CSTSS-Ventilator-Associated Pneumonia
Prevention Toolkit
The purpose of this toolkit is to support your efforts in implementing evidence-based practices and improve
care for all cardiac surgery patients. Many of the strategies outlined in this toolkit have been adopted by
academic and community hospitals of varying sizes. Many of these teams have improved adherence to
evidence-based practice and observed a significant reduction in their ventilator-associated pneumonia (VAP)
rates.
Your leadership is needed to achieve these results in your perioperative areas. Most of your efforts will be
spent working with staff that manages patients in CSICU (respiratory therapist, nursing staff, physical
therapist, other ICU personnel, attendings and surgeon). However, some of your time will be spent working
with staff that manages the surgical patient in the OR, OR (prep area) and intermediate care unit and other
inpatient surgical areas. We have developed a model to support your efforts to implement evidence-based
practices, reduce VAP and improve care for all cardiac surgical patients. We have applied this model to
improve adherence to evidence-based practices and achieved dramatic results for patients in the OR and
ICU. This model has 4 stages that answer the following questions:
1.
2.
3.
4.
Engage: How will this make the world a better place?
Educate: How will we do this?
Execute: What do I need to do?
Evaluate: How will we know we made a difference?
This toolkit details what you should do in each of these stages. Several tools that may help eliminate VAP in
your cardiac surgical patients are provided in the appendices below ; we need your leadership to adapt these
tools based on your local culture and resources.
List of Appendices
Appendix A: Literature Review – Head of Bed Elevation
Appendix B: Literature Review – Oral Care with Chlorhexidine
Appendix C: Literature Review – Subglottic Suctioning
Appendix D: Literature Review – Spontaneous Awakening and Spontaneous Breathing Trials
(SAT and SBT)
Appendix E: Fact Sheet – Head of Bed Elevation
Appendix F: Fact Sheet – Oral Care with Chlorhexidine
Appendix G: Fact Sheet – Subglottic Suctioning
Appendix H: Fact Sheet – Spontaneous Awakening and Spontaneous Breathing Trials (SAT and
SBT)
Appendix I: Fact Sheet – Policy-based or Structural Measures
Appendix J: Definitions and Techniques for Oral Care with Chlorhexidine
Appendix K: Definitions and Techniques for Spontaneous Awakening and Spontaneous
Breathing Trials (SAT and SBT)
Appendix L: Daily Data Collection Sheet and Instructions
Appendix M: PowerPoint presentation – Ventilator-associated Pneumonia
Appendix N: Quiz Questions for VAP
Appendix O: Michigan Keystone ICU – Oral Care Toolkit
Appendix P: Michigan Keystone ICU – Clinical Practice Assessment Form
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Engage: How does this make the world a better place?
You need to help staff understand that VAP is associated with significant preventable morbidity, mortality,
and costs.1-4 All mechanically ventilated patients have an increased risk of VAP and the risk increases as
the number of comorbidities, surgical procedures, use of other invasive devices, etc. increases. Patients
undergoing heart surgery are at a particularly high risk due to the presence of multiple comorbidities,
frequent postoperative use of multiple invasive devices (eg, intraaortic balloon counterpulsation, pulmonary
artery catheter), and the common use of cardiopulmonary bypass.5
There are nearly a half million inpatient cardiovascular operations occurring annually in the US. The VAP
rate in this patient group is high, with published rates between 3.2 and 8.5 per 1000 ventilator days.5-8
Tamayo et.al9. 2012 found that VAP had the highest independent mortality risk factor among all ICU patients,
with an increased hazard ratio in the cardiac surgery population of almost 9%. These are just some of the
reasons why efforts to improve the quality of perioperative care and decrease VAP rates are paramount.
Often times our frontline staff are not aware that their patients are at risk for VAP and the risks associated
with VAP. Sharing this information with frontline staff can often help to engage them in efforts to improve
care.
To engage your colleagues, first make the problem real by telling a story of a cardiac surgical patient who
suffered needless harm from VAP and share the patient’s story openly with your colleagues and leadership.
Ask them if this is the kind of care they would like for their family, if this is care they are proud of, if this is the
best your hospital can do?
