Norepinephrine weaning in septic shock patients by closed loop control based on fuzzy logic.

INTRODUCTION: The rate of weaning of vasopressors drugs is usually an empirical choice made by the treating in critically ill patients. We applied fuzzy logic principles to modify intravenous norepinephrine (noradrenaline) infusion rates during norepinephrine infusion in septic patients in order to reduce the duration of shock. METHODS: Septic patients were randomly assigned to norepinephrine infused either at the clinician's discretion (control group) or under closed-loop control based on fuzzy logic (fuzzy group). The infusion rate changed automatically after analysis of mean arterial pressure in the fuzzy group. The primary end-point was time to cessation of norepinephrine. The secondary end-points were 28-day survival, total amount of norepinephine infused and duration of mechanical ventilation. RESULTS: Nineteen patients were randomly assigned to fuzzy group and 20 to control group. Weaning of norepinephrine was achieved in 18 of the 20 control patients and in all 19 fuzzy group patients. Median (interquartile range) duration of shock was significantly shorter in the fuzzy group than in the control group (28.5 [20.5 to 42] hours versus 57.5 [43.7 to 117.5] hours; P < 0.0001). There was no significant difference in duration of mechanical ventilation or survival at 28 days between the two groups. The median (interquartile range) total amount of norepinephrine infused during shock was significantly lower in the fuzzy group than in the control group (0.6 [0.2 to 1.0] microg/kg versus 1.4 [0.6 to 2.7] microg/kg; P < 0.01). CONCLUSIONS: Our study has shown a reduction in norepinephrine weaning duration in septic patients enrolled in the fuzzy group. We attribute this reduction to fuzzy control of norepinephrine infusion. TRIAL REGISTRATION: Trial registration: Clinicaltrials.gov NCT00763906.

Are daily routine chest radiographs useful in critically ill, mechanically ventilated patients? A randomized study.

OBJECTIVE: Whether chest radiographs (CXRs) in mechanically ventilated patients should be routinely obtained or only when an abnormality is anticipated remains debated. We aimed to compare the diagnostic, therapeutic and outcome efficacy of a restrictive prescription of CXRs with that of a routine prescription, focusing on delayed diagnoses and treatments potentially related to the restrictive prescription. DESIGN: Randomized controlled trial. SETTING: Intensive care unit of the Avicenne Teaching Hospital, Bobigny, France. PATIENTS AND PARTICIPANTS: All consecutive patients mechanically ventilated for > or = 48h between January and June 2006. INTERVENTIONS: Patients were randomly assigned to have daily routine CXRs (routine prescription group) or clinically indicated CXRs (restrictive prescription group). MEASUREMENTS AND RESULTS: For each CXR, a questionnaire was completed addressing the reason for the CXR, the new findings, and any subsequent therapeutic intervention. The endpoints were the rates of new findings, the rates of new findings that prompted therapeutic intervention, the rate of delayed diagnoses, and mortality. Eighty-four patients were included in the routine prescription group and 81 in the restrictive prescription group. The rates of new findings and the rates of new findings that prompted therapeutic intervention in the restrictive prescription group and in the routine prescription group were 66% vs. 7.2% (p < 0.0001), and 56.4% vs. 5.5% (p < 0.0001) respectively. The rate of delayed diagnoses in the restrictive prescription group was 0.7%. Mortality was similar. CONCLUSIONS: Restrictive use of CXRs in mechanically ventilated patients was associated with better diagnostic and therapeutic efficacies without impairing outcome.

Does catheter-associated urinary tract infection increase mortality in critically ill patients?

