Usefulness of a strategy based on bronchoscopy with direct examination of bronchoalveolar lavage fluid in the initial antibiotic therapy of suspected ventilator-associated pneumonia.

OBJECTIVES: To evaluate (a) the routine accuracy of bronchoalveolar lavage by direct examination (BAL-D) in diagnosing ventilator-associated pneumonia (VAP), and (b) the impact of a diagnostic strategy including clinical judgment, bronchoscopy, and BAL-D on the initial diagnosis and appropriateness of treatment when VAP is suspected. DESIGN AND SETTING: Prospective cohort study in two academic ICUs in Paris, France. PATIENTS AND PARTICIPANTS: Mechanically ventilated patients with suspected VAP underwent bronchoscopy with BAL and protected specimen brush (PSB). BAL-D results were available within 2 h, BAL on culture and PSB results after 24 h, and antibiotic susceptibility after 48 h. At each step in the strategy the senior and the resident in charge of the patient were asked their diagnosis and their therapeutic plan on the basis of presently available data. Definite diagnosis of suspected VAP was based on histology, appearance of cavitation, positive pleural fluid culture, results of PSB and BAL culture, and follow-up. MEASUREMENT AND RESULTS: A total of 110 episodes of suspected VAP were studied; 94 definite diagnoses were made (47 VAP, 47 no VAP). Using a threshold 1% of infected cells, BAL-D discriminated well between patients with and those without VAP (sensitivity 93.6%, specificity 91.5%, area under the receiver-operating characteristic curve 0.953). The senior clinical judgment was correct in 71% cases. It was correct in 78% and 94% of cases after airway visualization and BAL-D findings, respectively. After BAL-D the positive and negative predictive values in diagnosing VAP were 90% and 98%, respectively. However, the therapeutic plan was correct in only 65% using clinical judgment (15 untreated patients, 3 ineffective treatment, 15 useless treatment), 66% using airway visualization (14 untreated VAP, 4 ineffective treatment, 14 useless treatment), and 88% using BAL-D results (1 untreated patients, 6 ineffective, 4 useless), according to definite diagnosis and final antibiotic susceptibility testings. CONCLUSIONS: A strategy based on bronchoscopy and BAL-D generally leads to a rapid and appropriate treatment of nosocomial pneumonia in ventilated patients.

Short-term effect of inhaled nitric oxide and prone positioning on gas exchange in patients with severe acute respiratory distress syndrome.

OBJECTIVE: To compare the short-term effects of inhaled nitric oxide (NO) and prone positioning in improving oxygenation in acute respiratory distress syndrome (ARDS). METHODS: Charts of consecutive ARDS patients (lung injury score >2) during a 2-yr period, tested for both inhaled NO and prone positioning efficacy were retrospectively reviewed. Variations in the Pao2/Fio2 ratio induced by inhaled NO and prone positioning were evaluated. MEASUREMENTS AND MAIN RESULTS: Twenty-seven patients (age, 42+/-17 yrs) were included. Simplified Acute Physiology Score II was 45+/-14. Mortality rate in the intensive care unit was 63%. The causes of ARDS were pneumonia (n = 14), extra-lung infection (n = 5), and noninfectious systemic inflammatory response syndrome (n = 8). Lung injury score was 2.7+/-0.3. At baseline, before the initiation of inhaled NO, the Pao2/Fio2 ratio was 97+/-46 torr and before prone positioning, 92+/-26 torr. Variations in the Pao2/Fio2 ratio were lower at start of NO therapy (11+/-4 ppm) than that observed at prone positioning initiation (23+/-31 vs. 62+/-78 torr, p<.05). An increase in variations in the Pao2/Fio2 ratio of >15 torr was associated with prone positioning in 16 patients (59%) and with NO inhalation in 13 patients (48%) (not significant). An increase in variations in the Pao2/Fio2 ratio of >15 torr was associated with both techniques in only six patients (22%). There was no correlation between the response to prone positioning and the response to inhaled NO (r2 = .005; p = .73). CONCLUSIONS: Prone positioning improves hypoxemia significantly better than does inhaled NO. The response to one technique is not predictive of the response to the other technique.