Second, post the number of people who have developed VAP each month and the total number of VAPs for
the previous year in your ICU. To keep staff engaged, post a trend line so nurses and physicians can see at
a glance your VAP rate and how it changes over time. Post the number of days (weeks or months) since
your last VAP. Use formal and informal opportunities to talk about your compliance with evidence-based
practices and about unit VAP rates. Make a point of recognizing providers who adopt evidence-based
practices. Invite your hospital infection control professional or epidemiologist to become an active part of the
preoperative improvement team and draw on their expertise to help with your specific challenges. Often
times expressing VAP rates in terms of potentially preventable deaths, dollars and days can be more
meaningful for staff and hospital leaders. To convert VAP rates into potential deaths, dollars and days
attributable to your current VAP rate, visit our ‘opportunity calculator’ at http://www.hopkins
medicine.org/quality_safety_research_group/our_projects/ventilator_associated_pheumonias/estimator.html.
Finally, make sure your staff recognizes that benchmarking your performance against similar hospitals and
striving for the 50th percentile is unacceptable for preventable complications. Your goal should be that no
patient suffers harm from a preventable complication while in our hospital. You may be able to eliminate
infections and any infection should be viewed as a defect.
Educate: How will we accomplish this?
There is a robust amount of literature that outlines effective strategies for the prevention of VAP. In 2011, we
convened a committee of 155 healthcare providers, including critical care physicians and nurses,
pulmonologists, infectious disease physicians, infection preventionists and respiratory therapists. This
committee was tasked to develop a new VAP prevention bundle based on current guidelines and literature.
Sixty-five candidate interventions were found through an extensive literature search and were presented to
this committee through an iterative evaluation process. Committee members were asked to evaluate each
measure for its importance in the prevention of VAP as well as the feasibility of implementation. The
strategies listed below are the results from this project. A manuscript is currently being written to describe
this process and the results. This work represents the first bundle of interventions specifically designed for
VAP prevention and teams in this collaborative are on the leading edge of the science for VAP prevention.
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The following strategies were chosen by the VAP Prevention Committee described above as the most
important strategies to be used for VAP Prevention. Please refer to the appropriate literature reviews in
Appendices A-D for references.
Strategies to employ and evaluate on a daily basis include:
1. Maintain elevation of the head of the bed to >=30 degrees
2. Perform oral care 6 times daily.
3. Use chlorhexidine while performing oral care twice daily.
4. Use of subglottic suctioning endotracheal tubes for patients ventilated for > 72 hours
5. Use of spontaneous awakening and spontaneous breathing (SAT and SBT) protocols.
Other strategies are “policy based” and include:
1. Perform hand hygiene
2. Avoid supine position
3. Use standard precautions while suctioning respiratory tract secretions
4. Use orotracheal not nasotracheal for elective intubation
5. Avoid the use of prophylactic systemic antimicrobials
6. Avoid non-essential tracheal suctioning
7. Avoid gastric over-distention
8. Use a closed ETT suctioning system
9. Change closed suctioning catheters only as needed
10. Change ventilator circuits only if circuits become damaged or soiled
11. Change HME every 5-7 days and as clinically indicated
12. Provide easy access to NIVV equipment and institute protocols to promote use
13. Periodically remove condensate from circuits, keeping the circuit drain closed during the removal,
taking precautions not to allow condensate to drain toward patient
14. Use an early mobility protocol
Execute: What do I need to do?
There are 6 steps in the VAP Prevention toolkit:
1. Educate all staff
- Use powerpoint slides, short Fact sheets and Literature reviews.
2. Standardize as much as you can in the ICU setting, for example:
- Assure the easy accessibility of supplies, such as daily oral tear-off care kits with
chlorhexidine
- Use protocols for spontaneous awakening and spontaneous breathing trials
- Use protocols for use of and accessibility of equipment, such as NIVV
3. Check ICU and hospital policies to see if they are in line with the policy-based strategies listed
above and work on the development of policies that are not yet in place.
4. Improve communication among providers by discussing Daily Goals during morning rounds for
each patient. Discuss spontaneous awakening and spontaneous breathing trials during the
rounding process.
