Therefore, it can be questioned if cIVC diameter can effectively predict fluid responsiveness in spontaneously breathing patients and if there are limitations to this technique.Therefore, the present study was aimed at assessing the EPZ-5676 msds usefulness of cIVC recorded by transthoracic echocardiography (TTE) to predict fluid responsiveness in spontaneously breathing critically ill patients with acute circulatory failure.Materials and methodsPatientsThis observational study was approved by our local institutional review board (N?mes University hospital review board, reference number 110702). It was stated that informed consent was not necessary; nevertheless, the patients or their relatives were orally informed, in accordance with French legislation.

The study was conducted in a 16-bed ICU of a university hospital within a 24-month period (April 2009 to April 2011). Forty patients with ACF were prospectively included within the study period. ACF was defined as mean arterial pressure (MAP) < 65 mmHg, urine output < 0.5 mL/Kg/h, tachycardia, mottled skin and/or biological signs of hypoperfusion (arterial blood lactate > 2 mmol/L). We excluded patients in whom fluid challenge would be deleterious: those with clinical evidence of pulmonary edema, echocardiographic evidence of right ventricular (RV) failure (right telediastolic ventricle area to left telediastolic ventricle area ratio > 1) [25] or echocardiographic evidence of elevated left atrial pressure (mitral inflow early (E) wave to atrial (A) wave ratio > 2) [26-28]. The decision was based on the opinion of the senior physician in charge of the ICU.

MeasurementsFor each patient, the following data were recorded: diagnosis, age (years), weight (Kg), height (cm), Acute Physiology and Chronic Health Evaluation (APACHE)-II score at admission, MAP (mmHg), heart rate (HR, bpm) and CVP (mmHg) when available.Echocardiographic measurements were performed by four trained (level 3 [29]) operators (LM, XB, MT, GL), for whom the intra- and interobserver variability for the velocity time index (VTI) = 4 and 5%, respectively [16]), using a Vivid S6 machine, General Electrics (GE Healthcare, Chalfont St Giles, UK).IVC was observed by a subcostal long axis view. In order to differentiate the aorta and IVC, the junction between the IVC and the right atrium was systematically assessed.

A pulse wave Doppler of the IVC was also recorded in order to verify the presence of a typical venous flow spectrum. A time-motion record of the IVC diameter Drug_discovery was generated by M-mode imaging at 2 to 3 cm from the right atrium [18,30]. Maximum and minimum IVC diameters (Dmax and Dmin, respectively) were measured over a single ventilatory cycle. The IVC collapsibility index (cIVC) was used as the primary endpoint [31]. This method was previously validated in spontaneously breathing patients undergoing renal replacement therapy [24].