The Diver
He is a 43-year-old male who is an experienced divemaster with more than 1,000 dives. He has gone diving almost weekly for 18 years. He is in good health and physically active, but he is also slightly overweight and smokes a half-pack of cigarettes daily. He does not take any medication and has no medical conditions. Recently, he has been diving every other day, usually not deeper than 110 ft (33 m).
The Incident
The dive was scheduled to go to the deck of a wreck at 90 ft (27 m). Midway through the descent, the diver lost his weight belt. He continued down the descent line and on to the bottom at 114 ft (35 m). There he searched unsuccessfully for the lost weight belt for 13 minutes; then he terminated the dive and began his ascent.
Without the weight belt, and as he became more buoyant due to the continued reduction of air in his tank, he was unable to control his ascent, surfacing in less than one minute. His computer showed an ascent violation alarm.
Feeling weak and nauseated, he swam back to the boat. As he boarded and got assistance in removing his gear, he recalled having a mild backache, dizziness and headache. He lay down in the back of the boat for the 15-minute ride back to shore.
According to other divers on the boat, he seemed to be awake, with his eyes open, but he could not respond to his fellow divers. On the ride to shore, the boat captain called EMS, and a local unit was waiting at the dock. The emergency personnel placed the diver on 100 percent oxygen and began intravenous fluids en route to the hospital.
The Complications
By the time the diver had arrived at the emergency department and was evaluated by the attending physician, he could describe in detail what he had felt. He denied any pain or discomfort, and the physician could find no weakness, numbness or tingling when he examined the diver. The physician then called Divers Alert Network®.
Concerned by the rapid ascent and the period of unresponsive change in behavior after the dive, the DAN® physician felt an arterial gas embolism could not be ruled out and that the patient should be transferred to the nearest recompression chamber.
The Treatment
The diver received a second evaluation at the hyperbaric facility. On further examination, the diver did not quite feel “like himself,” was dizzy and easily fatigued when he tried to walk. He was given a full U.S. Navy Treatment Table 6 (4 hours and 45 minutes). Afterward he said he felt much better.
He remained overnight for observation and experienced a return of unusual fatigue the following day. He was treated with another U.S. Navy Treatment Table 6 and continued to improve. He received a third, shorter and final hyperbaric oxygen treatment table the next day. After the third treatment, he experienced complete resolution of symptoms. He remained without symptoms and returned to diving after six months.
The Diagnosis
The diver’s rapid ascent and his subsequent disorientation, dizziness and unusual fatigue pointed to an arterial gas embolism (AGE).
The Discussion
Problems can occur during any dive, whether a diver has 10 dives or 1,000. While there were missed opportunities for this diver to correct his buoyancy problem and avoid the rapid ascent once the weight belt was lost, the central issue in this case was a failure to follow the safety principles all divers are taught. Had the diver followed his training and been able to call on the assistance of a buddy, the accident might have been avoided. For example: While it is unclear what caused the diver to lose his weight belt, the problem might have been discovered and corrected during a good predive buddy check.
Choosing the right option when a dive starts to go wrong is also vital to decreasing risk and avoiding possible injury. Once the belt was gone, the best decision this diver could have made was to call the dive and immediately return to the surface at a slow, controlled rate. When he decided to continue in search of his lost weight belt, he failed to consider the increased risk of additional bottom time and inert gas uptake.
When the diver reached the wreck and could not locate the lost weight belt, he faced an obvious buoyancy problem: less air in the tank and no extra weight to counterbalance his increased positive buoyancy. One option at this point would have been to return to the line and use it to control his ascent. Without a line to hold onto, a positively buoyant diver can also empty his buoyancy compensator and flare his arms and legs to offer more resistance while rising up the water column. These emergency techniques will slow the ascent rate, but they do not provide full control.
Even though oxygen wasn’t available on the boat, the diver received good care from the local EMS service and the emergency medical department. The call to DAN was the final step in ensuring that the diver got the proper care and treatment for a very successful outcome.
AGE Symptoms and First Aid
AGE is one of the two diseases encompassed by the term decompression illness. The other is decompression sickness. Both conditions share the same symptoms and require the same first aid treatment:
- Establish and monitor basic life support. Ensure the diver is breathing; if so, continue to make sure the airway stays open. If not, begin administering basic life support.
- If the diver is breathing, administer oxygen immediately. Keep the diver on the oxygen as long as possible.
- Call 911 (or the local number if outside the U.S.) for emergency medical assistance, then call the DAN 24-Hour Diving Emergency Hotline at (919) 684-9111.
Symptoms of AGE
- Paralysis or weakness
- Convulsions
- Dizziness
- Visual blurring
- Personality change
- Bloody froth from mouth or nose (sign of possible pulmonary barotraumas)
- Unconsciousness
- Cessation of breathing
- Chest pain
- Disorientation
© Alert Diver — Q4 Fall 2009