Mortality Associated with Nosocomial Pneumonia

MORBIDITY AND MORTALITY ASSOCIATED WITH NOSOCOMIAL PNEUMONIA 

Epidemiological studies evaluating adverse effects of nosocomial infections indicate that pneumonia is the leading cause of death from infections acquired during the hospital stay. Table 3 summarizes six studies that have reported crude mortality rates of ventilator-associated pneumonia ranging from 33% to 71% (20). 

Besides the role of pathogens, worsening of respiratory failure caused by nosocomial pneumonia, presence of shock, and an inappropriate antibiotic treatment were associated with higher fatality rate (22). The attributable mortality rate of nosocomial pneumonia is still not known from most of these studies, because of the well-known relationship between severity of illness and pneumonia. In addition, it is difficult to establish whether such critically ill patients would have survived if nosocomial pneumonia had not occurred (9,23). However, more recent studies have further clarified the influence of nosocomial pneumonia on death. Fagon et al. reported that the mortality rate attributable to nosocomial pneumonia exceeded 25%, corresponding to a relative risk of death equal to 2.0, (respectively 40% and 2.5 in cases of pneumonia caused by Pseudomonas or Acinetobacter species) (24). Bueno-Cavanillas supported these results by reporting that the risk of mortality was almost three times higher in patients with pneumonia than in noninfected patients (relative risk 2.95 Cl 95, 1.73-5.03) (25). 

Nosocomial pneumonia is also associated with substantial morbidity, and the associated costs are remarkable. According to estimates made by the CDC, an average of 5.9 days of increased length of stay and 5683 in extra hospital charges (in 1992 dollars) result from each episode of nosocomial pneumonia 

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VI. MORBIDITY AND MORTALITY ASSOCIATED WITH NOSOCOMIAL PNEUMONIA... 

Because S. pneumoniae and influenza viruses contribute to the morbidity and mortality associated with nosocomial pneumonia and vaccines against these infections are available and recommended for routine use in those at highest risk, this chapter focuses on use of vaccines against these diseases and... 

Similar to cases with P. aeruginosa, nosocomial ventilator-associated pneumonia caused by Acinetobacter is associated with a high mortality rate. In a study of 48 patients (70), pneumonia caused by these two organisms have a mortality rate of 71.4% compared to other pathogens (40.7%), with the observation that this rate was in excess of that observed for the underlying disease however, the impact of antimicrobial therapy was not discussed. 

In intensive care units (ICUs), pneumonia is the most frequent nosocomial infection (1-3) and occurs most often as ventilator-associated pneumonia (VAP) in patients on mechanical ventilation. The overall incidence of VAP in different studies varies between 10% and 85%, depending on the patient population and the criteria used to establish the diagnosis. Ventilator-associated pneumonia has been associated with an attributable mortality rate ranging from 13% to 47% (4-7), although this is not a consistent finding (8-10). 

Gouin F, Bregeon F, Thirion X, Saux P, Denis JP, Papazian L. Ventilator-associated pneumonia and mortality (abstr). 35th Interscience Conference on Antimicrobial Agents and Chemotherapy, San Francisco 1995 1119 278. Johanson WGJ, Pierce AK, Sanford J, Thomas GD. Nosocomial respiratory infections with gram-negative bacilli the significance of colonization of the respiratory tract. Ann Intern Med 1972 77 701-706. 

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