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Authors; Zahra Jafari, and Melissa Severn.
A mechanical ventilator — also known as a ventilator, respirator, or breathing machine — assumes respiratory function when an individual's natural breathing is insufficient.1 Various factors can necessitate ventilator use, with low oxygen levels or pronounced breath insufficiency due to conditions like pneumonia being the primary causes.1 The ventilator circuit encompasses tubing that transports gas from a positive pressure ventilator to the patient and includes any connected devices.2 This circuitry typically features 22 mm inner diameter tubing (adjustable for neonatal and pediatric cases) and links the ventilator to the patient. The ventilator circuit accommodates ancillary components such as heaters, humidifiers, filters, suction catheters, and therapeutic aerosol generators like nebulizers and inhalers. Collectively, these elements ensure effective ventilation and patient comfort during mechanical respiratory support.2
Ventilator-associated pneumonia (VAP) is a common infection acquired in the intensive care unit, with reported incidences ranging from 5% to 40%, depending on the setting and diagnostic criteria.3 Approximately 5% to 10% of patients with mechanical ventilation develop ventilator-associated events.4 The estimated mortality rate attributed to VAP is approximately 10%, with higher rates in surgical intensive care unit patients and those with average severity scores at admission.3 Prolonged mechanical ventilation, altered consciousness, burns, comorbidities, prior antibiotics, invasive procedures, and genetic polymorphisms are characterized as globally recognized VAP risk factors.5 Among vulnerable populations, neonates and children are more susceptible to VAP due to factors such as an immature immune system, incomplete mucosal barrier, lack of maternal immunoglobulins in preterm infants, and increased risk of aspiration.6 Common strategies used to prevent and control VAP are prevention bundles (including combined strategies, such as noninvasive positive pressure ventilation for respiratory failure, spontaneous breathing trials, elevated head of the bed to 30 to 45 degrees, and oral care) and drugs such as chlorhexidine, beta-lactam antibiotics, and probiotics.5
Careful evaluation of workflow, clinical outcomes, economic factors, and environmental impacts is crucial when adopting medical devices in health care management. This ensures that the medical devices not only meet the clinical needs of patients but also contribute to sustainable and cost-effective practices within health care settings.7 Nonetheless, recent studies comparing the environmental and cost-saving impacts of reusable and single-use devices highlight concerns about patient safety and increased labour and capital costs leading to the preference for single-use devices in many surgical settings.8 Despite this preference, in the pursuit of reducing negative environmental impacts and promoting sustainability, the concepts of the circular economy and life cycle assessments have gained attention in the medical device industry. The circular economy approach seeks to minimize waste and maximize the utilization of resources by designing devices that can be easily reused, recycled, or repurposed.9 However, barriers such as infection concerns, customer and manufacturer behaviours, and regulatory structures impact the full implementation of circularity in the medical device industry.8 To address these barriers, collaboration among health care professionals, manufacturers, policy-makers, and regulatory bodies will be needed to establish guidelines and standards that ensure patient safety while encouraging the adoption of more sustainable practices in medical device design, production, and disposal.8
In 2003, the US Centers for Disease Control and Prevention (CDC) recommended changing ventilator circuits only when visibly solid, rather than routinely at fixed intervals for all age groups.10,11 This recommendation was supported by randomized controlled trials (RCTs) conducted in adults, which demonstrated reduced health care costs and no increase in VAP rates when ventilator circuits were changed only when visibly solid.12-15 To update the current knowledge of ventilator circuit tubing replacement (VCTR), this report aims to summarize existing available evidence regarding the clinical effectiveness of different time intervals for VCTRs, as well as evidence-based guidelines for the replacement of ventilator circuits in patients with mechanical ventilation.
An information specialist conducted a literature search on key resources including MEDLINE, CINAHL, the Cochrane Database of Systematic Reviews, the International HTA Database, and the websites of Canadian and major international health technology agencies, as well as a focused internet search. The search approach was customized to retrieve a limited set of results, balancing comprehensiveness with relevancy. The search strategy included both controlled vocabulary, such as the National Library of Medicine’s MeSH (Medical Subject Headings), and keywords. Search concepts were developed based on research questions and selection criteria. The main search concepts were mechanical ventilation and timing of circuit replacement. The search was completed on July 6, 2023, and limited to English-language documents published since January 1, 2010.
One reviewer screened citations and selected studies. At the first level of screening, titles and abstracts were reviewed, and potentially relevant articles were retrieved and assessed for inclusion. The final selection of full-text articles was based on the inclusion criteria presented in Table 1.
Selection Criteria.
Articles were excluded if they did not meet the selection criteria outlined in Table 1, were duplicate publications, or were published before January 1, 2010.
