Ventilator-Associated Pneumonia (Perspectives on Critical Care Infectious Diseases)
The Canadian Critical Care Society appointed a chair to ensure that the panel achieved its objectives through group process At the panel meeting, each member recorded any potential conflicts of interest The pair of panel members responsible for critical appraisal of each intervention provided a structured written and oral presentation of the evidence. After the panel discussion, the initial evidence summary was revised if necessary. The panel members assigned levels of evidence, semi-quantitative scores to summarize the evidence and describe the intervention, and a status statement.
We classified trials as level 1 if they had all of the following: concealed randomization, blinded outcome adjudication, an intention-to-treat analysis, and an explicit definition of VAP. Trials were classified as level 2 if any one of these characteristics was unfulfilled and as level 3 if allocation was not strictly randomized.
We used a semi-quantitative score 0, 1, 2, or 3 to evaluate each intervention with respect to the validity of the randomized trials; the effect size of each intervention; the confidence intervals around the estimate of effect; the homogeneity of the trial results; and the safety, feasibility, and economic consequences of the intervention. The language of the status statement for each item was keyed to the levels of evidence and the semi-quantitative scores.
We used the term recommended if there were no reservations about endorsing an intervention and the term considered if the evidence supported an intervention but there were minor uncertainties about the benefits, harms, or costs. No recommendation was made if evidence regarding an intervention was inadequate or if there were major uncertainties about the benefits, harms, or costs. After the panel meeting, the chair compiled the summaries and status statements and sent them to all panel members to check accuracy and clarity.
In addition, the pairs of evidence appraisers wrote background documents for the interventions they appraised, including the rationale for each intervention, appraisal of randomized trials and systematic reviews, and harms and costs of the interventions. The chair and the writing committee organized the background documents, the evidence summaries, a table of the semi-quantitative scores, and the status statement for each item.
We formatted the document with a structured abstract 31 , a summary of the evidentiary basis for each recommendation, and a status statement for each item. We also created a quick reference guide. External reviewers were asked to critique whether the guideline was logical, clear, and practical and to critique the guideline development process. The panel revised the document on the basis of this feedback. The final guideline was returned to the external reviewers for further comments and official endorsement by their respective organizations. The final guideline was then piloted in 2 institutions.
To record the agreement of each panel member with the final status statement for each item, we sent the final document to all panel members.
The panel will formally review and update this guideline every 2 years The funding source played no role in study selection for this guideline and had no role in its development, review, reporting, approval, or submission for publication. The final summary statements, levels of evidence, and status statements for each of the interventions are reported. The semi-quantitative scores for each intervention are presented in Table 1 , and the agreement scores for each panel member are presented in Table 2. On the basis of direct evidence from one level 2 trial 33 , we conclude that orotracheal intubation is associated with a lower incidence of VAP compared with nasotracheal intubation.
Furthermore, this trial and four other level 2 trials have found that orotracheal intubation is associated with a decreased incidence of sinusitis and that incidence of VAP is lower in patients who do not develop sinusitis. Status: We recommend that the orotracheal route of intubation should be used when intubation is necessary. On the basis of one randomized, controlled trial 38 , we conclude that while a systematic search for maxillary sinusitis in patients who are intubated by the nasotracheal route may decrease the incidence of VAP, no evidence supports this practice in patients who are intubated by the orotracheal route.
Status: We make no recommendation because of insufficient evidence. On the basis of evidence from one level 2 trial 39 and two level 3 trials 40, 41 , we conclude that the frequency of ventilator circuit changes does not influence the incidence of VAP. Less frequent changes of ventilator circuits are not associated with harm, and more frequent changes are associated with increased cost. Status: We recommend new circuits for each patient, and changes if the circuits become soiled, but no scheduled ventilator circuit changes.
Type of Humidifier. On the basis of evidence from seven level 2 trials , we conclude that the use of heat and moisture exchangers may be associated with a slightly decreased incidence of VAP compared with heated humidifiers. Concern about endotracheal tube obstruction associated with the use of heat and moisture exchangers has not been confirmed in recent studies that have evaluated newer heat and moisture exchangers.
