Diagnostic utility of B-type natriuretic peptide in critically ill patients with pulmonary edema: a prospective cohort study.

INTRODUCTION: Distinguishing pulmonary edema due to acute lung injury (ALI) or the acute respiratory distress syndrome (ARDS) from hydrostatic or cardiogenic edema is challenging in critically ill patients. B-type natriuretic peptide (BNP) can effectively identify congestive heart failure in the emergency room setting but, despite increasing use, its diagnostic utility has not been validated in the intensive care unit (ICU). METHODS: We performed a prospective, blinded cohort study in the medical and surgical ICUs at the University of Chicago Hospitals. Patients were eligible if they were admitted to the ICU with respiratory distress, bilateral pulmonary edema and a central venous catheter suggesting either high-pressure (cardiogenic) or low-pressure (ALI/ARDS) pulmonary edema. BNP levels were measured within 48 hours of ICU admission and development of pulmonary edema and onward up to three consecutive days. All levels were drawn simultaneously with the measurement of right atrial or pulmonary artery wedge pressure. The etiology of pulmonary edema--cardiogenic or ALI/ARDS--was determined by three intensivists blinded to BNP levels. RESULTS: We enrolled a total of 54 patients (33 with ALI/ARDS and 21 with cardiogenic edema). BNP levels were lower in patients with ALI/ARDS than in those with cardiogenic edema (496 +/- 439 versus 747 +/- 476 pg/ml, P = 0.05). At an accepted cutoff of 100 pg/ml, specificity for the diagnosis of ALI/ARDS was high (95.2%) but sensitivity was poor (27.3%). Cutoffs at higher BNP levels improved sensitivity at considerable cost to specificity. Invasive measures of filling pressures correlated poorly with initial BNP levels and subsequent day BNP values fluctuated unpredictably and without correlation with hemodynamic changes and net fluid balance. CONCLUSION: BNP levels drawn within 48 hours of admission to the ICU do not reliably distinguish ALI/ARDS from cardiogenic edema, do not correlate with invasive hemodynamic measurements, and do not track predictably with changes in volume status on consecutive daily measurements.

Usefulness of the external jugular vein examination in detecting abnormal central venous pressure in critically ill patients.

BACKGROUND: Central venous pressure (CVP) provides important information for the management of critically ill patients. The external jugular vein (EJV) is easier to visualize than the internal jugular vein and may give a reliable estimate of CVP. METHODS: To determine the usefulness of the EJV examination in detecting abnormal CVP values, we performed a prospective blinded evaluation comparing it with CVP measured using an indwelling catheter in critically ill patients with central venous catheters. Blinded EJV examinations were performed by clinicians with 3 experience levels (attending physicians, residents and fellows, and interns and fourth-year medical students) to estimate CVP (categorized as low [/=10 cm of water]). The usefulness of the EJV examination in discriminating low vs high CVP was measured using receiver operating characteristic curve analysis. RESULTS: One hundred eighteen observations were recorded among 35 patients. The range of CVP values was 2 to 20 cm of water. The EJV was easier to visualize than the internal jugular vein (mean visual analog scale score, 8 vs 5; P<.001). The reliability for determining low and high CVP was excellent, with areas under the curve of 0.95 (95% confidence interval [CI], 0.88-1.00) and 0.97 (95% CI, 0.92-1.00), respectively, for attending physicians and 0.86 (95% CI, 0.78-0.95) and 0.90 (95% CI, 0.84-0.96), respectively, for all examiners. CONCLUSION: The EJV examination correlates well with catheter-measured CVP and is a reliable means of identifying low and high CVP values.

Acute Liver Failure Due to Budd-Chiari Syndrome in the Setting of Cardiac Synovial Sarcoma.

Primary malignant tumors of the heart, specifically cardiac sarcomas, are rare and mainly diagnosed at autopsy. Acute Budd-Chiari syndrome is a recognized cause of acute liver failure and has been associated with several rare cardiac tumors: atrial myxoma, caval rhabdomyosarcoma, and primary cardiac adenocarcinoma. We present the first case of a fatal, highly differentiated cardiac synovial sarcoma that presented as acute liver failure from Budd-Chiari syndrome.

Clinical outcomes associated with high, intermediate, and low rates of failed extubation in an intensive care unit.

