention groups than in the cohort groups.

Conclusions:

The rates of VAP in the control groups of the antibiotic prevention studies were significantly higher than expected and the patterns of pathogenic isolates were unusual. These observations suggest that inapparent outbreaks of VAP occurred in these studies. The possibility remains that antibiotic-based VAP prevention presents a major cross-infection hazard.

The effects of clinical and statistical heterogeneity on the predictive values of results from meta-analyses

Variance between studies in a meta-analysis will exist. This heterogeneity may be of clinical, methodological or statistical origin. The last of these is quantified by the I(2) -statistic. We investigated, using simulated studies, the accuracy of I(2) in the assessment of heterogeneity and the effects of heterogeneity on the predictive value of meta-analyses. The relevance of quantifying I(2) was determined according to the likely presence of heterogeneity between studies (low, high, or unknown) and the calculated I(2) (low or high). The findings were illustrated by published meta-analyses of selective digestive decontamination and weaning protocols. As expected, I(2) increases and the likelihood of drawing correct inferences from a meta-analysis decreases with increasing heterogeneity. With low levels of heterogeneity, I(2) does not appear to be predictive of the accuracy of the meta-analysis result. With high levels of heterogeneity, even meta-analyses with low I(2) -values have low predictive values. Most commonly, the level of heterogeneity in a meta-analysis will be unknown. In these scenarios, I(2) determination may help to identify estimates with low predictive values (high I(2) ). In this situation, the results of a meta-analysis will be unreliable. With low I(2) -values and unknown levels of heterogeneity, predictive values of pooled estimates may range extensively, and findings should be interpreted with caution. In conclusion, quantifying statistical heterogeneity through I(2) -statistics is only helpful when the amount of clinical heterogeneity is unknown and I(2) is high. Objective methods to quantify the levels of clinical and methodological heterogeneity are urgently needed to allow reliable determination of the accuracy of meta-analyses.

Observational study of current use of selective decontamination of the digestive tract in UK critical care units

BACKGROUND

Evidence supporting selective decontamination of the digestive tract (SDD) is reasonably strong. We set out to determine use in UK critical care units and to compare patient outcomes between units that do and those that do not use SDD.

METHODS

A total of 250 UK general critical care units were surveyed. Case mix, outcomes, and lengths of stay for admissions to SDD units (with and without an i.v. component) and non-SDD units were compared using data from the Intensive Care National Audit & Research Centre Case Mix Programme database.

RESULTS

A response was received from all the 250 critical care units surveyed. Of these, 13 (5.2%) reported using SDD on some or all admissions, and of these, 3 reported using an i.v. component. Data on 284,690 admissions (April 2008-March 2011) from units reporting to the ICNARC Case Mix Programme (CMP) were included in the analyses. Admissions to SDD (n=196) and non-SDD (n=9) units were a similar case mix with similar infection rates and average lengths of stay in the unit and hospital. There was no difference in risk-adjusted unit or hospital mortality. The rate of unit-acquired infections in blood was significantly lower in SDD units using an i.v. component.

CONCLUSIONS

Use of SDD in UK critical care is very low. The rate of unit-acquired infections in blood was significantly lower in SDD units using an i.v. component, but did not translate into a difference in acute hospital mortality or length of stay. There is a need to better understand the barriers to adoption of SDD into clinical practice and such work is underway.

Clinical stakeholders' opinions on the use of selective decontamination of the digestive tract in critically ill patients in intensive care units: an international Delphi study

Introduction

Selective decontamination of the digestive tract (SDD) is a prophylactic antibiotic regimen that is not widely used in practice. We aimed to describe the opinions of key ‘stakeholders’ about the validity of the existing evidence base, likely consequences of implementation, relative importance of their opinions in influencing overall practice, likely barriers to implementation and perceptions of the requirement for further research to inform the decision about whether to embark on a further large randomised controlled trial.

Methods

This was a Delphi study informed by comprehensive framework of possible determinants of health professionals’ behaviour to study Critical Care practice in four countries. There were four key stakeholder participant groups including ICU physicians, pharmacists, clinical leads, and clinical microbiologists/ infectious disease physicians. Round one comprised participant interviews and Rounds two and three were online questionnaires using Delphi method.

Results

In this study, 141 participants were recruited of whom 82% were retained. Participants rated themselves as knowledgeable about SDD. Antibiotic resistance was identified as the most important issue. SDD was seen as a low clinical priority but few participants reported strong opposition. There was moderate agreement that research to date has not adequately addressed concerns about antibiotic resistance and lacks generalizability. Participants indicated equipoise with regard to benefits and harms of SDD, and indicated strong support for a further randomised trial.

Conclusions

Clinicians have clinical equipoise about the effectiveness of SDD. Future research requires longer follow up to assess antibiotic resistance as well as greater validity/generalizability to provide definitive answers on the effectiveness of decontamination and effects on antibiotic resistance. SDD was regarded as not being a high clinical priority, which may limit future trial participation. These results have identified that further large randomised controlled trial of SDD in critical care is both warranted and appropriate.

Selective decontamination of the digestive tract in critically ill children: systematic review and meta-analysis

OBJECTIVE

We examined the impact of selective decontamination of the digestive tract on morbidity and mortality in critically ill children.

DATA SOURCES

We searched MEDLINE, EMBASE, the Cochrane Register of Controlled Trials, and previous meta-analyses.

STUDY SELECTION

We included all randomized controlled trials comparing administration of enteral antimicrobials in selective decontamination of the digestive tract with or without a parenteral component with placebo or standard therapy used in the controls.

DATA EXTRACTION

The primary end point was the number of acquired pneumonias. Secondary end points were number of infections and overall mortality. Odds ratios were pooled with the random effect model.

DATA SYNTHESIS

Four randomized controlled trials including 335 patients were identified. Pneumonia was diagnosed in five of 170 patients (2.9%) for selective decontamination of the digestive tract and 16 of 165 patients (9.7%) for controls (odds ratio 0.31; 95% confidence interval 0.11-0.87; p = .027). Overall mortality for selective decontamination of the digestive tract was 13 of 170 (7.6%) vs. control, 11 of 165 (6.7%) (odds ratio 1.18; 95% confidence interval 0.50-2.76; p = .70). In three studies (n = 109), infection occurred in ten of 54 (18.5%) patients on selective decontamination of the digestive tract and 24 of 55 (43.6%) in the controls (odds ratio 0.34; 95% confidence interval 0.05-2.18; p = .25).

CONCLUSIONS

In the four available pediatric randomized controlled trials, selective decontamination of the digestive tract significantly reduced the number of children who developed pneumonia.

