Ventilator-associated Events Training
Have done or are doing VAE now. Great, great. How many of you like it as compared to the -- [ Inaudible Conversations ] Okay. All right. I'm not sure how to take that.
I saw a lot of up and down hands there. All right. Well the objectives today are to review ventilator associated events, the definitions and the surveillance methods, describe important changes made to VAE surveillance in 2014, review the use of the VAE calculator and describe how to correctly enter VAE into NHN, and HSN, and then accurately apply the VAE algorithm to some example cases. So we will do -- have some case studies. I have the fortunate place of being the last presenter so I expect that you'll all look like this at the end [laughter]; very happy to leave, but I'm going to take it that you're really happy with my presentation. All right. So let's get started. To begin with, let's just -- I just would like to give you a little background and the rational for the change in the definitions.
So why the switch from the traditional pneumonia VAP to VAE? Well, we all know that ventilator associated pneumonia is or VAP is an important complication of mechanical ventilation. But of course, it's also true that other types of adverse events occur in critically ill patients who require mechanical ventilation. Currently, there's no valid reliable definition for VAP so there's no gold standard, whether we're talking about definitions used in public health and surveillance, clinical research or even bedside diagnosis and clinical care of patients. More accurate diagnostics are needed, but until then and when those are available, we still have a need to conduct surveillance for complications in mechanically ventilated patients and track prevention progress.
The traditional new VAP that we are -- have used over the years, those definitions include many subjective elements and they're neither particularly sensitive or specific for VAP. This is particularly challenging in a era in which public reporting of health care associated condition rates is becoming more common, which you're all very familiar with, and in which comparisons among facilities are being made and pay for performance programs are incorporated -- incorporating some of these conditions. So we needed a new approach. And the goals of changing the approach to VAP surveillance were to improve the reliability of the definitions, reduce burden of surveillance and enhance the ability to use surveillance data to drive improvements in patient care and safety. With these issues in mind, we set out to modify the approach to VAP surveillance to achieve face validity or clinical credibility and to improve the reliability of the definitions, and to reduce the burden of surveillance. A working group convened in 2011 to revamp the VAP surveillance. A new approach was finalized by the working group and implemented in NHSN in January of 2013 when ventilator associated events was released as a module in NHSN. VAE focuses on objectivity, reliability and automatability.
It's based on the work done by Dr. Michael Klompas, which some of you may be familiar with, and the CDC Prevention Epicenters, and it includes more general measures of ventilator associated conditions and complications, VAC and IVAC. And just given those chosen names, that emphases that this is not based on -- this is not necessarily clinically diagnosed VAP. We are using condition, complication and we -- the third tier then does throw in the traditional VAP level. VAE replaced in-plan new VAP surveillance for ventilated patients in adult locations. So this slide shows you the organizations that participated in that working group. You can see that there was a broad representation from societies representing professionals in a number of fields including critical care, respiratory therapy, public health, infectious disease, infection prevention and health care epidemiology, and we also had participation from some of our federal partners.
The working group is still intact and they are consulted with and drawn in to help with decisions as we make modifications to the protocol as we learn more of how -- with the use. So this being a new approach, we did anticipate that there would adjustments need to be made to the protocol and in part, those adjustments were based on feedback that you all provided, and we certainly do appreciate that and we take your feedback very seriously. The protocol modifications have been made in two different releases. If you had used the protocol in 2013, you probably were annoyed with the modifications that were made in July of 2013, and that was the introduction of the modification in the PEEP criterion. That was done to address concerns that were related to VACs that were being detected due to provider weaning preferences, or in some situations with selected clinical situations.
What that change meant was that the daily minimum PEEP values of zero to five centimeters of water were considered equivalent when you were making VAP determinations, and I'll go into this a little bit more detail later on. And then when we released the protocols in January of 2014, we made some additional modifications, and again I want to emphasize that these were made based on feedback we received from you all in things that weren't working, things that were causing problems and one of the changes was if you remember, the initial release of the VAE protocol was for patients 18 years and older. So we went switched and fell more in line with all the definitions in that it's a location based surveillance now and it's for use in adult locations. Again, we tweaked the daily minimum PEEP and FIO2 definitions. Must -- and that was to add the element that they missed the daily minimum PEEP in FIO2 had to be maintained for at least one hour for that value to count as the daily minimum PEEP.
We provided some additional ways for folks to meet the purulent respiratory secretions definitions because laboratories have different ways of doing their respiratory secretions screening and some folks were not able to ever meet the probable VAP definition as a result of that. And then finally, the list of antimicrobial agents that were eligible for IVAC was refined just a little bit, and again, I'll get into that a little bit more detail later. So this is a good time to review what lower respiratory events are available related to the patient location in an off plan. And as of January, 2014, VAE is the only in-plan option available for ventilated patients in adult locations. So is everybody aware of that? I'm sure you are.
Okay, and so and then also in 2014, current VAP protocol, the traditional PNEU VAP, which sometimes we refer to as new VAP and people get confused on site here alone. We get confused. We're wondering are you talking about new NEW VAP or PNEU VAP, but I'm referring to PNEU VAP protocol is in use for in-plan surveillance in pediatric locations only. An in-plan neonatal VAP surveillance is no longer available as of January 2014, and that's based on feedback that we have received from the pediatric and neonatal VAC surveillance working group who they're working on definitions for the pediatric and neonatal population. So what this means however, is that the current new definitions, they're still available for use off plan for surveillance of VAP in adults, children and neonatal patients, and they're also available for non-ventilated pneumonia in adults, children or neonates. And this also means that you can use these definitions when you're trying to assign a secondary blood stream infection. So I'm just going to throw that out there right now, but again, I'm going to circle back around a little later on and cover that in a little bit more detail.