Procalcitonin (PCT) is useful in predicting the bacterial origin of an acute circulatory failure in critically ill patients.

OBJECTIVE: To evaluate the accuracy of procalcitonin (PCT) in predicting bacterial infection in ICU medical and surgical patients. SETTING: A 10-bed medical surgical unit. DESIGN: PCT, C-reactive protein (CRP), interleukin 6 (IL-6) dosages were sampled in four groups of patients: septic shock patients (SS group), shock without infection (NSS group), patients with systemic inflammatory response syndrome related to a proven bacterial infection (infect. group) and ICU patients without shock and without bacterial infection (control group). RESULTS: Sixty patients were studied (SS group:n=16, NSS group,n=18, infect. group,n=16, control group,n=10). The PCT level was higher in patients with proven bacterial infection (72+/-153 ng/ml vs 2.9+/-10 ng/ml,p=0.0003). In patients with shock, PCT was higher when bacterial infection was diagnosed (89 ng/ml+/-154 vs 4.6 ng/ml+/-12,p=0.0004). Moreover, PCT was correlated with severity (SAPS:p=0.00005, appearance of shock:p=0.0006) and outcome (dead: 71.3 g/ml, alive: 24.0 g/ml,p=0.006). CRP was correlated with bacterial infection (p<10(-5)) but neither with SAPS nor with day 28 mortality. IL-6 was correlated with neither infection nor day 28 mortality but was correlated with SAPS. Temperature and white blood cell count were unable to distinguish shocked patients with or without infection. Finally, when CRP and PCT levels were introduced simultaneously in a stepwise logistic regression model, PCT remained the unique marker of infection in patients with shock (PCT> or =5 ng/ml, OR: 6.2, 95% CI: 1.1-37,p=0.04). CONCLUSION: The increase of PCT is related to the appearance and severity of bacterial infection in ICU patients. Thus, PCT might be an interesting parameter for the diagnosis of bacterial infections in ICU patients.

Association of TNF2, a TNF-alpha promoter polymorphism, with septic shock susceptibility and mortality: a multicenter study.

CONTEXT: Tumor necrosis factor alpha (TNF-alpha) is believed to be a cytokine central to pathogenesis of septic shock. TNF2, a polymorphism within the TNF-alpha gene promoter, has been associated with enhanced TNF-alpha production and negative outcome in some severe infections. OBJECTIVES: To investigate the frequency of the TNF2 allele in patients with septic shock and to determine whether the allele is associated with the occurrence and outcome of septic shock. DESIGN: Multicenter case-control study conducted from March 1996 to June 1997. SETTING: Seven medical intensive care units in university hospitals. SUBJECTS: Eighty-nine patients with septic shock and 87 healthy unrelated blood donors. MAIN OUTCOME MEASURES: Frequency of the TNF2 allele among patients with septic shock and among those who died and the level of corresponding TNF-alpha concentrations. RESULTS: Mortality among patients with septic shock was 54%, consistent with the predicted mortality from the Simplified Acute Physiologic Score (SAPS II) value. The polymorphism frequencies of the controls and the patients with septic shock differed only at the TNF2 allele (39% vs 18% in the septic shock and control groups, respectively, P =.002). Among the septic shock patients, TNF2 polymorphism frequency was significantly greater among those who had died (52% vs 24% in the survival group, P =.008). Concentrations of TNF-alpha were higher in 68% and 52% with the TNF2 and TNF1 polymorphisms, respectively, but their median values (48 pg/mL vs 29 pg/mL) were not statistically different (P = .31). After controlling for age and the probability of death, derived by the SAPS II score, multiple logistic regression analysis showed that, for the same rank of SAPS II value, patients with the TNF2 allele had a 3.7-fold risk of death (95% confidence interval, 1.37-10.24). CONCLUSION: The TNF2 allele is strongly associated with susceptibility to septic shock and death due to septic shock.