One reviewer critically appraised the included studies. The critical appraisal tools used were a MeaSurement Tool to Assess systematic Reviews (AMSTAR-2)16 for systematic reviews (SRs) and meta-analyses (MAs), and the Appraisal of Guidelines for REsearch and Evaluation (AGREE) II instrument17 for guidelines. Summary scores were not calculated for the studies; rather, the strengths and limitations observed among the included studies were summarized and described narratively in Appendix 3.
A total of 345 citations were identified in the literature search. Following the screening of titles and abstracts, 338 citations were excluded and 7 potentially relevant articles from the electronic search were retrieved for full-text review. No potentially relevant publications were identified from the grey literature search for full-text reviews. Of the 7 potentially relevant articles, 4 primary studies were excluded because they were already captured in 1 included SR.6 Three publications4,6,18 met the selection criteria and were included in this report.
Appendix 1 presents the PRISMA19 flow chart of the study selection. Additional references of potential interest are provided in Appendix 5.
Three peer-reviewed publications consisting of 2 SRs with MAs6,18 and 1 guideline4 were included in this report.
Additional details regarding the characteristics of the included publications are provided in Appendix 2 (Table 2 and Table 3).
Of the 3 publications that met the selection criteria for this report, 2 were SRs with MAs (including randomized and nonrandomized primary studies) on adult18 and pediatric6 patients. Of the 10 primary studies included in 1 SR on adults,18 8 studies (5 sequential comparison studies [SCSs] and 3 RCTs) were selected for MA. Of the 6 primary studies included in 1 SR on neonates and children,6 2 before-after studies were considered for MA.
The evidence-based guideline4 included in this report was a 2022 update of the Strategies to Prevent Ventilator-Associated Pneumonia in Acute Care Hospitals published in 2014,20 and was sponsored by the Society for Health care Epidemiology of America (SHEA) in collaboration with the Infectious Diseases Society of America (IDSA), the American Hospital Association (AHA), the Association for Professionals in Infection Control and Epidemiology (APICE), and the Joint Commission, with contributions from representatives of other organizations and societies with content expertise. The authors reported the use of tools to assess the quality of the evidence, but not the strengths of the recommendations (Table 3).
The authors of 2 SRs with MAs6,18 and 1 guideline were based in India,6 China,18 and the US,4 respectively.
Of the 3 selected publications on patients requiring VCTR, 1 SR with MA6 was conducted on neonates and children, 1 SR with MA18 was performed on adults, and 1 guideline4 included preterm neonates, children, and adults.
In 1 SR with MA on neonates and children,6 VCTR at more frequent intervals (e.g., once in less than 7 days) was compared with less frequent (e.g., once weekly) intervals (Table 2).
In 1 SR with MA on adult patients,18 VCTR every 2 was compared with VCTR every 7 days, or once every 2 or 7 days was compared with no routine circuit change (Table 2).
In 1 included guideline,4 among described interventions, the timing of VCTR was the intervention relevant to this report (Table 3).
In adult patients, the outcome reported was the odds ratio (OR) of VAP.18
In pediatric patients, the outcomes reported were VAP,6 all-cause mortality rate before discharge,6 VAP-related mortality rate,6 duration of mechanical ventilation,6 duration of hospital stay,6 and incidence of bloodstream infections.6
Of the 3 studies included in this report, 2 were SRs with MAs to examine the effect of VCTR intervals on VAP in children6 and adults18 on mechanical ventilation. We used the AMSTAR-2 checklist16 to evaluate the quality of the SRs and determine whether the most important elements of the SR methodology were reported (Table 4). The strengths of the SRs were in defining the research question and inclusion and exclusion criteria, describing the study design of the selected primary studies, using a comprehensive literature search strategy, conducting study selection and data extraction in duplicate, reporting potential sources of conflict of interest, and providing a list of excluded studies and justifying the exclusions. For the MAs, the authors reported risk ratios (RRs)6 or ORs18 of the VAP rate and the inconsistency index (I2). The I2 statistic describes the percentage of variation across studies due to heterogeneity rather than chance and is characterized as an intuitive and simple expression of the inconsistency of studies' results.21
The number of primary studies included in the 2 SRs was limited, consisting of 10 studies in the Han et al.18 SR on adults and 6 studies in the Abiramalatha et al.6 SR on neonates and children. Moreover, MAs were limited to 8 studies (5 SCSs and 3 RCTs) in the SR on adults18 and 2 before-after studies in the SR on neonates and children.6 In the SR on adult patients, the MA that combined the results of 5 SCSs did not yield a significant difference in the odds of VAP and had severe statistical heterogeneity. The authors then conducted a second MA of 4 SCSs that excluded a large-scale study from the analysis (based on the severity-of-illness scores of the patients), which yielded a significant difference in odds of VAP between the groups. However, it was unclear whether this was an ad hoc analysis or part of their planned statistical analysis, as the authors did not report sufficient details of their statistical analyses. The SR authors did not adequately examine publication bias, specifically small study bias, and its potential impact on outcomes. Small study effects refer to situations where smaller studies demonstrate varying, often larger, treatment effects compared to larger studies, posing a potential risk to the validity of SRs and MAs.22 Small study bias represents a specific type of publication bias in which smaller primary studies are more likely to be published when they exhibit positive results.23 Thus, the potential impact of small study bias (which could result in more extreme treatment effects)24 on the findings was unclear.