OBJECTIVE: To produce an accurate estimate of the association between catheter-associated urinary tract infection (UTI) and intensive care unit (ICU) and hospital mortality, controlling for major confounding factors. DESIGN: Nested case-control study in a multicenter cohort (the OutcomeRea database). SETTING: Twelve French medical or surgical ICUs. METHODS: All patients admitted between January 1997 and August 2005 who required the insertion of an indwelling urinary catheter. Patients who developed catheter-associated UTI (ie, case patients) were matched to control patients on the basis of the following criteria: sex, age (+/- 10 years), SAPS (Simplified Acute Physiology Score) II score (+/- 10 points), duration of urinary tract catheterization, and presence or absence of diabetes mellitus. The association of catheter-associated UTI with ICU and hospital mortality was assessed by use of conditional logistic regression. RESULTS: Of the 3,281 patients who had an indwelling urinary catheter, 298 (9%) developed at least 1 episode of catheter-associated UTI. The incidence density of catheter-associated UTI was 12.9 infections per 1,000 catheterization-days. Crude ICU mortality rates were higher among patients with catheter-associated UTI, compared with those without catheter-associated UTI (32% vs 25%, P=.02); the same was true for crude hospital mortality rates (43% vs 30%, P<.01). After matching and adjustment, catheter-associated UTI was no longer associated with increased mortality (ICU mortality: odds ratio [OR], 0.846 [95% confidence interval {CI}, 0.659-1.086]; P=.19 and hospital mortality: OR, 0.949 [95% CI, 0.763-1.181]; P=.64). CONCLUSION: After carefully controlling for confounding factors, catheter-associated UTI was not found to be associated with excess mortality among our population of critically ill patients in either the ICU or the hospital.

Agreement between quantitative cultures of postintubation tracheal aspiration and plugged telescoping catheter, protected specimen brush, or BAL for the diagnosis of nosocomial pneumonia.

BACKGROUND: The diagnosis of ventilator-associated pneumonia relies on protected specimen brush (PSB), BAL, and plugged telescoping catheter (PTC) procedures. In the particular setting of nosocomial pneumonia (NP) occurring in non-mechanically ventilated patients, no consensus exists on their use. When mechanical ventilation (MV) becomes mandatory, postintubation tracheal aspiration (PITA) could be a simple, fast, and cheap diagnostic tool. Our aim was to compare the diagnostic accuracy of PITA to that of PSB, BAL, or PTC in patients requiring MV for suspected NP. METHODS: Patients with a prior hospital stay of > or = 48 h who required MV for suspicion of NP were prospectively enrolled in the study. PITA was performed by sterile suction. Within 2 h, pulmonary samples were obtained by PSB, BAL, or blinded PTC, which are referred to hereafter as "reference methods" (RMs). The definite diagnosis of NP was made using a composite item of clinical, radiologic, and bacteriologic (ie, blood or pleural fluid cultures) patterns. The agreement between the quantitative microbiological results obtained with PITA and those of the RMs was assessed by the kappa-statistic. The sensitivity, specificity, and positive and negative likelihood ratios of PITA and RMs were calculated taking the definite diagnosis of NP as the reference. RESULTS: There were 44 cases (63.8%) of confirmed NP. The kappa-statistic was 0.71. The sensitivity, specificity, and positive and negative likelihood ratios were 77%, 84%, 4.80, and 0.27, respectively, for PITA, and 75%, 88%, 6.25, and 0.28, respectively, for RMs. CONCLUSIONS: PITA may be a reliable alternative to RMs in the particular setting of NP in newly mechanically ventilated patients.

Noninvasive ventilation improves preoxygenation before intubation of hypoxic patients.

RATIONALE: Critically ill patients are predisposed to oxyhemoglobin desaturation during intubation. OBJECTIVES: To find out whether noninvasive ventilation (NIV), as a preoxygenation method, is more effective at reducing arterial oxyhemoglobin desaturation than usual preoxygenation during orotracheal intubation in hypoxemic, critically ill patients. METHODS: Prospective randomized study performed in two surgical/medical intensive care units (ICUs). Preoxygenation was performed, before a rapid sequence intubation, for a 3-min period using a nonrebreather bag-valve mask (control group) or pressure support ventilation delivered by an ICU ventilator through a face mask (NIV group) according to the randomization. MEASUREMENTS AND MAIN RESULTS: The control (n = 26) and NIV (n = 27) groups were similar in terms of age, disease severity, diagnosis at admission, and pulse oxymetry values (Sp(O(2))) before preoxygenation. At the end of preoxygenation, Sp(O(2)) was higher in the NIV group as compared with the control group (98 +/- 2 vs. 93 +/- 6%, p < 0.001). During the intubation procedure, the lower Sp(O(2)) values were observed in the control group (81 +/- 15 vs. 93 +/- 8%, p < 0.001). Twelve (46%) patients in the control group and two (7%) in the NIV group had an Sp(O(2)) below 80% (p < 0.01). Five minutes after intubation, Sp(O(2)) values were still better in the NIV group as compared with the control group (98 +/- 2 vs. 94 +/- 6%, p < 0.01). Regurgitations (n = 3; 6%) and new infiltrates on post-procedure chest X ray (n = 4; 8%) were observed with no significant difference between groups. CONCLUSION: For the intubation of hypoxemic patients, preoxygenation using NIV is more effective at reducing arterial oxyhemoglobin desaturation than the usual method.

