Population-based assessment of intensive care unit-acquired bloodstream infections in adults: Incidence,risk factors,and associated mortality rate

OBJECTIVE: Nosocomial bloodstream infections have been extensively investigated, but relatively few studies have specifically evaluated the epidemiology of intensive care unit-acquired bloodstream infections. The study objective was to define the incidence, risk factors, microbiology, and clinical outcomes of intensive care unit-acquired bloodstream infections. DESIGN: Population-based prospective cohort. SETTING: Multidisciplinary intensive care units. PATIENTS: All Calgary Health Region (population 930,000) adult patients admitted to multidisciplinary intensive care units (>/=48 hrs) from May 1, 1999, to April 30, 2000. INTERVENTIONS: Blood sample analysis. MEASUREMENTS AND RESULTS: There were 1,158 admission episodes in 1,017 patients; 37% involved females, and mean +/- sd age and Acute Physiology and Chronic Health Evaluation II scores were 59.6 +/- 18.7 yrs and 23.4 +/- 7.7, respectively. Fifty-one patients developed intensive care unit-acquired bloodstream infections (first positive blood culture >/=48 hrs after intensive care unit admission) for an incidence of 4.4% and an incidence density of 5.2 per 1000 intensive care unit days. Younger age (adjusted odds ratio, 0.98; 95% confidence interval, 0.96-1.00, p =.01), longer intensive care unit length of stay (adjusted odds ratio, 4.74; 95% CI, 3.26-6.90, p <.001), and lower hematocrit (adjusted odds ratio, 0.95; 95% confidence interval, 0.90-1.00, p =.04) were significant independent predictors of intensive care unit-acquired bloodstream infections, and these infections were associated with an increased intensive care unit length of stay of 2.86 days (95% confidence interval, 2.29-3.57, p <.001). Staphylococcus aureus (27%), coagulase-negative staphylococci (14%), and Enterococcus faecium (12%) were most commonly isolated. Four (8%) bloodstream infections involved antibiotic-resistant organisms, and ten (20%) were polymicrobial. In multivariate analysis, intensive care unit-acquired bloodstream infection was associated with an increased intensive care unit mortality rate (adjusted odds ratio, 2.03; 95% confidence interval, 1.03-4.00, p = 0.04) but not overall hospital mortality rate. CONCLUSIONS: One patient in 20 admitted to Calgary Health Region intensive care units acquires bloodstream infection and suffers longer intensive care unit stay and increased mortality rates. In our region, multiple antibiotic-resistant organisms are uncommon causes of bloodstream infections, suggesting that it may be safe to use narrower spectrum empirical treatment regimens than current guidelines recommend.     

Determinants of postintensive care unit mortality: a prospective multicenter study

OBJECTIVE: Six to 25 percent of patients discharged alive from the intensive care unit (ICU) die before hospital discharge. Although this post-ICU mortality may indicate premature discharge from a full ICU or suboptimal management in the ICU or ward, another factor may be discharge from the ICU as part of a decision to limit treatment of hopelessly ill patients. We investigated determinants of post-ICU mortality, with special attention to this factor. DESIGN: Prospective, multicenter, database study. SETTING: Seven ICUs in or near Paris, France. PATIENTS: A total of 1,385 patients who were discharged alive from an ICU after a stay of > or = 48 hrs; 150 (10.8%) died before hospital discharge. Decisions to withhold or withdraw life-sustaining treatments were implemented in the ICUs in 80 patients, including 47 (58.7%) who died before hospital discharge. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: In the univariate analysis, post-ICU mortality was associated with advanced age, poor chronic health status, severe comorbidities, severity and organ failure scores (Simplified Acute Physiology Score II, sepsis-related organ failure assessment, and Logistic Organ Dysfunction at admission and at ICU discharge), decisions to withhold or withdraw life-sustaining treatments, and Omega score (reflecting ICU resource utilization and length of ICU stay). Multivariate stepwise logistic regression identified five independent determinants of post-ICU mortality: McCabe class 1 (odds ratio, 0.388 [95% confidence interval, 0.26-0.58]), transfer from a ward (odds ratio, 1.89 [95% confidence interval, 1.27-2.80]), Simplified Acute Physiology Score II score at admission >36 (odds ratio, 1.57 [95% confidence interval, 1.6-2.33]), decisions to withhold or withdraw life-sustaining treatments (odds ratio, 9.64 [95% confidence interval, 5.75-16.6]), and worse sepsis-related organ failure assessment score at discharge (odds ratio, 1.11 [95% confidence interval, 1.03-1.18] per point). CONCLUSIONS: More than 10% of ICU survivors died before hospital discharge. Determinants of post-ICU mortality included variables reflecting patient status before and during the ICU stay. However, the most powerful predictor of post-ICU mortality was the decision to withhold or withdraw life-sustaining treatments in the ICU, suggesting that the decision has been made not to use the unique services of the ICU for these patients.     