5. Create independent redundancy to help ensure that all patients receive the evidence-based
interventions they should for the prevention of VAP.
6. Monitor compliance with evidence based guidelines and VAP rates over time.
Step1. Educate staff
We’ve found that many healthcare providers are not aware that the interventions outlined in this ventilatorassociated pneumonia prevention bundle toolkit can dramatically improve patient outcomes and/or they are
not familiar with the evidence behind each of these measures. There are 4 guidelines for the prevention of
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healthcare-associated pneumonia that we have used for the development of this program from the Centers
for Disease Control and Prevention, the American Thoracic Society, The Society for Healthcare
Epidemiology of America and the Guidelines Committee and the Canadian Critical Care Trials Group. 10-12
Each of these guidelines addresses issues specific to VAP, though some are more specifically focused on
VAP than others. These are excellent resources to help you educate providers and increase awareness of
the evidence-based interventions for VAP Prevention.
To make it easier for you to educate staff, we have summarized the effective prevention strategies into
Powerpoint slides, short Factsheets and Literature reviews. We recommend that you distribute the Fact
Sheets (Appendices E-I) to all providers (anesthesia, nursing, medical/surgical staff, respiratory and physical
therapists etc.). For those providers that are interested, make sure that you have the Literature Reviews
(Appendices A-D) for each of the topics readily available. Hold staff in-services to review the PowerPoint
presentation (Appendix K) and Fact Sheets (Appendices E-I), and allow providers to have their questions
answered. Track the number of providers that have attended the in-services and received the fact sheet.
Continue to provide in-services until the information has been provided to at least 90% of staff.
There is a correlation between compliance with evidence-based interventions and better patient outcomes.
Posting run charts of compliance with the evidence-based interventions, the number of patients that
developed VAP, and the number of months without a case of VAP in your ICU areas is an effective method
for demonstrating to staff that their actions make a real difference in patient outcomes.
Several successful education strategies focus on changing physician behavior. These include person-toperson interventions (individualized educational information packets consisting of research literature,
evidence-based reviews, hospital specific data, national guidelines – Appendices A-D), brief reminders (emails, letters, phone calls), target information period reinforced via informal educational meetings and
networks, and educational outreach visits (for example, involving respiratory therapy staff). Therefore,
identify an appropriate forum within your cardiovascular service to formally involve ALL staff with this
initiative. In our experience, physicians respond best to other physicians so the physician champion in your
hospital should probably do this if at all possible. A medical staff meeting may be an appropriate forum for
dissemination of this educational information. A better forum may exist in your hospital (e.g. Grand Rounds)
to review the PowerPoint presentation and distribute the Fact Sheets and Literature Reviews. Ideally, this
information will be disseminated to the various types of caregivers at the same time, allowing each to know
what that other has learned and to allow for open discussion about local practices, barriers and plans.
Step 2: Standardizing Care
The reality is that most providers want to do the right thing, but ICU care is complex and it is often difficult to
remember everything we should do in real-time. Strategies and policies that help to decrease complexity, like
checklists, are used extensively in other industries and are increasingly being employed in health care.
Standardizing care can also improve compliance with evidence-based practice.
In this project, we are asking you to collect data on the following process measures daily. This will give you
an accurate view of how well staff are incorporating the new processes into their daily practice. Compliance
rates can be fed back to staff on a monthly basis for reinforcement.
Strategies to Evaluate Daily
1. Maintain elevation of the head of the bed to >=30 degrees
Several successful strategies have been published in the peer-reviewed literature to improve
compliance with the measure of keeping the head of the bed at an elevation of >=30 degrees.
These include the use of a bed with a specific attachment that will show the angle at a glance, the
use of a handheld protractor, a determination of what mark on which bed can signify the correct
angle for recline (and staff education to this effect), and the use of daily audits to assure compliance.
Rates of compliance would be fed back to the unit on a regular basis. Another strategy to improve
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adherence to the angle of the head of the bed is to involve other professionals, like respiratory or
physical therapy staff, to ensure the head of the bed is maintained at the correct angle.