Differential diagnostic value of procalcitonin in surgical and medical patients with septic shock.

OBJECTIVE: To assess whether different diagnostic and prognostic cutoff values of procalcitonin should be considered in surgical and in medical patients with septic shock. DESIGN: Prospective observational study. SETTING: Intensive care unit of the Avicenne teaching hospital, France. PATIENTS: All patients with septic shock or noninfectious systemic inflammatory response syndrome within 48 hrs after admission. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patients were allocated to one of the following groups: group 1 (surgical patients with septic shock), group 2 (surgical patients with noninfectious systemic inflammatory response syndrome), group 3 (medical patients with septic shock), and group 4 (medical patients with noninfectious systemic inflammatory response syndrome). Procalcitonin at study entry was compared between group 1 and group 2 and between group 3 and group 4 to determine the diagnostic cutoff value in surgical and in medical patients, respectively. Procalcitonin was compared between survivors and nonsurvivors from group 1 and group 3 to determine its prognostic cutoff value. One hundred forty-three patients were included: 31 in group 1, 36 in group 2, 36 in group 3, and 40 in group 4. Median procalcitonin levels (ng/mL [interquartile range]) were higher in group 1 than in group 3 (34.00 [7.10-76.00] vs. 8.40 [3.63-24.70], p = .01). In surgical patients, the best diagnostic cutoff value was 9.70 ng/mL, with 91.7% sensitivity and 74.2% specificity. In medical patients, the best diagnostic cutoff value was 1.00 ng/mL, with 80% sensitivity and 94% specificity. Procalcitonin was a reliable early prognostic marker in medical but not in surgical patients with septic shock. A cutoff value of 6.00 ng/mL had 76% sensitivity and 72.7% specificity for separating survivors from nonsurvivors. CONCLUSIONS: The diagnostic cutoff value of procalcitonin was higher in surgical than in medical patients. Early procalcitonin was of prognostic interest in medical patients.

Cardiac troponin I in patients with severe exacerbation of chronic obstructive pulmonary disease.

OBJECTIVES: Co-morbid conditions including risk factors for cardiovascular diseases and left ventricular dysfunction are common in patients with chronic obstructive pulmonary disease (COPD). This study assessed the incidence of cardiac troponin I (cTnI) elevation, a specific marker for cardiac injury, and its prognostic significance during severe exacerbation of COPD. DESIGN: Prospective cohort study. SETTING: Two intensive care units. PARTICIPANTS: Seventy-one consecutive patients admitted for severe exacerbation of COPD. INTERVENTION: None. MEASUREMENTS AND RESULTS: Cardiac troponin I was assayed in blood samples obtained on admission and 24 h later (Stratus II immunoassay analyser, Dade International). Levels above 0.5 ng/ml were considered positive. The following data were recorded prospectively: clinical symptoms, co-morbidities, cause of the exacerbation, diagnostic procedures and treatment, general severity score (SAPS II) and in-hospital outcome. CTnI was positive in 18% of patients (95% confidence interval (CI(95)), 11-29%), with a median value at 1.00 ng/ml; CI(95 )(0.60-1.70). Eighteen patients died in the hospital (25%; CI(95), 17-37%). Only cTnI (adjusted odds ratio (ORa), 6.52; CI(95),1.23-34.47) and SAPS II 24 h after admission (ORa, 1.07; CI(95), 1.01-1.13) were independent predictors of in-hospital mortality. CONCLUSION: Elevated cTnI is a strong and independent predictor of in-hospital death in patients admitted for acutely exacerbated COPD.

Calibration and discrimination by daily Logistic Organ Dysfunction scoring comparatively with daily Sequential Organ Failure Assessment scoring for predicting hospital mortality in critically ill patients.