Outcome and early prognostic indicators in patients with a hematologic malignancy admitted to the intensive care unit for a life-threatening complication

OBJECTIVES: To assess the outcome and to identify early prognostic indicators in a global population of patients with hematologic malignancy admitted to the intensive care unit for a life-threatening complication. DESIGN: Retrospective observational study. SETTING: Medical intensive care unit at a tertiary university hospital. PATIENTS: A total of 124 consecutive critically ill patients with a hematologic malignancy admitted to the intensive care unit during a 3.5-yr period.MEASUREMENTS We collected variables at admission and during admission and identified predictors of in-hospital mortality by stepwise logistic regression analysis. MAIN RESULTS: Mean Acute Physiology and Chronic Health Evaluation II score was 26 +/- 7.7. Sixty-one percent had a high-grade malignancy, and 27% had active disease. Thirty-five percent were leukopenic (leukocyte count, <1.0 x 10(9)/L) at admission. Respiratory failure (48%), sepsis (18.5%), and neurologic impairment (17%) were the major reasons for admission at the intensive care unit. Seventy-one percent of the patients required ventilatory support for a median duration of 6 (3-17) days, 46% received vasopressors at admission, and 26.6% needed renal replacement therapy during their intensive care unit stay. A recent bacteremia precipitating intensive care unit admission was found in 21.8% of the patients. Crude intensive care unit, in-hospital, and 6-month mortality rates were 42%, 54%, and 66%, respectively. Four variables were independently associated with outcome in a multivariate logistic regression analysis: leukopenia (odds ratio, 2.9; 95% confidence interval, 1.1-7.7), vasopressors (odds ratio, 3.74; 95% confidence interval, 1.4-9.8), and urea of >0.75 g/L (>12 mmol/L) (odds ratio, 9.4; 95% confidence interval, 4.2-26) at admission were associated with poor outcome, whereas recent bacteremia (odds ratio, 0.17; 95% confidence interval, 0.05-0.58) was associated with better prognosis. Using these variables, we arbitrarily categorized our population into three groups for survival analysis: a low-risk group (low urea with or without either leukopenia or vasopressors, n = 60), an intermediate-risk group (high urea or a combination of leukopenia and vasopressors, n = 34), and a high-risk group (high urea in combination with leukopenia or vasopressors, n = 27). Patients with a bacteremia prompting intensive care unit admission were allocated to a one-step-lower risk group. Survival probabilities at 30 days and 6 months were 75% and 55% in the first group, 35% and 21% in the second group, and 4% and 0%, respectively, in the third group ( <.001). CONCLUSION: The general reluctance to admit patients with a hematologic malignancy to the intensive care unit, even with severe critical illness, is unjustified. However, we identified four early predictors of outcome that may be of value in deciding in which patients advanced or prolonged support should not be continued.     

Effect of acute lung injury and acute respiratory distress syndrome on outcome in critically ill trauma patients

OBJECTIVE: Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are known to be associated with increased mortality and costs in trauma patients. We estimated the independent impact of these conditions on mortality and cost, beyond the severity of injury with which they are correlated. DESIGN: One-year prospective cohort. PATIENTS AND SETTING: All trauma patients admitted to the intensive care unit in a level I center were evaluated daily for ALI/ARDS using the American-European Consensus Conference definition. MEASUREMENTS AND MAIN RESULTS: The main outcome measures were hospital mortality and costs. Logistic regression was used to model hospital mortality in relation to the presence of ALI and ARDS, adjusting for trauma severity (Injury Severity Score), Acute Physiology Score, and age. Hospital costs were modeled using multivariable linear regression. Of the 1,296 trauma patients surviving beyond the first day, 4% experienced ALI (defined as Pao2/Fio2 of 201-300 mm Hg) and 12% had ARDS (Pao2/Fio2 < or = 200 mm Hg). The crude relative risk of mortality was 2.24 (95% confidence interval, 0.92-5.45) in patients with ALI and 3.84 (95% confidence interval, 2.41-6.13) in patients with ARDS compared with those without ALI/ARDS. However, there was no association of mortality with ALI (relative risk, 0.99; 95% confidence interval, 0.29-3.36) or with ARDS (relative risk, 1.23; 95% confidence interval, 0.63-2.43) after adjustment for age, Injury Severity Score, and Acute Physiology Score. Among patients of comparable age, severity score, and length of stay, median cost was 20% to 30% higher for those with ALI/ARDS. CONCLUSIONS: There is no additional mortality associated with ALI/ARDS above and beyond the factors that can be measured at intensive care unit admission. Therefore, mortality in trauma patients is explained by injury severity at admission and is not affected by the subsequent occurrence of ALI/ARDS. Nonetheless, ALI/ARDS was associated with increased intensive care unit stay and hospital cost, independent of trauma severity.     

Impact of delayed transfer of critically ill patients from the emergency department to the intensive care unit

OBJECTIVE: Numerous factors can cause delays in transfer to an intensive care unit for critically ill emergency department patients. The impact of delays is unknown. We aimed to determine the association between emergency department "boarding" (holding admitted patients in the emergency department pending intensive care unit transfer) and outcomes for critically ill patients. DESIGN: This was a cross-sectional analytical study using the Project IMPACT database (a multicenter U.S. database of intensive care unit patients). Patients admitted from the emergency department to the intensive care unit (2000-2003) were included and divided into two groups: emergency department boarding >or=6 hrs (delayed) vs. emergency department boarding <6 hrs (nondelayed). Demographics, intensive care unit procedures, length of stay, and mortality were analyzed. Groups were compared using chi-square, Mann-Whitney, and unpaired Student's t-tests. SETTING: Emergency department and intensive care unit. PATIENTS: Patients admitted from the emergency department to the intensive care unit (2000-2003). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Main outcomes were intensive care unit and hospital survival and intensive care unit and hospital length of stay. During the study period, 50,322 patients were admitted. Both groups (delayed, n = 1,036; nondelayed, n = 49,286) were similar in age, gender, and do-not-resuscitate status, along with Acute Physiology and Chronic Health Evaluation II score in the subgroup for which it was recorded. Among hospital survivors, the median hospital length of stay was 7.0 (delayed) vs. 6.0 days (nondelayed) (p < .001). Intensive care unit mortality was 10.7% (delayed) vs. 8.4% (nondelayed) (p < .01). In-hospital mortality was 17.4% (delayed) vs. 12.9% (nondelayed) (p < .001). In the stepwise logistic model, delayed admission, advancing age, higher Acute Physiology and Chronic Health Evaluation II score, male gender, and diagnostic categories of trauma, intracerebral hemorrhage, and neurologic disease were associated with lower hospital survival (odds ratio for delayed admission, 0.709; 95% confidence interval, 0.561-0.895). CONCLUSIONS: Critically ill emergency department patients with a >or=6-hr delay in intensive care unit transfer had increased hospital length of stay and higher intensive care unit and hospital mortality. This suggests the need to identify factors associated with delayed transfer as well as specific determinants of adverse outcomes.     

