Quantitative assessment of pleural effusion in critically ill patients by means of ultrasonography.

OBJECTIVE: To assess the ability of ultrasonography to identify the presence and assess the volume of pleural effusion in the intensive care unit setting. DESIGN: Prospective descriptive clinical study. SETTING: Medical-surgical intensive care unit of a teaching hospital. PATIENTS: Initial study group (group I) consisted of 97 patients (mean [+/-SD] Simplified Acute Physiology Score II, 40 +/- 14) with clinically suspected pleural effusion. Fifty-one patients were mechanically ventilated and 55 patients underwent a unilateral or bilateral thoracentesis (58 procedures). All patients underwent supine chest radiography and pleural ultrasonography at bedside. The testing group (group II) consisted of 19 additional patients (17 under ventilation) who underwent thoracentesis. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Maximal interpleural distance was measured at the base and apex of the pleural space, at both end-expiration and end-inspiration. In group I, interpleural distances were compared to actual volume of fluid in the subset of patients who underwent a complete thoracentesis (n = 49). Prediction of the volume of pleural effusion was subsequently tested prospectively in group II (25 complete thoracenteses). Portable chest radiography and pleural ultrasonography yielded discordant results for 47 patients (48%) in the diagnosis of pleural effusion. The expiratory interpleural distance measured at the thoracic base with ultrasonography was significantly correlated with the volume of fluid (p < .0001; coefficient of determination: right, 0.78; left, 0.51). A pleural effusion > or =800 mL was predicted when this distance was >45 mm (right) or >50 mm (left), with a sensitivity of 94% and 100% and a specificity of 76% and 67%, respectively. In group II, the mean bias between the predicted and observed volumes of pleural effusion determined by thoracentesis was 24 +/- 355 mL, and this decreased to 28 +/- 146 mL for the prediction of pleural effusion <1400 mL. CONCLUSIONS: Bedside ultrasonography is well suited for the quantitative assessment of unloculated pleural effusions in intensive care unit patients.

Diagnostic ability of hand-held echocardiography in ventilated critically ill patients.

STUDY OBJECTIVES: To compare the diagnostic capability of recently available hand-held echocardiography (HHE) and of conventional transthoracic echocardiography (TTE) used as a gold standard in critically ill patients under mechanical ventilation. DESIGN: A prospective and descriptive study. SETTING: The general intensive care unit of a teaching hospital. PATIENTS: All mechanically ventilated patients requiring a TTE study with a full-feature echocardiographic platform (Sonos 5500; Philips Medical Systems, Andover, MA, USA) also underwent an echocardiographic examination using a small battery-operated device (33 x 23 cm2, 3.5 kg) (Optigo; Philips Medical Systems). INTERVENTIONS: Each examination was performed independently by two intensivists experienced in echocardiography and was interpreted online. For each patient, the TTE videotape was reviewed by a cardiologist experienced in echocardiography and the final interpretation was used as a reference diagnosis. RESULTS: During the study period, 106 TTE procedures were performed in 103 consecutive patients (age, 59 +/- 18 years; Simplified Acute Physiology Score, 46 +/- 14; body mass index, 26 +/- 9 kg/m2; positive end-expiratory pressure, 8 +/- 4 cmH2O). The number of acoustic windows was comparable using HHE and TTE (233/318 versus 238/318, P = 0.72). HHE had a lower overall diagnostic capacity than TTE (199/251 versus 223/251 clinical questions solved, P = 0.005), mainly due to its lack of spectral Doppler capability. In contrast, diagnostic capacity based on two-dimensional imaging was comparable for both approaches (129/155 versus 135/155 clinical questions solved, P = 0.4). In addition, HHE and TTE had a similar therapeutic impact in 45 and 47 patients, respectively (44% versus 46%, P = 0.9). CONCLUSIONS: HHE appears to have a narrower diagnostic field when compared with conventional TTE, but promises to accurately identify diagnoses based on two-dimensional imaging in ventilated critically ill patients.