Selective digestive tract decontamination in critically ill patients

INTRODUCTION

Selective decontamination of the digestive tract (SDD) has been proposed to prevent endogenous and exogenous infections and to reduce mortality in critically ill patients. Although the efficacy of SDD has been confirmed by randomized controlled trials (RCTs) and systematic reviews, SDD has been the subject of intense controversy, based mainly on an insufficient evidence of efficacy and on concerns about resistance.

AREAS COVERED

This article reviews the philosophy, the current evidence on the efficacy of SDD and the issue of emergence of resistance. All SDD RCTs were searched using Embase and Medline, with no restriction of language, gender or age. Personal archives were also explored, including abstracts from major scientific meetings; references in papers and published meta-analyses on SDD were crosschecked. Up-to-date evidence of the impact of SDD on carriage, infections and mortality is presented, and the efficacy of SDD in selected patient groups was investigated, along with the problem of the emergence of resistance.

EXPERT OPINION

SDD significantly reduces the number of infections of the lower respiratory tract and bloodstream, multiple organ failure and mortality. It also controls resistance, particularly when the full protocol of parenteral and enteral antimicrobials is used.

A study of the perceived risks, benefits and barriers to the use of SDD in adult critical care units (the SuDDICU study)

BACKGROUND

Hospital acquired infections are a major cause of morbidity and mortality and markedly increased health care costs. Critically ill patients who require management in an Intensive Care Unit are particularly susceptible to these infections which are associated with a very high mortality. Selective decontamination of the digestive tract (SDD) may reduce these infections and improve mortality but it has not been widely adopted into practice. We aim to 1. Clarify reasons why clinicians have avoided implementing SDD into clinical practice despite the current best-evidence 2. Describe barriers to SDD implementation and 3. Identify what further evidence is required before full scale clinical implementation would be considered appropriate and feasible.

METHODS

We have developed an international 'multi-lens' approach to investigate SDD from several perspectives. In case studies we will identify accounts of implementation of SDD in practice, in terms of the behaviours performed by the full range of individual clinicians, accounts of how SDD was first introduced into the Unit and specific content that may be used to populate the content of behaviour change techniques to be used in an implementation intervention and procedures to consider in order to deliver an implementation trial. In a 4 round Delphi study we will identify the range of stakeholders' beliefs, views and perceived barriers relating to the use of SDD. We will generate hypotheses about key beliefs about SDD and will inform the feasibility of any future randomised controlled trial. In large-scale nationwide postal questionnaire surveys of the state of current practice we will identify the factors predicting acceptability of an effectiveness or implementation trial using, and informed by, the theoretical domains structure. In semi-structured interviews with active international clinical trialists we will assess the feasibility of a randomised controlled trial and identify challenges and barriers to undertaking research in the field of SDD research.

DISCUSSION

We believe these methods will allow us to determine whether clinical implementation trials or further large effectiveness trials are required before full scale implementation into clinical practice.

Selective decontamination of the digestive tract reduces pneumonia and mortality

Selective decontamination of the digestive tract (SDD) has been subject of numerous randomized controlled trials in critically ill patients. Almost all clinical trials showed SDD to prevent pneumonia. Nevertheless, SDD has remained a controversial strategy. One reason for why clinicians remained reluctant to implement SDD into daily practice could be that mortality was reduced in only 2 trials. Another reason could be the heterogeneity of trials of SDD. Indeed, many different prophylactic antimicrobial regimes were tested, and dissimilar diagnostic criteria for pneumonia were applied amongst the trials. This heterogeneity impeded interpretation and comparison of trial results. Two other hampering factors for implementation of SDD have been concerns over the risk of antimicrobial resistance and fear for escalation of costs associated with the use of prophylactic antimicrobials. This paper describes the concept of SDD, summarizes the results of published trials of SDD in mixed medical-surgical intensive care units, and rationalizes the risk of antimicrobial resistance and rise of costs associated with this potentially life-saving preventive strategy.

[Debates in intensive medicine: Pro: selective decontamination]

Selective decontamination of the digestive tract (SDD) has been proven to prevent infections of endogenous development and reduce mortality in critically ill patients under prolonged mechanical ventilation. Historical arguments against its use, like the development of bacterial resistance or the selection of resistant microorganisms and the absence of influence on mortality have not been confirmed. Moreover, recent clinical trials designed to evaluate these variables, show remarkable reductions in the incidence of resistant bacteria and a significant beneficial effect on mortality. Furthermore, no increases in workload or costs have been documented. A few studies with post-trial and intermediate range follow-up periods didn't find increases in resistance. Implementation of SDD requires motivation and leadership in order to achieve cooperation of other related hospital specialists, training of several categories of healthcare professionals, and continuous monitoring of results. In order to facilitate the use of SDD in the critically ill, this preventive measure should be incorporated in guidelines of national and international scientific societies and working groups involved in the care of the critically ill patient. The general implementation of SDD in our intensive care units must be accompanied by a registry in order to be able to monitor the effect on the incidence of infection and bacterial resistance. For this purpose, the Spanish national ICU infection and resistance surveillance programme ENVIN-HELICS, active over the last 15 years, constitutes both a more than adequate tool, and the convenient reference data base.

Antibiotic prophylaxis to reduce respiratory tract infections and mortality in adults receiving intensive care

BACKGROUND

Pneumonia is an important cause of mortality in intensive care units (ICUs). The incidence of pneumonia in ICU patients ranges between 7% and 40%, and the crude mortality from ventilator-associated pneumonia may exceed 50%. Although not all deaths in patients with this form of pneumonia are directly attributable to pneumonia, it has been shown to contribute to mortality in ICUs independently of other factors that are also strongly associated with such deaths.

OBJECTIVES

To assess the effects of prophylactic antibiotic regimens, such as selective decontamination of the digestive tract (SDD) for the prevention of respiratory tract infections (RTIs) and overall mortality in adults receiving intensive care.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009, issue 1), which contains the Cochrane Acute Respiratory Infections (ARI) Group's Specialised Register; MEDLINE (January 1966 to March 2009); and EMBASE (January 1990 to March 2009).

SELECTION CRITERIA

Randomised controlled trials (RCTs) of antibiotic prophylaxis for RTIs and deaths among adult ICU patients.

DATA COLLECTION AND ANALYSIS

At least two review authors independently extracted data and assessed trial quality.

MAIN RESULTS

We included 36 trials involving 6914 people. There was variation in the antibiotics used, patient characteristics and risk of RTIs and mortality in the control groups. In trials comparing a combination of topical and systemic antibiotics, there was a significant reduction in both RTIs (number of studies = 16, odds ratio (OR) 0.28, 95% confidence interval (CI) 0.20 to 0.38) and total mortality (number of studies = 17, OR 0.75, 95% CI 0.65 to 0.87) in the treated group. In trials comparing topical antimicrobials alone (or comparing topical plus systemic versus systemic alone) there was a significant reduction in RTIs (number of studies = 17, OR 0.44, 95% CI 0.31 to 0.63) but not in total mortality (number of studies = 19, OR 0.97, 95% CI 0.82 to 1.16) in the treated group.