PURPOSE: Extubation failure is associated with adverse outcomes in mechanically ventilated patients, and it is believed that high rates of failed planned extubation (FPE) should be avoided. However, many believe that very low rates may also correlate with adverse outcomes if resulting from overly conservative weaning practices. We examined the relationship between the percentage of FPE (%FPE) and associated outcomes, with the aim of elucidating a favorable middle range. METHODS: A total of 1395 extubations were analyzed in mechanically ventilated subjects. Monthly %FPE values were separated into tertiles. Ventilator-free days (VFDs), intensive care unit-free days (IFDs), and mortality were compared among tertiles. RESULTS: Monthly %FPE tertiles were as follows: low, less than 7%; intermediate, 7% to 15%; and high, greater than 15%. There were significant differences in VFDs and IFDs by tertile from low to high (VFDs: low, 11.8; intermediate, 12.1; high, 9.9 [P = .003]; IFDs: low, 10.5; intermediate, 10.7; high, 9.0 [P = .033]). Post hoc comparisons demonstrated significant differences between the middle and high tertiles for both VFDs and IFDs. CONCLUSIONS: Although exact rates may vary depending on setting, this suggests that a high %FPE (>15) should be avoided in the intensive care unit and that there may be an intermediate range where ventilator outcomes are optimized.

Daily sedative interruption in mechanically ventilated patients at risk for coronary artery disease.

OBJECTIVES: To determine the prevalence of myocardial ischemia in mechanically ventilated patients with coronary risk factors and compare periods of sedative interruption vs. sedative infusion. DESIGN: Prospective, blinded observational study. SETTING: Medical intensive care unit of tertiary care medical center. PATIENTS: Intubated, mechanically ventilated patients with established coronary artery disease risk factors. INTERVENTIONS: Continuous three-lead Holter monitors with ST-segment analysis by a blinded cardiologist were used to detect myocardial ischemia. Ischemia was defined as ST-segment elevation or depression of >0.1 mV from baseline. MEASUREMENTS AND MAIN RESULTS: Comparisons between periods of awakening from sedation vs. sedative infusion were made. Vital signs, catecholamine levels, and time with ischemia detected by Holter monitor during the two periods were compared. Heart rate, mean arterial pressure, rate-pressure product, respiratory rate, and catecholamine levels were all significantly higher during sedative interruption. Eighteen of 74 patients (24%) demonstrated ischemic changes. Patients with myocardial ischemia had a longer intensive care unit length of stay (17.4+/-17.5 vs. 9.6+/-6.7 days, p=.04). Despite changes in vital signs and catecholamine levels during sedative interruption, fraction of ischemic time did not differ between the time awake vs. time sedated [median [interquartile range] of 0% [0, 0] compared with 0% [0, 0] while they were sedated [p=.17]). The finding of similar fractions of ischemic time between awake and sedated states persisted with analysis of the subgroup of 18 patients with ischemia. CONCLUSIONS: Myocardial ischemia is common in critically ill mechanically ventilated patients with coronary artery disease risk factors. Daily sedative interruption is not associated with an increased occurrence of myocardial ischemia in these patients.

The relationship between sedative infusion requirements and permissive hypercapnia in critically ill, mechanically ventilated patients.

OBJECTIVE: Permissive hypercapnia (PH) may result from mechanical ventilation (MV) strategies that intentionally reduce minute ventilation. Sedative doses required to tolerate PH have not been well characterized. With increased attention to lung-protective ventilation, characterization of sedative requirements with PH and determination of sedative dose changes with PH are needed. DESIGN: Retrospective analysis. SETTING: Tertiary care university hospital. PATIENTS: We evaluated 124 patients randomized in a previous study to either propofol or midazolam. PH was employed in ten of 60 patients receiving propofol and 13 of 64 patients receiving midazolam. INTERVENTIONS: We analyzed dosing of propofol and midazolam in patients undergoing PH through a retrospective analysis of an existing database on MV patients. Total sedative (propofol and midazolam) dose was recorded for the first three days of MV. Linear regression analysis (dependent variable: sedative dose) was used to analyze the following independent variables: PH, age, gender, daily sedative interruption, type of respiratory failure, presence of hepatic and/or renal failure, Acute Physiology and Chronic Health Evaluation II score, morphine dose, and Ramsay sedation score. MEASUREMENTS AND MAIN RESULTS: Propofol dose was higher in PH patients (42.5+/-16.2 vs. 27.0+/-15.3; p=.02); Midazolam dose did not differ between PH and non-PH patients (0.05 [0.04, 0.14] vs. 0.05 [0.03, 0.07]; p=.17). By univariate linear regression analysis, propofol dose was significantly dependent on PH, age, type of respiratory failure, morphine dose, and Ramsay score, with PH (regression coefficient, 11.7; 95% confidence interval, 1.2-22.7; p=.03) and age (regression coefficient, -0.3; 95% confidence interval -0.5 to -0.08; p=.005) remaining significant by multivariate linear regression. By univariate linear regression analysis, midazolam dose was dependent on age, morphine dose, and Ramsay score, but not PH; only morphine dose (regression coefficient, 0.44; 95% confidence interval, 0.22-0.67 for a 0.1-unit increase in morphine dose; p<.001) was significant by multivariate linear regression. CONCLUSIONS: We conclude that higher doses of propofol but not midazolam are required to sedate patients managed with PH.