Jordi Vallés

Prediction of Postoperative Pulmonary Complications in a Population-based Surgical Cohort

Background:Current knowledge of the risk for postoperative pulmonary complications (PPCs) rests on studies that narrowly selected patients and procedures. Hypothesizing that PPC occurrence could be predicted from a reduced set of perioperative variables, we aimed to develop a predictive index for a broad surgical population. Methods:Patients undergoing surgical procedures given general, neuraxial, or regional anesthesia in 59 hospitals were randomly selected for this prospective, multicenter study. The main outcome was the development of at least one of the following: respiratory infection, respiratory failure, bronchospasm, atelectasis, pleural effusion, pneumothorax, or aspiration pneumonitis. The cohort was randomly divided into a development subsample to construct a logistic regression model and a validation subsample. A PPC predictive index was constructed. Results:Of 2,464 patients studied, 252 events were observed in 123 (5%). Thirty-day mortality was higher in patients with a PPC (19.5%; 95% [CI], 12.5–26.5%) than in those without a PPC (0.5%; 95% CI, 0.2–0.8%). Regression modeling identified seven independent risk factors: low preoperative arterial oxygen saturation, acute respiratory infection during the previous month, age, preoperative anemia, upper abdominal or intrathoracic surgery, surgical duration of at least 2 h, and emergency surgery. The area under the receiver operating characteristic curve was 90% (95% CI, 85–94%) for the development subsample and 88% (95% CI, 84–93%) for the validation subsample. Conclusion:The risk index based on seven objective, easily assessed factors has excellent discriminative ability. The index can be used to assess individual risk of PPC and focus further research on measures to improve patient care.

Type III protein secretion is associated with poor clinical outcomes in patients with ventilator-associated pneumonia caused by Pseudomonas aeruginosa.

OBJECTIVE Pseudomonas aeruginosa is a frequent cause of ventilator-associated pneumonia. Recent evidence suggests that production of type III secretion proteins is correlated with increased pathogenicity in both cellular and animal models of infection. The objective of this study was to determine whether this system contributes to disease severity in humans with ventilator-associated pneumonia. DESIGN Retrospective pilot cohort study. SETTING University hospital. PATIENTS Thirty-five mechanically ventilated patients with bronchoscopically confirmed ventilator-associated pneumonia caused by P. aeruginosa. MEASUREMENTS AND MAIN RESULTS Ventilator-associated pneumonia was categorized as severe (patients died or had a recurrence of their pneumonia despite appropriate antibiotic therapy) or mild (patients uneventfully recovered from their pneumonia). The type III secretion genotypes and phenotypes of isolates cultured from the patients with ventilator-associated pneumonia were determined. Whereas every examined isolate harbored type III secretion genes, only 27 (77%) were capable of secreting detectable amounts of type III proteins in vitro. Twenty-two (81%) of the patients infected with these 27 isolates had severe disease. Of the eight isolates that did not secrete type III proteins, only three (38%) were cultured from patients with severe disease. Thus, infection with a type-III-secreting isolate correlated with severe disease (p < .05). In vitro assays indicated that ExoU, the type III effector protein most closely linked to mortality in animal models, was secreted in detectable amounts in vitro by 10 (29%) of the 35 examined isolates. Nine (90%) of these 10 isolates were cultured from patients with severe disease (p < .05 when compared with the nonsecreting isolates). In contrast, ExoS was secreted by 16 (46%) of the 35 examined isolates. Twelve (75%) of these 16 isolates were cultured from patients with severe disease (p = .14 when compared with the nonsecreting isolates). CONCLUSIONS In patients with ventilator-associated pneumonia, type-III-secreting isolates were associated with worse clinical outcomes, suggesting that this secretion system plays an important role in human disease. Our findings support the hypothesis that antibodies targeted against these proteins may be useful as adjunctive therapy in intubated patients with P. aeruginosa colonization or infection.

Survival in patients with nosocomial pneumonia: impact of the severity of illness and the etiologic agent.

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.