AUTHORS' CONCLUSIONS

A combination of topical and systemic prophylactic antibiotics reduces RTIs and overall mortality in adult patients receiving intensive care. Treatment based on the use of topical prophylaxis alone reduces respiratory infections but not mortality. The risk of resistance occurring as a negative consequence of antibiotic use was appropriately explored only in one trial which did not show any such effect.

Survival benefit of the full selective digestive decontamination regimen

PURPOSE

We assessed the impact of the full protocol of selective decontamination of the digestive tract (SDD) using parenteral and enteral antimicrobials on mortality.

MATERIALS AND METHODS

A systematic review was performed searching MEDLINE, EMBASE, the Cochrane Register of Controlled Trials, previous meta-analyses, and conferences proceedings. We included all randomized controlled trials (RCTs) comparing the full protocol of SDD, including oropharyngeal and intestinal administration of antibiotics combined with the parenteral component, with no treatment or placebo. The primary end points were overall mortality, mortality attributable to infection, early, and late mortality.

RESULTS

Twenty-one RCTs on 4902 patients were included. Overall mortality was significantly reduced (odds ratio [OR], 0.71; 95% confidence interval [CI]; 0.61-0.82; P < .001). There was a nonsignificant reduction in infection-related mortality (6 RCTs; OR, 0.40; 95% CI, 0.10-1.59; P = .19) and early mortality (4 RCTs; OR, 0.64; 95% CI, 0.34-1.19; P = 0.16), and a significant reduction in late mortality (5 RCTs; OR, 0.56; 95% CI, 0.40-0.77; P < .001). The subgroup analysis showed a significant mortality reduction in successfully decontaminated patients (OR, 0.58; 95% CI, 0.45-0.77; P < .001), and when parenteral and enteral antimicrobials were administered to every patient receiving treatment in the intensive care unit (OR, 0.59; 95% CI, 0.42-0.82; P < .001).

CONCLUSIONS

The findings strongly indicated that the full protocol of SDD reduces mortality in critically ill patients, in particular when successful decontamination is obtained. Eighteen patients should be treated with SDD to prevent one death.

Impact of Selective Decontamination of the Digestive Tract on Carriage and Infection Due to Gram-Negative and Gram-Positive Bacteria: A Systematic Review of Randomised Controlled Trials

Meta-analyses of randomised controlled trials of selective digestive decontamination have clinical outcome measures, mainly pneumonia and mortality. This meta-analysis has a microbiological endpoint and explores the impact of selective digestive decontamination on Gram-negative and Gram-positive carriage and severe infections. We searched electronic databases, Cochrane Register of Controlled Trials, previous meta-analyses and conference proceedings with no language restrictions. We included randomised controlled trials which compared the selective digestive decontamination protocol with no treatment or placebo. Three reviewers independently applied selection criteria, performed the quality assessment and extracted the data. The outcome measures were carriage and severe infection due to Gram-negative and Gram-positive bacteria. Odds ratios were pooled with the random effect model. Fifty-four randomised controlled trials comprising 9473 patients were included; 4672 patients received selective digestive decontamination and 4801 were controls. Selective digestive decontamination significantly reduced oropharyngeal carriage (odds ratio [OR] 0.13, 95% confidence interval [CI] 0.07 to 0.23), rectal carriage (OR 0.15, 95% CI 0.07 to 0.31), overall infection (OR 0.17, 95% CI 0.10 to 0.28), lower respiratory tract infection (OR 0.11, 95% CI 0.06 to 0.20) and bloodstream infection (OR 0.35, 95% CI 0.21 to 0.67) due to Gram-negative bacteria. Reduction in Gram-positive carriage was not significant. Gram-positive lower airway infections were significantly reduced (OR 0.52, 95% CI 0.34 to 0.78). Gram-positive bloodstream infections were not significantly increased (OR 1.03, 95% CI 0.75 to 1.41). The association of parenteral and enteral antimicrobials was superior to enteral antimicrobials in reducing carriage and severe infections due to Gram-negative bacteria. This meta-analysis confirms that selective digestive decontamination mainly targets Gram-negative bacteria; it does not show a significant increase in Gram-positive infection.

Gastric alkalinization after major trauma

BACKGROUND

Gastric function in trauma patients is poorly understood. In animals, shock causes gastric luminal alkalinization and bile reflux. In trauma patients, studies of stress gastritis prophylaxis demonstrated with continuous gastric pH monitoring that the stomach became alkaline even without antisecretory therapy. Therefore, we hypothesized that trauma patients have an alkaline gastric environment that may be because of bile reflux.

METHODS

A prospective observational study at an urban Level I trauma center was performed. All major torso trauma patients (severe head injuries excluded) who met the criteria for standardized shock resuscitation were eligible for inclusion. A 12.5 Fr silastic pH probe (Sandhill Scientific) was placed in the stomach and the gastric pH continuously monitored for 7 days. Patients received no stress gastritis prophylaxis. Gastric samples were obtained each day and assayed for total bile acids and pH.

RESULTS

Twelve patients were entered into the study. Mean age was 31 years +/- 4 years, 67% men, 75% blunt mechanism of injury, and mean Injury Severity Score 28 +/- 3. Three patients (25%) developed multiple organ failure and four acquired ventilator-associated pneumonia. During the first day of continuous pH monitoring, 9 of 12 patients had a gastric pH >4 for the majority of the day with 7 patients having essentially no acid production. During subsequent days, gastric pH began to drop and by the 4th day the majority of each day was spent at a pH <4. Additionally, gastric pH of patients with ventilator-associated pneumonia or multiple organ failure tended to be more alkaline. Bile acid was present in the gastric fluid of all patients in varying amounts. However, there was no significant correlation between gastric pH and bile acid concentration.

CONCLUSIONS

Traumatic injury causes gastric luminal alkalinization that may be related, only in part, to bile acid reflux. Other alkalinizing factors remain to be elucidated.

Clinical review: airway hygiene in the intensive care unit

Maintenance of airway secretion clearance, or airway hygiene, is important for the preservation of airway patency and the prevention of respiratory tract infection. Impaired airway clearance often prompts admission to the intensive care unit (ICU) and can be a cause and/or contributor to acute respiratory failure. Physical methods to augment airway clearance are often used in the ICU but few are substantiated by clinical data. This review focuses on the impact of oral hygiene, tracheal suctioning, bronchoscopy, mucus-controlling agents, and kinetic therapy on the incidence of hospital-acquired respiratory infections, length of stay in the hospital and the ICU, and mortality in critically ill patients. Available data are distilled into recommendations for the maintenance of airway hygiene in ICU patients.

Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock: 2008

OBJECTIVE

To provide an update to the original Surviving Sepsis Campaign clinical management guidelines, "Surviving Sepsis Campaign Guidelines for Management of Severe Sepsis and Septic Shock," published in 2004.

DESIGN

Modified Delphi method with a consensus conference of 55 international experts, several subsequent meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee. This process was conducted independently of any industry funding.

METHODS

We used the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) system to guide assessment of quality of evidence from high (A) to very low (D) and to determine the strength of recommendations. A strong recommendation (1) indicates that an intervention's desirable effects clearly outweigh its undesirable effects (risk, burden, cost) or clearly do not. Weak recommendations (2) indicate that the tradeoff between desirable and undesirable effects is less clear. The grade of strong or weak is considered of greater clinical importance than a difference in letter level of quality of evidence. In areas without complete agreement, a formal process of resolution was developed and applied. Recommendations are grouped into those directly targeting severe sepsis, recommendations targeting general care of the critically ill patient that are considered high priority in severe sepsis, and pediatric considerations.

RESULTS

Key recommendations, listed by category, include early goal-directed resuscitation of the septic patient during the first 6 hrs after recognition (1C); blood cultures before antibiotic therapy (1C); imaging studies performed promptly to confirm potential source of infection (1C); administration of broad-spectrum antibiotic therapy within 1 hr of diagnosis of septic shock (1B) and severe sepsis without septic shock (1D); reassessment of antibiotic therapy with microbiology and clinical data to narrow coverage, when appropriate (1C); a usual 7-10 days of antibiotic therapy guided by clinical response (1D); source control with attention to the balance of risks and benefits of the chosen method (1C); administration of either crystalloid or colloid fluid resuscitation (1B); fluid challenge to restore mean circulating filling pressure (1C); reduction in rate of fluid administration with rising filing pressures and no improvement in tissue perfusion (1D); vasopressor preference for norepinephrine or dopamine to maintain an initial target of mean arterial pressure > or = 65 mm Hg (1C); dobutamine inotropic therapy when cardiac output remains low despite fluid resuscitation and combined inotropic/vasopressor therapy (1C); stress-dose steroid therapy given only in septic shock after blood pressure is identified to be poorly responsive to fluid and vasopressor therapy (2C); recombinant activated protein C in patients with severe sepsis and clinical assessment of high risk for death (2B except 2C for postoperative patients). In the absence of tissue hypoperfusion, coronary artery disease, or acute hemorrhage, target a hemoglobin of 7-9 g/dL (1B); a low tidal volume (1B) and limitation of inspiratory plateau pressure strategy (1C) for acute lung injury (ALI)/acute respiratory distress syndrome (ARDS); application of at least a minimal amount of positive end-expiratory pressure in acute lung injury (1C); head of bed elevation in mechanically ventilated patients unless contraindicated (1B); avoiding routine use of pulmonary artery catheters in ALI/ARDS (1A); to decrease days of mechanical ventilation and ICU length of stay, a conservative fluid strategy for patients with established ALI/ARDS who are not in shock (1C); protocols for weaning and sedation/analgesia (1B); using either intermittent bolus sedation or continuous infusion sedation with daily interruptions or lightening (1B); avoidance of neuromuscular blockers, if at all possible (1B); institution of glycemic control (1B), targeting a blood glucose < 150 mg/dL after initial stabilization (2C); equivalency of continuous veno-veno hemofiltration or intermittent hemodialysis (2B); prophylaxis for deep vein thrombosis (1A); use of stress ulcer prophylaxis to prevent upper gastrointestinal bleeding using H2 blockers (1A) or proton pump inhibitors (1B); and consideration of limitation of support where appropriate (1D). Recommendations specific to pediatric severe sepsis include greater use of physical examination therapeutic end points (2C); dopamine as the first drug of choice for hypotension (2C); steroids only in children with suspected or proven adrenal insufficiency (2C); and a recommendation against the use of recombinant activated protein C in children (1B).

CONCLUSIONS

There was strong agreement among a large cohort of international experts regarding many level 1 recommendations for the best current care of patients with severe sepsis. Evidenced-based recommendations regarding the acute management of sepsis and septic shock are the first step toward improved outcomes for this important group of critically ill patients.

Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock: 2008

OBJECTIVE

To provide an update to the original Surviving Sepsis Campaign clinical management guidelines, "Surviving Sepsis Campaign guidelines for management of severe sepsis and septic shock," published in 2004.

DESIGN

Modified Delphi method with a consensus conference of 55 international experts, several subsequent meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee. This process was conducted independently of any industry funding.

METHODS

We used the GRADE system to guide assessment of quality of evidence from high (A) to very low (D) and to determine the strength of recommendations. A strong recommendation indicates that an intervention's desirable effects clearly outweigh its undesirable effects (risk, burden, cost), or clearly do not. Weak recommendations indicate that the tradeoff between desirable and undesirable effects is less clear. The grade of strong or weak is considered of greater clinical importance than a difference in letter level of quality of evidence. In areas without complete agreement, a formal process of resolution was developed and applied. Recommendations are grouped into those directly targeting severe sepsis, recommendations targeting general care of the critically ill patient that are considered high priority in severe sepsis, and pediatric considerations.