OBJECTIVE: The Logistic Organ Dysfunction (LOD) score has been proved effective in evaluating severity during the first day in an intensive care unit but has not been evaluated later. To evaluate attributable mortality related to nosocomial events, organ dysfunction scores that remain accurate throughout the intensive care unit stay are needed. The objective of this study was to evaluate how accurately daily LOD scoring predicts mortality comparatively with daily Sequential Organ Failure Assessment (SOFA) scoring. DESIGN: Prospective multicenter study. SETTING: Six intensive care units in France. PATIENTS: A total of 1685 patients with intensive care unit stays longer than 48 hrs were included in this study (511 hospital deaths). Median age was 66 yrs, and median Simplified Acute Physiology Score II at admission was 38. For each patient, a senior physician recorded the variables needed to compute organ dysfunction scores daily throughout the intensive care unit stay. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: SOFA and LOD scores were computed daily during the first 7 days. Calibration was evaluated based on goodness-of-fit by the Hosmer-Lemeshow chi-square statistic (lower chi-square values and higher values indicate better fit) and discrimination based on the receiver operating characteristics (ROC) area under the curve (AUC; a ROC-AUC of 1 indicates faultless discrimination and a ROC-AUC of 0.5 indicates the effects of chance alone). Because calibration of both scores was poor at all time points ( p<.001), customization was performed using the total score (model 1) or separate introduction of each dysfunction (model 2). The performance of customized LOD and SOFA scores on a given day in predicting mortality was assessed in those patients who spent at least one more calendar day in the intensive care unit. The original LOD and SOFA scores had satisfactory ROC-AUC values (0.720 to 0.766). Internal consistency of both scores was acceptable ( p< 10(-4) for each organ dysfunction). After customization, the original scores calibrated well between days 1 and 7. Discrimination by both scores was better with model 2 (AUC-ROC, 0.729-0.784). CONCLUSION: Daily LOD and SOFA scores showed good accuracy and internal consistency, and they could be used to adjust severity for events occurring in the intensive care unit.

Mortality associated with late-onset pneumonia in the intensive care unit: results of a multi-center cohort study.

OBJECTIVE: To evaluate the attributable mortality associated with late-onset nosocomial pneumonia (LOP) while taking into account the severity at admission, the evolution of the patients during the first 4 days after admission to the ICU and the appropriateness of initial empiric antibiotic treatment. DESIGN: Multicenter cohort study with prospective standardization of diagnostic interventions when nosocomial pneumonia develops. SETTING: Medical and surgical ICUs of four university-affiliated teaching hospitals. PATIENTS: Seven hundred sixty-four consecutive patients requiring ICU hospitalization for at least 4 days. MAIN OUTCOME MEASURES: The clinical and biological data as well as the therapeutic data and the outcome were prospectively recorded from the day of admission to ICU discharge. Simplified Acute Physiologic Score (SAPS II) and Logistic Organ Dysfunction (LOD) score were collected and computed within the first 4 calendar days of ICU admission. Variables associated with the outcome were selected using a stepwise Cox model. The time to acquisition of the first LOP was then introduced in the final model as a time-dependent covariate. The analysis was stratified by ICU center. Finally, as initial antibiotic therapy could have an impact on the increased risk of death induced by LOP, the Cox model was applied again introducing LOP immediately adequately treated and LOP not immediately adequately treated as two different time-dependent covariates. RESULTS: Late-onset pneumonia developed in 89 patients (12%). A McCabe score of more than 1, SAPS II score and increases in SAPS between days 1 and 2, days 2 and 3, and days 3 and 4 were significantly associated with an increased risk of death. When the time to acquisition of the first episode of LOP was introduced into the Cox model, the LOP occurrence was associated with increased mortality, even adjusted over the selected prognostic parameters and after stratification by center (hazard ratio (HR)=1.53, 95% CI 1.02-2.3, p=0.04). When LOP immediately adequately treated and LOP not immediately adequately treated were separately introduced into the Cox model, inappropriately treated LOP remained significantly associated with an increased risk of mortality (HR=1.69, 95% CI 1.08-2.65, p=0.022), whereas appropriately treated LOP did not (HR=1.44, 95% CI 0.75-2.76, p=0.27). CONCLUSION: These data suggest that, in addition to severity scores, the underlying medical conditions and the evolution of severity within the first 4 days in ICU, late-onset pneumonia independently contribute to ICU patient mortality when empirical antibiotic treatment is not immediately appropriate.