Antibiotic Prescription for Community-Acquired Pneumonia in the Intensive Care Unit: Impact of Adherence to Infectious Diseases Society of America Guidelines on Survival

BACKGROUND The purpose of our study was to analyze prognostic factors associated with mortality for patients with severe community-acquired pneumonia (CAP). METHODS We conducted a prospective multicenter study including all patients with CAP admitted to the intensive care unit during a 15-month period in 33 Spanish hospitals. Admission data and data on the evolution of the disease were recorded. Multivariate analysis was performed using the SPSS statistical package (SPSS). RESULTS A total of 529 patients with severe CAP were enrolled; the mean age (+/-SD) was 59.9+/-16.1 years, and the mean Acute Physiology and Chronic Health Evaluation (APACHE) II score (+/-SD) was 18.9+/-7.4. Overall mortality among patients in the intensive case unit was 27.9% (148 patients). The rate of adherence to Infectious Diseases Society of America (IDSA) guidelines was 57.8%. Significantly higher mortality was documented among patients with nonadherence to treatment (33.2% vs. 24.2%). Multivariate analysis identified age (odds ratio [OR], 1.7), APACHE II score (OR, 4.1), nonadherence to IDSA guidelines (OR, 1.6), and immunocompromise (OR, 1.9) as the variables present at admission to the intensive care unit that were independently associated with death in the intensive care unit. In 15 (75%) of 20 cases of Pseudomonas aeruginosa infection, the antimicrobial treatment at admission was inadequate (including 8 of 15 cases involving patients with adherence to IDSA guidelines). Chronic obstructive pulmonary disease (OR, 17.9), malignancy (OR, 11.0), previous antibiotic exposure (OR, 6.2), and radiographic findings demonstrating rapid spread of disease (OR, 3.9) were associated with P. aeruginosa pneumonia. CONCLUSIONS Better adherence to IDSA guidelines would help to improve survival among patients with severe CAP. Pseudomonas coverage should be considered for patients with chronic obstructive pulmonary disease, malignancy, or recent antibiotic exposure.

Clinical consequences of the implementation of a weaning protocol

ObjectiveTo analyze the clinical and economic consequences of the implementation of a weaning protocol in patients mechanically ventilated (MV) for more than 48 h.DesignComparative studySettingGeneral intensive care unit (ICU) in a county hospital covering 360 000 inhabitants.Patients51 patients weaned by a fixed protocol were studied prospectively and compared with 50 retrospective controls.MeasurementsThe following variables were assessed: Acute Physiology and Chronic Health Evaluation (APACHE) II score, age, cause of respiratory failure, type of extubation (direct extubation or extubation using a weaning technique), number of days on MV before the weaning trial, weaning time, total duration of MV, complications (reintubations and tracheostomies), length of ICU stay, and mortality.ResultsThe groups were comparble in terms of age, APACHE II score, and main cause of acute respiratory failure. Number of days on MV up to the weaning trial were similar in the two groups (8.4±7.7 in the protocol group vs 7.5±5.5 in the control group, NS). Most of the patients (80%) in the protocol group were directly extubated without a weaning technique, unlike the control group (10%) (p<0.01). When a weaning technique was used, the weaning time was similar in both groups (3.5±3.9 days vs 3.6±2.2 days in the control group). Duration of MV was shorter in the protocol group (10.4±11.6 days) than in the control group (14.4±10.3 days) (p<0.05). As a result, the ICU stay was reduced by using the weaning protocol (16.7±16.5 days vs 20.3±13.2 days in the control group,p<0.05). We found no differences in reintubation rate (17 vs 14% in the control group) and need for tracheostomies (2 vs 8% in the control group).ConclusionThe implementation of a weaning protocol decreased the duration of MV and ICU stay by increasing the number of safe, direct extubations.