So let's take a look at what we know so far based on what all you have reported in to NHSN, and this represents data up to and including February 1st of this year. Over 1500 facilities are doing VAE surveillance, and this includes general hospitals, ALTCS, critical access and other types of facilities, and we have reports that represent 2714 locations with the largest proportion coming from medical surgical ICU's and medical ICU's, which is probably not a surprise. Close to 14.5 thousand VAE's have been reported, so give yourselves a hand [applause]. That's a lot of VAE's and it's on your backs and your work that is providing this information that -- and we appreciate. 62% of those VAE's met the VAC definition. 21% met the IVAC definition and the remaining 17% met possible or probable VAC with 13% meeting possible and only 4% progressing on to the probable.
38% met the -- at least the IVAC definition. Now on your handout, I want to point out that that very first day, less than three; the VAE representation should be zero. You probably have like a zero point one or some miniscule, but it should be corrected to be zero. Now this slide is here for comparison sake to show the times from admission to event onset of all VAE's, that's shown in the yellow, and the times from admission to event onset for 2012 VAP events, and that's shown in blue. Although we see the distribution shifted a bit to the left overall for VAE earlier in the course of hospitalization, we can see that like original VAP, the new VAP, a large portion of the events are detected in patients who have been in the hospital for 10 days or more.
So this should increase the confidence in that most of the events detected really are health care associated infections, so there's a little concern that we're detecting things early on that perhaps shouldn't be attributed as a health care associated event. So let's look at the breakdown of VAE's in different locations. Cardiac -- or CCU care has the most VAC, 67% of their reports are VAC, at the VAC level and 11% met the VAP definition. Trauma ICU has the fewest VAC's at 53% and the most VAP's at 29%, so that's a little -- you can see where your particular ICU may fall in this reporting scheme. Overall, of the two criteria available to use in meeting the VAC definition, which are an increase in at least .20 or 20% in FIO2, or an increase in PEEP at least three centimeters of water.
By far the most commonly used criterion was the PEEP criterion. For 66% of the cases, this was the only VAC criterion that was met -- or that was reported to have been met. FIO2 was used alone or along with PEEP criterion in just about a third of all the VAE's and used along with PEEP, what that would indicate and what that tells us, and if this is not what was meant to be reported take note of this. What that tells us is that you detected a VAC in both the PEEP and the FIO2 parameter. So if that's not what -- if that's how you've been reporting it and that's not what you're trying to tell us, take note of that. This may -- the fact that most of these events are reported using the PEEP parameter. This may reflect practice preferences with providers relying more on addressing worsening oxygenation through changes in PEEP as opposed to changing or adjusting the FIO2, or it may reflect an issue with the criteria in that an increase of three in PEEP is less substantial than an increase of .20 in FIO2, and is therefore easier to identify in any given patient. The modification that we made in July hopefully addressed this to some degree, and of course some of this data would have included that information reported prior to July.
We're hoping that that will maybe clean that up a little bit in that there's a little bit less distribution in the PEEP. So we'll be keeping an eye on this. When we look at the criteria that are used to meet IVAC, keep in mind that a patient may have either an abnormal temp or white count here to satisfy the IVAC, the criterion, that one particular criterion for meeting IVAC. And unlike the situation with VAC, there's a bit more evenly distribution of how things are being reported. And perhaps not surprisingly, a large portion of the patients, 40%, were reported to have both an abnormal white count and an abnormal temp, which is not surprising since when a person has an infection, commonly they have a temp and their white count rises. When we look at the time from intubation to event onset in comparison with the 2012 new VAP definition and the data that's generated from that, we can see that even though the VAE's, which are again in yellow here, or orange, however you interpret that color, tend to be detected a bit earlier in the course of mechanical ventilation than the VAP's that are shown in blue.
The proportion of the events detected in the first three to four days of mechanical ventilation is not very dissimilar however. About 27% of old VAP events versus about 35% of VAE's were in that three to four day. A main difference is that there are no VAE's detected in the first two days of mechanical ventilation, and of course 2012 was before the definition, the device definition was changed.
A limitation of the old VAP data that I have to disclose is that we didn't always have date of intubation that -- because it was not a required field for a new VAP. So we have that information on only about 63% of the patients when we have it for all of the patients for VAE. So this is still an area for additional discussion and consideration for the working group.
It is important to strike the right balance between a sensitive definition and that that can be applied to a large proportion of mechanical ventilated patients, and a definition that is specific for health care associated and mechanical ventilator associated events. So we'll again be keeping an eye on this. So let's now take a look at the time from admission to event onset to see if we can hone in on the issue of the definitions perhaps not being specific enough for health care associated events. And again, on your handout that was on the web that you printed out or that you have pulled up on your tablet, the day two should be represented of a zero event since you cannot have a VAE prior to day three. So if we look at the time from admission to VAE onset among patients identified with onset on mechanical ventilation three and four; so that would be early in their course of mechanical ventilation, we can see that a majority of these patients, about 60% were also early in the course of their hospitalization. As we consider the time frames of the current definitions, this is arguably a group to focus on in terms of striking the balance between sensitivity and specificity for identifying conditions that are truly healthcare associated. Somewhat reassuringly, a substantial portion of those events occurred early in the course of mechanical ventilation.
40% are occurring in patients who have been in the hospital for at least a few days. So we're -- we can be more confident these events are truly healthcare associated. So it may have been early in mechanical ventilation but the patients had been in the hospital for you know, a substantial period of time that there's no question the event would have been hospital associated. So what about prevention of VAE's? What do we know? How does that correlate? Well, admittedly, this is our most important knowledge gap. The surveillance is new. We're still assessing and learning, but based on work that has been done and you can find more detail related to this information at the two links, the two references provided at the bottom of the slide. Based on this information, we do know that patients who have VAC and IVAC do worse than patients who do not meet these definitions. We need to know a lot more about possible and probable but as you saw from the information I provided, that was a smaller group reported.
VAC definition detects important clinical conditions. It detects atelectasis. It detects ARDS. It detects patients with pulmonary edema, as well as patients with ventilator associated pneumonia.
And again, we need more work to be done in the IVAC and possible VAP tier. And there's emerging evidence that VAC rates may be responsive, and this is good news, to evidence based interventions in mechanically ventilated patients. And we obviously still need more evidence. But again, this is a new definition, new surveillance. Okay, so let's run through the surveillance protocol. So who's eligible for VAE surveillance? Inpatients of acute care hospitals, long-term care hospitals and inpatient rehab facilities. And of course that's adult locations in those facilities. In-plan VAE surveillance changed in 2014, as I mentioned earlier, from age based surveillance to location based.