Characteristics associated with analgesia ordering in the intensive care unit and relationships with outcome

OBJECTIVE: To describe clinical characteristics associated with analgesia utilization in the intensive care unit. DESIGN: A prospective cohort study of adult patients admitted to a medical intensive care unit. SUBJECTS: Four hundred adult patients. SETTING: Twelve-bed medical intensive care unit of an inner-city, university-affiliated hospital. MEASUREMENTS AND MAIN RESULTS: Collected data included demographics, sedation and neuromuscular blocking agents used, mechanical ventilation, hemodynamic monitoring, Therapeutic Intervention Scoring System score, Logistic Organ Dysfunction System (LODS) score, and Acute Physiology and Chronic Health Evaluation (APACHE) II score. Hospital outcome was noted. The odds ratio and 95% confidence intervals were determined by using multiple logistic regression analyses. Patients' mean age (+/-sd) was 47.8 +/- 17.1 yrs; 58% were male, 84% African-American. Their APACHE II-predicted hospital mortality rate was 33%. Analgesics were used in 36% of patients. There were no differences in demographics, initial LODS score, APACHE II score, and mechanical ventilation use between patients who did and did not receive analgesics. Multiple logistic regression analysis showed that analgesic use was independently associated with sedation (odds ratio, 2.47; 95% confidence interval, 1.47-4.14), neuromuscular blockade (odds ratio, 4.98; 95% confidence interval, 1.85-13.41), and pulmonary artery flotation catheter utilization (odds ratio, 2.31; 95% confidence interval, 1.27-4.20). The median duration of mechanical ventilation was 5 days for those who received analgesia compared with 2 for those who did not (p =.0001). The median length of stay in the intensive care unit (4 vs. 2, p <.0001) and hospital (11 vs. 7, p <.0001) was higher in patients who received analgesics. There were no significant differences in intensive care unit and hospital mortality rates between patients who did and did not receive analgesics. CONCLUSIONS: Intensive care unit patients for whom analgesics were prescribed have a higher frequency of hemodynamic monitoring and use of sedative and neuromuscular blocking agents, more mechanical ventilation days, and longer intensive care unit and hospital lengths of stay.     

Bacteremia in patients with ventilator-associated pneumonia is associated with increased mortality: A study comparing bacteremic vs. nonbacteremic ventilator-associated pneumonia

OBJECTIVE: To assess whether bacteremic ventilator-associated pneumonia (B-VAP) differs in terms of risk factors, organisms, and outcomes from nonbacteremic VAP (NB-VAP). DESIGN: A retrospective, single-center, observational, cohort study. SETTING: Multidisciplinary teaching intensive care unit. PATIENTS: Adult patients requiring mechanical ventilation, identified as having VAP in a 44-month prospective surveillance database. INTERVENTIONS: Each B-VAP patient was matched with two controls with VAP and negative blood cultures based on the microbial etiology responsible for VAP, Acute Physiology and Chronic Health Evaluation II score on admission (+/-3 points), diagnostic category, and length of stay before pneumonia onset. MEASUREMENTS AND MAIN RESULTS: B-VAP was documented in 35 (17.6%) of 199 microbiologically confirmed VAP episodes. B-VAP developed later (median 8 vs. 5 days, p = .03) and was more frequent in previously hospitalized patients (34.3% vs. 11.0%, p < .01) and in older patients (57.4 +/- 15.2 vs. 49.5 +/- 19.3 yrs, p = .02). B-VAP was more often caused by methicillin-resistant Staphylococcus aureus (12 [20.7%] vs. 13 [5.1%] episodes, p < .01), whereas Haemophilus influenzae was associated with NB-VAP (52 [20.4%] vs. 0, p < .01). Multivariate analysis confirmed an association between B-VAP and both methicillin-resistant S. aureus (odds ratio 3.18; 95% confidence interval 1.15-8.76, p < .01) and prior hospitalization (odds ratio 2.56; 95% confidence interval 1.01-6.54, p = .05). After adjustment for potential confounders, B-VAP (hazard ratio for death 2.55; 95% confidence interval 1.25-5.23, p = .01) and vasopressor use (hazard ratio 2.43; 95% confidence interval 1.23-4.82, p = .01) remained associated with mortality. The estimated relative risk of death for bacteremic cases was 2.86 (95% confidence interval 1.09-7.51), since mortality for cases and matched NB-VAP controls was 40.6% (13 of 32) and 19.3% (11 of 57), respectively. CONCLUSIONS: B-VAP occurs later during intensive care unit stay, is more frequent in previously hospitalized patients, is more often caused by methicillin-resistant S. aureus, and is independently associated with increased intensive care unit mortality.     