RESULTS

Key recommendations, listed by category, include: early goal-directed resuscitation of the septic patient during the first 6 hrs after recognition (1C); blood cultures prior to antibiotic therapy (1C); imaging studies performed promptly to confirm potential source of infection (1C); administration of broad-spectrum antibiotic therapy within 1 hr of diagnosis of septic shock (1B) and severe sepsis without septic shock (1D); reassessment of antibiotic therapy with microbiology and clinical data to narrow coverage, when appropriate (1C); a usual 7-10 days of antibiotic therapy guided by clinical response (1D); source control with attention to the balance of risks and benefits of the chosen method (1C); administration of either crystalloid or colloid fluid resuscitation (1B); fluid challenge to restore mean circulating filling pressure (1C); reduction in rate of fluid administration with rising filing pressures and no improvement in tissue perfusion (1D); vasopressor preference for norepinephrine or dopamine to maintain an initial target of mean arterial pressure > or = 65 mm Hg (1C); dobutamine inotropic therapy when cardiac output remains low despite fluid resuscitation and combined inotropic/vasopressor therapy (1C); stress-dose steroid therapy given only in septic shock after blood pressure is identified to be poorly responsive to fluid and vasopressor therapy (2C); recombinant activated protein C in patients with severe sepsis and clinical assessment of high risk for death (2B except 2C for post-operative patients). In the absence of tissue hypoperfusion, coronary artery disease, or acute hemorrhage, target a hemoglobin of 7-9 g/dL (1B); a low tidal volume (1B) and limitation of inspiratory plateau pressure strategy (1C) for acute lung injury (ALI)/acute respiratory distress syndrome (ARDS); application of at least a minimal amount of positive end-expiratory pressure in acute lung injury (1C); head of bed elevation in mechanically ventilated patients unless contraindicated (1B); avoiding routine use of pulmonary artery catheters in ALI/ARDS (1A); to decrease days of mechanical ventilation and ICU length of stay, a conservative fluid strategy for patients with established ALI/ARDS who are not in shock (1C); protocols for weaning and sedation/analgesia (1B); using either intermittent bolus sedation or continuous infusion sedation with daily interruptions or lightening (1B); avoidance of neuromuscular blockers, if at all possible (1B); institution of glycemic control (1B) targeting a blood glucose < 150 mg/dL after initial stabilization ( 2C ); equivalency of continuous veno-veno hemofiltration or intermittent hemodialysis (2B); prophylaxis for deep vein thrombosis (1A); use of stress ulcer prophylaxis to prevent upper GI bleeding using H2 blockers (1A) or proton pump inhibitors (1B); and consideration of limitation of support where appropriate (1D). Recommendations specific to pediatric severe sepsis include: greater use of physical examination therapeutic end points (2C); dopamine as the first drug of choice for hypotension (2C); steroids only in children with suspected or proven adrenal insufficiency (2C); a recommendation against the use of recombinant activated protein C in children (1B).

CONCLUSION

There was strong agreement among a large cohort of international experts regarding many level 1 recommendations for the best current care of patients with severe sepsis. Evidenced-based recommendations regarding the acute management of sepsis and septic shock are the first step toward improved outcomes for this important group of critically ill patients.

[Selective digestive decontamination. Why don't we apply the evidence in the clinical practice?]

Selective digestive decontamination (SDD) is a prophylactic strategy whose objective is to reduce the incidence of infections, mainly mechanical ventilation associated pneumonia in patients who require intensive cares, preventing or eradicating the oropharyngeal and gastrointestinal carrier state of potentially pathogenic microorganisms. Fifty-four randomized clinical trials (RCTs) and 9 meta-analysis have evaluated SDD. Thirty eight RCTs show a significant reduction of the infections and 4 of mortality. All the meta-analyses show a significant reduction of the infections and 5 out of the 9 meta-analyses report a significant reduction in mortality. Thus, 5 patients from the ICU with SDD must be treated to prevent pneumonia and 12 patients from the ICU should be treated to prevent one death. The data that show benefit of the SDD on mortality have an evidence grade 1 or recommendation grade A (supported by at least two level 1 investigations). The aim of this review is to explain the pathogeny of infections in critical patients, describe selective digestive decontamination, analyze the evidence available on it efficacy and the potential adverse effects and discuss the reasons published by the experts who advise against the use of SDD, even though it is recognized as the best intervention evaluated in intensive cares to reduce morbidity and mortality of the infections.

Diagnosis, management and prevention of ventilator-associated pneumonia in the UK

BACKGROUND AND OBJECTIVE

Ventilator-associated pneumonia is a nosocomial infection that occurs in patients receiving mechanical ventilation for >48 h. Many aspects of its diagnosis, treatment and management are controversial. We used a postal questionnaire to survey current practice within the UK.

METHODS

Questionnaire study of 207 general intensive care units in the UK.

RESULTS

The response rate was 77.3%. Regarding diagnosis, 30% of units obtained specimens from the lungs invasively, while the remainder relied on tracheal aspirates. In only 28.2% of units using tracheal aspirates were results reported in a quantitative manner. A clinical suspicion of ventilator-associated pneumonia would lead to the administration of empirical antibiotic therapy in the majority of units (77.2%), opinion being almost equally divided on whether this should be mono (49.1%) or combination therapy (50.9%). Although most units received regular microbiology feedback (90.5%), the involvement of a microbiologist in the antibiotic decision-making process was variable. Antibiotics were continued for a median of 7 days (inter-quartile range 5-8.5, range 2-14 days). Compliance with the principal methods of ventilator-associated pneumonia prevention was good.

CONCLUSION

There is widespread variation in the methods used for the diagnosis of ventilator-associated pneumonia within the UK. The majority of units rely on non-quantitative analysis of tracheal aspirates. This technique has a high percentage of false-positives, and suggests widespread over utilization of antibiotics. However, most agree that antibiotics should be given empirically when there is a clinical suspicion of ventilator-associated pneumonia. The widespread introduction of 'ventilator bundles' appears to have ensured that most units actively take measures to prevent ventilator-associated pneumonia.

Oral decontamination for prevention of pneumonia in mechanically ventilated adults: systematic review and meta-analysis

OBJECTIVE

To evaluate the effect of oral decontamination on the incidence of ventilator associated pneumonia and mortality in mechanically ventilated adults.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline, Embase, CINAHL, the Cochrane Library, trials registers, reference lists, conference proceedings, and investigators in the specialty.

REVIEW METHODS

Two independent reviewers screened studies for inclusion, assessed trial quality, and extracted data. Eligible trials were randomised controlled trials enrolling mechanically ventilated adults that compared the effects of daily oral application of antibiotics or antiseptics with no prophylaxis.

RESULTS

11 trials totalling 3242 patients met the inclusion criteria. Among four trials with 1098 patients, oral application of antibiotics did not significantly reduce the incidence of ventilator associated pneumonia (relative risk 0.69, 95% confidence interval 0.41 to 1.18). In seven trials with 2144 patients, however, oral application of antiseptics significantly reduced the incidence of ventilator associated pneumonia (0.56, 0.39 to 0.81). When the results of the 11 trials were pooled, rates of ventilator associated pneumonia were lower among patients receiving either method of oral decontamination (0.61, 0.45 to 0.82). Mortality was not influenced by prophylaxis with either antibiotics (0.94, 0.73 to 1.21) or antiseptics (0.96, 0.69 to 1.33) nor was duration of mechanical ventilation or stay in the intensive care unit.

CONCLUSIONS

Oral decontamination of mechanically ventilated adults using antiseptics is associated with a lower risk of ventilator associated pneumonia. Neither antiseptic nor antibiotic oral decontamination reduced mortality or duration of mechanical ventilation or stay in the intensive care unit.