And so what this means is that patients in adult locations are eligible for surveillance. So now, if you have a pediatric patient in an adult location, they would be included in your VAE surveillance, and conversely, if you happen to have an adult patient in a pediatric location, you would include them in pediatric VAP surveillance. Now I do want to mention that we have had one or two facilities that have voiced concern in that they have an ICU location where they held every aged patient from the baby to the adult, and there was concern, and legitimate concern about including those babies in VAE surveillance.
And the recommendation is if you have a very, very young children in that ICU, you should probably create a virtual location for those very young children that are not physiologically similar to adults and create -- do PEED that surveillance in that. But that's really, I think, a very rare occurrence. I don't know.
Do any of you have a location in your facility where you would house infants along with adults? Okay, there's one hand. Anybody else? So that -- okay, so there's a couple hands out there so I guess it's not all that -- it's not too terribly uncommon, but in those situations, you all would want to consider a virtual location for the very young. Okay. All right. So who's not eligible? Well obviously the patients who are not in the facilities that I previously mentioned.
Patients in pediatric locations are not eligible and patients who have been ventilated for less than three days are not eligible for VAE surveillance. So if you have a patient who is you know, had a surgery, comes back to the ICU, they are on the vent for two days and then you've successfully gotten them off the vent, they would not be included in VAE surveillance. Patients on high frequency ventilation and extracaporiel life support; sometimes an example of that would be ekmal, are not eligible for VAE surveillance during the time they are receiving those therapies. So if they're on those therapies for the whole calendar day, you would exclude them. If there's portions of the day when they're using a conventional mode and then placed on those modes of ventilation, you would want to include them during the periods of time that they are on the conventional mode. And I'll cover this a little bit more detail as it relates to APRV, but you can apply the same concept. And that's so -- I'm not a respiratory therapist, but I'm not so certain that patients so on and off of ekmal and high frequency ventilation in a calendar day. So I don't think this necessarily applies as much as it does to APRV.
It may apply as in the calendar day when they are switched, but that's about the end of it. So what about other alternative modes of mechanical ventilation? I do want to point out that patients who are receiving conventional mechanical ventilation or are also receiving therapy such as prone positioning, nitric oxide therapy, helium oxygen mixture or sometimes heliox, referred to a heliox, those who are on epoproneseral [assumed spelling] therapy, those are -- those patients are included. And also, include patients on airway pressure release ventilation, APRV, or related modes. It's just that the VAC determinations are made using only FIO2; again, when the patient is on APRV. We'll cover that in a little bit more detail. So APRV, we get a lot of questions what is it. Again, not professing to be a respiratory therapist, but from what I've been told, APRV is a mode of mechanical ventilation that's characterized by continuous application of positive airway pressure with intermittent pressure release phase. And this is used in patients with acute lung injury, acute respiratory distress syndrome, ARDS, and also after major surgeries to prevent or treat atelectasis.
So the bottom line here is I encourage you all to discuss further these respiratory related types of ventilation with your respiratory care and/or your critical care colleagues to determine first, is this mode used in our facility. If it's not you know, you're done. You don't have to worry about it. If it is, then you're going to need to determine a way that you're going to be able to be notified or an easy way for you to identify when this type of mode of ventilation is in use. Okay, so while on a APRV and similar modes, while they are included, it's important to note that when you're evaluating for VAC, you will be limited to using the FIO2 parameter when the patient is on APRV for the entire calendar day. Changes in PEEP as indicated in this surveillance algorithm are not applicable to APRV. So you'll get PEEP values recorded.
You'll get high low values. You'll find documentation of a PEEP or you could find documentation of PEEP in the chart, but when the patient is on APRV, you're not to be using those values that are recorded when you're selecting your daily minimum value. And important to note is when a patient is on APRV and you do not have a daily minimum value for PEEP and you're just making your VAC determinations based on FIO2, and if you're using the VAE calculator, you don't want to enter zero. You just want to leave the field blank. Zero is an interpretable value in the calculator, so the calculator doesn't know that that zero means the patient's on APRV. It's looking at it as a zero, which now will be interpreted as a five. So no values are entered into the calculator in this instance. So now when a patient is on APRV for portions of the calendar day, PEEP values that are recorded in the medical record or on the respiratory therapy's documentation during period of time when the patient was on conventional mode of ventilation, those can be used to make your selection of your daily minimum PEEP.
And in that case, now you can use both PEEP that was collected on conventional mode of ventilation and your FIO2 values for use in making VAC determinations. Does that make sense or is that confusing? Okay, I'm not hearing any real loud groans so I'll take that as a got it. Okay, so let's jump into the algorithm and walk through the algorithm step by step. It's important to note that this is not a clinical definition algorithm, and it's not intended for use in the management of patients. So this slide shows you a summary of the VAE definition algorithm. You can see that there are three tiers; VAC and IVAC in the brighter yellow and possible and probably VAP represented in the pale yellow at the bottom of the screen. The algorithm is progressive such that you have to meet VAC to move on to IVAC. You have to meet IVAC to move on to possible and probably VAC.
So a key feature of course is that there's no chest x-ray. [Applause] Yeah. So to start, there's lots of definitions as you all know, related to VAE so as we're running through the algorithm, I'm going to throw the definitions out there and try to intertwine them so that they hopefully make sense.
So to start, let's look at the VAE definition that's used for ventilator. It's the same exact definition you've been using when you were doing pneumonia VAP surveillance. A ventilator is defined a device to assist or control respiration continuously inclusive of the weaning periods where tracheostomy or an endrotracheal intubation. So those modes such as IPPB, PEEP, nasal PEEP or CPAP or Hypo PAP, they're not considered ventilators unless delivered via tracheostomy or an endrotracheal intubation. Okay, so an episode of mechanical ventilation, because there is reference to this in the VAE protocol, is the period of days which the patient was mechanically ventilated for some portion of each consecutive day. A break in mechanical ventilation of at least one full calendar followed by re-intubation or re-initiation of mechanical ventilation in the case of patient who's trachea'd, during the same hospitalization, would be a new episode.