Complicated acute myocardial infarction requiring mechanical ventilation in the intensive care unit: prognostic factors of clinical outcome in a series of 157 patients

OBJECTIVE: To determine prognostic factors associated with death in patients with complicated acute myocardial infarction requiring mechanical ventilation. DESIGN: Retrospective chart-based analysis. SETTING: A 22-bed medical intensive care unit in a university hospital. PATIENTS: A total of 157 consecutive patients with acute myocardial infarction requiring endotracheal intubation and mechanical ventilation admitted to an intensive care unit during a 6-yr period. INTERVENTIONS: Coronary reperfusion strategy within 12 hrs following symptom onset. MEASUREMENTS AND MAIN RESULTS: Clinical characteristics at admission of survivors (n = 77) and nonsurvivors (n = 80) were similar regarding demographics, medical history, and Glasgow Coma Scale score. Twenty-eight-day intensive care unit mortality rate was 51%. The following criteria were higher for nonsurvivors: Simplified Acute Severity Score II, 79 +/- 18 vs. 64 +/- 17 (p <.0001); Acute Physiology and Chronic Health Evaluation (APACHE) II, 33 +/- 13 vs. 25 +/- 6 (p <.0001); incidence of cardiogenic shock (p =.0085) and failing organs (p <.0001); coronary artery disease extension (p =.045); and delay between symptom onset and coronary reperfusion (p =.0348). Nonsurvivors also had higher serum urea and creatinine and lower urine output, arterial pH, and left ventricular ejection fraction (p <.05). Mortality rate was higher in patients with PaO2/FiO2 ratio <200 than in patients with PaO2/FiO2 ratio >200 at admission (log-rank, 5.016; p =.0251). By multivariate analysis, only three factors were independently associated with death: APACHE II >29 (odds ratio, 1.132; 95% confidence interval, 1.013-1.265, p =.0287), serum creatinine >180 micromol/L (odds ratio, 6.151; 95% confidence interval, 1.446-26.166, p =.0139), and initial left ventricular ejection fraction <0.4 (odds ratio, 1.121; 95% confidence interval, 1.049-1.347, p =.0316). Overall, good discrimination was achieved for the risk score model (c-index, 0.852). CONCLUSIONS: We confirmed the high mortality rate of patients admitted to an intensive care unit with acute myocardial infarction requiring mechanical ventilation. In these patients, the main risk factors for death found, namely high APACHE II, early development of acute renal failure, and low resting left ventricular function, reflected the severity of the myocardial infarction.     

Impact of admission hyperglycemia on hospital mortality in various intensive care unit populations

OBJECTIVE: Hyperglycemia in intensive care unit patients has been associated with an increased mortality rate, and institutions have already begun tight glucose control programs based on a limited number of clinical trials in restricted populations. This study aimed to assess the generalizability of the association between hyperglycemia and in-hospital mortality in different intensive care unit types adjusting for illness severity and diabetic history. DESIGN: Retrospective cohort study. SETTING: The medical, cardiothoracic surgery, cardiac, general surgical, and neurosurgical intensive care units of the University of Maryland Medical Center. PATIENTS: Patients admitted between July 1996 and January 1998 with length of stay > or = 24 hrs (n = 2713). INTERVENTIONS: On intensive care unit admission, blood glucose and other physiologic variables were evaluated. Regular measurements were taken for calculation of Acute Physiology and Chronic Health Evaluation III scoring. Patients were followed through hospital discharge. Admission blood glucose was used to classify patients as hyperglycemic (> 200 mg/dL) or normoglycemic (60-200 mg/dL). The contribution of hyperglycemia to in-hospital mortality stratified by intensive care unit type and diabetes history while controlling for illness severity was estimated by logistic regression. MEASUREMENTS AND MAIN RESULTS: The adjusted odds ratios for death comparing all patients with hyperglycemia to those without were 0.81 (95% confidence interval, 0.37, 1.77) and 1.76 (95% confidence interval, 1.23, 2.53) for those with and without diabetic history, respectively. Higher mortality was seen in hyperglycemic patients without diabetic history in the cardiothoracic, (adjusted odds ratio, 2.84 [1.21, 6.63]), cardiac (adjusted odds ratio, 2.64 [1.14, 6.10]), and neurosurgical units (adjusted odds ratio, 2.96 [1.51, 5.77]) but not the medical or surgical intensive care units or in patients with diabetic history. CONCLUSIONS: The association between hyperglycemia on intensive care unit admission and in-hospital mortality was not uniform in the study population; hyperglycemia was an independent risk factor only in patients without diabetic history in the cardiac, cardiothoracic, and neurosurgical intensive care units.     

Length of stay and mortality in neurocritically ill patients: impact of a specialized neurocritical care team

OBJECTIVE: To determine predictors of in-hospital and long-term mortality and length of stay in patients admitted to the neurosciences critical care unit. DESIGN: Retrospective analysis of a prospectively collected database. SETTING: Neurosciences critical care unit of a large academic tertiary care hospital. PATIENTS: Adult patients (n = 2381) admitted to our neurosciences critical care unit from January 1997 to April 2000. INTERVENTIONS: Introduction of a specialized neurocritical care team. MEASUREMENTS AND MAIN RESULTS: Data obtained from the database included demographics, admission source, length of stay, neurosciences critical care unit and hospital disposition, admission Acute Physiology and Chronic Health Evaluation (APACHE) III score, and principal and secondary diagnoses. The introduction of a neurocritical care team in September 1998 was also collected, as was death at 1 yr after admission. Univariate analysis was carried out using Student's t-test, Mann-Whitney U test, or chi-square test (significance, p < .05). A logistic regression model was used to create a prediction model for in-hospital and long-term mortality. A general linear model was used to determine predictors of length of stay (after log transformation). Independent predictors of in-hospital mortality included APACHE III (odds ratio, 1.07 [1.06-1.08]) and admission from another intensive care unit (odds ratio, 2.9 [1.4-6.2]). The presence of a neurocritical care team was an independent predictor of decreased mortality (odds ratio, 0.7 [0.5-1.0], p = .044). Admission after the neurocritical care team was implemented was associated with reduced length of stay in both the neurosciences critical care unit (4.2 +/- 4.0 vs. 3.7 +/- 3.4, p < .001) and the hospital (9.9 +/- 8.0 vs. 8.4 +/- 6.9, p < .0001). There was no difference in readmission rates to the intensive care unit or discharge disposition to home before and after the neurocritical care team was established. The availability of the neurocritical care team was not associated with significant changes in long-term mortality. Factors independently associated with long-term mortality included female gender, admission from another intensive care unit, APACHE III score, and being moderately disabled before admission. CONCLUSION: Introduction of a neurocritical care team, including a full-time neurointensivist who coordinated care, was associated with significantly reduced in-hospital mortality and length of stay without changes in readmission rates or long-term mortality.     