Selective decontamination of the digestive tract reduces bacterial bloodstream infection and mortality in critically ill patients. Systematic review of randomized, controlled trials

A systematic review and meta-analysis of randomized controlled trials (RCTs) of selective decontamination of the digestive tract (SDD) was undertaken to evaluate the impact of this procedure on bacterial bloodstream infection and mortality. Data sources were Medline, Embase, Cochrane Register of Controlled Trials, previous meta-analyses, and conference proceedings, without restriction of language or publication status. RCTs were retrieved that compared oropharyngeal and/or intestinal administration of antibiotics as part of the SDD protocol, with or without a parenteral component, with no treatment or placebo in the controls. The three outcome measures were patients with bloodstream infection, causative micro-organisms, and total mortality. Fifty-one RCTs conducted between 1987 and 2005, comprising 8065 critically ill patients were included in the review; 4079 patients received SDD and 3986 were controls. SDD significantly reduced overall bloodstream infections [odds ratio (OR), 0.73; 95% confidence interval (CI), 0.59-0.90; P=0.0036], gram-negative bloodstream infections (OR, 0.39; 95% CI, 0.24-0.63; P<0.001) and overall mortality (OR, 0.80; 95% CI, 0.69-0.94; P=0.0064), without affecting gram-positive bloodstream infections (OR, 1.06; 95% CI, 0.77-1.47). The subgroup analysis showed an even larger impact of SDD using parenteral and enteral antimicrobials on overall bloodstream infections, bloodstream infections due to gram-negative bacteria and overall mortality with ORs of 0.63 (95% CI, 0.46-0.87; P=0.005), 0.30 (95% CI, 0.16-0.56; P<0.001), and 0.74 (95% CI, 0.61-0.91; P=0.0034), respectively. Twenty patients need to be treated with SDD to prevent one gram-negative bloodstream infection and 22 patients to prevent one death.

The effect of selective decontamination of the digestive tract on mortality in multiple trauma patients: a multicenter randomized controlled trial

OBJECTIVE

Evaluation of selective decontamination of the digestive tract (SDD) on late mortality in ventilated trauma patients in an intensive care unit (ICU).

METHODS

A multicenter, randomized controlled trial was undertaken in 401 trauma patients with Hospital Trauma Index-Injury Severity Score of 16 or higher. Patients were randomized to control (n=200) or SDD (n=201), using polymyxin E, tobramycin, and amphotericin B in throat and gut throughout ICU treatment combined with cefotaxime for 4 days. Primary endpoint was late mortality excluding early death from hemorrhage or craniocerebral injury. Secondary endpoints were infection and organ dysfunction.

RESULTS

Mortality was 20.9% with SDD and 22.0% in controls. Overall late mortality was 15.3% (57/372) as 29 patients died from cerebral injury, 16 SDD and 13 control. The odds ratio (95% confidence intervals) of late mortality for SDD relative to control was 0.75 (0.40-1.37), corresponding to estimates of 13.4% SDD and 17.2% control. The overall infection rate was reduced in the test group (48.8% vs. 61.0%). SDD reduced lower airway infections (30.9% vs. 50.0%) and bloodstream infections due to aerobic Gram-negative bacilli (2.5% vs. 7.5%). No difference in organ dysfunction was found.

CONCLUSION

This study demonstrates that SDD significantly reduces infection in multiple trauma, although this RCT in 401 patients was underpowered to detect a mortality benefit.

Management of severe sepsis and septic shock: challenges and recommendations

Sepsis and related aspects has become an area of active and intense research, leading to important advances for an early diagnosis and appropriate management useful to improve patient outcome. The septic response is an extremely complex cascade of events, including proinflammatory, anti-inflammatory, humoral, cellular, and circulatory involvement. The pathophysiology of this syndrome, its various and changing clinical aspects, and the vast variety of therapeutic options available, not always of well-proved efficacy, make its management a goal difficult to achieve.

Acute complications associated with bedside placement of feeding tubes

Several types of feeding tubes can be placed at a patient's bedside; examples include nasogastric, nasointestinal, gastrostomy, and jejunostomy tubes. Nasoenteral tubes can be placed blindly at bedside or with the assistance of placement devices. Nasoenteric tubes can also be placed via fluoroscopy and endoscopy. Gastrostomy and jejunostomy tubes can be placed using endoscopic techniques. This paper will describe the indications and contraindications for different types of tubes that can be placed at the bedside and complications associated with tube placement. Complications associated with nasoenteral tubes include inadvertent malpositioning of the tube, epistaxis, sinusitis, inadvertent tube removal, tube clogging, tube-feeding-associated diarrhea, and aspiration pneumonia. Complications from percutaneous gastrostomy and jejunostomy tube placements include procedure-related mishaps, site infection, leakage, buried bumper syndrome, tube malfunction, and inadvertent removal. These complications will be reviewed, along with a discussion of incidence, cause, treatment, and prevention approaches.

[Management of ventilator acquired pneumonia]

Ventilator-associated pneumonia occurs in the evolution of 8 to 70% of patients in the Intensive Care Unit. It is the main site of nosocomial infection for mechanically ventilated patients. Nosocomial pneumonia represents an important cause of morbidity and mortality, despite progresses in antibiotic prescription, use of intensive care and prevention. This review is based on the ATS guidelines, and reviews epidemiology, diagnosis and treatment of ventilator-acquired pneumonia, in non-immunocompromised adults.

Pathogenesis of multiple organ dysfunction syndrome: gut origin, protection, and decontamination

Clinical and experimental studies performed over the past several decades have implicated bacterial and endotoxin translocation (BET) from the gut to distant organs in the pathogenesis of multiple organ dysfunction syndrome (MODS). Experimental studies in animals directed at maintaining the integrity of the intestinal mucosa have shown efficacy in preventing BET and the induction of distant inflammatory processes, suggesting that the egress of bacteria and their surface endotoxins might be pivotal in inducing MODS. However, clinical studies have failed to convincingly recapitulate these beneficial effects. Selective digestive decontamination, although it effectively decreases rates of respiratory infection, has failed to reduce MODS in critically ill patients and, except in certain patient subsets, has had no demonstrable effect on mortality. Nevertheless, the gut is an immunologically active organ that, irrespective of BET occurrence, appears to contribute significantly to the development of distant organ dysfunction following ischemia/reperfusion injury. Resuscitation strategies aimed at minimizing the inflammatory effects of gut-derived mediators, such as toxic oxygen species, appear promising in preventing the development of distant organ injury in the critically ill patient.

Impact of selective decontamination of the digestive tract on fungal carriage and infection: systematic review of randomized controlled trials

OBJECTIVE

To determine the impact of the antifungal component of selective decontamination of the digestive tract on fungal carriage, infection and fungaemia.

DESIGN

Meta-analysis of randomized controlled trials of selective decontamination of the digestive tract.