2. Perform oral care 6 times daily.
Compliance with recommended oral care practices can be difficult. The use of a set of “tear-off”
daily oral care packets that can be hung on the wall by the patient’s bed can remind providers. This
also serves as a way to track compliance. If only 4 packets have been used out of 6, 2 have not
been used during that 24 hour period.
3. Use chlorhexidine while performing oral care twice daily
As above, compliance can be difficult. Many of the tear-off sets mentioned above have the
chlorhexidine incorporated into two of the packets. Again, remaining packets can be used both for
reminders that the product needs to be used and for compliance checks.
4. Use of subglottic suctioning endotracheal tubes for patients ventilated for > 72 hours
Maintaining a well-stocked supply of subglottic suctioning endotracheal tubes enables providers to
choose them when clinically appropriate. At our organization we have replaced standard ETTs in
code carts and emergency intubation roles with subglottic suctioning endotracheal tubes. In the OR
however, the determination of which patients are most likely to be mechanically ventilated for more
than 72 hours is difficult. Our goal is to learn together how we may best be able to incorporate this
evidence into practice while balancing the additional costs of the special ETTs. Nevertheless, the
use of these special ETTs has been shown to be exceedingly effective for VAP prevention and
economic modeling suggests the use of these tubes may actually reduce cost.
5. Use of a spontaneous awakening and readiness to wean protocol.
The adoption of spontaneous awakening (SAT) and spontaneous breathing trial (SBT) protocols is
paramount to reducing the length of time a patient remains on mechanical ventilation. This
concomitantly reduces the risk of VAP. Girard et. al.13 showed that pairing an SAT with an SBT has
been shown to be effective, reducing the length of intubation by 3.1 days.
Step 3: Other “policy based” strategies
The implementation of hospital or unit-based protocols has also been shown to improve success with
evidence-based interventions. For instance, most hospitals have existing policies and campaigns to
increase hand hygiene rates. Protocol and policies in the ICU can help improve compliance.
We encourage you to review your existing policies and implement additional new policies as needed to target
VAP prevention that are specific to the ICU. For instance, focusing on the decision to intubate and on
intubation techniques and choices, consider implementing the following policies:
1. A policy to assure the availability of NIVV equipment and standardize equipment practices - This
policy defines when, where and under what conditions NIVV equipment should be used. It states
that the equipment should be easily accessible to the providers working in the ICU and that it should
be kept in good working condition, with the required supplies. Such a protocol without the ease of
access to the equipment is not practical, and the availability of the equipment without the protocol to
encourage the use will not decrease the use of mechanical ventilation on the unit.
2. To help prevent colonization of the aerodigestive tract the following policies should be used:
a. A policy to encourage the use of orotracheal intubation over nasotracheal whenever
orotracheal intubation is not contraindicated.
b. A policy to encourage the use of closed ETT suctioning systems, and remove open systems
from supplies.
c. A policy to discourage the scheduled changing of closed suctioning catheters. These should
only be changed as needed.
d. A policy to avoid the use of prophylactic systemic antimicrobials. The use of prophylactic
antimicrobials for VAP is inappropriate and long-term use of antimicrobials is known to lead
to antimicrobial resistance. There are situations where prophylaxis is warranted, but these
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are cases where there is the possibility of a contaminated wound (trauma, surgery, etc.) or
prophylaxis due to another comorbidity such as an immunodeficiency and have nothing to do
with VAP.
3. To help prevent aspiration:
a. A policy to keep patients in a semi-recumbent position (>=30 degrees) whenever possible,
unless it is contraindicated.
b. A policy to discourage the use of non-essential tracheal suctioning. Place reminders to
discourage orders for regular suctioning, i.e. q. 2 hours.
c. Policies to prevent gastric-over-distention. Keep feedings to a minimum volume and
decompress the abdomen. For example, assuring the patient has an OGT or NGT in place if
there is an anticipation of longer-term intubation.
d. A policy to encourage the use of an early mobility protocol. Encouraging mobility may
decrease the propensity to atelectasis and increase clearance of bronchopulmonary
secretions.
Several of these policy-related strategies are focused on practices for both nursing staff and respiratory
therapists.