Mortality rate attributable to ventilator-associated nosocomial pneumonia in an adult intensive care unit: a prospective case-control study.

OBJECTIVE: To evaluate the mortality rate attributable to nosocomial ventilator-associated pneumonia in an intensive care unit. DESIGN: Prospective, matched, risk-adjusted cohort study. SETTING: A 18-bed adult medical-surgical intensive care unit in a 1,100-bed regional and teaching hospital in France. PATIENTS: From January 1, 1996, to April 30, 1999, 135 patients who developed nosocomial pneumonia were matched with 135 control patients without nosocomial pneumonia. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Nosocomial pneumonia was identified on the basis of results of distal bronchial samples. The matching process was conducted according to the following primary criteria: cause of admission, indication for ventilatory support, immunologic status, cardiac status, probability of death (+/-5%), Glasgow Coma Scale score (+/-2 points), age (+/-7 yrs), and duration of exposure to risk. When possible, case and control patients were matched according to five secondary criteria: respiratory and alcoholism status before admission, diagnosis categories, surgical procedure or not, and gender. The mortality rates were compared between case and control patients by using the Kaplan-Meier estimate and the log-rank test. The influence of nosocomial pneumonia on mortality rate then was tested by adjusting for the secondary criteria and other possible confounding factors by using the Cox proportional-hazards model. The matching process was successful for 1,080 of 1,080 primary criteria. The crude intensive care unit mortality rate was higher in patients with nosocomial pneumonia than in control patients (41 vs. 14%; p <.0001). In actuarial survival analysis, the probability of intensive care unit death was higher in the case patients (odds ratio = 2.7, 95% confidence interval = 1.8-3.1, p =.028). After adjustment, the occurrence of nosocomial pneumonia remained an independent risk factor of death (odds ratio = 2.1, 95% confidence interval = 1.2-3.6, p =.008). Nosocomial pneumonia attributable to multiresistant microorganisms was significantly associated with death (odds ratio = 2.6, 95% confidence interval = 1.1-5.8, p =.02). The length of intensive care unit stay was higher in case than in control patients (31 +/- 19 vs. 26 +/- 17 days, p <.0001). CONCLUSIONS: Nosocomial pneumonia is independently associated with death in the intensive care unit. In addition, it increases the length of intensive care unit stay.     

Thrombocytopenia in patients in the medical intensive care unit: bleeding prevalence,transfusion requirements,and outcome

OBJECTIVE: To determine prevalence, risk factors, and outcome of thrombocytopenia in medical intensive care patients. DESIGN: Prospective observational study. SETTING: The 12-bed medical intensive care unit of a university hospital. PATIENTS: All consecutively admitted patients with normal platelet count at admission and an intensive care unit stay of >48 hrs during a 13-month period (n = 145). MEASUREMENTS AND MAIN RESULTS: The prevalence of intensive care unit-acquired thrombocytopenia (platelet count, <150.0/nL) was 64 of 145 patients (44%). Intensive care unit mortality was 31% in thrombocytopenic patients and 16% in nonthrombocytopenic patients (p =.03). Mortality was higher in patients with a nadir platelet count of <100.0/nL (p <.001) and in patients with a drop in platelet count of >/=30% (p <.001). In nonsurvivors, the decrease in platelet count was greater (p <.001), the nadir platelet count lower (p <.001), and the duration of thrombocytopenia longer (p =.008) than in survivors. A logistic regression analysis identified septic shock (odds ratio [OR], 3.65; 95% confidence interval [CI], 1.40-9.52), a higher Acute Physiology and Chronic Health Evaluation II Score at admission (OR, 1.06 for 1 point; 95% CI, 1.01-1.12), and a drop in platelet count exceeding 30% (OR, 3.73; 95% CI, 1.24-11.21), but not thrombocytopenia, as independent risk factors for intensive care unit death. Correction of thrombocytopenia was associated with reduced mortality (OR, 0.002; 95% CI, 0-0.08). Major bleeding prevalence and transfusion requirements were significantly higher with thrombocytopenia. Nadir platelet count was the only independent risk factor for bleeding (OR, 4.1 for every 100.0/nL; 95% CI, 1.9-8.8). Independently associated with thrombocytopenia were disseminated intravascular coagulation (OR, 14.94; 95% CI, 3.92-57.00), cardiopulmonary resuscitation as an admission category (OR, 5.17; 95% CI, 1.42-18.85), and a higher Sequential Organ Failure Assessment score (OR, 1.20 for a 1 point change; 95% CI, 1.02-1.40). CONCLUSIONS: Thrombocytopenia is common in medical intensive care unit patients. Thrombocytopenic patients have a higher prevalence of bleeding and greater transfusion requirements. A drop in platelet counts of > or = 30%, but not thrombocytopenia per se, is independently associated with intensive care unit death. Serial measurements of platelet counts are important and readily available markers for monitoring the patient's condition. Any drop in platelet count requires urgent clarification. Disseminated intravascular coagulation, signs of organ failure at admission, and cardiopulmonary resuscitation are predictors of intensive care unit-acquired thrombocytopenia.     