So if a patient is on and off the vent during a calendar day and that is considered -- that is during a calendar that is considered one continuous episode of mechanical ventilation. If for example, a patient is extubated today, reintubated tomorrow, that would still be considered one episode of mechanical ventilation. But if the patient is extubated today, remains off the vent tomorrow and then Sunday they reintubate him or her, Sunday would begin a new episode of mechanical ventilation.
The VAP definition is identified by observance of deterioration and respiratory status after a period of stability or improvement and the baseline period and subsequent deterioration are determined based on changes in daily minimum PEEP and FIO2. So let's review what is meant by the terms PEEP and FIO2. Again, we're not respiratory therapists. Maybe we have some in here. Do we have a respiratory therapist in here? All right. Darn.
I was going to bring you up here and you could take over here. All right. So let's look at review what the terms PEEP and FIO2 mean. Hopefully, in a little bit of plain English. PEEP or positive and expiratory pressure is a technique used in respiratory therapy in which airway pressure greater than the atmospheric pressure is achieved at the end of the exhalation by the introduction of mechanical impedance to exhalation. Clear as mud, right? In patients on conventional mechanical ventilation, PEEP is one of the parameters that can be adjusted dependent on the patient's oxygenation needs.
That's really all we need to know. A sustained increase in the daily minimum PEEP of greater than three centimeters of water following a period of stability or improvement on the ventilator is one of the two criteria that can be used in meeting the VAC definition. Now the caveat to this is that the daily minimum PEEP must be maintained for at least one hour, and that's a new protocol modification as of January of this year. So let's move on to FIO2. FIO2 stands for the fraction of oxygen in expired gas.
So for example, the air in this room is .21 or 21%. The oxygen concentration is 21% in here. In patients on mechanical ventilation, the FIO2 is one of the key parameters that can be adjusted depending on the patient's oxygenation needs. A sustained increase in the daily minimum FIO2 of greater than or equal to 20 points or .20 points or 20% following again a period of stability or improvement, same thing as with PEEP, on the ventilator is the second of the two criteria that can been used in meeting the VAC definition. And again, for the daily minimum value to be determined, the FIO2 must be maintained for at least one hour.
Okay, now starting at the top of the algorithm and focusing on the first tier VAC, ventilator associated condition; the patient must be on the mechanical ventilator for more than two days to be eligible. They must have a baseline of stability or improvement followed by a sustained period of worsening oxygenation. And again, as previously mentioned, this is based on changes in either the PEEP or the FIO2 parameter. I had some lady email me oh, I think it was last week, wanting to know if those two days had to be consecutive, and they do.
I thought it was obvious in the protocol, but you know we do not say consecutive days, but just for the record, those two days have to be back to back in case there's any question on that. So this parameter obviously is based on FIO2 and PEEP. So this is just the cut and paste from the protocol. I'm not going to read it for you. I think you all can read. And it's basically what I just said in the previous slide. So we have a baseline period of stability or improvement.
This is after the patient has been on the ventilator for greater than or equal to three days. That is then followed by an increase in either the FIO2 parameter or the PEEP parameter, and this is relative to the baseline. So a point to remember is if the baseline is established in FIO2, the evidence of worsening oxygen must occur in the same parameter. So it's hard to have a 20% jump over PEEP if you're looking at FIO2. So you're comparing. You're staying within the parameter one parameter at a time. So you would not look for stability for example, in FIO2 and then say "Oh, but I have evidence of worsening oxygenation in PEEP," because you have to be able to do the comparison and meet that criterion of 20% in FIO2 or three centimeters of water in PEEP. So what are we talking about when we say daily minimum FIO2 and PEEP? When a patient's ventilated, the FIO2 and PEEP ventilator settings are routinely documented across the calendar day, and these are what is used to identify the daily FIO2 and PEEP for purposes of VAE surveillance.
So FIO2 and PEEP settings are typically recorded in the paper or electronic medical record on the respiratory therapy and/or nursing flow sheets in the section of the flow sheet that pertains to the respiratory status or mechanical ventilation. What you want to do is choose each calendar day. Choose the lowest FIO2 and the lowest PEEP setting that was taken from the ventilator during the calendar day that was maintained for at least one hour. So for example, documentation in the medical record may look something like this. Probably doesn't look anything like this, but for -- just for this purpose, this is what it might look like. Use your imagination. The mode of the ventilation is assist control ventilation, which is a conventional mode of ventilation so you know that the patient's eligible for VAE, and eight times over the course of the calendar day, the FIO2 and PEEP settings have been documented.
And in this case, the documentation has occurred every three hours so we know that the values have been maintained for at least one hour. So this is easy. We can just go across and pick the lowest value in each parameter. So in the example, the daily minimum values for the calendar day are .70 for FIO2 and five centimeters of water for PEEP. So these are the value that are of interest for that calendar day. Those are the values you're going to be using to make that -- to be looking to make VAC determinations.
So in this example, there are periods of time where the values are documented on an hourly basis, so it's important to choose the value that was maintained for at least one hour. So in this example, the daily minimum PEEP is eight, and that's easy because it was eight all day. And the daily minimum FIO2 is .75. Now the lowest value across that calendar day was .70, but it was .70 at 3:00 a.m. And by 4:00 a.m.
It was .80, so it was not maintained for a full hour, so that's why the daily minimum value for this particular calendar day is .75 not necessarily the lowest value that you would find, but the lowest value that was maintained for at least one hour. Does that make sense? All right. When choosing the daily minimum values, include FIO2 and PEEP values recorded during spontaneous and awaking -- spontaneous awakening and spontaneous breathing trials or in other forms -- or any other form of weaning from mechanical ventilation.
