PURPOSE: The clinical use of miniaturized echocardiograph devices is expanding due to the potential to rapidly assess cardiac function in the critically ill patient. The pocket echocardiograph (PE) increases portability and can be carried inside a lab coat pocket. Current studies of this device are limited, and have not examined its use in an intubated patient. We hypothesize that a novice echocardiographer can use PE to acquire interpretable cardiac images, and provide an accurate tool for estimating ejection fraction.
METHODS: Unselected subjects (n=22) scheduled for cardiac surgery underwent blinded transesophageal echocardiography (TEE) and PE (Acuson P10, Siemens) during a hemodynamically stable period after endotracheal intubation immediately prior to incision. A single cardiology fellow with two months of dedicated echocardiography training acquired all PE images. The fellow and an experienced echocardiographer both interpreted PE studies offline in a blinded fashion, visually estimating ejection fraction. All image windows were graded as technically adequate, limited, or inadequate by the expert echocardiographer. Comparisons were made to the TEE study.
RESULTS: Subjects were 81% male; age 69±9 years, and had a mean ejection fraction of 51% ±10.0%. At least one PE imaging plane was interpretable in 95% of patients, with the majority (64%) of studies having overall adequate images. Parasternal images were adequate in the vast majority of patients (77%), limited in 14%, and unacceptable in 9%, while apical (41%, 45%, 14%) and subcostal (36%, 32%, 32%) image quality was noticeably inferior. Ejection fraction showed fair correlation, bias, and limits of agreement for the fellow’ s interpretation (r=0.50, 4.9%, ±20.7%), with stronger association for the experienced echocardiographer (r=0.76, 3.3%, ±16.6%).
CONCLUSION: A novice echocardiographer using PE can acquire interpretable images in the majority of intubated patients. When parasternal imaging is inadequate to assess ejection fraction, other imaging planes are usually obtainable. Novice and expert echocardiographers can reasonably estimate ejection fraction using PE.
CLINICAL IMPLICATIONS: PE may allow novice echocardiographers to rapidly assess cardiac function at the bedside in intubated patients in the perioperative and critical care settings.
DISCLOSURE: Benjamin Culp, No Financial Disclosure Information; No Product/Research Disclosure Information