Cost considerations favor the use of heat and moisture exchangers. Status: We recommend the use of heat and moisture exchangers in patients who have no contraindications such as hemoptysis or requirement for high minute ventilation. Frequency of Humidifier Changes. On the basis of evidence from three level 2 trials , infrequent changes to heat and moisture exchangers may be associated with a slightly decreased incidence of VAP. Reduction in the frequency of humidifier changes might be considered as a cost-reduction measure.
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Status: We recommend weekly changes of heat and moisture exchangers. On the basis of evidence from two level 2 trials 52, 53 and two level 3 trials 54, 55 , we conclude that type of suctioning systems open or closed has no effect on the incidence of VAP. On the basis of evidence from one level 2 trial 56 , we conclude that scheduled daily changes and unscheduled changes of closed suctioning systems have no effect on the incidence of VAP.
Cost considerations favor the use of closed suctioning systems that are changed only as clinically indicated. Status: We recommend the use of closed endotracheal suction systems that are changed for each new patient and as clinically indicated. On the basis of evidence from five level 2 trials , we conclude that subglottic secretion drainage is associated with decreased incidence of VAP, especially early-onset VAP.
Status: We recommend that clinicians consider the use of subglottic secretion drainage. On the basis of evidence from one level 3 trial 62 , we conclude that chest physiotherapy may be associated with decreased incidence of VAP.
Ventilator-associated pneumonia in the ICU | Critical Care | Full Text
However, methodologic limitations of this level 3 trial and the lack of feasibility of universal application preclude widespread use of this intervention. Status: We make no recommendation. On the basis of evidence from one level 2 trial 63 and two level 3 trials 64, 65 , we conclude that there is no difference in incidence of VAP between early tracheostomy and late tracheostomy.
However, serious methodologic flaws threaten the validity of these trials. On the basis of evidence from seven level 2 trials and one level 3 trial 73 , we conclude that the use of kinetic beds is associated with decreased incidence of VAP. However, feasibility and cost concerns may be barriers to implementation. Status: We recommend that clinicians consider the use of kinetic beds.
On the basis of evidence from one level 2 trial 74 , we conclude that semi-recumbent positioning caring for patients positioned at 45 degrees from horizontal is associated with decreased incidence of VAP. Semi-recumbent positioning may be unsafe for some patients but is a feasible and low-cost intervention.
Status: We recommend the use of semi-recumbent positioning, with a goal of 45 degrees, in patients without contraindications. On the basis of evidence from one level 2 trial 75 , we conclude that use of prone positioning may be associated with decreased incidence of VAP. However, methodologic concerns about this trial and the lack of feasibility of universal application preclude widespread use of this intervention.
In patients at very low risk for clinically important bleeding for example, those spontaneously breathing without coagulopathy , the best option to minimize the risk for VAP is to avoid stress ulcer prophylaxis. On the basis of evidence from two level 2 trials 76, 77 , we conclude that the use of sucralfate does not influence the incidence of VAP compared with placebo.
Status: We recommend that sucralfate not be used to minimize the risk for VAP in patients at high risk for stress ulcer bleeding. On the basis of evidence from 10 meta-analyses , we conclude that selective digestive decontamination using topical antibiotics intratracheal or oral or intravenous and topical antibiotics is associated with a decreased incidence of VAP.
Cost-effectiveness of selective digestive decontamination is of unknown magnitude. The long-term risk for emergence of antibiotic-resistant bacteria when topical antibiotics are administered in the digestive tract or the trachea is unclear and is potentially harmful. Furthermore, only the combination of intravenous and topical antibiotics is associated with a decrease in mortality.
Status: We recommend that topical antibiotics alone not be used. We make no recommendations regarding selective digestive decontamination using intravenous and topical antibiotics because of insufficient data about antibiotic resistance and cost-effectiveness.
We make no recommendation regarding intravenous antibiotics alone because of insufficient evidence. The VAP prevention guidelines published in by the Centers for Disease Control and Prevention 23 and in by the American Thoracic Society 24 provided a strong foundation for our work.
However, these documents did not explicitly outline how evidence was identified, interpreted, or integrated into recommendations. Our guideline is based on interventions tested in randomized trials that were in turn critically appraised with respect to study validity; the magnitude, precision, and homogeneity of the intervention's effect on VAP; and the safety, feasibility, and cost of the intervention.