STUDY SELECTION

Data sources included Medline, Embase, Cochrane Register of Controlled Trials, previous meta-analyses, personal communications and conference proceedings, without restriction of language or publication status. All randomized trials were selected that compared oropharyngeal and/or intestinal administration of antifungals amphotericin B or nystatin, as part of selective decontamination protocol, with no treatment in the controls. There were 42 randomized controlled trials with a total of 6,075 critically ill patients.

METHODS

Three reviewers independently applied selection criteria, performed quality assessment and extracted the data. The main outcome measures were patients with fungal carriage, patients with fungal infections and patients with fungaemia. Odds ratios were pooled with the random effect model.

MEASUREMENTS AND RESULTS

Enteral antifungals significantly reduced fungal carriage (odds ratio 0.32, 95% confidence interval 0.19-0.53) and overall fungal infections (0.30, 0.17-0.53). Fungaemia was not significantly reduced in the treatment group (0.89, 0.16-4.95).

CONCLUSIONS

Antifungals, as part of selective decontamination of the digestive tract, reduce fungal carriage and infection but not fungaemia in critically ill patients and may justify the inclusion of an antifungal component in the decontamination protocol.

Recent Trends in the Management of Ventilator-Associated Pneumonia

Ventilator-associated pneumonia (VAP) occurs frequently in mechanically ventilated patients and has a high mortality rate. To date, there is no consensus for the diagnosis of VAP. Effective reduction in VAP-inducedmortality requires amultifaceted approach to include assessment of individual risks for VAP, implementation of effective ventilator handling procedures, routine use of VAP prevention strategies, appropriate use and interpretation of invasive and noninvasive diagnostic tests, and early broad spectrum antibiotic coverage with narrowing of coverage and cessation of therapy based on clinical improvement. Pharmacokinetic and pharmacodynamic principlesmust be used in designingempiric antibiotic regimens. Because an inappropriate empiric regimen in VAP has been associated with increasedmortality, it is imperative to maintain intensive care unit–specific epidemiologic data.

Prevention and Treatment of Aspiration Pneumonia in Intensive Care Units

Aspiration is a leading cause of nosocomial infection in the intensive care unit. Techniques to avoid or reduce aspiration are important in preventing pneumonia and pneumonitis. The most important preventive measures include the semi-recumbent position, the surveillance of enteral feeding, the use of promotility agents, and avoiding excessive sedation. The analysis of the pathogens involved in these syndromes usually shows a minor role for the anerobes. With regard to treatment, aspiration pneumonitis does not require any antimicrobials; on the contrary, aspiration pneumonia has to be treated. Empiric antimicrobials treatment should be started on clinical suspicion. The choice of the drug has to be guided by local pathogen epidemiology and clinical features; in fact, community type pneumonia requires a first-line antimicrobial such as amoxicillin/clavulanic acid. On the contrary, a nosocomial type of infection needs to be treated as a ventilator-associated pneumonia in agreement with published guidelines. Nevertheless, quantitative culture should be obtained in order to de-escalate antimicrobials. In conclusion, aspiration pneumonia is a frequently encountered disease that can be prevented by relatively simple measures.

Selective decontamination of the digestive tract attenuated the myocardial inflammation and dysfunction that occur with burn injury

This study examined the effects of oral antibiotics to selectively decontaminate the digestive tract (SDD) on postburn myocardial signaling, inflammation, and function. We hypothesized that antibiotic therapy to eliminate pathogens from the gastrointestinal (GI) tract would reduce myocardial inflammatory responses and improve postburn myocardial performance. Sprague-Dawley rats received polymyxin E (15 mg), tobramycin (6 mg), and 5-flucytosin (100 mg) by oral gavage twice daily for 3 days preburn and 24 h postburn. Experimental groups included 1) sham burn given vehicle (3 ml water), 2) sham plus SDD, 3) burn over 40% total body surface area (TBSA) plus SDD, and 4) burn over 40% TBSA given vehicle. All burns received lactated Ringer solution (4 mg·kg−1·%burn−1); myocardial signaling (PKCε/p38 MAPK/NF-κB) was studied 2, 4, and 24 h postburn; and cytokine secretion (systemic and myocyte secreted cytokines, ELISA) and cardiac function were examined 24 h postburn. Vehicle-treated burn injury increased myocardial PKCε/p38 MAPK expression, promoted NF-κB nuclear translocation, promoted TNF-α, IL-1β, IL-6, and IL-10 secretion, and impaired myocardial function. SDD attenuated burn-related proinflammatory myocardial signaling, cytokine secretion, and myocardial contractile defects. Our data suggest that burn-related loss of GI barrier function and translocation of microbial products serve as upstream mediators of postburn myocardial inflammatory signaling and dysfunction.

Impact of enteral versus parenteral nutrition on the incidence of fungal infections: a retrospective study in ICU patients on mechanical ventilation with selective digestive decontamination

BACKGROUND

Infections are an important cause of morbidity and mortality in patients in intensive care units (ICUs). Fungal infections have increased substantially over recent years and fungi have become one of the important pathogens in ICU patients. This study tests the hypothesis that the incidence of fungal infections is lower in critically ill patients under mechanical ventilation receiving enteral rather than total parenteral nutrition.

METHODS

By using a prospectively built database, we analyzed retrospectively the charts of 110 critically ill, intubated patients hospitalized in surgical and medical ICUs and receiving selective digestive topical decontamination (SDD), which consisted of administering non-absorbable antibiotics. Patients without contraindications, and expected to be intubated for more than 72 h, received enteral nutrition within 24 h after intubation. Patients with contraindications for enteral nutrition received total parenteral nutrition, which was discontinued when the criteria for enteral nutrition were met. The incidence of fungal infections in both subgroups of patients was compared.

RESULTS

Seventy-nine patients received enteral nutrition and 31 total parenteral (10 patients did not meet the inclusion criteria). Both subgroups were similar with regard to their APACHE II score, age, sex distribution and comorbidities at the time of study entry. No difference was observed in the rate of fungal infections between enteral nutrition (5/29) and total parenteral nutrition (7/71) patient groups.

CONCLUSION

No significant decrease in the incidence of fungal infections in critically ill patients receiving SDD was observed between those receiving enteral and total parenteral nutrition.

Antibiotic prophylaxis to reduce respiratory tract infections and mortality in adults receiving intensive care

BACKGROUND

Pneumonia is an important cause of mortality in intensive care units. The incidence of pneumonia in such patients ranges between 7% and 40%, and the crude mortality from ventilator associated pneumonia may exceed 50%. Although not all deaths in patients with this form of pneumonia are directly attributable to pneumonia, it has been shown to contribute to mortality in intensive care units independently of other factors that are also strongly associated with such deaths.