1. A policy that promotes the use of standard precautions while suctioning respiratory secretions. This
is very important for both the protection of the healthcare provider and for their patients. If the
patient does have an infection or is colonized with a communicable organism, standard precautions
can protect the healthcare provider and their subsequent patients.
2. Closed suctioning catheters should only be changed as needed.
This can help prevent the patient from colonization of the lower respiratory tract which might lead to
infection. Change only when needed to minimize this risk.
3. In order to protect the patient from inadvertent contamination, the ventilator circuit should be
periodically drained and during this procedure the caregiver should take care not to allow the
condensate to drain toward the patient.
4. The ventilator circuits should only be changed if damaged or soiled.
5. Heat moist exchangers (HMEs) should be changed every 5-7 days and as clinically indicated.
Implementation of these protocols and interventions may look overwhelming, but if you approach it with the
goal of VAP reduction and take the policy changes in groups, i.e. all equipment related changes. The
process will be easier. Far too many patients suffer preventable harm. Our goal is to eliminate that harm.
Step 4: Improve communication among providers
One powerful strategy to improve communication and to increase the likelihood that patients will receive the
therapies they should is the ‘Daily Goals’ form. The Daily Goals form is filled out every day on every patient
and has been successfully used in the ICU. We will be talking much more about the Daily Goals form during
this project. We encourage you to explore the use of the Daily Goals form as part of this project and
specifically as we work together to prevent VAP.
Step 5: Create independent redundancy
Creating independent redundancy involves developing unique and separate system checks for critical
procedures. High reliability industries use independent redundancies to monitor those procedures that are
highest risk or most likely to cause harm if not done correctly. We are just beginning to develop independent
redundancies in healthcare.
We see many opportunities to create redundancy and to improve adherence with the VAP prevention
measures. For example, you can adopt the use of a tear-off oral care tool as mentioned above, and you can
post standardized laminated posters in every ICU room delineating the criteria and steps for the spontaneous
awakening and spontaneous breathing trials. In addition, all appropriate healthcare providers can be given
laminated pocket guides to have with them at all times.
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Another successful idea is to incorporate redundancy at the time of nurse-to- nurse or RT-to-RT handoffs.
For example, these handoffs typically include important information about the patients on the ventilator, such
as oxygenation status, status history, particulars about attempted SATs and SBTs, etc. To create
redundancy, these handoffs could include a checklist to assure that patients are receiving their needed
therapies.
There are several other ways to create redundancy in the system. Consider incorporating SAT and SBT
reminders using computer decision support systems. Computerized decision support is one of the most
effective tools described in the literature. Automated reminders, supported by computer-based decision
systems, lead to reductions in human error (error of omission) and decrease the variability of the process.
Engaging all caregivers can provide another independent redundancy. Include respiratory and physical
therapists, nurses and pharmacists in the care choices that are made. Talk to your front line providers! They
likely have many many other suggestions for creating redundancy in your system.
Summary: Suggestions for creating redundancy
Oral care tear off packets
Posters for reinforcement of SAT and SBT steps
Adding reminders and standing orders to computer decision support systems. Require answers!
Include all healthcare provider types in the decision making process.
Use a protocol for RN to RN and RT to RT handoffs. Set up a checklist that meets the needs of your site.
Talk to your front line providers for other suggestions for creating redundancy in your system.
We suspect you will be able to identify additional opportunities to create redundancy in your ICU and we
hope that you will share your ideas with other ICUs. Nevertheless, there is no “one-size-fits-all” solution that
will be effective for every health care setting. Implementation of the different strategies and suggestions must
be adapted based on the situations and circumstances of every clinical setting.
Step 6: Monitor compliance with evidence based guidelines
Conducting periodic audits with continuous timely feedback of both process and outcome measures to all
staff involved in this quality improvement process is essential. To accomplish this, we recommend that you
monitor compliance with the evidence-based process measures above and report back to your staff each
month. Share the reports for percentages of compliance for each measure with your team to help them track
their performance. Also let your staff know about each month that goes by without a VAP!!
Evaluate: How will we know that we added value?
