SRF-JRMC Divers Cure Pilot’s Decompression Sickness
Story by Keiichi Adachi, CFAY Public Affairs
July 16, 2010

On the evening of June 8, the U.S. Naval Ship Repair Facility and Japan Regional Maintenance Center (SRF-JRMC) dive locker responded to an F/A-18 pilot from USS George Washington (CVN 73) who, while underway, contracted altitude decompression sickness and needed to be transported to Yokosuka for treatment.

SRF-JRMC Diving Officer Lt. Cmdr. Christopher Williams explained that altitude decompression sickness is a condition most commonly brought on by a sudden loss in cabin pressure inside an aircraft at altitude.

Most naval aircraft maintain a cockpit pressure of approximately equivalent to 8,000 ft, and a sudden loss in that pressure can allow nitrogen inside the pilot’s blood and tissues to form bubbles which can cause symptoms such as joint pain or, in more serious cases, neurological deficits and unconsciousness.

This condition can be treated by increasing the ambient pressure on the victim inside a hyperbaric chamber which reduces the size of the bubbles and forces the nitrogen back into solution so that it can be expelled from the body naturally.

The pilot and ship’s flight surgeon were transported by helicopter from the carrier to Yokosuka where they were met at the helipad by an ambulance and Undersea Medical Officer Lt. Thomas Murphy of Commander, Submarine Group (COMSUBGRU) 7.

“I provide medical support for submarines under COMSUBGRU 7 command, which are submarines deployed to the 5th and 7th Fleets,” said Murphy. “I advise the independent duty corpsmen on board the submarines and arrange medical evacuations off the submarines when necessary. I also serve as the diving medical officer for SRFJRMC dive locker by providing medical care for our divers and helping with diving medical issues and hyperbaric treatments.”

During transport, the pilot was given interveneous fluids and oxygen. From the helipad, he was driven to the SRF-JRMC dive locker where a complete neurological exam was performed by Hospital Corpsman 3rd Class (DV) Cory Dalton, a diving medical technician assigned to SRF-JRMC.

The purpose of the neurological exam is to identify all symptoms in the patient so that they can be monitored for improvement during the recompression treatment. Following the exam it was determined that recompression was necessary and the patient was put inside the dive locker’s hyperbaric chamber with Dalton acting as an inside tender.

The pilot was treated following the protocols of a U.S. Navy Diving Manual Treatment Table 6 which consists of compressing the chamber occupants to a pressure equivalent to 60 feet of sea water (FSW) and having the patient breathe oxygen for three periods of twenty minutes each.

A neurological examination was performed inside the chamber by Dalton once the patient arrived at 60 FSW and despite the continued symptoms of fatigue, the patient started responding positively to the treatment.

According to Murphy, there is no physiological difference between the sea and sky. Decreasing the pressure around someone’s body whether by going up in the air or down in the water, can cause the same problematic bubbles in the body.

After the bubbles are created, like when you open a can of soda, they can collect in different parts of the body. If the bubbles collect in the joints, they will cause stiffness and pain, if they collect in the blood vessels, they can block blood flow, causing tissue or nerve damage.

Following oxygen periods at 60 FSW, the chamber was brought up to 30 FSW, where two more oxygen periods were conducted for an hour each. At the conclusion of these oxygen periods, the chamber was brought to the surface pressure (0 FSW), and the patient was evaluated again by Murphy. The patient showed a complete recovery from the original symptoms.

Accoring to Murphy the key to recover from decompression sickness is to “recompress” the patient in the hyperbaric chamber, and that the SRF-JRMC divers practice this frequently and are experts in this process.

“When we recompress the patient, the SRF-JRMC divers run the treatment by adding air pressure into the closed chamber,” explained Murphy.

“The increased pressure forces the bubbles to dissolve back into the blood stream. As the recompression treatment nears its end, the patient is slowly decompressed back to the normal atmospheric pressure all of us live at. This decompression is done very, very slowly and methodically to keep the bubbles from reforming.

“I really appreciate [the help of the] additional members of the chamber team, Master Chief Navy Diver (MDV) Mike Miller, Chamber Supervisors Chief Navy Diver (DSW) Laszlo Cservak and Senior Chief Navy Diver (DSW/SG) Will Sinrich, Inside Tender Navy Diver 1st Class (DSW/SW) Nathan Kralemann, Chamber Operators Navy Diver 2nd Class John Hofstedt and Navy Diver 2nd Class Zachary Hanson, and Communications and Log Keepers Navy Diver 2nd Class Daniel Bradley and Navy Diver Seaman Shawn Bourguet,” Murphy added.