The exceptions for exclusion are as I mentioned before, periods of time when a patient is on high frequency ventilation or extracaporiel life support, periods of time when the patient is not receiving mechanical ventilation. So if the patient is being weaned and for example, there's a T-piece trial or a trach collar trial and the patient is receiving supplemental oxygen but they're not receiving additional support from the mechanical ventilator, during those times of the day, you're not going to be choosing -- using any documentation for selecting your daily minimum PEEP. Now periods of time when the patient is being mechanically ventilated using APRV or a related strategy, again you're only going to review the FIO2 data and record those values for selecting your daily minimum PEEP. Excuse me. So daily minimum PEEP and FIO2 are the values you're collecting and recording and evaluating to determine if VAC definition is met. You use the daily minimum FIO2 and PEEP values when assessing for both the period of stability and/or improvement and the period that indicates worsening oxygenation. You're not going to be comparing values across the calendar day to determine oh, the patient's stable or oh, the patient is not stable. We get questions about this.
Well, the patient wasn't stable. The values were up and down all day long. We're not looking at the stability across the calendar day. You're looking at stability based on each calendar day's daily minimum PEEP and FIO2 and comparing those values looking for stability.
Daily minimum FIO2 and PEEP must be maintained for at least one hour, and remember that daily minimum PEEP values of zero to five centimeters of water are considered equivalent equal to five for the purposes of VAE surveillance. So this is a good time to talk about that last bullet; the change that was made in the protocol in July 2013. Daily minimum PEEP values of zero to five as I said, are now considered equivalent. And let's talk a little bit about what that means. Well we learned based on feedback from users that VAC's were being detected as a result of usual processes of care or due to provider preferences. So example, patient Y, or let's just call this patient Mrs.
Unlucky. We'll tail on Kathy's presentation. So Mrs.
Unlucky didn't really get worse, but a VAC was detected prior to July 2013 because the provider's differences in how they do spontaneous breathing trials. So Dr. X is on, and he likes to wean patients using a PEEP of zero and then there's a change of coverage in the ICU and Dr. Z, his protocol is he likes to wean them using a PEEP of five.
So this would have previously resulted in detection of VAC when the patient was not having any worsening in oxygenation. It just was provider preference in how they do weaning. In another example of this kind of detection that was no indication of the patient being -- oxygenation status worsening is that some providers do not use PEEP in mechanically ventilated patients when they have high inner cranial pressure, so in neural units we were hearing that the patients were -- PEEP was withheld and it was zero, but then when they would stabilize, the PEEP was introduced and added, and if it was even added at three VAC was detected. Another example was in a hypertensive patient.
PEEP is sometimes not added and they have a zero PEEP and then when the blood pressure stabilizes, they introduce some PEEP. And again, a VAC was being detected in these low ranges. So that's no longer an issue, okay. All right. So let's look at this again, and look at it now that it's updated. So in January of 2013 until July or August when everybody started to reread the protocol, this would have been a VAC detection. But now, you would only have detected a VAC if there was a change from five to eight or greater, okay? And when we take a look at the ventilator, the calculator a little later in the presentation, you'll see how the calculator automatically does that for you. You don't have to change the values you entered.
The calculator will automatically adjust. Okay. Period -- let's review again some more of the elements of the VAC definition. The period of stability or improvement; a patient has a baseline period of stability or improvement on the ventilator defined by greater than two calendar days of stable or decreasing daily minimum FIO2 or PEEP. The baseline period is defined as the two calendar days immediately preceding the first day of the increased daily minimum PEEP or FIO2. The second part that has to be established to meet the VAC definition is after that period of stability or improvement on the ventilator, the patient has at least one of the following indicators of worsening oxygenation; the increase of FIO2 greater than 20 points or an increase in PEEP greater than three centimeters.
And again, remember this is reference to the same parameters baseline not a cross parameters. So let's look at an example. Here we have an IP's worksheet from -- and they have recorded the daily minimum values across the calendar days, and let's observe to see if at any point a period of stability or improvement is immediately followed by evidence of worsening oxygenation that is sustained for greater than or equal to two days. So what do you think? Okay, so we have two -- a two day period of stability.
And actually, in this case we have it in PEEP and FIO2 where the PEEP was five on day two and three and it was 40 on day two and three as well in the FIO2 parameter. Now we do observe worsening immediately following. In this example, there's an increase over the baseline in the PEEP parameter of greater than three centimeters, and this satisfies the requirement for meeting the VAC definition. The increase must be sustained in reference to both days of stability. So if the PEEP on day -- or yes, if the PEEP on day four was eight and then the PEEP dropped to seven on day five, would we have met the VAC definition? I heard no's. That's good. Yes. We would not have met the VAC definition.
That increase has to be sustained for two days, so eight is definitely over on day four, and it's definitely over again three on day five. So that's exactly why in the FIO2 parameter, even though we did have a baseline period of stability, it does not meet the VAC definition in the FIO2 parameter. It went up 20 points on day four in reference to a period of stability, but then it's only a 10 point difference on day five. So in this example, the VAC definition is met in the PEEP parameter. There's greater than or equal to two days of stability immediately followed by a greater than two days of worsening oxygenation, and the event date is day four. Event date is defined as the first day of worsening oxygenation.
So date of event or event date for VAE surveillance is the date of onset of worsening oxygenation, which is day one of the required greater than two day period of worsening oxygenation. It is not the date on which all the VAC criteria are met. So why is the event data so important? Why do we even care what day we call the date of event. Well the date of event defines the VAE window period, and the VAE window period is the period during which the criteria of the other events, if you progress on through the algorithm, that's when those criteria have to be established. Detecting multiple VAE's in that same patient, it's important to -- that's based on the event date, as well. Each VAE is 14 days in duration, and that's totally arbitrary to standardize.
14 days was selected. Day one is the event date. So if June 1st is the date of onset of worsening oxygenation and a VAC is reported, a second VAE cannot be reported until June 15th. So the event date is a full 14 days. A new event cannot be reported until the 15th day. Once you have established a VAC definition within that window period, you can't upgrade to IVAC or possible or probably VAP based on data that's collected outside the VAE window period but still within the 14 day event period. You may not report a new VAE until after the 14 day period has elapsed, but keep in mind during that 14 day period; the baseline period can begin in the last two days.