OBJECTIVES

The objective of this review was to assess the effects of antibiotics for preventing respiratory tract infections and overall mortality in adults receiving intensive care.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (issue 3, 2003), which contains the Acute Respiratory Infections (ARI) Group specialised trials register; MEDLINE (January 1966 to September 2003); EMBASE (January 1990 to September 2003); proceedings of scientific meetings and reference lists of articles from January 1984 to December 2002. We also contacted investigators in the field.

SELECTION CRITERIA

Randomised trials of antibiotic prophylaxis for respiratory tract infections and deaths among adult intensive care unit patients.

DATA COLLECTION AND ANALYSIS

At least two reviewers independently extracted data and assessed trial quality.

MAIN RESULTS

Overall 36 trials involving 6922 people were included. There was variation in the antibiotics used, patient characteristics and risk of respiratory tract infections and mortality in the control groups. In 17 trials (involving 4295 patients) that tested a combination of topical and systemic antibiotic, the average rates of respiratory tract infections and deaths in the control group were 36% and 29% respectively. There was a significant reduction of both respiratory tract infections (odds ratio 0.35, 95% confidence interval 0.29 to 0.41) and total mortality (odds ratio 0.78, 95% confidence interval 0.68 to 0.89) in the treated group. On average 5 patients needed to be treated to prevent one infection and 21 patients to prevent one death. In 17 trials (involving 2664 patients) that tested topical antimicrobials alone (or comparing topical plus systemic versus systemic alone) the rates of respiratory tract infections and deaths in the control groups were 30% and 26% respectively. There was a significant reduction of respiratory tract infections (odds ratio 0.52, 95% confidence interval 0.43 to 0.63) but not in total mortality (odds ratio 0.97, 95% confidence interval 0.81 to 1.16) in the treated group.

REVIEWER'S CONCLUSIONS

A combination of topical and systemic prophylactic antibiotics reduces respiratory tract infections and overall mortality in adult patients receiving intensive care. A treatment based on the use of topical prophylaxis alone reduces respiratory infections but not mortality. The risk of occurrence of resistance as a negative consequence of antibiotic use was appropriately explored only in the most recent trial by de Jonge which did not show any such effect.

Prevention of hospital-acquired pneumonia:

Several preventive measures for VAP have been empirically tested. There is clear evidence that antibiotic-containing preventive strategies, such as SDD and oropharyngeal decontamination, are very effective in different patient populations. Selection of antibiotic resistance remains the major disadvantage of these strategies, however, limiting its applicability in settings with high levels of antibiotic resistance. This probably precludes the use of these strategies in many American settings, but may allow their use in European countries with much lower endemic levels of resistance. There is little evidence that systemic prophylaxis is effective for the prevention of VAP, and initial studies were associated with resistance problems. Of the non antibiotic-containing preventive strategies, subglottic aspiration was effective in several studies, whereas other strategies, such as immunonutrition with glutamine or the semirecumbent patient position, were effective in single studies. All these studies were executed in European ICUs. For these interventions, more data are needed on the generalizability, feasibility, and cost effectiveness. Few data support the use of sucralfate for stress ulcer prophylaxis and modulation of enteral nutrition practices as preventive measures for VAP.

Pharmaceutical strategies to prevent ventilator-associated pneumonia

The increasing incidence of hospital-acquired (nosocomial) infection is a disturbing phenomenon resulting in significant patient mortality and putting considerable strain on healthcare budgets and personnel. One particularly serious aspect of nosocomial infection is that of ventilator-associated pneumonia (VAP). This arises in patients who receive mechanical ventilation within the intensive care unit. The quoted incidence of VAP varies widely (5-67%) and the reported mortality of patients with VAP is in the range of 24-71%. This review will examine the many factors that account for these wide ranges reported, including the patient population under investigation, the causative organism, the method of diagnosis, interventions employed and preventative strategies. The use of bioactive and drug-impregnated biomaterials for endotracheal tube construction is discussed as novel approaches to the prevention of VAP.

Selective decontamination of the digestive tract reduces mortality in critically ill patients

Several emotional responses may be invoked in critical care physicians when confronted with selective decontamination of the digestive tract (SDD). Although recent meta-analyses have shown that the use of SDD reduces the occurrence of ventilator-associated pneumonia and improves ICU survival, the effectiveness of SDD has remained controversial. We recently concluded a large randomized, controlled trial on the use of SDD that showed improved survival of ICU patients treated with SDD. A second concern regarding use of SDD has been the fear for the emergence of antimicrobial resistance. Interestingly, a recently published study did not confirm this fear, and our recently finished study even demonstrated a decline in colonization with P. aeruginosa and enterobacteriaceae that were resistant against tobramycin, ceftazidime, imipenem and ciprofloxacin. The hopes are that this study will at long last end the debate about the efficacy and safety of SDD in critically ill patients.

Descontaminación digestiva selectiva

OBJECTIVES

The objectives of the study were: to explain our protocol of selective digestive decontamination (SDD); to know the therapeutic activity that the protocol implies in the nursing staff; to assess the impact on the incidence of ventilatorassociated pneumonia.

METHODS DESIGN

Prospective descriptive study for time measurements, and non randomized comparative study for the incidence of ventilatorassociated pneumonia. We calculate time means and 95 percent confidence interval (CI). We calculate ventilatorassociated pneumonia relative risk and number-needed-to-treat (NNT).

SETTING

Intensive care unit with 13 beds reference for neurocritical illness.

STUDY PERIOD

Control group from November-2001 to April-2002. Treatment group from May-2002 to November 2002.

PATIENTS

consecutive patients who were admitted in our intensive care department with mechanical ventilation for more than 48 hours.Results. A total of 122 consecutive patients were included: control group 62 patients, treatment group 60 patients. We have recorded 136 SDD administration time and 16 vigilance culture records. The SDD administration mean time was 8.11 minutes (95% CI, 7.59-8.63). Morning Nursing Duty Schedule spent significantly more time mean 10.7 minutes (95% CI, 9.87- 11.89) than afternoon 8.1 (95% CI, 7.20-9.08) (p < 0.05) and night 6.9 (95% CI, 6.39-7.46). There was a significant difference between time spent in SDD administration in trauma patients (p < 0.05) 7.45 (95% CI, 6.63-8.27) and medical patients 8.71 minutes (95% CI, 8.41-9.01). We spent a mean of 9 minutes (CI 8-10) in culture sampling. In the treatment group the ventilator associated pneumonia incidence relative risk was 0.28 (CI 0.13-0.63) with a NNT of 4 (CI 3-8).

CONCLUSION

In our patients SDD administration represents the 2.5% of our therapeutic activity time per patient and reduces the ventilator associated pneumonia risk.