The blurring of specialty domains is becoming more obvious. A good example of this is the use of ultrasound by intensivists. Portable ultrasound as an extension of the physical examination is a fast growing area of expertise. A recent Canadian report  summarized several new hand-carried ultrasound units for point of care (POC) cardiac examination, including OptiGo™ (Philips Medical Systems, Andover, MA, USA), which has a laptop design, colour Doppler and smartcard storage. In a prototype study conducted by Rugolotto and coworkers, the handheld device was compared with standard echocardiography in 121 patients. The studies were performed by echocardiographers with level II and III training. Parameters of ventricular and valvular function with two-dimensional and colour Doppler were graded on a point system using both devices. There were statistically significant differences between the two methods, although these were clinically minor in degree. The investigators concluded that the handheld device did represent an acceptable tool for conducting a focused assessment of a limited number of parameters of structure and function. OptiGo™ (Philips Medical Systems, Andover, MA, USA) hand-carried ultrasound unit.

However, conflicting results were reported from another study with the same prototype unit. Spencer and coworkers compared the diagnostic power of physical examination, POC echocardiography and standard echocardiography when performed by cardiologists. POC echocardiography was an improvement on physical examination but still missed 21% of major cardiovascular findings as compared with standard echocardiography. This emphasizes some of the difficulties in implementing new devices, among which are defining the limitations of use and ensuring standards in training.