We used structured evidence reviews 88 to generate evidence-based practice guidelines Other strengths of this guideline include the detailed, explicit processes used to search for, select, and appraise the evidence 90 ; the multidisciplinary panel; and the panel's balance of university-based and community-based clinicians.
In addition, the external reviewers represented nursing, respiratory therapy, respirology, infectious diseases, and critical care. To translate the findings into status statements, we used a semi-quantitative score to evaluate 7 domains for each intervention, integrating evidence and judgment about safety, feasibility, and cost. These judgments were based on qualitative and relative comparisons with other interventions in Canadian ICUs.
For example, the feasibility and cost concerns related to kinetic beds reflected increased nursing workload and significant rental or retail costs, respectively. We used a transparent method to grade the evidence and a final score to reflect the panelists' confidential agreement with each status statement The panel also highlighted areas that were unsuitable for evidence-based recommendations but suitable for future research These include the systematic search for maxillary sinusitis among mechanically ventilated patients, chest physiotherapy, prone positioning, the timing of tracheostomy, and intravenous or intravenous plus topical antibiotic prophylaxis as interventions to prevent VAP.
Further randomized trials of VAP prevention strategies are necessary since practice guidelines, like systematic reviews 93 , need to be updated as new evidence emerges and as values and health resources change This document meets the 3 quality criteria for a guideline from a specialty society as proposed by Grilli and colleagues 94 ; it describes the developers, the data sources, and the methods used to grade the status statements.
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This document also meets all 10 methodologic criteria on guideline development and 8 of 10 criteria on evidence identification and summary proposed by Shaneyfelt and colleagues We did not specify the health care costs of implementing each intervention in specific practice settings because of the sparse reporting of economic outcomes in these trials, the absence of guideline implementation costs in the ICU, and the limited validity and generalizability of cost-effectiveness statements for these interventions within and among different health care systems Finally, this document meets 20 of 20 criteria on the rigor of guideline development and 12 of 12 criteria on context and content proposed by Cluzeau and colleagues One aspect of guideline appraisal as proposed by Cluzeau and colleagues 97 focuses on 5 criteria addressing applicability in practice, including whether monitoring criteria, acceptable thresholds, and outcome measures for guideline adherence are specified; whether key considerations for local guideline groups are identified; and whether methods for dissemination and implementation are indicated.
We believe that these criteria should be developed by guideline consumers regionally. While no evidence informs these issues, a strong body of evidence exists on effective dissemination and implementation methods, including academic detailing, opinion leaders, audit and feedback, interactive education, computer decision support systems, and multifaceted approaches Prevention strategies for VAP that are behavioral instead of pharmacologic or technological may require different implementation techniques in the complex, dynamic setting of the ICU.
Qualitative studies 99 and observational studies can identify attitudinal and clinical barriers to implementing specific VAP prevention guidelines. We propose that the next steps for implementation of this guideline should be review by local clinician groups and adaptation to individual practice settings and health care systems. Although there are several methods for development of practice guidelines 29, 90, 91, , critical appraisal of many guidelines reveals room for improvement. Since endorsement by professional organizations influences physicians' confidence in guidelines , , it is crucial that guidelines developed by specialty societies are valid.
This guideline has several limitations. First, we did not elicit patient perspectives during the guideline development process. Second, we did not conduct formal economic evaluations for each intervention appraised. Third, we did not formally incorporate published economic analyses into the guideline development. Our statement to consider subglottic secretion drainage is thus supported.
Rigorous guideline development efforts are easily dwarfed by the skills and time of the experienced individuals needed to implement them Evidence-based implementation of evidence-based medicine requires knowledge of the most successful strategies for behavior change Rather than making recommendations about guideline implementation in the current document , we endorsed a programmatic approach.
Thus, we separated the development of the guideline from its implementation and evaluation. Phase 1 of this program is development of this evidence-based VAP prevention guideline. Phase 2 is being led by a Guideline Implementation and Evaluation Panel, which is testing the clinical outcomes associated with different guideline implementation strategies in a multicenter trial. Only with effective implementation will guidelines have the potential to decrease the risk for VAP and its attendant morbidity and mortality in critically ill, mechanically ventilated patients.
The search strategy used in the development of this guideline was as follows:. To increase the sensitivity of the search, we performed additional searches by using the terms mechanical ventilation , enteral nutrition , and nutrition instead of critical care and intensive care unit.
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