Risk factors and prognosis of catheter-related bloodstream infection in critically ill patients: a multicenter study

ObjectiveTo assess the risk factors associated with CR-BSI development in critically ill patients with non-tunneled, non-cuffed central venous catheters (CVC) and the prognosis of the episodes of CR-BSI. Design and setting; prospective, observational, multicenter study in nine Spanish Hospitals.PatientsAll subjects admitted to the participating ICUs from October 2004 to June 2005 with a CVC.InterventionsNone.Measurement and resultsOverall, 1,366 patients were enrolled and 2,101 catheters were analyzed. Sixty-six episodes of CR-BSI were diagnosed. The incidence of CR-BSI was significantly higher in CVC compared with peripherically inserted central venous catheters (PICVC) without significant differences among the three locations of CVC. In the multivariate analysis, duration of catheterization and change over a guidewire were the independent variables associated with the development of CR-BSI whereas the use of a PICVC was a protective factor. Excluding PICVC, 1,598 conventional CVC were analyzed. In this subset, duration of catheterization, tracheostomy and change over a guidewire were independent risk factors for CR-BSI. A multivariate analysis of predictors for mortality among 66 patients with CRSI showed that early removal of the catheter was a protective factor and APACHE II score at the admission was a strong determinant of in-hospital mortality.ConclusionsPeripherically inserted central venous catheters is associated with a lower incidence of CR-BSI in critically ill patients. Exchange over a guidewire of CVC and duration of catheterization are strong contributors to CR-BSI. Our results reinforce the importance of early catheter removal in critically ill patients with CR-BSI.

Pressure support ventilation via face mask in acute respiratory failure in hypercapnic COPD patients.

ObjectiveTo test whether non-invasive ventilation via facial mask could reduce the need for tracheal intubation via when mechanical ventilation must be initiated in COPD patients.DesignOpen prospective interventional study.SettingGeneral Intensive Care Service of a County Hospital.PatientsWe have studied 12 COPD patients during 14 episodes of acute exacerbation of chronic respiratory failure who failed to improve with intensive medical therapy and showed impairements in severe respiratory acidosis and/or hypercapnic encephalopathy leading their attending physicians to order mechanical ventilationInterventionsIn these circumstances, a trial of pressuresupport (PS) ventilation (Servo Ventilator 900Cℜ) via facial mask Vital Signs Inc.ℜ) was performed. The level of pressure support was adjusted to obtain a tidal volume>400 ml. If the patient deteriorated, tracheal intubation and standard mechanical ventilation were performed.Measurements and resultsMeasurements are presented as means±SEM. A pressure-support level of 14±3 cmH2O was used during a period of 8±4 h. Low levels of external PEEP were used in 4 patients, while it generated excessive leaks in the others. Significant differences (p<0.05 ANOVA for repeated measures) in data obtained on admission, when patients deteriorated and after pressure support was administered were only observed in PaCO2 (68±3 versus 92±3 versus 67±3 mmHg), arterial pH (7.27±0.03 versus 7.19±0.02 versus 7.31±0.01). SaO2 (60±4 versus 86±3 versus 92±1%) and respiratory rate (35±2 versus 32±2 versus 23±1 breaths·min−1). Three patients needed intubation and one of them died in the ICU.ConclusionNon-invasive ventilation (pressure-support) via face mask may reduce the need for tracheal intubation in the severe hypercapnic failure of COPD patients.

A 7-year study of severe hospital-acquired pneumonia requiring ICU admission

ObjectiveTo examine the characteristics, prognostic factors, and outcome of patients with severe hospital-acquired pneumonia admitted to the ICU.Design and settingProspective observational clinical study in two medical-surgical ICUs with 16 and 20 bedsPatients and participantsDuring a 7-year period all hospitalized patients requiring admission to either ICU for hospital-acquired pneumonia were followed up.Measurements and resultsWe diagnosed 96 episodes of severe hospital-acquired pneumonia, and in 67 cases a causal diagnosis was made. Most episodes were late-onset pneumonia. Gram-negative micro-organisms were isolated in 51% of episodes diagnosed, and Pseudomonas aeruginosa was the most frequent pathogen isolated (24%). Clearly significant variations happened between hospitals, particularly affecting the incidence of Aspergillus spp. and Legionella pneumophila. Forty-nine patients developed septic shock (51%). Fifty-one patients died (53%). Aspergillosis and pneumonia due to P. aeruginosa were associated with the highest mortality. Septic shock (OR: 14.27) and chronic obstructive pulmonary disease (OR: 6.11) were independently associated with a poor prognosis.ConclusionsPatients with severe hospital-acquired pneumonia admitted to the ICU present high mortality. The presence of septic shock and chronic obstructive pulmonary disease in conjunction with specific microorganisms are associated with a poor prognosis. Local epidemiological data combined with a patient-based approach may allow a more accurate therapy decision making.

