The iPhone may be the latest “it” gadget, but a flurry of recent innovation has given portable ultrasound devices a healthy buzz within the biomedical community.
Beyond the gee-whiz factor, though, a growing number of studies demonstrate the everyday value of putting portable units in the hands of hospitalists.
“The big news has been the tiny portable scanner,” says Stephen Smith, a biomedical engineer at Duke University, in North Carolina, and a pioneer in ultrasound technology. Siemens recently introduced a hand-held device called the Acuson P10, which weighs 1.6 pounds, retails for $9,499 and can fit within a hospitalist’s coat pocket. Not to be outdone, GE has announced plans to introduce an ultrasound unit no bigger than an iPod.
Smith and his collaborators have taken the technology one step farther. They incorporate electrocardial leads on the unit’s transducer face to permit electrocardiograms and a microphone to let hospitalists use the ultrasound like a stethoscope.
Eric Isaacs, MD, a clinical professor of medicine at San Francisco General Hospital, says he routinely uses ultrasound for vascular access “to ensure the safety of procedures that we previously performed either blind or by anatomical landmarks.” Beyond improving the accuracy of placing central and peripheral lines, he says, “the reason we are using ultrasound more now is that the machine is so portable. The radiologists are no longer in the hospital 24 hours a day, and so by necessity we are using the tools that were previously only accessible from 9 to 5.”
Range of Uses
Among the reports recognizing ultrasound’s value, he cited a 2003 study in the British Medical Journal affirming the technology’s superiority to relying on physical landmarks in gaining central venous access, resulting in a lower technical failure rate, reduced complications, and faster access.1 Dr. Issacs says ultrasound also has helped guide procedures such as thorancentesis and paracentesis, other applications once confined to radiology. “It’s something that’s allowing me to do at the bedside what I would otherwise have to wait several hours for,” he says.
For heart patients, he says, a hospitalist can bring ultrasound to the bedside during a cardiac arrest to inspect cardiac motion and fluid, and monitor the patient’s hydration status by examining the size of the inferior vena cava. Internists likewise could examine the size of a patient’s aorta to look for signs of an aneurism, especially for a patient experiencing abdominal pain in the middle of the night. “Quite frankly, it seems like the only limit to ultrasound use is imagination,” Dr. Isaacs says.
Robert Rodriguez, MD, a clinical professor of medicine and emergency medicine at San Francisco General Hospital, says he uses ultrasound on 25% of the patients he sees on an in-patient basis. His biggest use, he says, is for placing central lines—though that could soon change.
“I work with a population that has a very high percentage of injection drug abuse, in whom it’s very difficult to find even a peripheral vein,” he says. At least once a day, he uses ultrasound to locate the brachial vein for such peripheral lines, circumventing the need for a central line through the subclavian vein and the risk of a pneumothorax. “In the past, we would have to put in a central line for just about anything,” he says. “And now we can put in a peripheral line that saves them the risk.”
Another benefit, he says, is in breeding better patient interactions—for example, with gallstones. “You can say to the patient: ‘This is the gallbladder, these are the stones in the gallbladder, this is what’s causing the pain,’” he says. “I think patients appreciate being able to see that firsthand. I think they also appreciate that it’s going to lessen their likelihood of having a complication.”