Respiratory Variability of Pulmonary Velocity-Time Integral As a New Gauge of Fluid Responsiveness For Mechanically Ventilated Patients in the ICU.

OBJECTIVES: To evaluate reliability and feasibility of the respiratory variability of pulmonary velocity-time integral as a new dynamic marker of fluid responsiveness in mechanically ventilated patients. DESIGN: Prospective observational study. SETTING: Medical-surgical ICU of a general hospital. PATIENTS: Fifty mechanically ventilated patients with acute circulatory failure. INTERVENTIONS: Transthoracic echocardiography was performed at inclusion (transthoracic echocardiography baseline). Fluid therapy was prescribed to patients exhibiting one value greater than or equal to 13% among commonly used variables of fluid responsiveness: respiratory variability of aortic velocity-time integral, respiratory variability of inferior vena cava diameter, or pulse pressure variation. MEASUREMENTS AND MAIN RESULTS: Respiratory variability of pulmonary velocity-time integral was assessed at baseline. Respiratory variability of pulmonary velocity-time integral was significantly greater in patients who received fluid therapy (26.9 ± 12.5% vs 6.2 ± 4.3%; p < 0.0001). Respiratory variability of pulmonary velocity-time integral was correlated with respiratory variability of aortic velocity-time integral (r = 0.75; p < 0.0001), respiratory variability of inferior vena cava diameter (r = 0.42; p < 0.01), and pulse pressure variation (r = 0.87; p < 0.0001) at baseline and with the relative increase in cardiac output after fluid therapy (r = 0.44; p = 0.019). Fluid responsiveness was defined as a 10% increase in cardiac output after fluid therapy, assessed by a second transthoracic echocardiography. Respiratory variability of pulmonary velocity-time integral was associated with fluid responsiveness (adjusted odds ratio, 1.58; 95% CI, 1.08-2.32; p = 0.002). Area under the receiver operating characteristics curve was 0.972, and a value of respiratory variability of pulmonary velocity-time integral greater than or equal to 14% yielded a sensitivity of 92% and specificity of 87% to predict fluid responsiveness. Interobserver reproducibility was excellent (intraclass correlation coefficient = 0.94). CONCLUSIONS: Respiratory variability of pulmonary velocity-time integral is a simple and reliable marker of fluid responsiveness for ventilated patients in ICU.

Body mass index. An additional prognostic factor in ICU patients.

OBJECTIVE: To examine the association between body mass index (BMI) and mortality in adult intensive care unit (ICU) patients. DESIGN. A prospective multi-center study. INTERVENTIONS: None. METHODS: A cohort study (yielding the OUTCOMEREA database) was conducted over 2 years in 6 medical-surgical ICUs. In each participating ICU, the following were collected daily: demographic information, admission height and weight, comorbidities, severity scores (SAPS II, LOD, and SOFA), ICU and hospital lengths of stay, and ICU and hospital mortality rates. RESULTS: A total of 1,698 patients were examined and divided into 4 groups based on BMI: <18.5, 18.5-24.9, 25-29.9, and >30 kg/m(2). These groups differed significantly for age, gender, admission category (medical, scheduled surgery, unscheduled surgery), ICU and hospital lengths of stay, and comorbidities. Severity at admission and within the first 2 days was similar in the 4 groups, except for the SOFA score. Overall hospital mortality was 31.3% (532 out of 1,698 patients). By multivariate analysis, a BMI below 18.5 kg/m(2) was independently associated with increased mortality (odds ratio 1.63; 95% confidence intervals 1.11-2.39). None of the other BMI categories were associated with higher mortality and even a BMI>30 kg/m(2) was protective of mortality (odds ratio 0.60, 95% confidence intervals 0.40-0.88). CONCLUSIONS: A low BMI was independently associated with higher mortality and a high BMI with lower mortality in this large cohort of critically ill patients. Since BMI is absent from currently available scoring systems, further studies are needed to determine whether adding BMI would improve the effectiveness of scores in predicting mortality.