Is HELICS the Right Way? Lack of Chest Radiography Limits Ventilator-Associated Pneumonia Surveillance in Wales

Probiotics for the Prevention of Ventilator-Associated Pneumonia: An Updated Systematic Review and Meta-Analysis of Randomised Controlled Trials

BACKGROUND

Presently, there is conflicting evidence regarding the efficacy of probiotics in the prevention of ventilator-associated pneumonia (VAP). This meta-analysis was conducted to update current clinical evidence and evaluate the efficacy and safety of probiotics for the prevention of VAP.

METHODS

We searched three databases and two trial registers to retrieve randomised controlled trials (RCTs) comparing probiotics or synbiotics with placebo or standard treatment for the prevention of VAP in adult patients receiving mechanical ventilation in the intensive care unit (ICU).

RESULTS

Our meta-analysis included 18 RCTs involving 4893 patients. Our results showed that probiotics may reduce the incidence of VAP (RR 0.68, 95% CI: 0.55-0.84; low certainty). However, in our subgroup and sensitivity analyses, the effect was not significant in double-blind studies, and in studies with a low risk of bias in the randomisation process. Probiotics reduced the length of ICU stay (MD -2.22 days, 95% CI: -4.17 to -0.28; moderate certainty) and the duration of antibiotic use (MD -1.25 days, 95% CI -1.86 to -0.64; moderate certainty).

CONCLUSIONS

Probiotics may reduce the incidence of VAP but due to the low quality of pooled evidence, the use of probiotics warrants caution. Further, large-scale, high-quality RCTs need to be conducted to provide conclusive evidence.

Procalcitonin Increase Is Associated with the Development of Critical Care-Acquired Infections in COVID-19 ARDS

Secondary bacterial infection in COVID-19 patients is associated with increased mortality and disproportionately affects critically ill patients. This single-centre retrospective observational study investigates the comparative efficacy of change in procalcitonin (PCT) and other commonly available biomarkers in revealing or predicting microbiologically proven secondary infection in critical COVID-19 patients. Adult patients admitted to an intensive care unit (ICU) with confirmed SARS-CoV-2 infection between 9 March 2020 and 5 June 2020 were recruited to the study. For daily biomarker and secondary infection, laboratory-confirmed bloodstream infection (LCBI) and ventilator-associated pneumonia/tracheobronchitis (VAP/VAT) data were collected. We observed a PCT rise in 53 (81.5%) of the patients, a C-reactive protein (CRP) rise in 55 (84.6%) and a white blood cell count (WBC) rise in 61 (93.8%). Secondary infection was confirmed in 33 (50.8%) of the patients. A PCT rise was present in 97.0% of patients with at least one confirmed VAP/VAT and/or LCBI event. CRP and WBC rises occurred in 93.9% and 97.0% of patients with confirmed VAP/VAT and/or LCBI, respectively. Logistic regression analysis found that, when including all biomarkers in the same model, there was a significant association between PCT rise and the occurrence of LCBI and/or VAP/VAT (OR = 14.86 95%CI: 2.20, 342.53; p = 0.021). Conversely, no statistically significant relationship was found between either a CRP rise (p = 0.167) or a WBC rise (p = 0.855) and the occurrence of VAP/VAT and/or LCBI. These findings provide a promising insight into the usefulness of PCT measurement in predicting the emergence of secondary bacterial infection in ICU.

The prevalence of suspected ventilator-associated pneumonia in Scottish intensive care units

Ventilator-associated pneumonia is the most common healthcare-associated infection in mechanically ventilated patients. Despite this, accurate diagnosis of ventilator-associated pneumonia is difficult owing to the variety of criteria that exist. In this prospective national audit, we aim to quantify the existence of patients with suspected ventilator-associated pneumonia that would not be detected by our standard healthcare-associated infection screening process. Furthermore, we aim to assess the impact of tracheostomy insertion, subglottic drainage endotracheal tubes and chlorhexidine gel on ventilator-associated pneumonia rate. Of the 227 patients recruited, suspected ventilator-associated pneumonia occurred in 32 of these patients. Using the HELICS definition, 13/32 (40.6%) patients were diagnosed with ventilator-associated pneumonia (H-posVAP). Suspected ventilator-associated pneumonia rate was increased in our tracheostomy population, decreased in the subglottic drainage endotracheal tube group and unchanged in the chlorhexidine group. The diagnosis of ventilator-associated pneumonia remains a contentious issue. The formalisation of the HELICS criteria by the European CDC should allow standardised data collection throughout Europe, which will enable more consistent data collection and meaningful data comparison in the future. Our data add weight to the argument against routine oral chlorhexidine. The use of subglottic drainage endotracheal tubes in preventing ventilator-associated pneumonia is interesting and requires further investigation.

Ventilator-associated events versus ventilator-associated respiratory infections-moving into a new paradigm or merging both concepts, instead?

Despite ventilator-associated respiratory infections (VARI) are reported as the most common and fatal complications related to mechanical ventilation (MV), they are not the unique occurrences. The new classification of ventilator-associated events (VAE) proposed by the centers for disease control and prevention (CDC) enhance the spectra of complications due to MV including both infection-related and non-infectious events. Both VAEs and VARIs are associated with prolonged duration of MV, longer stay in hospital and in the intensive care unit (ICU) and more antibiotic consumption, nonetheless patients with VAEs have worst outcomes. The VARI and VAE algorithms are focused on different targets and the correlation between both classifications is shown to be poor. The diagnostic criteria of the traditional classification have limited accuracy and the non-infectious complications may be misinterpreted as VARI. While the VAE surveillance enhances the spectra of MV complications but excludes less severe VARIs. Noninfective events explain up to 30% of VAEs, the main causes being atelectasis, acute respiratory distress syndrome, pulmonary edema and pulmonary embolism. The bundles assessing VAE are associated with less incidence of VAP and improved outcomes but they fail to reduce the rates of VAE. Automated VAE surveillance is efficient and useful as a quality indicator in the ICU while the differences in the interpretation of VARI criteria limit its role in the design of global protocols and preventive strategies. We suggest that a more comprehensive strategy should combine both algorithms with emphasis on clinical outcomes.