Clinical impact of pneumonia caused by Acinetobacter baumannii in intubated patients: a matched cohort study

OBJECTIVE: To determine whether ventilator-associated pneumonia caused by Acinetobacter baumannii (VAPAB) is associated with increased mortality rate. DESIGN: A retrospective matched case-control study in which all intensive care unit adult patients with microbiologically documented VAPAB were defined as cases. SETTING: Four intensive care units from teaching hospitals. PATIENTS: Sixty patients were matched to sixty controls. MEASUREMENTS AND MAIN RESULTS: Controls were matched based on stay before pneumonia onset, disease severity (Acute Physiology and Chronic Health Evaluation II) at admission, and diagnostic category. Population characteristics and intensive care unit mortality rates of patients with VAPAB and their controls were compared. Attributable mortality was determined by subtracting the crude mortality rate of the controls from the crude mortality rate of the case patients. Twenty-four of the 60 case patients died, representing a crude mortality rate of 40%, whereas 17 of the 60 controls died, a crude mortality rate of 28.3% (p =.17). Crude intensive care unit mortality was the same (12 of 35, 34.2%) in patients with VAPAB caused by strains sensitive to imipenem and in their matched controls. It was 44% for the 25 patients with imipenem-resistant strains with an estimated attributable mortality rate of 20.0% (95% confidence interval, -5.6% to 45.7%). Mean intensive care unit stay of patients and controls was 35.3 and 36.6 days, respectively (p = nonsignificant). CONCLUSION: In intubated patients, pneumonia by A. baumannii is not significantly associated with attributable mortality rate or an increased length of intensive care unit stay.     

Predictive value of N-terminal pro-brain natriuretic peptide in severe sepsis and septic shock

OBJECTIVE: The aim of this study was to evaluate the predictive value of N-terminal pro-brain natriuretic peptide (NT-proBNP) on mortality in a large, unselected patient population with severe sepsis and septic shock. DESIGN AND SETTING: Prospective observational cohort study about incidence and prognosis of sepsis in 24 intensive care units in Finland (the FINNSEPSIS study). PATIENTS: A total of 254 patients with severe sepsis or septic shock. MEASUREMENTS: After informed consent, the blood tests for NT-proBNP analyses were drawn on the day of admission and 72 hrs thereafter. Patients' demographic data were collected, and intensive care unit and hospital mortality and basic hemodynamic and laboratory data were recorded daily. MAIN RESULTS: NT-proBNP levels at admission were significantly higher in hospital nonsurvivors (median, 7908 pg/mL) compared with survivors (median, 3479 pg/mL; p = .002), and the difference remained after 72 hrs (p = .002). The receiver operating characteristic curves of admission and 72-hr NT-proBNP levels for hospital mortality resulted in area under the curve values of 0.631 (95% confidence interval, 0.549-0.712; p = .002) and 0.648 (95% confidence interval, 0.554-0.741; p = .002), respectively. In logistic regression analyses, NT-proBNP values at 72 hrs after inclusion and Simplified Acute Physiology Score for the first 24 hrs were independent predictors of hospital mortality. Pulmonary artery occlusion pressure (p < .001), plasma creatinine clearance (p = .001), platelet count (p = .03), and positive blood culture (p = .04) had an independent effect on first-day NT-proBNP values, whereas after 72 hrs, only plasma creatinine clearance (p < .001) was significant in linear regression analysis. CONCLUSION: NT-proBNP values are frequently increased in severe sepsis and septic shock. Values are significantly higher in nonsurvivors than survivors. NT-proBNP on day 3 in the intensive care unit is an independent prognostic marker of mortality in severe sepsis.     

Operational performance of validated physiologic scoring systems for predicting in-hospital mortality among critically ill emergency department patients

OBJECTIVES: New Simplified Acute Physiology Score (SAPS) II, Morbidity Probability Model at admission (MPM0 II), and Logistic Organ Dysfunction System (LODS) have all demonstrated high accuracy for predicting mortality in intensive care unit populations. We tested the prognostic accuracy of these instruments for predicting mortality among a cohort of critically ill emergency department patients. DESIGN: Secondary analysis of a randomized controlled trial. SETTING: Urban, tertiary emergency department, census >100,000. PATIENTS: Nontrauma emergency department patients admitted to an intensive care unit, aged >17 yrs, with initial emergency department vital signs consistent with shock (systolic blood pressure <100 mm Hg or shock index >1.0), and with agreement of two independent observers for at least one sign and symptom of inadequate tissue perfusion. INTERVENTIONS: Emergency department variables needed for calculation of each scoring system were prospectively collected, and published formulas were used to calculate the probability of in-hospital death for each scoring system. The main outcome was actual in-hospital mortality. The area under the receiver operating characteristic curve was used to evaluate the predictive ability of each scoring system. MEASUREMENTS AND MAIN RESULTS: Ninety-one of 202 patients (45%) were included. The mean age was 56 +/- 16 yrs, 42% were female, the mean initial systolic blood pressure was 84 +/- 13 mm Hg, and the average length of stay in the emergency department was 4.2 +/- 2.0 hrs. The in-hospital mortality rate was 21%. The area under the receiver operating characteristic curve for calculated probability of in-hospital mortality for SAPS II was 0.72 (95% confidence interval, 0.57-0.87), for MPM0 II 0.69 (95% confidence interval, 0.54-0.84), and for LODS 0.60 (95% confidence interval, 0.45-0.76). CONCLUSIONS: Using variables available in the emergency department, three previously validated intensive care unit scoring systems demonstrated moderate accuracy for predicting in-hospital mortality.     

