Background. The potential of pocket-sized ultrasound devices (PUDs) to improve global healthcare delivery is limited by the lack of a suitable imaging protocol and trained users. Therefore, we investigated the feasibility of performing a brief, evidence-based cardiac limited ultrasound exam (CLUE) through wireless guidance of novice users. Methods. Three trainees applied PUDs on 27 subjects while directed by an off-site cardiologist to obtain a CLUE to screen for LV systolic dysfunction (LVSD), LA enlargement (LAE), ultrasound lung comets (ULC+), and elevated CVP (eCVP). Real-time remote audiovisual guidance and interpretation by the cardiologist were performed using the iPhone 4/iPod (FaceTime, Apple, Inc.) attached to the PUD and transmitted data wirelessly. Accuracy and technical quality of transmitted images were compared to on-site, gold-standard echo thresholds. Results. Novice versus sonographer imaging yielded technically adequate views in 122/135 (90%) versus 130/135 (96%) ( ). CLUE’s combined SN, SP, and ACC were 0.67, 0.96, and 0.90. Technical adequacy (%) and accuracy for each abnormality ( ) were LVSD (85%, 0.93, ), LAE (89%, 0.74, ), ULC+ (100%, 0.94, ), and eCVP (78%, 0.91, ). Conclusion. A novice can perform the CLUE using PUD when wirelessly guided by an expert. This method could facilitate PUD use for off-site bedside medical decision making and triaging of patients. 1. Background Although pocket-sized ultrasound devices (PUDs) can augment the physical exam, their potential to improve global healthcare delivery in the emergent setting or in areas of limited resources has been limited by the lack of a suitable imaging protocol and trained users [1]. We have previously shown that an evidence-based, 5-minute “quick-look” cardiac limited ultrasound exam (CLUE) has diagnostic and prognostic value [2], affects medical decision making [3], and can be taught to internal medicine residents [4]. Unlike the traditional bedside cardiac examination, CLUE has the potential for wireless transmission. Recent reports have shown the feasibility of remotely mentored ultrasound examination to evaluate apnea and pneumothorax in trauma [5] and in off-line remote expert echo interpretation using a smartphone-based application [6]. We investigated the feasibility of utilizing low-cost, readily available wireless video conferencing software to guide novice users in performing CLUE in real time. 2. Methods The CLUE examined 4 targets using 4 previously-validated, nonquantitative ultrasound “signs” [2]. In brief, the parasternal long axis view was assessed for
References
[1]
S. Singh, M. Bansal, P. Maheshwari, et al., “American society of echocardiography: remote echocardiography with web-based assessments for referrals at a distance (ASE-REWARD) study,” Journal of the American Society of Echocardiography, vol. 26, no. 3, pp. 221–233, 2013.
[2]
B. J. Kimura, N. Yogo, C. W. O'Connell, J. N. Phan, B. K. Showalter, and T. Wolfson, “Cardiopulmonary limited ultrasound examination for “quick-look” bedside application,” American Journal of Cardiology, vol. 108, no. 4, pp. 586–590, 2011.
[3]
B. J. Kimura, D. J. Shaw, D. L. Agan, S. A. Amundson, A. C. Ping, and A. N. DeMaria, “Value of a cardiovascular limited ultrasound examination using a hand-carried device on clinical management in an outpatient medical clinic,” American Journal of Cardiology, vol. 100, no. 2, pp. 321–325, 2007.
[4]
B. J. Kimura, S. A. Amundson, J. N. Phan, D. L. Agan, and D. J. Shaw, “Observations during development of an internal medicine residency training program in cardiovascular limited ultrasound examination,” Journal of Hospital Medicine, vol. 7, no. 7, pp. 537–542, 2012.
[5]
P. B. McBeth, I. Crawford, M. Blaivas et al., “Simple, almost anywhere, with almost anyone: remote low-cost telementored resuscitative lung ultrasound,” Journal of Trauma, vol. 71, no. 6, pp. 1528–1535, 2011.
[6]
B. G. Choi, M. Mukherjee, P. Dala et al., “Interpretation of remotely downloaded pocket-size cardiac ultrasound images on a web-enabled smartphone: validation against workstation evaluation,” Journal of the American Society of Echocardiography, vol. 24, no. 12, pp. 1325–1330, 2011.
[7]
E. Picano, F. Frassi, E. Agricola, S. Gligorova, L. Gargani, and G. Mottola, “Ultrasound lung comets: a clinically useful sign of extravascular lung water,” Journal of the American Society of Echocardiography, vol. 19, no. 3, pp. 356–363, 2006.
[8]
R. M. Lang, M. Bierig, R. B. Devereux et al., “Recommendations for chamber quantification: a report from the American Society of Echocardiography's guidelines and standards committee and the Chamber Quantification Writing Group, developed in conjunction with the European Association of Echocardiography, a branch of the European Society of Cardiology,” Journal of the American Society of Echocardiography, vol. 18, no. 12, pp. 1440–1463, 2005.
[9]
A. Chockalingam, A. Mehra, S. Dorairajan, and K. C. Dellsperger, “Acute left ventricular dysfunction in the critically ill,” Chest, vol. 138, no. 1, pp. 198–207, 2010.
[10]
B. J. Kimura, E. Kedar, D. E. Weiss, C. L. Wahlstrom, and D. L. Agan, “A bedside ultrasound sign of cardiac disease: the left atrium-to-aorta diastolic diameter ratio,” American Journal of Emergency Medicine, vol. 28, no. 2, pp. 203–207, 2010.
[11]
D. Lichtenstein, G. Mézière, P. Biderman, A. Gepner, and O. Barré, “The comet-tail artifact: an ultrasound sign of alveolar-interstitial syndrome,” American Journal of Respiratory and Critical Care Medicine, vol. 156, no. 5, pp. 1640–1646, 1997.