So you can establish baseline within the event, but you cannot have a new event, which is the day of onset of worsening oxygen until the 15th day. The other reason why the event date is important is that in establishing that 14 day event period, blood cultures must be collected within the 14 day event period for the blood stream infection to be determined secondary to VAE. And we'll talk a little bit more about blood cultures later, but that is one of the parameters that have to be met for a blood culture to be secondary to VAE. So a little bit about the VAE window period. The VAE window period is a period of days around the event and it is with the event date being the day of onset of worsening oxygenation, within which the VAE criteria must be met. And it is usually a five day period and includes the two days before the event, the day of the event and the two days after the event.
So in this example our event date is mechanical ventilation day 13. That is the day of onset of worsening oxygenation. Two days after the event are included in the VAE window period and two days before the event, and that is when if you'll notice below in gray, that's when you have to have the documented temperature or white blood cell count that meets the abnormal criteria of the definition. That's when the antimicrobial agents have to be started and continued for at least four days, and that is when the laboratory test result order date or collection date has to fall within that five day period. So as with every rule, there's an exception.
So the exception to this VAE window period is when events occur early in mechanical ventilation. So when you have an event that has an event date of mechanical ventilation day three or four, the VAE window period may only be three or four days because if you remember, you cannot include any days before the third day of mechanical ventilation, because the patient is not eligible for VAE surveillance until day three or greater. So for example, if the VAE event date is mechanical ventilation day three then the window period only includes the day of VAE onset and the two days after. If the mechanical ventilation day event date is day four of mechanical ventilation, it would include the event date ,one day before, which would be day three of mechanical ventilation, and the two days after. So let's get a visual on this. So here we have the event date occurring on day three of mechanical ventilation. The day one of a worsening oxygenation is the event date.
You can only include three days, so day of the worsening oxygenation and the two days after. So that three day period now is when you need to establish the criteria to meet IVAC or possible or probably VAC, okay? Okay, so let's go back to our original example that we were working on with Ms. Unlucky. And if we say the VAE window is the day of event two days before and two days after the event, and the event day in this case is day four, what's wrong with this shaded area? Okay. We can't use the second day. In this case, there's only one day before onset of mechanical ventilation, or before the onset of the event that we can use; the event date and the two day period after the event date or the onset of mechanical ventilation or onset of worsening oxygenation.
I'm sorry. Okay, so let's move to the second tier, which is IVAC. To satisfy the IVAC definition, patients must first meet VAC. So you can't jump in and say, "Oh, I have an abnormal temp and I have antimicrobial started. Oh, it must be an IVAC." They had to have met VAC first and then they can progress on and you can take a look at your white counts and your temps and your antimicrobial agents. So we're looking at in this parameter, temperature and white blood cell count and the addition of a new antimicrobial agent.
Here's the cut and paste from the protocol. Again, I'm not going to read it to you but these are the parameters that you're looking at. And let's look first at the temperature and the white count criterion. So back to Mrs.
Unlucky, she met the VAC. The yellow shaded area identifies the VAE window, which is in this case, a four day window. She has multiple temps and white counts that satisfy the IVAC criterion. So as long as there's an abnormal temperature or white blood cell count documented during the VAE window period, it should be used to determining whether the patient meets the IVAC definition regardless of whether the temperature or the white blood cell count was also present on admission or before the start of the VAE window period. So you're only looking at the five day, or three, or four day, depending on the event date for temp and white count, and it doesn't matter what happened outside of it on either side. The second criterion, the addition of a new antimicrobial agent, which is the second step of meeting the IVAC definition, this is undoubtedly the most complicated portion of the VAE surveillance definition.
So we have a complicated criterion to meet within a complicated protocol. Rules of meeting this criterion are not perfect, but we needed to standardize a method for assessment of antimicrobial therapy without needing the knowledge of dosing, renal function, indication of therapy, whether the patients' antimicrobials were de-escalated, because remember one of the goals is to reduce the burden, and one way to do that is to make the definition such that the data collection can be automated. So if you have to go back and start figuring out why was this antibiotic given, was the patient needed to be adjusted for renal dosing, automation goes out the window.
So what antimicrobial drugs are in the appendix of the VAE protocol? Well, they're most antibacterial, antifungals and there are some limited antiviral agents. Drugs that are not included are anti HIV agents, anti tuburcal agents, agents used to treat viral hepatitis and agents used to treat herpes simplex virus and antiparasitics. Originally, this was a broad range of agents that could be used to treat health care associated infections, not just respiratory related infections. The IVAC definition was originally developed to identify -- was not originally developed to identify respiratory infections alone, and therefore the list of the antimicrobial agents that were eligible was broad and included drugs that were not used to treat respiratory infections. This caused a lot of concern and confusion among users and particularly in situations where the new antimicrobial agent that resulted in the IVAC determination was not used to treat a respiratory infection, but however it had the patient progress on to meet a subsequent possible or probable VAP definition. So that just didn't sit well with you all. So we heard you.
So we took this back to the VAE working surveillance group and there were possible solutions that were tossed around. Problem was discussed but the working group thought it was important to find a solution that did not increase the complexity of this already complex criterion. So therefore, the decision was made to refine the existing IVAC antimicrobial list by removing some select antimicrobial agents; primarily oral drugs, oral cephalosporins, penicillin, Azithromycin for example, and these are agents that would not be used or would be unlikely to be used to treat a lower respiratory infection in a critically ill patient.
In the event -- in an event -- if an event isn't detected, keep in mind that IVAC may still be detected and should be reported in patients who have non-respiratory sources of infection. The change does not mean that every IVAC detected is indicative of a respiratory infection. If you identify an IVAC, you report it. Okay. So how do you figure out if a new antimicrobial agent has been given? Well, a new antimicrobial agent for the VAE surveillance protocol is defined as any agent listed in the protocol that's initiated on or after the third calendar day of mechanical ventilation because remember, patients aren't eligible until the third or later, and in the VAE window period.
