Episode 18- Ventilator-associated tracheo-what?
Tune in as we discuss ventilator-associated tracheobronchitis and what the guidelines say we should do about this little-known entity!
– Ventilator-associated treacheobronchitis (VAT) is defined as fever along with new/increased sputum production and positive respiratory cultures, but without radiographic evidence of pneumonia
– Both ventilator-associated pneumonia (VAP) and VAT arise after 48 hours of intubation and are caused by similar organisms. It is estimated that at least 10% of mechanically-ventilated patients can develop VAT, which is similar to the rates of VAP
– However, unlike VAP, per the 2016 IDSA guidelines on HAP/VAP, patients with VAT should not be given antibiotics. This is based on low-quality evidence that suggest antibiotic therapy could shorten the duration of mechanical ventilation, but it is unclear if they improve other clinical outcomes
– The authors stress the importance of antibiotic stewardship and recommend against the use of routine treatment of VAT
– However, some interpretation is needed on a case-by-case basis, as the sensitivity and specificity of chest X-Rays for detecting pneumonias are relatively low. In the presence of a positive gram stain, systemic signs of infection, and worsening oxygenation or increasing ventilator settings, antibiotic therapy may be considered as this may actually represent a new VAP
Hello and welcome to Episode 18 of ER-Rx. In this episode, we discuss a hotly-debated topic: whether or not to treat ventilator-associated tracheobronchitis (VAT) with antibiotics. VAT is defined as fever along with new/increased sputum production and positive respiratory cultures, but without radiographic evidence of pneumonia. Some consider VAT an intermediate process between lower respiratory tract colonization and ventilator-associated pneumonia (VAP). Others consider it a completely separate entity. Although much is known about VAP, studies on VAT are limited and have shown conflicting results, as we will discuss later.
VAT has been described in the ICU since the 1990s, but it wasn’t until the early 2000s that our knowledge on VAT expanded. There are some similarities between VAP and VAT. They both arise after 48 hours of intubation and are caused by similar organisms, including multi-drug resistant (MDR) strains. It is estimated that at least 10% of mechanically-ventilated patients can develop VAT, which is similar to the rates of VAP. Given the similarities, what do the guidelines say about routinely treating VAT?
Per the 2016 IDSA HAP/VAP guidelines, patients with VAT should not be given antibiotics (this was a weak recommendation based on low-quality evidence). When they looked at the admittedly low number of randomized trials, they only took into account one trial of 58 patients. The group that received antibiotics had lower ICU mortality rates (18% vs 47%, P=0.047), less progression to VAP (13% vs 47%, P=0.011), and more mechanical-ventilation free days (median 12 days vs 2 days, P < 0.001). There was no difference in the duration of mechanical ventilation or length of ICU stay. However, this trial was not blinded and was stopped early, and with its low number of patients this trial should not be weighed too heavily.
When looking at observational studies, antibiotic therapy in the setting of VAT was associated with a shorter duration of mechanical ventilation (-3.5 days, 95% CI -6.88 – -0.019), but no differences in mortality or duration of ICU stay.
Therefore, the authors of the IDSA guideline admit that the evidence may suggest that antibiotic therapy could shorten the duration of mechanical ventilation, but it is unclear if it improves other clinical outcomes. Reading these results personally, I’m almost convinced that we should give these patients antibiotics. Although it’s not the best data, surely less time on ventilators is a good thing?
And this is the problem that we encounter. The authors of the IDSA guidelines state that the lower days of mechanical ventilation do not outweigh the downsides of antibiotics, including drug allergies, cost, and the development of c. diff. as well as antibiotic resistance. We touched a little bit about how unnecessary broad-spectrum antibiotics can lead to the development of MDR organisms in Episode 9. But, just like in a lot of things in medicine, and especially our favorite fields, emergency medicine and critical care, there is a fair amount of grey area and provider interpretation. To highlight this, the authors conclude by stating that since the sensitivity and specificity of chest X-Rays for detecting pneumonias are relatively low, in the presence of a positive gram stain, systemic signs of infection, and worsening oxygenation or increasing ventilator settings, antibiotic therapy may be considered as this may actually represent a new VAP.
In conclusion, there are arguments both for and against treating VAT. Some providers will state that no treatment or delayed treatment could result in more severe clinical outcomes including progression to VAP and increased mechanical ventilation duration. Others will argue that the high prevalence of VAT could mean that a policy of treating all VATS could results in significant increases in antibiotic use and the development of MDR strains. Since higher mortality in patients with VAT has not been definitely proven, we ask ourselves if this is a good approach. Personally, I say that we have to consider each case individually, and maybe this is the best approach to these grey situations in medicine.
As always, thank you for your time. We would love for you to subscribe to our podcast and leave a review. Also, check out errxpodcast.com for a list of references and a full transcript of each episode. See you next week!