The risk of bias (RoB) in the primary studies included in the SR was assessed in 1 SR6 (using the Cochrane Effective Practice and Organization of Care [EPOC] Risk of Bias Tool), but the impact of RoB in individual studies was not accounted for in interpreting and discussing the review results in either study. In the other SR18 the authors did not assess the RoB of the primary studies. RoB in primary studies can distort the results and conclusions of an SR.25 If the RoB is not assessed or addressed, it can lead to misleading or inaccurate findings, potentially influencing subsequent decision-making or interventions.25 Further, RoB in primary studies may result in an overestimation of treatment effects. Biased studies tend to report more positive or exaggerated results, which can lead to an inflated perception of treatment effectiveness.26
The AGREE II Reporting Checklist17 (Table 5) was used for the critical appraisal of the guideline4 included in this report. The checklist is a tool to improve the completeness of reporting in guidelines and is intended to provide guidance to guideline developers, guideline users, guideline funders, peer reviewers, and journal editors about the essential components of a high-quality practice guideline.27 The checklist entails 6 quality domains (scope and purpose, stakeholder involvement, rigour and development, clarity of presentation, applicability, and editorial independence) and 23 key items.27
The areas clearly described or reported in the guideline were overall objectives; main questions; target patients; using a systematic search to identify, synthesize, and summarize evidence; the use of tools to assess the quality of evidence; the methods for formulating the recommendations; and the consideration of health benefits, side effects, and risks in formulating the recommendations. In the guideline, key recommendations were easily identifiable; recommendations were specific and unambiguous; and different options for the management of preterm neonates,4 children, and adults4 on mechanical ventilation were presented.
However, the included guideline4 did not specify a procedure for updating its recommendations, and it was uncertain if the strengths and limitations of the body of evidence were evaluated as it was not reported in the article. Assessing the limitations of the evidence can indicate whether the findings of an intervention (or treatment comparison) for a specific outcome are adequately protected against bias based on the study design (i.e., possess good internal validity).28
We identified 3 studies including 2 SRs with MAs and 1 guideline4 on patients requiring VCTR.
Appendix 4 presents the main outcomes of the included studies.
The included SR6 found that the risk of VAP in pediatric patients with mechanical ventilation was similar when the following VCTR intervals were compared (Table 6):
The included SR6 found that the RR of all-cause mortality before discharge in pediatric patients was similar when the following VCTR intervals were compared (Table 6):
The authors of the SR used the GRADE tool to assess the certainty of the evidence for the VAP rate and all-cause mortality rate before discharge, which was assessed as very low.
According to the included SR,6 the mortality rate in children with VAP was similar when the following VCRT intervals were compared (Table 6):
According to the included SR,6 the duration of mechanical ventilation (days) in pediatric patients was similar when the following VCTR intervals were compared (Table 6):
In adults with mechanical ventilation, VCTR every 2 days compared with every 7 days may result in little to no increase in odds (OR = 1.501; 95% confidence interval [CI], 0.952 to 2.365) or in higher odds of VAP (OR = 1.93; 95% CI, 1.08 to 3.44) (Table 7);18 however, there is some uncertainty in the findings from this systematic review.
In adults with mechanical ventilation, VCTR every 2 days or every 7 days may result in little to no increase in the odds of VAP (OR = 1.126; 95% CI, 0.79 to 1.59) compared to no routine circuit changes (Table 7).
According to a 2022 guideline for patients in all age groups (preterm neonates, children, and adults requiring mechanical ventilation),4 the ventilator circuit should only be replaced if it is visibly soiled, not functioning properly, or as recommended in the manufacturer’s instructions (Table 8). These recommendations were based on low-quality evidence for preterm neonates, and moderate-quality evidence for pediatric and adult patients.
