Ventilator-Associated Pneumonia

To investigate trade-offs in deciding optimal strategies for the management of ventilator-associated pneumonia, Ost and coworkers  performed a decision-analysis model involving 16 management strategies. Initial coverage with three antibiotics was superior to expectant management or use of one or two antibiotics: survival of 54% versus 66%; cost of $41,483 versus $55,447 per survivor. Testing with nonbronchoscopic mini-bronchoalveolar lavage decreased costs ($39,967 versus $41,483) and antibiotic use (39 versus 63 antibiotic days per survivor), but did not improve survival. The authors conclude that use of mini-bronchoalveolar lavage and three antibiotics is the optimal strategy for minimizing cost, minimizing use of antibiotics, and maximizing survival in patients with ventilator-associated pneumonia. An editorial commentary by Amin and Hebert  accompanies this article.

The clinical pulmonary infection score has been reported to have a sensitivity and specificity of greater than 90% for diagnosis of pneumonia. In 79 episodes of suspected ventilator-associated pneumonia, Fartoukh and coworkers  tested the reliability of the score against culture of bronchoalveolar lavage fluid as a reference standard. A physician's estimate of the probability of pneumonia had a sensitivity of 50% and a specificity of 58%. The clinical pulmonary infection score was not statistically higher in 40 episodes of confirmed pneumonia than in 39 episodes not confirmed: mean score of 6.5 versus 5.9. The score had a sensitivity of 60% and a specificity of 59%. Addition of gram-stain results of directed or blinded protected telescoping catheter to the score increased sensitivity to 78% and specificity to 56%. Addition of gram-stain results of bronchoalveolar lavage to the score achieved a sensitivity of 85% and specificity of 49%. The authors conclude that the clinical pulmonary infection score has low diagnostic accuracy and the addition of gram-stain results from a protected telescoping catheter or bronchoalveolar lavage may improve clinical decision-making.

To define the microbiology of severe aspiration pneumonia in institutionalized elderly patients, El-Solh and coworkers  prospectively studied 95 patients with severe aspiration pneumonia older than 65 years of age admitted to their ICU from a long-term care facility. Quantitative bronchial samples were obtained in 95 patients and 67 pathogens were identified. Organisms were gram-negative enteric bacilli (49%), anaerobic bacilli (16%), and S. aureus (12%); Prevotella and Fusobacterium species were the most common anaerobes. Aerobic gram-negative bacilli were recovered in conjunction with 55% of anaerobic isolates. Dental plaque did not differ between the aerobic and anaerobic groups. Functional status was the only determinant of anaerobic bacteria. Seven patients with anaerobic isolates initially received inadequate antimicrobial therapy, yet 6 had an effective clinical response. Crude mortality was 33% for the aerobic group and 36% for the anaerobic group. Multivariate analysis revealed hypoalbuminemia and the burden of comorbid diseases as independent risk factors for poor outcome. The authors conclude that anaerobes represent a significant proportion of oral flora in institutionalized elderly patients, but their role in causing aspiration pneumonia has been overemphasized.

Because measurement of the concentration of antimicrobial agents in bronchial epithelial lining fluid would enable more informed decisions about dosing, Yamazaki and coworkers  developed a bronchoscopic microsampling probe for this purpose. Ten healthy subjects took levofloxacin orally. The concentration of levofloxacin in epithelial lining fluid was 43% of the corresponding serum value at 1 hour, reached the same level as serum at 2 hours, and decreased in a manner similar to that in serum, becoming undetectable at 24 hours. After 6 hours, the concentration of levofloxacin exceeded minimal inhibitory concentrations for Staphylococcus aureus, Klebsiella species, and Haemophilus influenzae. The subjects tolerated the procedure well without complications. The authors conclude that bronchoscopic microsampling of bronchial epithelial lining fluid is a feasible and promising method for directly and repeatedly measuring the concentrations of antimicrobial agents in target sites of the respiratory tract. An editorial commentary by Fish  accompanies this article

Citations 1-7 of 7 total displayed.

Impact of Methicillin Resistance on Outcome of Staphylococcus aureus Ventilator-associated Pneumonia

Alain Combes, Charles-Edouard Luyt, Jean-Yves Fagon, Michel Wollf, Jean-Louis Trouillet, Claude Gibert, and Jean Chastre
Am. J. Respir. Crit. Care Med. 170: 786 -792. First published online as doi:10.1164/rccm.200403-346OC [Abstract] [Full text]  

Bronchoscopic Sampling of Drug Concentrations: Penetration to Tissue Is the Issue

Douglas N. Fish
Am. J. Respir. Crit. Care Med. 168: 1263-1265. [Full text]  

Bronchoscopic Microsampling Method for Measuring Drug Concentration in Epithelial Lining Fluid

Koichi Yamazaki, Shigeaki Ogura, Akitoshi Ishizaka, Toshinari Oh-hara, and Masaharu Nishimura
Am. J. Respir. Crit. Care Med. 168: 1304 -1307. First published online as doi:10.1164/rccm.200301-111OC [Abstract] [Full text]  

What to Learn from Decision Analysis of Diagnosis and Treatment of Ventilator-associated Pneumonia?

Mohammad Amin and Paul C. Hébert
Am. J. Respir. Crit. Care Med. 168: 1025-1026. [Full text]  

Decision Analysis of Antibiotic and Diagnostic Strategies in Ventilator-associated Pneumonia

David E. Ost, Charles S. Hall, Gnanaraj Joseph, Christine Ginocchio, Susan Condon, Emily Kao, Michele LaRusso, Richard Itzla, and Alan M. Fein
Am. J. Respir. Crit. Care Med. 168: 1060 -1067. First published online as doi:10.1164/rccm.200302-199OC [Abstract] [Full text]  

Diagnosing Pneumonia during Mechanical Ventilation: The Clinical Pulmonary Infection Score Revisited

Muriel Fartoukh, Bernard Maître, Stéphanie Honoré, Charles Cerf, Jean-Ralph Zahar, and Christian Brun-Buisson
Am. J. Respir. Crit. Care Med. 168: 173 -179. First published online as doi:10.1164/rccm.200212-1449OC [Abstract] [Full text]  

Microbiology of Severe Aspiration Pneumonia in Institutionalized Elderly

Ali A. El-Solh, Celestino Pietrantoni, Abid Bhat, Alan T. Aquilina, Mifue Okada, Vikas Grover, and Nancy Gifford
Am. J. Respir. Crit. Care Med. 167: 1650 -1654. First published online as doi:10.1164/rccm.200212-1543OC [Abstract] [Full text]