Background: Focused rapid echocardiographic evaluation (FREE) is a comprehensive transthoracic echocardiogram tailored for the intensive care unit. It assesses both the cardiac index (CI) and left ventricular ejection fraction (EF). FREE and vascular catheter-derived CI was compared, and the ability of CI to detect moderate to severe dysfunction (EF <40%) was determined.
Methods: FREE quality assurance database was reviewed to identify patients who had a hemodynamic catheter.
Results: Of 507 FREEs, 115 patients were identified, 25 pulmonary artery catheters (PACs) and 90 FloTrac Vigileo (FT/V) arterial catheters. There were 27 patients with an EF <40%. In 86%, the CI was determined by FREE, and it changed care in 59%. The CI correlation for FREE versus PAC was r = 0.88 and versus FT/V was r = 0.63 (p < 0.05). The PAC-FREE bias was -0.07 (95% confidence interval -0.89 to 0.74) and the FT/V-FREE bias was -0.13 (95% confidence interval -1.4 to 1.1). FREE-PAC categorized patients the same way 87% and FREE-FT/V 76%; in patients with EF <40%, this changed to 90% and 63%, respectively. Using a threshold value (CI ≤ 2.5), the PAC detected dysfunction in 62.5% and the F/VT in 6%, p < 0.05.
Conclusions: There was excellent agreement between FREE and PAC but less with FT/V, especially in patients with and EF <40%. FREE can be used to validate catheter-derived data and provide important additional information. Further studies are needed to determine its impact on patient outcome.
Level of evidence: III, diagnostic study.