In the review of the clinical effectiveness of various fixed or nonfixed intervals for VCTR in patients with mechanical ventilation, we only identified 3 articles that met the selection criteria for this report. These articles consisted of 1 SR with MA (2010)18 in adults (including 10 primary studies published between 1992 and 2004), 1 SR with MA (2021)6 in neonates and children (including 6 primary studies published between 1995 and 2014), and 1 guideline (2022)4 in preterm neonates, children, and adults. The number of primary studies included in the 2 SRs was limited, and not all included studies were considered for MA. In addition, all of the primary studies captured in the SRs were published before 2014, and we did not find any primary studies that met the selection criteria and were published after 2014.
Regarding the potential harms associated with the VCRT intervals, negative aspects or disadvantages such as increased all-cause mortality rate before discharge, VAP-related mortality rate, duration of mechanical ventilation, and duration of hospital stay were only reported in 1 SR in pediatric patients.6
Regarding guidelines or recommendations, we only identified 1 guideline4 that met the section criteria for this report. We did not find any guidelines that specifically addressed routine versus no routine VCTR in patients with mechanical ventilation.
In addition, none of the 3 studies selected for this report, or the primary studies included in the 2 SRs6,18 were conducted in Canada. Therefore, the generalizability of the findings and the extent to which studies from other cultures and health system policies might contribute to the Canadian context remain uncertain and require further research.
This report comprises 2 SRs6,18 and 1 evidence-based guideline.4
In adult patients requiring mechanical ventilation,18 more frequent VCTR (i.e., every 2 days) may increase the odds of VAP compared to less frequent changes (i.e., every 7 days), but the findings are uncertain (1 SR with 2 MAs).18 In addition, occasionally changing the ventilator circuit tubing (i.e., every 2 days or every 7 days) may have similar odds of VAP compared to no routine circuit changes (1 SR with MA).18
In neonates and children requiring mechanical ventilation,6 the RR of VAP, all-cause mortality rate before discharge, bloodstream infections, and the mortality rate in patients with VAP, as well as the mean difference of the duration of mechanical ventilation and the duration of hospital stay, were similar for the 3 VCTR intervals that were compared (i.e., once per week versus less than 7 days, once in 3 days versus daily, and once per week versus once in 2 weeks) (1 SR with MA).
According to a 2022 guideline on preterm neonates, children, and adult patients requiring mechanical ventilation,4 the ventilator circuit should only be replaced if it appears soiled or is not functioning properly, or as per the manufacturer’s instructions.
We only found 3 publications meeting our inclusion criteria for this report. Overall, the relevant evidence was limited, and there were no recent primary studies identified (i.e., all of the relevant primary studies were captured by the included SRs and published in or before 2014). Additionally, the recommendations provided in 1 guideline might have been affected by the low to moderate quality of evidence used to develop the relevant recommendations. Furthermore, we identified no guidelines regarding routine versus no routine ventilator circuit changes. Given the low number and limitations of the included publications in this report, and as we identified no relevant study conducted in Canada, the generalizability of the findings and their contribution to the Canadian context are uncertain. Therefore, the findings reported should be interpreted with caution, and further research is suggested to inform decision-making.
When making decisions about ventilator circuit replacement, clinical decision-makers and policy-makers may also wish to consider the associated costs and environmental implications. This involves evaluating the financial implications of device usage, including expenses related to materials, sterilization, personnel time, and salaries,8 as well as the environmental impacts and sustainability of the medical devices. By taking into account these factors, health care decision-makers can strive for a sustainable choice of devices that are clinically effective and cost-effective, while minimizing environmental impact. Policy-makers may also wish to consider these factors when establishing guidelines and policies that promote sustainable device use.
Appraisal of Guidelines for REsearch and Evaluation
A MeaSurement Tool to Assess systematic Reviews 2
meta-analysis
odds ratio
randomized controlled trial
risk ratio
sequential comparison study
systematic review
ventilator-associated pneumonia
ventilator circuit tubing replacement
Contributors: Kendra Brett
Selection of Included Studies.
Characteristics of Included Systematic Reviews.
Characteristics of Included Guidelines.
Note that this appendix has not been copy-edited.
Strengths and Limitations of Included Systematic Reviews Using AMSTAR-2.
Strengths and Limitations of Guidelines Using AGREE II Checklist.
Note that this appendix has not been copy-edited.
Summary of Findings on VCTR Intervals in Neonates and Children in an SR by Abiramalatha et al. (2021).
Summary of Findings on VCTR Intervals in Adult Patients in an SR and MA by Han et al. (2010).
Summary of Recommendations Regarding Timing of VCTR.
Note that this appendix has not been copy-edited.
The following publications were identified because they may provide additional information associated with this report.
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