A new article that generated a lot of press coverage investigated the possible role of a novel therapy in the prevention of ventilator-associated pneumonia (VAP). Klarin and colleagues published this study on use of probiotics in intubated ICU patients in the online journal Critical Care.
This was a randomized controlled trial in intubated, mechanically ventilated patients. Half received oral application of the probiotic lactobacillus Lp299 and the other half (control group) received chlorhexidine oral decontamination. Subsequent bacteriologic cultures of oropharyngeal or tracheal specimens failed to show any difference in potentially pathogenic bacteria between the probiotic group and the chlorhexidine group. No adverse effects were seen in the probiotic group.
Note that this was a pilot study, intended to determine the power needed to study possible use of such probiotic therapy to prevent VAP.
Though oral decontamination with chlorhexidine (CHX) has been shown to prevent VAP (Chlebick 2007), it does not reduce the time on the ventilator, the length of stay (LOS) in the ICU or rates of mortality (Chan 2007). You’ll recall in our September 2, 2008 Patient Safety Tip of the Week “Updates on VAP Prevention” we criticized the studies touting use of silver-coated endotracheal tubes for the same reason (i.e. they did not duration of intubation, ICU or hospital length of stay, or mortality).
The concept is based on the empiric observation that probiotics reduced pathogenic bacteria on biofilms in patients with vocal prostheses. It makes a lot of sense to consider the probiotic intervention but it is far too early to jump on the probiotic bandwagon. All this study did was demonstrate that probiotics did reduce colonization by pathogenic bacteria. The next step is to see whether that not only reduces the incidence of VAP but also reduces the more important clinical outcomes like mortality, time on the ventilator, ICU and hospital LOS, and costs. Stay tuned.
But what should you be doing in the meantime? In this month’s What’s New in the Patient Safety World we directed you to a great new free resource: the supplement to the October issue of Infection Control & Hospital Epidemiology “A Compendium of Strategies to Prevent Healthcare-Associated Infections in Acute Care Hospitals”. In that compendium is an article on recommendations for prevention of VAP. Those recommendations include the most important ones from the IHI VAP Bundle, i.e. use of the semirecumbent position and daily assessment of readiness to extubate, plus many others. They recommend many practical general measures (surveillance, handwashing, education, etc.) but one of the most important general measures is assessment of the need to intubate at all. The emergence of noninvasive ventilation techniques in the last decade has made it possible to avoid intubation in a substantial number of patients. Avoiding unplanned extubation and reintubation is also important (see our back-to-back articles “Managing Delirium” and “Preventing Delirium” in October 2008). They recommend use of a cuffed endotracheal tube with in-line or subglottic suctioning and maintenance of an endotracheal cuff pressure of at least 20 cm. H2O. To reduce bacterial colonization, orotracheal intubation is preferred over nasotracheal intubation. As we have mentioned previously, the practice of gastric acid suppression with proton pump inhibitors or H2-blockers, as had originally been recommended in some VAP bundles is very controversial because there is some evidence that such actually increases the likelihood of colonization with pathogenic bacteria (and may also be a risk factor for C. diff). So the current guideline recommends avoiding these drugs unless the patient is at high risk for stress ulcer or stress gastritis. They do recommend oral care, using an antiseptic solution, but note that the ideal frequency of oral care has not been determined. And they provide recommendation regarding the care and cleaning of the ventilator circuits and equipment. As part of the surveillance for VAP, they also strongly recommend surveillance for compliance with the preventive measures noted above. Most of you familiar with the IHI VAP Bundle also use the IHI ventilator bundle checklist. Those of you who are regular readers of this column know we are big advocates of simple checklists, which can be some of our most valuable (and cost-effective!) patient safety tools.
Ventilator-associated pneumonia remains a serious cause of morbidity, mortality and cost in our ICU’s. Preventing VAP must be a serious patient safety goal for all organizations. Though VAP did not make Medicare’s list of “never events” yet, it has clearly been on their radar for a long time and you can bet it will someday make that list. Lack of agreement on how to best diagnose VAP may have been the only thing keeping it off the final list for 2009. So make sure you have good VAP prevention programs in place now – it will help your patients and you will save money while doing that.
Update (11/13/08): This month’s issue of CHEST contains the results of a randomized controlled trial of CASS (continuous aspiration of subglottic secretions) (Bouza 2008) which confirms previous studies demonstrating that CASS is effective in preventing VAP. CASS not only significantly reduced the incidence of VAP, but also significantly reduced the duration of ventilation, reduced ICU LOS, reduced antibiotic usage, and produced significant cost savings. So, unlike the probiotic and silver-coated ETT studies, CASS has documented significant improvement in clinically relevant outcomes. As noted above, subglottic suctioning is already recommended by most VAP prevention guidelines. The current study emphasizes the clinical and business case for use of CASS.
Klarin B, Goran Molin G, Jeppsson B, Larsson A. Use of the probiotic Lactobacillus plantarum 299 to reduce pathogenic bacteria in the oropharynx of intubated patients: a randomised controlled open pilot study. Critical Care 2008, 12:R136 (6 November 2008)
Chlebick MP, Safdar N: Topical chlorhexidine for prevention of ventilator-associated
pneumonia: A meta-analysis. Crit Care Med 2007, 35:595–602
Chan EY, Ruest A, O Meade M and Cook DJ: Oral decontamination for prevention of
systematic review and meta-analysis pneumonia in mechanically ventilated adults.
BMJ 2007, 334:889
Coffin SE, Klompas M, Classen D, Arias KM, et al. Supplement Article: SHEA/IDSA Practice Recommendation. Strategies to Prevent Ventilator-Associated Pneumonia in Acute Care Hospitals. Infect Control Hosp Epidemiol 2008; 29: S31–S40
Bouza E, Pérez MJ, Muñoz P, Rincón C, Barrio JM, Hortal J. Continuous Aspiration of Subglottic Secretions in the Prevention of Ventilator-Associated Pneumonia in the Postoperative Period of Major Heart Surgery. Chest 2008: 938–946
Update: See also January 2009 What’s New in the Patient Safety World “Preventing Infections in the ICU”