CHARM
Research type
Research Study
Full title
Comparing heat -moisture exchange filter (HMEF) and Lower Respiratory Tract (LRT) microbiomes in mechanically ventilated adult patients by using advanced molecular techniques.
IRAS ID
311129
Contact name
Mahableshwar Albur
Contact email
Duration of Study in the UK
1 years, 0 months, 0 days
Research summary
Despite extensive infection-control efforts, hundreds of millions of patients become infected in hospitals every year around the world. Of particular concern is pneumonia developing during artificial ventilation or ‘life support’ (using a machine called ventilator and breathing tube containing a filter) to support the lungs in critically-ill patients admitted to an intensive care unit. This is called ventilator associated pneumonia (VAP). VAP is the leading cause of death from infections acquired in the Intensive Care Unit. There is, at best guess, an extra cost of at least £10,000 per patient with VAP in the UK.
VAP was thought to be caused by ‘accidental introduction’ of bacteria into previously clean lungs (for example, when the breathing tube was inserted through the mouth). It is now known that the healthy lungs are not clean. They naturally have many resident microorganisms (the microbiota). This undermines the ‘accidental introduction’ theory as bacteria are already present in the lung. VAP is not the result of external bacteria alone.
Both resident and external bacteria, and the interactions between them, are important. With modern laboratory analysis the interactions can be tracked in detail. It is clear that significant shifts occur in this microbial community during the development of VAP. These changes occur before VAP is obvious in the patient. If we could detect these shifts in clinical practice it would allow early and more effective diagnosis. This would allow better treatment of these patients and improvement in clinical outcome.This analysis is limited by getting samples from patients’ lungs. Currently, sampling usually involves pushing a suction tube into the windpipe of the patient every few days. However, this traditional method can be “invasive” and traumatising for the patient. There are cost implications (consumables and ICU staff time), and collection of samples in this way may generate aerosols, putting staff and other patients at risk of cross infection. In this study we will get samples from an easily accessible filter, called a heat and moisture exchange filter (HEMF) that collects moisture from the patients' breath. As the filter is routinely changed daily we can get frequent samples from something that is otherwise thrown away. It also does not involve inserting tubes into patients as the filter sits near the ventilator machine and hence mitigates all the associated complications.
In this study involving a total of 100 samples, we will compare the filter samples with the “invasive” ones to see if they are similar. The next step would be to collect information on VAP as well as filter samples to see if they could be useful in practice. In the long term, if they are, we could use filter samples instead of tube ones. Daily monitoring of the shifts in microbiota could allow VAP to be identified before it is clinically obvious. There are obvious benefits to patients and the NHS. If successful this work would reduce deaths, save the NHS money and reduce antibiotic use and antibiotic resistance.
REC name
East of England - Essex Research Ethics Committee
REC reference
23/EE/0022
Date of REC Opinion
9 Feb 2023
REC opinion
Favourable Opinion