And again, remember that that is typically five days but can be as short as three or four days. The agent is considered new for the purposes of this definition if it was not given to the patient on either the two days preceding the current start date. Don't get hung up on that statement.
Just trust me, it's true. Don't even try to figure it out. It's true and [laughter] it really only comes into play when you're looking at an agent that was started outside of the VAE window period. But people get confused with that whole sentence, but it is true. A new agent must be continued for greater than or equal to four consecutive days, and there's no requirement that the same antimicrobial agent be given on those four consecutive days. So you can get a combination of antimicrobial agents that line up that are all new and are spaced adequately that they can count as qualifying antimicrobial days. These agents have to be administered IV, IM, via the digestive tract or the respiratory tract. So how do you figure out if you have greater than or equal to four days of therapy? We term this the days qualifying antimicrobial days, or QADS or QUADS and a QAD is a day in which the patient was administered an antimicrobial agent that was determined to be new within the VAE window period.
Or consecutive QID's are needed to meet the IVAC antimicrobial criteria and they must be started within the VAE window. So let's pictures worth a thousand words. So days between administrations of a new antimicrobial agent also count as a QAD as long as there's a gap -- we love that word gap don't we, a gap of no more than one calendar day between administrations of the same drug. So for example and this, this allowance is built in for trying to capture those people who are renal dosed and you can't give it every day so this is, this is how we address the renal dosing problem. If levofloxacin is given on the VAE day one, has not been given in the two preceding calendar days, so it wasn't given outside the window period and it's given again on VAE days three, five, and seven you have a total of seven QAD's.
Because the days between that levofloxacin doses because it's the same antimicrobial agent also count as QAD's. Okay now let's look at what that looks like when it's not the same agent. QAD's with different agents in contrast days between administration of different antimicrobial agents do not count as QAD's. So let's go back to Levofloxacin again. It's given to the patient on VAE days minus two and minus one, and there's no antimicrobials given on VAE day one, and then Meropenem is given only on VAE day two. Then there are not four QAD's because the VAE days two and one count as two consecutive days. But the gap is between different antimicrobial agents so you're not counting that day VAE day one to tag onto your Meropenem.
Okay let's go back to Ms. Unlucky. We know that she met the VAP definition, she met the temperature and white count criteria and she had an agent administered for the first time one VAE day four -- or I'm sorry on the ventilator day four mechanical ventilation day four it was continued for five days so she meets the IVAC definition. So let me just say a little something about this two days before. So that sentence that I said don't worry about it, this is why I'm telling you not to worry about it.
If you have an antimicrobial agent started on this day, which is within the VAE window period. If it was also given on one day before or two days before it's no longer new because it was started outside the VAE window period, okay. Does that make sense? So where the confusion gets started is whenever you are inside the window period and you say, "Oh, it was started on day five but it was given two days earlier." Well it wasn't started on day five it was started on day three so -- now you understand why I said don't worry about it. Just don't, don't try to dissect that sentence and understand it just know that you don't want it starting outside your window period unless its greater than two days. All right I probably just confused you more didn't I? Okay wipe that from your brain. All right so now lastly the final tier of the algorithm possible and probable VAP -- how are we doing for time here. Patients who have met the VAC and IVAC definitions and additionally also have purulent respiratory secretions and or some other laboratory evidence of infection respiratory tract infection can satisfy possible or probably VAP.
This is the third and last tier. Again a cut and paste and this is the possible VAP definition for possible VAP, VAC must be met IVAC must be met and then additionally the presence of one of the following; you either meet purulent respiratory secretions or you can meet the positive culture criterion. In some instances you may meet both and because you have a qualitative culture and it doesn't meet the probable definition you still reported it as a possible. But the important thing here to remember is with possible VAP you can meet it with either or and the culture result is less restrictive. It can be a qualitative report, a semi-quantitative report or a quantitative report and it does include sputum as an acceptable specimen for submission to the laboratory. There are exclusions of pathogens that cannot be deemed at meeting the positive culture result. Of course we're not going to include normal respiratory flora or oral flora that's really not a reportive a pathogen. Candida species or yeast not otherwise specified, coagulated staphylococcus species or enterococcus species are not acceptable pathogens unless they are isolated from lung tissue or a pleural, pleural fluid, which is a part of the probable VAP definition.
A little bit about what this candida species or yeast not otherwise specified mean, we get this question a little bit sometimes from users in that does that mean just a report of candida species. That means a report of candida species, a report of candida albicans, a report of candida glabrata, a report of candida torulopsis, any candida or if your laboratory doesn't even identify yeast to the genus or the species level, if they say many yeast that is an excluded pathogen. The probable VAP tier, again VAC and IVAC must be met before you can even start considering meeting probable VAP. This is met when you have the presence of the purulent respiratory secretions and a positive culture that meets the quantitative requirements or the semi quantitative equivalents that satisfy -- and that will satisfy your VAP definition. And note that this respiratory specimens that are eligible are endotracheal aspirate, bronchoalveolar lavage, lung tissue or a protected specimen brush.
So sputum is not a means of meeting probably VAP. Alternately you can meet the probable VAP definition using one of the other less frequently used laboratory tests. A positive pleural fluid culture and again any, there's excluded pathogens would be considered acceptable for a pleural fluid culture if the pleural fluid was obtained when the chest tube was placed or during thoracentesis. So if you have a chest tube and stuff's draining out and you're collecting a culture on a tube that's been in there a week, then you isolate a pathogen candida or that's not acceptable. It has to be isolated on placement of the chest tube or during thoracentesis. Okay so possible and probable VAP definitions are met using purulent respiratory secretions, positive or low respiratory tract cultures. Other criteria that are less commonly used for the probable VAP definition and many other pathogens including respiratory pathogens such as micro plasma and Chlamydia that may be detected using non-culture based techniques are not currently included in the probable VAP definition. So let's explore each of these ways of meeting possible and probable VAP a little bit more to put in context what we're talking about because a lot of you are probably not microbiologists.
