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Ventilator-Associated Pneumonia: Issues Related to the Artificial Airway
Emili Diaz MD PhD, Alejandro H Rodrıguez MD, and Jordi Rello MD PhD ´

Introduction Subglottic Secretion Drainage Control of Intracuff Pressure Silver-Coated Endotracheal Tubes Tracheotomy Summary

Pooling of contaminated secretions above the cuff of the endotracheal tube predisposes patients to ventilator-associatedpneumonia (VAP). Subglottic secretion drainage requires a special endotracheal tube that has a separate lumen that opens in the subglottic region above the tracheal tube. A recent meta-analysis of the 5 randomized clinical trials that evaluated the efficacy of removing these secretions found that this technique significantly reduces the incidence of VAP. One cost-effectiveness analysis showedsavings of $4,900 per episode of VAP prevented. Greatest benefit is derived by patients requiring fewer than 10 days of mechanical ventilation and not exposed to antibiotic therapy. Maintaining the intracuff pressure between 25 and 30 cm H2O is mandatory to guarantee effective drainage and safety. While silver-coated endotracheal tubes reduce pseudomonas pneumonia in intubated dogs and delay airwaycolonization in intubated patients, evaluation of studies with a variety of case mixes is warranted to identify subsets likely to benefit from the technique before it is implemented on a large scale. A patient who has a colonized airway and who undergoes percutaneous tracheotomy has an increased risk of VAP, particularly due to Pseudomonas aeruginosa, in the week following the procedure. As manystudies suggest that incidence of VAP is highly dependent on the strategies of airway management, health care workers should be alerted to issues related to the artificial airway. Key words: ventilator-associated pneumonia, VAP, artificial airway, subglottic secretion drainage, silver-coated endotracheal tube, tracheotomy. [Respir Care 2005;50(7):900 –906. © 2005 Daedalus Enterprises]

IntroductionImplementing mechanical ventilation (MV) implies several changes in the patient’s airways. The most important change when a patient is intubated is that the airway loses

sterility and becomes colonized within a few hours of starting MV.1 Many complications can occur in this situation. Ventilator-associated pneumonia (VAP) is the leading infectious complication in patients under MV, affectingfrom 8% to 28% of patients admitted in the intensive

Emili Diaz MD PhD, Alejandro H Rodrıguez MD, and Jordi Rello MD ´ PhD are affiliated with the Critical Care Department, University Rovira and Virgili. Institut Pere Virgili, Joan XXIII University Hospital, Tarragona, Spain. Jordi Rello MD PhD presented a version of this article at the 35th RESPIRATORY CARE Journal Conference,Ventilator-Associated Pneumonia, held February 25–27, 2005, in Cancun, Mexico. ´

This research was supported in part by grants from the Comissio Inter´ departamental de Recerca i Innovacio Tecnologica (CIRIT) Suport dels ´ ` Grups de Recerca (SGR) 2001/414, Distincio Recerca Universitaria (JR), ´ ` Red Respira (ISCiii-RTIC O3/11). Correspondence: Jordi Rello MD PhD, Critical Care Department, Joan XXIII UniversityHospital, Carrer Dr Mallafre Guasch 4, 43007 Tarragona, Spain. E-mail: jrc@hjxxiii.scs.es.

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RESPIRATORY CARE • JULY 2005 VOL 50 NO 7

VENTILATOR-ASSOCIATED PNEUMONIA: ISSUES RELATED
care unit (ICU).2 The risk of VAP is present throughout the MV period, though it is greatest during the first days. Cook et al showed that the risk for VAP is 3% per day in the first week of MV, 2% perday in the second week, and 1% per day later.3 Indeed, in this period airway care is critical in preventing VAP. From the ventilator to the lungs, all parts and pieces need to be considered when caring for patients on artificial ventilation. Infection is due to a disequilibrium between host defenses, inoculum size, and microorganism virulence. The presence of a mechanical device inside the airways...