Coping with our girth – and our disease

The medical community is struggling to respond to and accommodate the special needs of a population that keeps getting bigger.

As the obesity epidemic intensifies in the United States, the medical community is learning new ways to accommodate patients who require an expanding range of medical services due to comorbidities associated with overweight.

Data from the Centers for Disease Control indicate that about two of three American adults are overweight or obese, the rates having doubled in a couple of decades. With more children and teenagers tipping the scales toward obesity, their life expectancies may be diminished as a result.

Changes to emergency vehicles

Caring for patients who are overweight or obese can be compromised by equipment designed for average weight patients that does not function well for larger patients. Ambulance companies have started building specially equipped vehicles to transport obese patients.

Southwest Ambulance in Mesa, Arizona, realized about five years ago that it would need to respond to the increasing size of patients. Emergency personnel were reporting more back problems from lifting heavier patients, and more personnel were needed to respond to calls from obese patients before the adjustments were made. “We would often have to take several ambulances out of service just to help with the lift,” said Josh Weiss, a spokesman for Southwest Ambulance.

The company has modified its fleet of ambulances. All of its 911 ambulances are now equipped with gurneys that can hold 650-pound patients, and some of its vehicles have gurneys that can hold up to 1,000 pounds, with further modifications built into those units.

One $20,000 modification included raising the floor and fitting a ramp to the back of the vehicle. Air bags were added to the back tires to lower the angle, as well as a stronger suspension. A cable assists in moving the gurney with the patient.

“We have two of these ambulances in service,” Weiss said. Without these retrofitted vehicles, some patients will choose to sit at home and refuse to go to the hospital, he said.

Problems with equipment

Diagnostic procedures can be compromised by a patient’s girth, prompting physicians and industry to come up with new solutions for the challenges presented by obesity.

John A. McKnight, MD, a cardiologist at West Virginia’s Morgantown Internal Medicine Inc., said that many CT scans and cath labs are designed to deal with patients who do not exceed a certain weight.

“Industry is dealing with the problem as equipment is being made to take larger patients, but only so much can be done since the morbidly obese patient is unlike any other and specialized equipment is often only available at large centers.”

“Most imaging procedures are more difficult to perform in the morbidly obese,” said Samuel Wann, MD, chairman, department of cardiovascular medicine at the Wisconsin Heart Hospital in Wauwatosa. The poorer quality images obtained with obese patients decrease diagnostic confidence and increase costs when the patient must be sent for further testing, Wann said.

He noted several problems associated with imaging obese patients:

• Ultrasound: The quality of transthoracic echocardiograms is often suboptimal in obese patients, resulting in reduced accuracy of measurements and poor visualization of some structures. If the quality is sufficiently poor and the clinical question sufficiently important, a transesophageal echo may be the better choice.
• Nuclear cardiology: These images suffer degradation due to excessive attenuation in severely obese patients, particularly in the inferior wall of the heart. Attenuation correction can help, but images in these patients are still often substandard. The tables used for SPECT imaging have weight limits and cannot be used for patients weighing more than 250 to 300 pounds.
• CTA: Patients too heavy for the SPECT table can undergo CTA, but x-ray attenuation can be a problem and the image quality suffers.
• MRI: Large bore scanners can accommodate many obese patients but there are still weight limits for the table.

Treating obese patients in the catheterization lab can also be problematic. Cath tables have weight limits, Wann said. Also, x-ray attenuation by excess body tissue requires use of higher radiation energies, which can cause the x-ray tube to overheat.

Industry responding

Manufacturers of imaging and diagnostic equipment are responding to these changing needs. Flat panel digital detector systems are better able to handle overweight patients.

Stephen Green, MD, associate director of the cardiac cath lab at the North Shore Long Island Jewish Health System in New York, said that flat panel systems offer the best imaging quality in terms of handling overweight people and being able to see background and vessels.

Green said that GE Healthcare’s Innova 2100 can successfully handle a large patient. “I just performed an angiogram on a patient who was 550 pounds. To do that with any of the older systems would have been very difficult. I was able to get excellent images on this patient and the table tolerated the patient’s weight. That is a big difference from technologies we have had in the past.”

Toshiba has an ultrasound application for its Aplio ultrasound system that features improvements in imaging to accommodate larger patients.

That system uses expanded differential tissue harmonic imaging, a patented technology the company developed to obtain better penetration on heavy patients without compromising resolution loss. The company has also developed a vascular table for the cath lab that can now hold a patient weighing up to 600 pounds.

McKnight developed his own device — the KangarooWeb (Milamy Partners) — to improve femoral site access during cath procedures in obese and overweight patients.

“It is important for industry to devote time and money for equipment for the morbidly obese,” McKnight said.

“We need myriad new technologies that can accept the very large patient. I believe this area of new technology will expand in the near future simply out of necessity,” he said. – by Suzanne Bryla