So purulent respiratory secretions are defined as secretions from the lungs, bronchi or tracheal trachea that contain greater than 25 neutrophils and on your gram stain results you might have a report of poly's your lab might refer to it as PMN's. Indication of white cells is what you're looking for and greater than, or less than or equal to 10 squamous epithelial cells per low power field. This can used alone to meet possible VAP or in combination with semi quantitative or quantitative culture results with the appropriate amount of growth to meet the probable VAP definition. And we have provided additional ways for you to meet the purulent respiratory secretion since we know that clinical laboratories use different result reporting formats and we didn't want you all to be locked out from meeting from probable VAP just because your lab does not report exactly greater than 25 or less than 10 so different parameters are established now for you to meet that. When we're talking about the lower respiratory culture results the appropriate specimen types include sputum, endotracheal aspirate, a BAL, protected specimen brushings, lung tissue and pleural fluid and again note that sputum's not acceptable for meeting probable VAP.
We exclude the following as pathogens unless isolated from lung tissue or pleural fluid. Again as a review candida species or yeast not otherwise specified, coag negative staph or enterococcus species. And then the following findings on a respiratory culture result that's just indicative of normal flora that's obviously not to be interpreted as a pathogen. So when we're talking about the positive culture result reporting under possible VAP we say that a qualitative, semi quantitative or quantitative result is acceptable and under probable VAP you have to have a semi quantitative equivalent or a quantitative report so what's that mean. Qualitative refers to your lab just simply reporting the organism. You sent a sputum down and they said there's normal flora with staph aureus.
They no quantitation established or associated with it. Semi quantitative is a estimated quantity. A common way for laboratories to do this is using a one plus two plus three plus scale or some labs use descriptors like rare, few, moderate, many, heavy. That would be indicative of a semi quantitative report.
A quantitative report is when they have set the culture up such that they can give you a pretty much exact amount based on colony counts. So you'll get something like 10 to the fourth colony forming units per ml or for milligram if it's a tissue, and then they'll report the pathogen following that that descriptor. So the question comes up how you relate your lab semi quantitative culture result reporting to the quantitative thresholds in the probable VAP. Well first of all just like I encourage you to seek out your respiratory therapist do you seek out your microbiology or laboratory colleagues. They may be able to tell you what they're semi quantitative quantitation equates to on a quantitative level and if they can't we've provided you a catchall so that if your report of moderate or heavy growth or two plus, three plus, four plus is met, you could use that to meet the probable VAP definition. And this is not saying that that's exactly equates we are giving you a ballpark to reference. For the non culture based results for meeting probable VAP pathogens likely legionella identified using non culture based diagnostic testing may qualify as a criterion for meeting VAP so you could have testing using antigen testing, PCR, direct fluorescent antibody testing or serology as long as you have a pathogen identified by a non culture base.
Histopathology results from a lung tissue you might find something that says identification of abscess formation or foci of consolidation. You might have something that says evidence of lung parenchyma invasion by fungi so they're seeing hyphy, pseudo hyphy or yeast, and again in this case, it's a lung tissue so yeast is an acceptable pathogen for report. And then evidence of infection with viral pathogens so your influenza's, human metapneumovirus any of those, those viral pathogens that are identified using non-culture based techniques are available for meeting the probable VAP definition. Pathogens can only be reported for possible VAP or probable VAP and according to the usual pathogen and antimicrobial susceptibility reporting methods utilized in the NHSN for the other events and the exception of course is the excluded pathogens. Pathogens are not reported for VAC or IVAC.
This week I had a question from somebody I am reporting an IVAC that the pathogen field is pre-filled with no, and I can't enter the -- it doesn't drop down to let me enter the pathogen. That's because you don't report pathogens for VAC or IVAC. There's a reason, and, as best we can, we build those little stop gaps into the application, and, in this case, we have a little business rule in there that will not allow you to enter a pathogen for VAC or IVAC. Oaky, back to Mrs. Unlucky. So, she met the VAC. She met the IVAC. She had greater than or equal to four QIDs.
And then, within that window period, you found out that she had an endotracheal aspirate submitted to the lab on mechanical ventilation day three, which is a part of the VA window period, and her Gram stain or the direct exam report was that there were greater than 25 polys and less than 10 eppis, and the organism grew -- and the culture grew staph aureus, and that's just the way it was reported as staph aureus. So, the purulent respiratory secretion definition was met, and you have a qualitative report of an eligible pathogen from the endotracheal aspirate, and you meet the possible VAP definition. Now, why don't you meet the probable? You have a culture result, and you have the purulent respiratory secretions.
Why aren't you meeting the probable VAP? The quantity is not provided as a semi-quantitative equivalent or a quantitative result. Okay, in this example, Mrs. Lucky, Miss Lucky, because, now, she did have a quantitative specimen submitted. An endotracheal aspirate was submitted, and the laboratory reported 10 to the fifth CFUs per ML of staph aureus, and she also met the purulent respiratory secretions definition, so she's reported as a probable VAP, in this case. Now, they sent another -- this lady had a lot of things sent on her.
Poor Mrs. Unlucky. In this case, they put in a chest tube, and they sent a pleural fluid, and staph aureus was reported. Note there's no quantity, but the fact that a pathogen was recovered from this sterile site where you shouldn't have anything growing, she meets the probable VAP definition. Okay, all right, now here's the favorite topic. Everybody likes to talk about blood cultures because it gets back to CLABSIs, and we don't want CLABSIs.
What about positive blood cultures that occur around the same time as the VAE? Well, per the VAE protocol, a BSI is secondary, can be secondary to VAE. A secondary BSI may be only reported, though, for possible improbable VAP and only when the requirements are met, so one organism from the blood culture specimen must match the organism from appropriate respiratory tract specimen, and that respiratory tract specimen had to have been collected in the VAE window period. The blood culture can be collected outside of the VAE window period, but it must have been collected within the 14-day event period. Secondary BSIs are not reported for VAC or IVAC because we don't report pathogens for VAC or IVAC, so you can't have a secondary. Keep in mind that secondary blood stream infections cannot be reported for possible improbable VAP whe
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