Chest
Volume 133, Issue 3, March 2008, Pages 625-632
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ORIGINAL RESEARCH
PNEUMONIA
Ventilator-Associated Pneumonia: Impact of Organisms on Clinical Resolution and Medical Resources Utilization

https://doi.org/10.1378/chest.07-2020Get rights and content

Background

Clinical resolution of ventilator-associated pneumonia (VAP) determines the duration of treatment and mechanical ventilation. The aim of this study was to evaluate the influence of organisms and their susceptibility to treatment on outcomes.

Methods

Prospective observational study in three teaching ICUs. Sixty episodes of VAP with appropriate therapy (Haemophilus influenzae, 15 episodes; methicillin-sensitive Staphylococcus aureus [MSSA], 15 episodes; Pseudomonas aeruginosa, 15 episodes; and methicillin-resistant S aureus [MRSA], 15 episodes), and 30 episodes with initial inappropriate therapy, all due to P aeruginosa, were compared. The main outcome measures were clinical resolution variables and, in survivors, length of mechanical ventilation after VAP onset.

Results

A significant delay in the resolution of hypoxemia was observed in VAP episodes due to MRSA and P aeruginosa with inappropriate antibiotic therapy (IAT) (median time to resolution, 10 and 8 days, respectively) when compared with the remaining pathogens (median time to resolution, 2 days). A multiple regression model, adjusted for disease severity, confirmed the delayed clinical resolution for MRSA and P aeruginosa with IAT. Similar associations were documented for defervescence. Among survivors, the median duration of mechanical ventilation after VAP onset was significantly longer for MRSA (17 days) and P aeruginosa IAT (11 days) when compared with episodes due to H influenzae or MSSA (6 days). Multiple regression analysis, adjusted for disease severity, confirmed that MRSA required significantly (R2 = 0.132; p < 0.01) longer respiratory support than other organisms.

Conclusions

When treated promptly, the resolution of VAP due to MSSA, H influenzae, and P aeruginosa was comparable. The resolution of MRSA VAP, regardless of the appropriateness of initial antibiotic therapy, was associated with longer respiratory support.

Section snippets

Study Participants

This prospective, observational study was performed in three ICUs. Each center has an infection control surveillance program with prospective recording of nosocomial infections. The first 15 consecutive patients with VAP due to MSSA, H influenzae, P aeruginosa, and MRSA who had received appropriate antibiotic therapy were included. Thirty consecutive patients with episodes of VAP due to P aeruginosa with IAT were also included in the study.

Potential exclusion criteria included death within 72

Results

Sixty VAP episodes with appropriate empirical antibiotic therapy were included in the study. As regards etiology, 15 episodes were due to methicillin- susceptible S aureus (polymicrobial, 1 episode), 15 episodes were due to susceptible P aeruginosa (polymicrobial, 5 episodes), 15 episodes were due to H influenzae (polymicrobial, 3 episodes), and 15 episodes were due to MRSA with appropriate antibiotic therapy, all of them monomicrobial. There were no significant differences in baseline

Discussion

The most important finding in this study is that MRSA VAP treated with appropriate therapy resolves more slowly than VAP due to H influenzae, MSSA, and P aeruginosa treated with appropriate therapy. In addition, the slow rate of resolution of MRSA is comparable to that of P aeruginosa when the latter organism is treated with inappropriate initial therapy. The delay in resolution for these organisms was associated with excess medical resource utilization.

Differences in the evolution of

ACKNOWLEDGMENT

We are indebted with Montse Olona, MD, for statistical advice and Mike Maudsley for editing of the English language.

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    Presented in part at the 19th European Society of Intensive Care Medicine annual congress, Barcelona, Spain, September 25 to 27, 2006.

    Supported in part by Centro Investigación Biomédica en Red de Enfermedades Respiratorias grants CB06/06/0036, FISS PI05/2410, and AGAUR 2005/SGR/920.

    Dr. Rello has served in the speakers bureau or has been a consultant for Pfizer, Wyeth Pharmaceuticals, Arpida, Basilea, Johnson & Johnson, Intercell, AstraZeneca, Novartis, and Schering Plough; and he has received research grants from Lilly and Pfizer. Drs. Vidaur, Planas, Sierra, Dimopoulos, Ramirez, and Lisboa have reported to the ACCP that no significant conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

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