title: The pocket echocardiograph: validation and feasibility.
abstract: BACKGROUND
  A new, miniaturized ultrasound device, the pocket echocardiograph (PE), is highly portable and can be carried inside a lab-coat pocket. Studies of this device are limited and have not examined the use by novice echocardiographers. We hypothesize that a novice echocardiographer can use PE to produce interpretable cardiac images, and that both novice and expert echocardiographers can use PE to accurately quantify ejection fraction.
  
  
  METHODS
  Unselected subjects (n = 40) in an echocardiography laboratory underwent blinded formal transthoracic echocardiography (TTE) and PE (Acuson P10, Siemens, Mountain View, CA, USA). A cardiology fellow with 2 months of echocardiography training acquired PE images. The fellow and an experienced echocardiographer interpreted the PE studies offline in a blinded fashion. To assess adequacy, studies were graded as technically adequate, limited, or inadequate. A visual estimation of ejection fraction was made. Comparisons were made to the formal reported TTE.
  
  
  RESULTS
  Subjects were heterogeneous, 43% male; age 64 ± 17 years, and ejection fraction 52.4%± 12.3%. All PE studies were interpretable, and the vast majority of PE and TTE images were considered technically adequate (77.5% and 85% respectively; P = 0.32). Ejection fraction showed a good correlation, bias, and limits of agreement for the fellow's interpretation (r = 0.78, -5.9%, ±16.6%) with stronger association for the experienced echocardiographer (r = 0.88, -0.8%, ±11.4%).
  
  
  CONCLUSIONS
  Novice echocardiographers using the PE can produce adequate quality images. Both expert and novice echocardiographers can use PE to quantify ejection fraction over a broad range of patients. The device's low cost and portability may greatly expand the availability of bedside echocardiography for routine or urgent cardiovascular assessment.
authors.affiliation: Department of Internal Medicine, The TexasA&M University System Health Science Center College of Medicine/Scott and White Hospital, Temple, TX, USA. bcculp@swmail.sw.org
authors.forename: Benjamin C
authors.initials: BC
authors.lastname: Culp
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Mock
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Chiles
authors.forename: William C
authors.initials: WC
authors.lastname: Culp
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004452:Echocardiography / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008904:Miniaturization; D013318:Stroke Volume; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*; D055815:Young Adult