Paola Jubert

In order to assess potential risk factors for pneumonia within the first 8 d of ventilation, we studied 83 consecutive intubated patients undergoing continuous aspiration of subglottic secretions (CASS). Multivariate analysis showed the protective effect of antibiotic use (relative risk [RR] = 0.10; 95% confidence interval [CI] = 0.01 to 0.71), whereas failure of the CASS technique (RR = 5.29; 95% CI = 1.24 to 22.64) was associated with a greater risk of pneumonia. In addition, there was a trend toward a higher risk of pneumonia (RR = 2.57; 95% CI = 0.78 to 8.03) among patients with persistent intracuff pressures below 20 cm H2O. The remaining factors analyzed were not significant. Failure of CASS did not influence the development of pneumonia among patients undergoing antibiotic treatment (33.0% versus 38.5%, p > 0.20), but was strongly associated with pneumonia (42.1% versus 8.3%, p < 0.01) among intubated patients not receiving antibiotics. When multivariate analysis was repeated in this subpopulation, failure of CASS (RR = 7.52, 95% CI = 1.48 to 38.07) and persistent intracuff pressure below 20 cm H2O (RR = 4.23, 95% CI = 1.12 to 15.92) were factors independently associated with the development of pneumonia. We conclude that leakage of colonized subglottic secretions around the cuff of the endotracheal tube is the most important risk factor for pneumonia within the first 8 d of intubation. This study confirms the importance of maintaining adequate intracuff pressure and effective aspiration of subglottic secretions in preventing pneumonia in intubated patients not receiving antibiotic treatment.

OBJECTIVE: To assess the impact of severity of illness at different times, using the Mortality Probability Models (MPM II), and the impact of etiologic agent on survival in patients with nosocomial pneumonia. DESIGN: Retrospective, observational study. SETTING: Fourteen-bed medical-surgical intensive care unit (ICU) in a teaching hospital. PATIENTS: Sixty-two patients with nosocomial pneumonia who were receiving early appropriate antibiotic treatment. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Severity of illness at the time of admission to the ICU (M0), 24 hrs after admission (M24), and at the time of pneumonia diagnosis (M1) was determined using MPM II. Bacteriology was established by quantitative cultures from bronchoscopic samples. The outcome measure was the crude mortality rate. The crude mortality rate in the ICU was 59.7%, compared with average predicted mortality rates of 43.5% (M0), 36.4% (M24), and 52.2% (M1). We observed significant differences in mean MPM II determinations between survivors and nonsurvivors at M1 (39.3% vs. 60.9%, p = .001) but not at M0 and M24. In the univariate analysis, the variables most predictive of mortality were the presence of coma (p = .02), inotropic medication use (p = .001), and an MPM II determination of > 50% (p = .001) when pneumonia was diagnosed (M1). Multivariate analysis showed that, in the absence of Pseudomonas aeruginosa, an MPM II determination of > 50% at M1 was associated with a relative risk of death of 4.8. The presence of P. aeruginosa was associated with an increase in the risk of death of 2.6 and 6.36 in both populations with MPM II determinations at M1 of < or = 50% and > 50%, respectively. CONCLUSIONS: Severity of illness when pneumonia is diagnosed is the most important predictor of survival, and this determination should be used for therapeutic and prognostic stratification. In addition, the presence of P. aeruginosa contributed to an excess of mortality that could not be measured by MPM II alone, suggesting the importance of the pathogen in prognosis.

Ninety-five patients with severe community-acquired pneumonia (SCAP) who were ≥ 65 years of age were studied prospectively. A definite pathogen was identified in 37 cases (38.9%) and was most commonly Streptococcus pneumoniae, Haemophilus injluenzae, or another gram-negative bacillus. The overall death rate was 40%. Eighty-three patients required mechanical ventilation and 40 needed vasoactive drugs. Multivariate analysis showed that the risk of death was higher in cases involving rapid radiological spread (relative risk [RR] = 6.99; 95% confidence interval (95% CI) = 1.54–31.70), shock (RR = 6.70; 95% CI = 2.13–21.02), previous steroid treatment or immunosuppression (RR = 5.50; 95% CI = 0.77–39.10), acute renal failure (RR = 3.88; 95% CI = 1.30–11.59), or an APACHE II score of >22 on admission (RR = 2.25; 95% CI = 0.73–6.95). We conclude that SCAP in elderly patients is associated with high mortality, but it is inappropriate to withhold intensive care on account of age. The presence of complications and the severity of illness at initial presentation were the major variables affecting outcome. Except for inununosuppression, comorbidities did not seem to influence outcome. Finally, our data reinforce the current American Thoracic Society guidelines concerning therapy for patients with SCAP.

Thirty consecutively intubated patients with pneumonia due to Pseudomonas aeruginosa (cases) were prospectively observed to establish the attributable mortality rate and the prognostic value of APACHE (Acute Physiological and Chronic Health Evaluation) II scores. Four cases did not receive accurate empirical therapy and were excluded from the study. APACHE II scores were calculated within 24 hours of admission (T0), at the time of the diagnosis of pneumonia (T1), and after 72 hours of therapy (T2). The outcomes for these cases (n = 26) were compared with those for matched controls (n = 52) without pneumonia. Six cases died of causes directly related to pneumonia (group D). Two cases whose conditions clinically improved died of cardiac complications, and 18 cases had clinical resolution (group R); however, only 15 of these cases were alive at discharge. The mean APACHE II score at admission was similar (P > .20) for group R, group D, and controls. In contrast, the mean score at T1 (15.40 +/- 6.07 vs. 20.83 +/- 4.66; P < .05) and the mean score at T2 (10.40 +/- 3.57 vs. 25.50 +/- 3.93; P < .01) differed significantly for groups R and D, respectively. The overall observed and predicted mortality rates among cases and controls were 42.3% and 28.1% and 28.8% and 28.7%, respectively, while the attributable mortality rate among cases was estimated to be 13.5% (95% confidence interval, 1.95%-25.04%). We conclude that the attributable mortality rate among intubated patients with pneumonia due to P. aeruginosa is high. The APACHE II score at admission is not useful as a prognostic factor, while progression of organ dysfunction after the onset of pneumonia is an ominous sign.