Effect of acute kidney injury on weaning from mechanical ventilation in critically ill patients

OBJECTIVES: Acute kidney injury (AKI) worsens outcome in various scenarios. We sought to investigate whether the occurrence of AKI has any effect on weaning from mechanical ventilation. DESIGN AND SETTING: Observational, retrospective study in a 23-bed medical/surgical intensive care unit (ICU) in a cancer hospital from January to December 2003. PATIENTS: The inclusion criterion was invasive mechanical ventilation for > or =48 hrs. AKI was defined as at least one measurement of serum creatinine of > or =1.5 mg/dL during the ICU stay. Patients were then separated into AKI and non-AKI patients (control group). The criterion for weaning was the combination of positive end-expiratory pressure of < or =8 cm H2O, pressure support of < or =10 cm H2O, and Fio2 of < or =0.4, with spontaneous breathing. The primary end point was duration of weaning and the secondary end points were rate of weaning failure, total length of mechanical ventilation, length of stay in the ICU, and ICU mortality. RESULTS: A total of 140 patients were studied: 93 with AKI and 47 controls. The groups were similar in regard to age, sex, and type of tumor. Diagnosis of acute lung injury/acute respiratory distress syndrome as cause of respiratory failure and Simplified Acute Physiology Score II at admission did not differ between groups. During ICU stay, AKI patients had markers of more severe disease: increased occurrence of severe sepsis or septic shock, higher number of antibiotics, and longer use of vasoactive drugs. The median (interquartile range) duration of mechanical ventilation (10 [6-17] vs. 7 [2-12] days, p = .017) and duration of weaning from mechanical ventilation (41 [16-97] vs. 21 [7-33.5] hrs, p = .018) were longer in AKI patients compared with control patients. Cox regression analysis demonstrated that a > or =85% increase in baseline serum creatinine (hazard rate, 2.30; 95% confidence interval, 1.30-4.08), oliguria (hazard rate, 2.51; 95% confidence interval, 1.24-5.08), and the number of antibiotics (hazard rate, 2.64; 95% confidence interval, 1.51-4.63) predicted longer duration of weaning. The length of ICU stay and ICU mortality rate were significantly greater in the AKI patients. After adjusting for Simplified Acute Physiology Score II, oliguria (odds ratio, 30.8; 95% confidence interval, 7.7-123.0) remained as a strong risk factor for mortality. CONCLUSION: This study shows that renal dysfunction has serious consequences in the duration of mechanical ventilation, weaning from mechanical ventilation, and mortality in critically ill cancer patients.     

Prognostic factors,clinical course,and hospital outcome of patients with chronic obstructive pulmonary disease admitted to an intensive care unit for acute respiratory failure

OBJECTIVE: To describe prognostic factors, clinical course, and hospital outcome of patients with chronic obstructive pulmonary disease admitted to an intensive care unit for acute respiratory failure. DESIGN: Analysis of prospectively collected data. SETTING: A multidisciplinary intensive care unit of an inner-city university hospital. PATIENTS: Patients with chronic obstructive pulmonary disease admitted to an intensive care unit for acute respiratory failure from August 1995 through July 1998. MEASUREMENTS AND MAIN RESULTS: Data were obtained concerning demographics, arterial blood gas, Acute Physiology and Chronic Health Evaluation (APACHE) II score, sepsis, mechanical ventilation, organ failure, complications, and hospital mortality rate. Fifty-nine percent of patients were male, 63% white, and 36% African-American; the mean age was 63.1 +/- 8.9 yrs. Noninvasive mechanical ventilation was tried in 40% of patients and was successful in 54% of them. Invasive mechanical ventilation was required in 61% of the 250 admissions. Sepsis developed in 31% of patients, nonpulmonary organ failure in 20%, pneumothorax in 3%, and acute respiratory distress syndrome in 2%. Multiple organ failure developed in 31% of patients with sepsis compared with 3% without sepsis (p <.0001). Predicted and observed hospital mortality rates were 30% and 15%, respectively. Differences in age and arterial carbon dioxide and oxygen tensions between survivors and nonsurvivors were not significant. Arterial pH was lower in nonsurvivors than in survivors (7.21 vs. 7.25, p =.0408). The APACHE II-predicted mortality rate (p =.0001; odds ratio, 1.046; 95% confidence interval, 1.022-1.070) and number of organ failures (p <.0001; odds ratio, 5.524; 95% confidence interval, 3.041-10.031) were independent predictors of hospital outcome; invasive mechanical ventilation was not an independent predictor. CONCLUSIONS: Physiologic abnormalities at admission to an intensive care unit and development of nonrespiratory organ failure are important predictors of hospital outcome for critically ill patients with chronic obstructive pulmonary disease who have acute respiratory failure. Improved outcome would require prevention and appropriate treatment of sepsis and multiple organ failure.     

