Hospitals across the country have had great success with ventilator bundles aimed at preventing ventilator-associated pneumonia (VAP). However, pneumonia is no longer the only game in town, so new strategies may be needed to address the CDC's broader 2013 definition of "ventilator-associated events" (VAE), which includes atelectasis and acute lung injury.
Tasked with a 9-month performance improvement project under the auspices of the Institute for Healthcare Improvement and the Alliance of Independent Academic Medical Centers, clinicians from Christiana Care Health System in Wilmington, Del., put their heads together to find an appropriate collaborative undertaking that could be completed in the assigned time frame.
"Nine months is relatively short for any major studies, so we were looking for a small test of change and something that could be rapidly implemented. We needed to test it, see how it works, determine what changes are needed, etc.," said participant Marci Drees, MD, MS, of Christiana Care. "I had been interested in VAEs. Everyone knows what VAP is, but what are these other entities - ventilator-associated conditions (VACs) and infection-related ventilator-associated conditions (IVACs) -- and are they derived from a definitional issue or some other disease process? We've spent a lot of time over the years trying to prevent pneumonia and doing a lot of things that prevent VAP, but we don't necessarily know how to prevent some of these other things."
National data has suggested that some VACs are caused by acute respiratory distress syndromes (ARDS), atelectasis, edema and other non-infectious things, so Drees and colleagues wanted to examine an intervention that might affect those things and which wasn't currently part of their existing ventilator bundle.
"We ultimately decided to explore the use of higher positive-end expiratory pressure (PEEP) because there aren't a lot of data out there in terms of just exactly what the right PEEP is," she explained. "Sepsis and ARDS guidelines actually suggest using higher PEEP as opposed to just increasing FiO2 (fraction of inspired oxygen). So what we implemented was a program to start with a PEEP of 8 cm of H2O rather than the usual 5 cm of H2O (which has been the habit, but has no real data behind it). We thought that that extra little oomph might help keep the alveoli in lungs open, and maybe prevent some of the atelectasis, etc."
At Christiana Care, a pilot program was implemented in the surgical ICU, typically where most VAEs are observed. "We wanted to have a smaller test of change and fewer people to educate about it. So we educated all the respiratory therapists dedicated to our ICU," said Drees. "Initially there was some concern that a person who has a PEEP of 8 is thought to be sicker than one who is at 5, and we didn't want that perception to impact spontaneous breathing trials. So the education upfront ensured that RTs would do all their standard protocols just as they would otherwise; the only difference was that we were starting the PEEP higher."
The original plan was to do a two-week trial, but it was extended -- indefinitely. "I was expecting the VACs to decrease, but actually it was more the pneumonias that decreased. And the total VAE rate dropped as well," said Drees.
During the first four months, 263 patients underwent mechanical ventilation in the ICU. Compared to the previous four months (with 291 ventilated patients), the total VAE, IVAC and possible/probable VAP rates decreased, while the VAC rate remained stable; average vent days decreased slightly from 5.1-5.9 days to 4.6-4.8 days during the PEEP trial, though average length of stay in the ICU remained stable.
"Now granted, the unit does many other preventative things as well, but we decided it certainly doesn't hurt anything, it is easy to implement, there is no cost to it, and it seems to decrease VAEs. So we decided to continue," said Drees. "We are talking about whether it is time to spread it to other units, but for now it's still just in the surgical ICU."
For other facilities that may wish to try this strategy, Drees offered advice. She said it is essential to work with the unit, RTs in particular, but also nurses and physicians, and gain full support from directors of respiratory and critical care to make sure there will be no unwanted consequences.
"The only concern people voiced to us was the possibility of barotrauma, but the difference between 5 and 8 is minimal, and we haven't detected anything like that at all," said Drees. The other thing she advised was to be sure there is clarity around the CDC definitions for VAE ". because you could actually end up causing yourself more VAEs if you are not aware of the definitions. For example, right now the definition regards all PEEP between 0 and 5 as equivalent. So that if you drop your PEEP to zero from 8, instead of 5, to do an SBT [spontaneous breathing trial], for at least 2 days in a row, then fail to do an SBT for 2 days in a row, that could be deemed a VAC. You have to be aware of some of those intricacies of the definition to make sure that you are not triggering more of these events just by virtue of the way you are doing things."
Drees and colleagues presented their findings on Optimization of PEEP as a Strategy to Reduce Ventilator-Associated Events as a poster presentation at IDWeek, a joint meeting of the Infectious Diseases Society of America, the Society for Healthcare Epidemiology of America, HIV Medicine Association and Pediatric Infectious Diseases Society, October 2014, in Philadelphia.
Valerie Neff Newitt is on staff at ADVANCE. Contact: firstname.lastname@example.org.
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