The first step is to collect 2 years of baseline VAP rates in your unit. Enter this information into the electronic
database. As your monthly VAP rates improve, you will need to have these rates for comparison. When you
begin the project, enter your VAP rates monthly. Comparing monthly rates against the baseline and other
ICUs will give you the incentive you need to keep focus on your work towards eliminating VAP in your unit.
The more real-time data you have access to the better. We partnered with Quality Improvement Department
to send letters from the ICU leadership to providers who were not compliant with a given measure and
requested that they investigate why the defect occurred and submit a response for the team to review. This
enhances the sense that everybody is responsible for the successes – and the failures. Furthermore, while
the Quality Improvement Department had previously been investigating each defect, the front line providers
frequently had important insights into why there was a failure and new protocols, guidelines or practices have
been implemented as a result.
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REFERENCES
1. Safdar N, Dezfulian C, Collard HR, Saint S. Clinical and economic consequences of ventilator-associated
pneumonia: A systematic review. Crit Care Med. 2005;33(10):2184-2193.
2. Edwards JR, Peterson KD, Mu Y, et al. National healthcare safety network (NHSN) report: Data summary
for 2006 through 2008, issued december 2009. Am J Infect Control. 2009;37(10):783-805. doi:
10.1016/j.ajic.2009.10.001.
3. Chastre J, Fagon JY. Ventilator-associated pneumonia. Am J Respir Crit Care Med. 2002;165(7):867-903.
4. Klevens RM, Edwards JR, Richards CL,Jr, et al. Estimating health care-associated infections and deaths
in U.S. hospitals, 2002. Public Health Rep. 2007;122(2):160-166.
5. Leal-Noval SR, Marquez-Vacaro JA, Garcia-Curiel A, et al. Nosocomial pneumonia in patients undergoing
heart surgery. Crit Care Med. 2000;28(4):935-940.
6. Bouza E, Pérez M, Muñoz P, Rincón C, Barrio J, Hortal J. Continuous aspiration of subglottic
secretions in the prevention of ventilator-associated pneumonia in the postoperative period of major
heart surgery.. Chest. 2008;134(5):938-46.
7. Rebollo MH, Bernal JM, Llorca J, Rabasa JM, Revuelta JM. Nosocomial infections in patients having
cardiovascular operations: A multivariate analysis of risk factors. J Thorac Cardiovasc Surg.
1996;112(4):908-913.
8. El Solh AA, Bhora M, Pineda L, Dhillon R. Nosocomial pneumonia in elderly patients following cardiac
surgery. Respir Med. 2006;100(4):729-736. doi: 10.1016/j.rmed.2005.07.011.
9. Tamayo E, Alvarez FJ, Martinez-Rafael B, et al. Ventilator-associated pneumonia is an important risk
factor for mortality after major cardiac surgery. J Crit Care. 2012;27(1):18-25. doi:
10.1016/j.jcrc.2011.03.008.
10. Tablan OC, Anderson LJ, Besser R, Bridges C, Hajjeh R. Guidleines for preventing healthcareassociated pneumonia, 2003: Recommendations of CDC and the healthcare infection control practices
advisory committee. MMWR Recomm Rep. 2004;53:1-36.
11. American Thoracic Society, Infectious Diseases Society of America. Guidelines for the management of
adults with hospital-acquired, ventilator-associated, and healthcare-associated pneumonia. Am J Respir Crit
Care Med. 2005;171(4):388-416. doi: 10.1164/rccm.200405-644ST.
12. Coffin S, MD, Klompas M, MD, Classen D, MD, et al. Strategies to prevent Ventilator‐Associated
pneumonia in acute care hospitals • . Infection Control and Hospital Epidemiology. 2008;29(S1, A
Compendium of Strategies to Prevent Healthcare‐Associated Infections in Acute Care Hospitals):pp. S31S40.
13. Girard TD, Kress JP, Fuchs BD, et al. Efficacy and safety of a paired sedation and ventilator weaning
protocol for mechanically ventilated patients in intensive care (awakening and breathing controlled trial): A
randomised controlled trial. Lancet. 2008;371(9607):126-134. doi: 10.1016/S0140-6736(08)60105-1.
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