Why Mortality Is Increased in Health-Care-Associated Pneumonia: Lessons From Pneumococcal Bacteremic Pneumonia

BACKGROUND A cohort of patients with bacteremic Streptococcus pneumoniae pneumonia was reviewed to assess why mortality is higher in health-care-associated pneumonia (HCAP) than in community-acquired pneumonia (CAP). METHODS A prospective cohort of all adult patients with bacteremic pneumococcal pneumonia attended at the ED was used. RESULTS One hundred eighty-four cases were classified as CAP and 44 (19%) as HCAP. Fifty-two (23%) were admitted to the ICU. Three (1.5%) isolates were resistant to beta-lactams, and only two patients received inappropriate therapy. The CAP cohort was significantly younger (median age 68 years, interquartile range [IQR] 42-78 vs 77 years, IQR 67-82, P < .001). The HCAP cohort presented a higher Charlson index (2.81 +/- 1.9 vs 1.23 +/- 1.42, P < .001) and had higher severity of illness at admission (altered mental status, respiratory rate > 30/min, Pao(2)/Fio(2) < 250, and multilobar involvement). HCAP patients had a lower rate of ICU admission (11.3% vs 25.5%, P < .05), and a trend toward lower mechanical ventilation (9% vs 19%, P = .17) and vasopressor use (9% vs 18.4%, P = .17) were documented. More patients in the HCAP cohort presented with a pneumonia severity index score > 90 (class IV-V, 95% vs 65%, P < .001), and 30-day mortality was significantly higher (29.5% vs 7.6%, P < .001). A multivariable regression logistic analysis adjusting for underlying conditions and variables related to severity of illness confirmed that HCAP is an independent variable associated with increased mortality (odds ratio = 5.56; 95% CI, 1.86-16.5). CONCLUSIONS Pneumococcal HCAP presents excess mortality, which is independent of bacterial susceptibility. Differences in outcomes were probably due to differences in age, comorbidities, and criteria for ICU admission rather than to therapeutic decisions.

Role of bronchoalveolar lavage in mechanically ventilated patients with suspected pneumonia

To determine the usefulness of samples obtained by bronchoalveolar lavage (BAL) in establishing the diagnosis of ventilator-associated pneumonia, quantitative cultures of BAL and protected specimen brush (PSB) samples obtained via fiberoptic bronchoscope were compared in 42 patients with suspected ventilator-associated pneumonia. Direct examination of BAL fluid was also used to identify cells with intracellular organisms. Ventilator-associated pneumonia was diagnosed in 18 patients; a total of 39 microorganisms were recovered from BAL fluid and 29 from PSB specimens. Cultures of 21 BAL and 23 PSB specimens were sterile. Quantitative BAL and PSB cultures coincided in 76 % of cases. Sterile BAL and PSB cultures agreed in 87 % of cases. Cultures were completely discordant in only three cases. The sensitivity of BAL for diagnosis of ventilator-associated pneumonia using bacterial counts of ≥104 cfu/ml was 89 %, and specificity was 100 %. In 14 of the 18 patients with ventilator-associated pneumonia, the percentage of cells containing intracellular organisms in specimens recovered by BAL was 11.6 % versus 0.45 % in patients without pneumonia (p<0.05). In the remaining four patients, all of whom hadPseudomonas aeruginosa pneumonia, no intracellular organisms could be detected. Using a cut-off point of ≥ 5 % of cells with intracellular organisms, the sensitivity and specificity for the early diagnosis of ventilator-associated pneumonia was 67 % and 96 %, respectively. The results confirm the usefulness of the quantitative BAL culture (with a cut-off at 104 cfu/ml) for the diagnosis of ventilator-associated pneumonia. The identification of intracellular organisms in BAL fluid is a good early indicator of pneumonia, but the sensitivity of this technique may be lower forPseudomonas aeruginosa infections.