High-Pressure Chambers Could Prevent Paralysis After Spinal Cord Injury

Dr. Philip James of the University of Dundee reported at a conference here that putting patients under high pressure forces more cell-resuscitating oxygen into damaged spinal nerves than is possible at normal atmospheric pressure.

"It may mean the difference between significant disability and no disability," James said.

James made his remarks at a meeting of the Space and Underwater Research Group of the World Federation of Neurology. The meeting is being coordinated by the Stroke Research Center of the Wake Forest University Baptist Medical Center.

James has been a consulting physician to North Sea diving operations for 25 years. Divers sometimes suffer from bubbles in their spinal cord, resulting in tissue damage that is similar to the bruising that spinal cords suffer from traumatic injury.

Typically, nerve tissue in the spinal cord is starved of oxygen because the small capillaries that carry blood to the tissue are damaged. If adequate blood flow is not restored within hours, the nerve cells in the spinal cord die from lack of oxygen. This can result in complete or partial paralysis.

Placing these divers in hyperbaric chambers and raising the pressure to 2.8 times the normal atmospheric pressure hastens their recovery, James said, because under high pressure the blood carries proportionally more oxygen. This raises the oxygen levels in the damaged nerve tissue toward normal levels to assist recovery. For spinal cord injury patients, raising the pressure to two times atmospheric pressure would be adequate, James said.

An estimated 250,000 Americans have spinal cord injuries, according to the American Paralysis Association. On average, 11,000 new injuries are reported every year. The cost of treating and caring for these individuals can range from $600,000 to $1.3 million over a lifetime, depending on age and the degree of injury.

James cautioned that hyperbaric oxygen therapy, as the high-pressure procedure is called, is useful only in cases where the spinal cord is bruised, but not in cases where it is physically severed.

The National Spinal Cord Injury Statistical Center does not keep statistics on what proportion of spinal cord injuries are limited to bruising, but James said "the vast majority" fall into this category.

A number of very positive animal studies on the use of hyperbaric oxygen therapy in treating spinal cord injury have been published, James said. On humans, it has been used on a number of spinal cord injured patients over the past 20 years in the United States, Germany and Australia but no large scale studies have been conducted.

One impediment was that until recently, there was no way to tell whether the spinal cord was bruised or severed, James said.

"If you go on the physical symptoms of the patient you can't tell," he said.

Recent improvements in magnetic resonance imaging (MRI), however, now make it possible to determine which spinal cord casualties should be treated with hyperbaric oxygen therapy.

Unfortunately, James said, "most trauma centers do not have hyperbaric chambers, which is a tragedy, and most physicians don't understand the need to increase the dissolved oxygen in the plasma of the blood. They stop at hemoglobin saturation."