Clinician predictions of intensive care unit mortality

OBJECTIVE: Predicting outcomes for critically ill patients is an important aspect of discussions with families in the intensive care unit. Our objective was to evaluate clinical intensive care unit survival predictions and their consequences for mechanically ventilated patients. DESIGN: Prospective cohort study. SETTING: Fifteen tertiary care centers. PATIENTS: Consecutive mechanically ventilated patients > or = 18 yrs of age with expected intensive care unit stay > or = 72 hrs. INTERVENTIONS: We recorded baseline characteristics at intensive care unit admission. Daily we measured multiple organ dysfunction score (MODS), use of advanced life support, patient preferences for life support, and intensivist and bedside intensive care unit nurse estimated probability of intensive care unit survival. MEASUREMENTS AND MAIN RESULTS: The 851 patients were aged 61.2 (+/- 17.6, mean + SD) yrs with an Acute Physiology and Chronic Health Evaluation (APACHE) II score of 21.7 (+/- 8.6). Three hundred and four patients (35.7%) died in the intensive care unit, and 341 (40.1%) were assessed by a physician at least once to have a < 10% intensive care unit survival probability. Independent predictors of intensive care unit mortality were baseline APACHE II score (hazard ratio, 1.16; 95% confidence interval, 1.08-1.24, for a 5-point increase) and daily factors such as MODS (hazard ratio, 2.50; 95% confidence interval, 2.06-3.04, for a 5-point increase), use of inotropes or vasopressors (hazard ratio, 2.14; 95% confidence interval, 1.66-2.77), dialysis (hazard ratio, 0.51; 95% confidence interval, 0.35-0.75), patient preference to limit life support (hazard ratio, 10.22; 95% confidence interval, 7.38-14.16), and physician but not nurse prediction of < 10% survival. The impact of physician estimates of < 10% intensive care unit survival was greater for patients without vs. those with preferences to limit life support (p < .001) and for patients with less vs. more severe organ dysfunction (p < .001). Mechanical ventilation, inotropes or vasopressors, and dialysis were withdrawn more often when physicians predicted < 10% probability of intensive care unit survival (all ps < .001). CONCLUSIONS: Physician estimates of intensive care unit survival < 10% are associated with subsequent life support limitation and more powerfully predict intensive care unit mortality than illness severity, evolving or resolving organ dysfunction, and use of inotropes or vasopressors.     

Study of clinical course of organ dysfunction in intensive care

OBJECTIVE: Multiple organ dysfunction is a common cause of death in intensive care units. We describe the daily course of multiple organ dysfunction measured by the Sequential Organ Failure Assessment score in a population-based cohort of critically ill patients. DESIGN: Prospective cohort study. SETTING: Adult multisystem intensive care units in the Calgary Health Region. PATIENTS: A total of 1,436 patients admitted from May 1, 2000 to April 30, 2001. MEASUREMENTS: Temporal change in Sequential Organ Failure Assessment score. INTERVENTIONS: None; observational study. MAIN RESULTS: The mean age was 58 yrs (range, 14-100). The mean +/- sd intensive care unit admission Acute Physiology and Chronic Health Evaluation II score was 25 +/- 9. The median intensive care unit length of stay was 4 days (interquartile range, 2-8), and the median hospital length of stay was 15 days (interquartile range, 7-32). A total of 20.5% of patients were infected at admission, and 26.0% were immediately postoperative. Intensive care unit mortality was 27.0%, and hospital mortality was 35.1%. The daily Sequential Organ Failure Assessment score was significantly higher in nonsurvivors than survivors. A population-averaged model determined a mean rate of change of Sequential Organ Failure Assessment score to be -0.29 per day (95% confidence interval, -0.32 to -0.25) for survivors and -0.03 per day (95% confidence interval, -0.08 to 0.03) for nonsurvivors (overall regression, p <.0001). Patients with infection had higher admission Sequential Organ Failure Assessment scores compared with patients without infection (difference, 1.8; p <.001), but a similar rate of daily change. CONCLUSIONS: Multiple organ dysfunction, does not follow a course of progressive and sequential failure. Evidence of differential daily change should further inform the use of organ failure scores as surrogate outcomes in clinical trials.     

Pneumonia caused by oxacillin-resistant Staphylococcus aureus treated with glycopeptides

OBJECTIVE: To determine whether ventilator-associated pneumonia caused by oxacillin-resistant Staphylococcus aureus (VAP-ORSA) treated with glycopeptides is associated with an increased mortality rate. DESIGN: Retrospective matched cohort study. SETTING: Four intensive care units in teaching hospitals. PATIENTS: Seventy-five patients were matched to 75 controls. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: All adult intensive care unit patients with microbiologically documented VAP-ORSA were matched to intubated controls who did not develop VAP-ORSA, based on disease severity (Acute Physiology and Chronic Health Evaluation II score) at admission (+/-3 points), diagnostic category, and length of stay before pneumonia onset. Population characteristics and intensive care unit mortality rates of patients with VAP-ORSA and their controls without pneumonia were compared. Attributable mortality was determined by subtracting the crude mortality rate of controls from the crude mortality rate of VAP-ORSA patients. Thirty-six of the 75 matched VAP-ORSA patients died, representing a crude mortality rate of 48%, whereas 19 of the 75 controls died, a crude mortality rate of 25.3% (p < .01). Excess mortality was estimated to be 22.7% (95% confidence interval, 2.4-42.9%). Median length of intensive care unit stay in the surviving pairs was 33 days (interquartile range, 25-75%: 25-45 days) for VAP-ORSA patients and 21 days (interquartile range, 25-75%: 15-34.75 days) days for controls (p = .054). CONCLUSIONS: Despite appropriate glycopeptide therapy, there is an increased attributable mortality for pneumonia by ORSA, after careful adjustment for disease severity and diagnostic category.